Preoperative medical consultation

Med Clin N Am 87 (2003) xv–xvi Preface Preoperative medical consultation Steven L. Cohn, MD, FACP Guest Editor Preo...

Author: Steven L. Cohn

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Med Clin N Am 87 (2003) xv–xvi

Preface

Preoperative medical consultation

Steven L. Cohn, MD, FACP Guest Editor

Preoperative medical consultation plays an important role in the practices of both primary care physicians and subspecialists. Despite this fact, many physicians feel inadequately trained to function as consultants in the perioperative period. Prior to 1980, there were essentially no textbooks on the subject, and there were only a few ‘‘landmark’’ papers. The November 1979 issue of the Medical Clinics of North America on ‘‘Medical Evaluation of the Preoperative Patient’’ was essentially the first ‘‘book’’ on the subject. Subsequently, numerous articles and textbooks on various aspects of preoperative medical consultation were published. Preoperative medical consultation was covered in the May 1987 issue, select topics in medical consultation in the March 1993 issue, and postoperative medical complications was the topic of the September 2001 issue of the Medical Clinics of North America. The goal of this current issue is to review and update the major topics in preoperative medical consultation. This publication is not intended to be an all-inclusive reference book. It was written by practicing internists with extensive experience in perioperative medicine and expertise in their selected areas. The vast majority of our authors are general internists and members of the Medical Consultation Interest Group of the Society for General Internal Medicine (www.sgim.org). Based on our experience, we have chosen topics we think are the most important or those most commonly encountered in clinical practice. The 15 articles in this issue range from the role of the consultant, preoperative laboratory testing, and perioperative medication management to preoperative risk assessment of patients with diseases

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S.L. Cohn / Med Clin N Am 87 (2003) xv–xvi

of the major organ systems and risk reduction strategies to minimize potential postoperative complications. I feel that this information will be useful to all clinicians involved in preoperative medical consultation. I would like to thank my wife Deborah and children Alison and Jeffrey for their support, patience, and understanding during this project. Steven L. Cohn, MD, FACP Guest Editor Chief-Division of General Internal Medicine Clinical Professor of Medicine State University of New York, Downstate Medical Center 470 Clarkson Avenue-Box 68 Brooklyn, NY 11203, USA Director-Medical Consultation Service Kings County Hospital 451 Clarkson Avenue Brooklyn, NY 11203, USA

Med Clin N Am 87 (2003) 1–6

The role of the medical consultant Steven L. Cohn, MD, FACP* Division of General Internal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY, USA Medical Consultation Service, Kings County Hospital, Brooklyn, NY, USA

Internists as well as subspecialists are often asked to evaluate a patient prior to surgery. Many primary care physicians, however, feel inadequately trained to function as consultants for preoperative medical evaluations [1]. Additionally, a recent survey of hospitalists found preoperative medical consultation to be an area of importance and one in which the hospitalists felt a need for additional training [2]. Much of the literature on perioperative medicine and medical consultation has been scattered among different disciplines, and only recently has this information appeared in medical journals and textbooks typically read by internists. The role of the preoperative medical consultant is to identify and evaluate a patient’s current medical status and provide a clinical risk profile, to decide whether further tests are indicated prior to surgery, and to optimize the patient’s medical condition in an attempt to reduce the risk of complications. Knowledge of medical illnesses that influence surgical risk, an understanding of the surgical procedure, effective communication and interaction with the other members of the preoperative team, and integration of a management plan are crucial for the medical consultant. This article focuses on the general principles of consultative medicine, techniques to improve compliance, and the concept of risk assessment. Specific aspects of preoperative risk evaluation and perioperative management as they pertain to individual organ systems are discussed in subsequent articles. General principles of medical consultation The American Medical Association (AMA) noted nine ethical principles pertaining to consultation [3]. Three of these pertain to the referring physician: * Division of General Internal Medicine, State University of New York, Downstate Medical Center, 470 Clarkson Avenue, Box 68, Brooklyn, NY 11203. E-mail address: [email protected] (S.L. Cohn). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 4 8 - 7

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S.L. Cohn / Med Clin N Am 87 (2003) 1–6

(1) consultations are indicated on request in doubtful or difficult cases, or when they enhance the quality of medical care; (2) consultations are primarily for the patient’s benefit; and (3) a case summary should be sent to the consulting physician unless a verbal description of the case has already been given. The other six ethical principles of consultation address the responsibilities and role of the consultant: (1) one physician should be in charge of the patient’s care; (2) the attending physician has overall responsibility for the patient’s treatment; (3) the consultant should not assume primary care of the patient without consent of the referring physician; (4) the consultation should be done punctually; (5) discussions during the consultation should be with the referring physician, and with the patient only by prior consent of the referring physician; and (6) conflicts of opinion should be resolved by a second consultation or withdrawal of the consultant; however, the consultant has the right to give his or her opinion to the patient in the presence of the referring physician. The concepts for performing effective consultations were described by Goldman’s ‘‘Ten Commandments’’ [4]. These include: (1) determine the question; (2) establish urgency; (3) look for yourself; (4) be as brief as appropriate; (5) be specific and concise; (6) provide contingency plans; (7) honor thy turf; (8) teach with tact; (9) talk is cheap and effective; and (10) follow-up. Determining the question It is of paramount importance for the consultant to determine precisely why the consultation was actually requested. The manner in which the referring physician phrases the request can influence the consultant’s response. For example, the consultant is often asked (inappropriately) to ‘‘clear a patient for surgery.’’ Beside the fact that this phrase should never be used because it incorrectly implies that if a patient is ‘‘cleared,’’ he or she will not develop any postoperative complication, it does not specify what the referring physician really wants. The surgeon may be asking for surgical risk assessment, approval to operate, diagnostic or management advice, reassurance, or documentation for medical legal reasons. Without effective communication, the consultant’s response may not answer the question adequately. This need for direct communication in order to minimize the potential for misunderstanding was highlighted by two studies—the first study reporting disagreement between the requesting physician and consultant about the primary reason for consultation in 14% of cases [5], and the second study finding that no specific question was asked in 24% of consults for diabetic patients, and that consultants ignored explicit questions in another 12% [6]. Answering the question Operative risk is the probability of an adverse outcome or death associated with surgery and anesthesia. It can be divided into four components:


3

(1) patient-related; (2) procedure-related; (3) provider-related; and (4) anesthetic-related. The consultant, in conjunction with the other members of the team, must ultimately decide, based on the patient’s risk factors, whether the patient is in his or her ‘‘optimal medical condition’’ or ‘‘acceptable’’ condition to undergo the planned surgical procedure. In order to do so, the following questions must be taken into account: (1) what is the status of the patient’s health? (2) if there is evidence of a medical illness, how severe is it, and does it affect or increase operative risk? (3) how urgent is the surgery? (4) if surgery is delayed, will the severity of the medical illness be lessened by treatment? and (5) if there is no reason to delay surgery, what changes need to be made perioperatively in the patient’s management? An estimation of perioperative risk is based on a thorough history, physical examination, review of the available data, and selectively ordered laboratory tests (when indicated). This information should be obtained or confirmed independently, and the consultant should make an extra effort to obtain any additional existing information felt to be necessary to the evaluation. The consultant must also be able to function in the absence of complete data as it may be lacking, unavailable, or irrelevant to the question being asked. The consultant’s advice and recommendations need to be concise and specific to the question asked by the requesting physician. Whereas a subspecialist who is asked to evaluate a patient’s preoperative cardiac status usually restricts comments to the cardiovascular system, general internists often are more compulsive and try to do more than they were asked. It is important to recognize that the internist’s role as a preoperative medical consultant should focus only on issues relevant to the planned surgical procedure. If other problematic concerns unrelated to the primary reason for consultation are discovered, they can usually be addressed after surgery, but the consultant should first discuss them with the referring physician. The disadvantage of making a long list of recommendations that are not really pertinent for surgery is that the other more relevant recommendations may be ignored. Similarly, the consultant should restrict advice to his area of expertise and not make recommendations about the type of anesthesia to be given without having had formal training in anesthesiology. Comments such as ‘‘no absolute contraindication to general anesthesia’’ or ‘‘cleared for spinal anesthesia only’’ are of no value. As noted by Choi [7], ‘‘The prudent medical consultant is wise enough to choose the anesthesiologist rather than the agent or choice of anesthesia.’’ Improving compliance Depending on the setting, referring physicians comply with the consultant’s recommendations 54–95% of the time [8–12]. Factors influencing compliance are shown in Table 1 [13] and correspond to Goldman’s Ten

4


Commandments [4]. As noted earlier, the primary reason for the consultation must be determined and addressed [5,9,12]. A timely response is important [14]. Urgent or emergent consultations need to be seen promptly, and elective in-patient consultations should usually be answered the same day as requested but in all cases within 24 hours. The consultant’s report should be informative yet concise. It should include an overall risk assessment, status of the patient for surgery, recommendations for management of the patient’s medications perioperatively, and recommendations to minimize risk of postoperative complications, including prophylaxis for venous thromboembolism, endocarditis, and surgical wound infection. In order to highlight the most important information for the referring physician, we recommend a format where the first page of the written consultation report contains the reason for consultation, pertinent medical problems, impression as to whether or not the patient is in optimal medical condition for surgery, and recommendations for perioperative management. The history, physical examination, laboratory and test results, and additional discussion can follow on another page. Definitive language should be used [5,6,10,14,15], and recommendations should be prioritized, precise, and preferably limited to no more than five [11,12,16]. Recommendations felt to be ‘‘crucial’’ or ‘‘critical’’ are more likely to be followed [8,11,16], as are therapeutic as opposed to diagnostic recommendations [12,14]. Direct personal communication with the referring physician is preferable to only leaving a note in the chart [5,6,11]. The consultant’s responsibilities rarely end with the initial preoperative consultation. Appropriate follow-up visits with documentation in the chart improve compliance [14,16] and may improve care. The patient’s medical problems and type of surgery will dictate the frequency and duration of follow-up by the consultant. The consultant should sign off in writing when he or she no longer needs to follow the patient, and arrangements for long-term follow-up after discharge should be noted. Table 1 Factors influencing or improving compliance with consultant recommendations

Prompt response (within 24 hours) Limit number of recommendations ( 5) Identify crucial or critical recommendations (versus routine) Focus on central issues Make specific relevant recommendations Use definitive language Specified drug dosage, route, frequency, and duration Frequent follow-up including progress notes Direct verbal contact Therapeutic (versus diagnostic) recommendations Severity of illness

(From Cohn SL, Macpherson DS. Overview of the principles of medical consultation. In: Rose BD, editor. Wellesley, MA: UptoDate; 2002; with permission.)


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Comanagement and benefits of medical consultation Whether or not the consultant should write orders depends on the arrangement with the referring physician. In some cases the consultant is being asked only to provide an opinion or advice that the primary attending physician may or may not choose to implement. In other cases, the consultant may actually comanage the case. This latter scenario is being seen more frequently with the proliferation of hospitalists, managed care, and disease management programs. One small study demonstrated a decrease in length of stay when an internist routinely cared for patients after thoracic surgery [17], and comanagement of orthopedic patients with hip fractures and joint replacement surgery is increasing. Other potential benefits provided by preoperative medical consultants include findings of new diagnoses as well as assessments of pre-existing conditions resulting in changes in patient management, warranting additional work-up or treatment prior to surgery [18–24]. In this regard, they provide added value to the patient and referring physician. Additional outcome measures concerning quality of care should be forthcoming to determine their impact on optimal patient care. Summary The basic concepts of medical consultation have been reviewed. The referring physician and the consultant both have responsibilities to fulfill in order to maximize the effectiveness of the consultation in improving patient care. The reasons for and urgency of the consultation need to be communicated to and understood by the consultant. The consultant needs to respond by promptly evaluating the patient, concisely documenting his findings, and communicating his recommendations to the referring physician. As described by Bates, the ideal medical consultant will ‘‘render a report that informs without patronizing, educates without lecturing, directs without ordering, and solves the problem without making the referring physician appear to be stupid’’ [25]. The consultant should try to support the referring physician and comfort the patient. By following these guidelines, the consultant will be more effective in providing useful, informative advice likely to result in enhanced compliance with the recommendations and improved patient outcome. References [1] Devor M, Renvall M, Ramsdell J. Practice patterns and the adequacy of residency training in consultation medicine. J Gen Intern Med 1993;8:554–60. [2] Plauth III WH, Pantilat SZ, Wachter RM, et al. Hospitalists’ perceptions of their residency training needs: results of a national survey. Am J Med 2001;111:247–54. [3] Opinions and reports of the judicial council. In: Gross RJ, Caputo GM. Kammerer and Gross’ medical consultation: the internist on surgical, obstetric, and psychiatric services. Philadelphia, PA: Lippincott, Williams & Wilkins; 1998. p. 8.

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[4] Goldman L, Lee T, Rudd P. Ten commandments for effective consultations. Arch Intern Med 1983;143:1753–5. [5] Lee T, Pappius EM, Goldman L. Impact of inter-physician communication on the effectiveness of medical consultations. Am J Med 1983;74:106–12. [6] Rudd P, Siegler M, Byyny RL. Perioperative diabetic consultation: a plead for improved training. J Med Educ 1978;53:590–6. [7] Choi JJ. An anesthesiologist’s philosophy on Ômedical clearanceÕ for surgical patients. Arch Intern Med 1987;147:2090–2. [8] Ballard WP, Gold JP, Charlson ME. Compliance with the recommendations of medical consultants. J Gen Intern Med 1986;1:220–4. [9] Ferguson RP, Rubinstien E. Preoperative medical consultations in a community hospital. J Gen Intern Med 1987;2:89–92. [10] Klein LE, Moore RD, Levine DM, et al. Effectiveness of medical consultation. J Med Educ 1983;58:149–51. [11] Pupa Jr LE, Coventry JA, Hanley JF, et al. Factors affecting compliance for general medicine consultations to non-internists. Am J Med 1986;81:508–14. [12] Sears CL, Charlson ME. The effectiveness of a consultation. Compliance with initial recommendations. Am J Med 1983;74:870–6. [13] Cohn SL, Macpherson DS. Overview of the principles of medical consultation. In: UptoDate, Rose, BD (Ed), UptoDate, Wellesley, MA, 2002. [14] Horwitz RI, Henes CG, Horwitz SM. Developing strategies for improving the diagnostic and management efficacy of medical consultations. J Chronic Dis 1983;36:213–8. [15] Klein LE, Levine DM, Moore RD, et al. The preoperative consultation. Response to internists’ recommendations. Arch Intern Med 1983;143:743–4. [16] Mackenzie TB, Popkin MK, Callies AL, et al. The effectiveness of cardiology consultation. Concordance with diagnostic and drug recommendations. Chest 1981;79:16–22. [17] Macpherson DS, Parenti C, Nee J, et al. An internist joins the surgery service: does comanagement make a difference? J Gen Intern Med 1994;9:440–4. [18] Charlson ME, Cohen RP, Sears CL. General medicine consultation. Lessons from a clinical service. Am J Med 1983;75:121–8. [19] Clelland C, Worland RL, Jessup DE, et al. Preoperative medical evaluation in patients having joint replacement surgery: added benefits. South Med J 1996;89:958–60. [20] Devereaux PJ, Ghali WA, Gibson NE, et al. Physicians’ recommendations for patients who undergo noncardiac surgery. Clin Invest Med 2000;23:116–23. [21] Jainkittivong A, Yeh CK, Guest GF, et al. Evaluation of medical consultations in a predoctoral dental clinic. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;80(4): 409–13. [22] Levinson W. Preoperative evaluations by an internist—are they worthwhile? West J Med 1984;141:395–8. [23] Mollema R, Berger P, Girbes AR. The value of peri-operative consultation on a general surgical ward by the internist. Neth J Med 2000;56:7–11. [24] Robie PW. The service and educational contributions of a general medicine consultation service. J Gen Intern Med 1986;1:225–7. [25] Bates RC. The two sides of every successful consultation. Med Econ 1979;7:173–80.

Med Clin N Am 87 (2003) 7–40

The case against routine preoperative laboratory testing Gerald W. Smetana, MD, FACPa,*, David S. Macpherson, MD, MPHb a

Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA b Department of Medicine, University of Pittsburgh, VA Pittsburgh Healthcare System, 130-U/University Drive C, Pittsburgh, PA 15240, USA

Most physicians order a battery of tests before surgery. This practice is widespread and is often based on policy or procedure at the facility where the physician practices. A practice of extensive testing of all patients before surgery is expensive—both in terms of direct costs of the tests and the need for follow-up of unanticipated minor abnormalities, many of which are normal on repeat testing or have no clinical relevance. Since the last review of this topic in 1993 in the Medical Clinics of North America [1], several new studies have been published including a large randomized trial for patients being considered for cataract surgery [2]. We write this article to guide physicians and facility policy makers regarding rational testing before surgery. We focus on adults being considered for elective surgical procedures and consider only preoperative blood tests, urinalyses, electrocardiograms, and chest radiographs—tests that are considered routine by institutions, physicians, and many patients. The reader is referred elsewhere for reviews of preoperative cardiac stress testing and pulmonary function testing. Normal and abnormal test results It is important for physicians to understand how laboratories define normal and abnormal test results. For many blood test results, a continuous distribution of results is possible. For example, a hemoglobin level may theoretically be measured from 0 through infinity with any value in between. Other tests may have only ordinal results. For example, the degree of proteinuria reported on a dipstick determination may be reported only in * Corresponding author. 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 4 7 - 5

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G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40

a small number of discrete values (1þ, 2þ, etc.). Finally, some tests have only categorical results, normal or abnormal. The chest radiograph and electrocardiogram are examples. For test results that are continuous, the cut points for determining abnormally high or low values are set by the ‘‘reference range.’’ The reference range is determined as follows. For many test results, the distribution of values within a population of patients without disease is assumed to be normal. That is, if the distribution were plotted, a bell-shape curve would exist. The typical cut point for an abnormally high result is 2 standard deviations from the mean or the top 2.5% of results from a population without known disease. Likewise, an abnormally low result is reported in the bottom 2.5% of results in the population. Thus, in a population of patients without known disease, 5% would be found to have an abnormal test result. The reference range for many continuous tests results simply represents the middle 95% of the population. From the above, one can see that the probability of discovering an abnormal test result is 5% when a single test is ordered. When multiple tests with continuous results are ordered, the probability that at least one result will be abnormal quickly increases. For example, the likelihood of at least one abnormal test result from a chemistry panel of 20 tests is 64%, even in a patient with no disease. Thus, an institutional practice pattern of ordering multiple blood tests routinely before surgery will result in a large number of spuriously abnormal findings.

Rationale for preoperative testing There are several theoretic reasons why clinicians might order routine preoperative tests. These include: (1) to detect unsuspected abnormalities that might influence the risk of perioperative morbidity or mortality; (2) to establish a baseline value for a test that has a high likelihood of being monitored and changing after the surgical procedure is complete; and (3) for medical-legal reasons. For the first rationale, three actions are possible regarding an abnormal test result. First, clinicians may take action to correct the abnormality before surgery with the hope that correction will decrease the risk of perioperative complications. Second, a serious abnormality might result in the clinician recommending that the surgery be canceled or the nature of the surgery be modified to a less intensive procedure. Third, the abnormality simply may be ignored. This is discussed further below. In the sections that follow about specific preoperative tests, we have framed our discussion around the first rationale, as little literature exists regarding the use of preoperative tests to serve as a baseline for postoperative values or for medicallegal reasons. Some physicians and institutions may believe that routine screening tests before surgery protect them from legal liability. This is probably not true for


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the following reason. The existing literature suggests that clinicians ignore 30–60% of abnormalities discovered on routine preoperative tests [3]. Thus, in about half the patients in whom an abnormality is discovered, no notation exists in the medical record to reflect the physician’s thinking about the abnormality. Should the patient suffer a poor outcome, the lack of any documentation before the procedure about the abnormality would increase the probability of a judgment against the physician, should a suit be brought. For this reason, a strategy of routine preoperative screening in the absence of a careful system of documentation regarding even minor abnormalities may expose the physician to more risk than selective screening. Our review of the literature focuses on investigations of preoperative testing in patients for whom abnormal results were unsuspected. In many of these investigations, it was not possible to separate tests that may have been ordered because of findings on the history and physical exam from those that were ordered for routine reasons. Thus, estimates of the proportion of results that are abnormal probably overestimate the true prevalence of unsuspected abnormalities. We believe this limitation strengthens our overall conclusion that routine testing in patients without signs and symptoms suggesting a significant likelihood of abnormal results is unwise. By contrast, investigations of preoperative testing in patients suspected to have abnormal results [4] or in patients whose recent previous results were abnormal [5] show a high prevalence of abnormal results. Normal test results obtained within 4 months before surgery may be safely used as preoperative tests if there has been no change in the clinical status of the patient during the interval. In one report, only 0.4% of such tests repeated at the time of surgery were abnormal; most could have been predicted by the patient’s history [5]. Screening implies that a patient has no known conditions that would increase the likelihood of an abnormal test result. A preoperative test must meet several characteristics to be valuable as a screening test for patients without known disease [6,7]. The disease must be common and contribute to perioperative morbidity. The screening test should be inexpensive and carry little risk to the patient. The test must be highly sensitive and have an acceptably high specificity so as to minimize false-positive results. A long interval of time must exist between the onset of an abnormal screening test and the development of clinically apparent disease (the detectable preclinical phase). Effective and safe interventions must be available to reduce risk when clinicians identify patients during this phase. We will show in this article that most potential preoperative tests do not meet these criteria. Hemoglobin Blood loss as a result of surgery is common and, in many types of surgery, perioperative transfusion is necessary. Severe anemia during surgery risks tissue hypoxia from impaired oxygen delivery. Thus, unsuspected severe anemia theoretically may predispose the patient to tissue hypoxia

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in the perioperative period if not corrected preoperatively. For this reason, a case can be made on the basis of physiology for routine hemoglobin (or hematocrit) measurements for patients in whom significant blood loss is anticipated. The prevalence of anemia discovered on routine screening varies depending on the study population. In our review of 8 studies (Table 1), the overall incidence of hemoglobin abnormalities was 1.8%. Studies of older patients [8,9] show a prevalence of anemia ranging from 4–9%. The positive likelihood ratio for abnormal hemoglobin, derived from only 2 studies that allowed such calculation, was 3.3. A baseline hemoglobin determination has been shown to predict the need for subsequent transfusion in patients undergoing surgical procedures associated with significant blood loss [10]. Thus, a rationale can be made for a baseline hemoglobin to aide in planning for transfusions perioperatively. We recommend that patients have preoperative hemoglobin or hematocrit determination only if the planned surgical procedure is likely to result in significant blood loss. Patients undergoing surgery not anticipated to result in significant blood loss should be screened only if a history and physical examination suggest severe anemia. A medical history of profound fatigue, past history of anemia, malignancy, or renal insufficiency or physical examination findings suggesting anemia (resting tachycardia or conjunctival pallor) should prompt a hemoglobin determination even in patients undergoing minor surgery. White blood cell count The prevalence of unanticipated elevations of white blood cell counts is very low. In 4 of the 5 available studies, the prevalence was less than 1% (Table 2). In the two studies in which authors assessed management changes related to abnormal white blood cell counts, no patient underwent a management change [11,12]. In the two studies that allow the calculation of likelihood ratios for abnormal white blood cell counts, the findings suggest that an unanticipated elevated white blood cell count is unrelated to perioperative morbidity [11,12]. For this reason, we believe that routine screening white blood cell determinations should not be obtained before surgery. Clinicians should obtain preoperative white blood cell counts in patients with symptoms suggesting infection, those in whom a myeloproliferative disease is known or suspected (on the basis of splenomegaly or diffuse lymphadenopathy) or in those patients at high risk for leukopenia related to drugs or other known diseases. Platelet count Ten investigations have been published regarding the usefulness of platelet counts (Table 3). The incidence of abnormalities of platelet counts is

Ambulatory surgery Total hip arthroplasty for osteoarthritis Elective ASA class 1

1988 Prospective 1989 Retrospective

1991 Retrospective

1995 Retrospective

2001 Prospective

McKee and Scott [65] Johnson et al [48] Sanders et al [9]

Narr et al [29]

Perez et al [49]

Dzankic et al [8]

Noncardiac

Elective

Cholecystectomy

193 100

397

ASA class 1 or 2 70 years of age Hemoglobin or older > 10.0 g/dL

9363

1402

526

Hemoglobin 3782 >10.0 g/dL Reference range 3068

Reference range Reference range

Reference range

Hemoglobin 292 >10.0 g/dL or 18 g/dL Reference range 1005

Definition of normal test

1.8

10.5

1.4

0.8

9.8 4.0

3.3

0.7

0.3

0.1

0.1

0.2

0.0

3.3

0.6

20.4

0.9

1.1

0.7

Percent of Total Percent of all tests number tests that that influence LRþ LR of patients are abnormal management (CI) (CI)

Abbreviations: ASA, American Society of Anesthesiologists; CI, Confidence Interval; LR, likelihood ratio.

Subtotal for studies with outcomes data Total

Elective

1987 Prospective

Turnbull and Buck [12]

No known medical conditions

1987 Retrospective

Kaplan et al [21]

All types

1985 Retrospective

Study

Population characteristics

Study design (prospective or Type of Year retrospective) surgery

Table 1 Hemoglobin abnormalities G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40 11

1985 1987

1988 1989

1995 1999

Kaplan et al [21] Turnbull and Buck [12]

Johnson et al [48] Sanders et al [9]

Perez et al [49] Haug and Reifeis [50]


Year

Study

Retrospective Prospective

Prospective Retrospective

Retrospective Retrospective

Study design (prospective or retrospective)

Table 2 White blood cell count abnormalities

Ambulatory surgery Total hip arthroplasty for osteoarthritis Elective Oromaxillofacial surgery in office setting

All types Cholecystectomy

Type of surgery

ASA class 1 or 2 ASA class 1 or 2



5359

1109

3047 380

212 104

611 1005

Total number of patients

0.7

0.9 0.8

0.0 2.9

0.2 0.1

Percent of tests that are abnormal

0.0

0.0 0.0

Percent of all tests that influence management

0.0

0.00

LRþ (CI)

1.1

1.0

1.0 1.1

LR (CI)

12 G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40

Elective Ambulatory surgery Total hip arthroplasty for osteoarthritis Elective Elective major surgery Elective Oromaxillofacial surgery in office setting Noncardiac

1988 Prospective 1988 Prospective

1989 Retrospective

1991 Retrospective 1993 Prospective

Sanders et al [9]

Narr et al [29] Macpherson et al


Dzankic et al [8]

2001 Prospective

Perez et al [49] 1995 Retrospective Haug and Reifeis [50] 1999 Prospective

All types Cholecystectomy

1985 Retrospective 1987 Retrospective

Kaplan et al [21] Turnbull and Buck [12] Rohrer et al [11] Johnson et al [48]

Study

Study design (prospective or Year retrospective) Type of surgery

Table 3 Abnormalities of platelet count

70 years of age or older

ASA class 1 Excluded those with bleeding history or on asprin ASA class 1 or 2 ASA class 1 or 2



>115K

Reference range Not stated

9670

1116

520

3068 380

3782 111

63

Reference range

>100K >150K

163 212


>115K and 1.9 mg/dL was second only to emergency surgery as a risk factor for postoperative morbidity and mortality [24]. This proved to be a stronger predictor than established risk factors including left ventricular dysfunction, advanced age, and diabetes. Other investigators have also shown renal insufficiency to be a major predictor of adverse events after aortic and valvular surgeries [25,26]. Modest renal insufficiency, such as that shown to be a risk factor in the above studies, will not always be clinically apparent. In our review (Table 7), 8.2% of all renal function tests (either blood urea nitrogen [BUN] or creatinine) were abnormal and 2.6% of all tests were abnormal and influenced management. This rate of influential test results is higher than that for most other potential preoperative tests. The positive LR for an abnormal renal function test was 3.3 and is clinically useful. Like all potential routine preoperative tests, the negative LR approaches one and a normal test result does not substantially reduce the likelihood of an adverse event. Though previous large studies of preoperative testing found a low prevalence of unexpected abnormal results of renal function testing, we believe that more recent data showing the power of renal insufficiency as a risk predictor warrant reconsideration of the indications for this test. We therefore recommend preoperative testing of renal function for patients with a substantial likelihood of renal insufficiency and in those undergoing major surgery. Our recommended indications include age >50 years old, diabetes,

Coronary bypass

Coronary bypass


1996 Retrospective

1998 Prospective

1999 Retrospective

Velanovich [53]a Higgins et al [24]

Kurki and Kataja [27] Mangano et al [55]b

Skenderis [54]

Colectomy

Elective Coronary bypass

All Total hip arthroplasty


Charpak et al [4] Sanders [9]

Cholecystectomy

1987 Retrospective

Turnbull and Buck [12]

Study


Table 7 Renal function abnormalities

Reference range


Reference range Reference range Otherwise healthy patients with osteoarthritis Reference range Creatinine < 1.9 mg/dL Creatinine < 1.24 mg/dL No preexisting Creatinine renal failure < 2.0 mg/dL Colorectal Reference range cancer



105

2222

366

520 5051

995 95

995

3.8

14.1

13.7

11.9 3.1

26.2 1.1

0.3

Percent of tests Total number that are of patients abnormal

0.0

5.5

0.0

2.8

2.1

2.3 4.3

0.0

0.88

0.72

0.88 0.54

1.09

Percent of all tests that influence LRþ LR management (CI) (CI)

20 G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40

1999 Prospective

2000 Prospective

2001 Prospective

Lee et al [22]

Anderson et al [25]c

Dzankic et al [8]

c

b

a

Carotid No concurrent endarterectomy non carotid vascular surgeries Elective 50 years of age noncardiac or older Cardiac valve surgery Noncardiac 70 years of age or older Creatinine < 2.0 mg/dL Creatinine < 1.5 mg/dL Reference range

Creatinine < 1.5 mg/dL

Estimated based on 12% prevalence of abnormal results. Complication ¼ cardiac and metabolic. Adverse outcome ¼ postoperative renal dysfunction. Adverse outcome ¼ mortality.


1999 Retrospective

Hamdan et al [56]

15437

14337

360

834

2893

1001

8.2

11.7

23.6

3.6

7.3

2.6

3.3

2.9

2.7

5.2

5.7

0.81

0.63

0.89

0.93

0.69

G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40 21

22


hypertension, known cardiac disease, use of medications that may influence renal function such as ACE inhibitors or NSAIDs, and major procedures including cardiac, vascular, chest, and abdominal surgeries.

Serum glucose Established diabetes requiring treatment is a risk factor for postoperative cardiac complications. In the recent revised cardiac risk index by Lee et al, diabetes requiring insulin therapy was 1 of 6 independent risk factors for postoperative cardiac complications; the relative risk associated with this factor was 3.0 [22]. Diabetes also increases morbidity and mortality among patients undergoing coronary artery bypass surgery [24,27]. In addition, diabetes increases the risk of sternal wound infections among patients undergoing coronary bypass grafting, and evidence exists that tighter perioperative control of blood glucose may decrease this risk [28]. These observations, however, apply to patients with established and clinically apparent diabetes that requires treatment. Whether a similar risk applies to patients without a clinical diagnosis of diabetes who are found to have an elevated serum glucose on routine preoperative screening is the subject of our discussion. Table 8 details the value of an abnormal serum glucose as part of routine preoperative testing based on our review of clinical series. Overall, 9.3% of measurements were abnormal. Most of these values occurred in patients with known diabetes. Only 0.5% of all values were abnormal and influenced perioperative management. Most abnormalities were clinically insignificant or ignored. For example, in the study of Kaplan et al, only 4 of 3100 preoperative glucose measurements were unindicated by clinical criteria and abnormal [21]. Two of these values were normal on repeat; and two were abnormal though ignored by the surgeon with no resulting postoperative complications. In a study of 3782 American Society of Anesthesiologists (ASA) class I patients, only 16 patients had abnormal serum glucose values that prompted further assessment [29]. Five patients were advised to delay surgery and lose weight; only one patient among the 3782 was found to have a new diagnosis of diabetes that required treatment. Among the subset of studies in our review that reported postoperative complications, the positive and negative LRs approached 1, being 1.68 and 0.85, respectively. Given the low incidence of unsuspected diabetes (0.5%) among patients preparing for surgery and the lack of evidence that identification and treatment of patients with clinically occult diabetes reduces postoperative complications, we do not recommend routine preoperative measurement of serum glucose. Such measurements are helpful, however, as part of the perioperative management of patients with known diabetes, and clinicians may consider preoperative testing of serum glucose in patients with symptoms that suggest undiagnosed diabetes or in obese patients. The available litera-

a

All types Cholecystectomy No known medical conditions All Total hip Otherwise healthy arthroplasty patients with osteoarthritis Elective Elective ASA class 1 Elective ASA class 1 or 2 Colectomy Colorectal cancer Oromaxillofacial ASA class 1 or 2 surgery in office setting Noncardiac 70 years of age or older


705 91

464 436

Reference range

9.4 9.3

9540

6.8

18.1 1.9 5.2 19.3 0.2

71.5 4.4

5.4 1.8

1306

251

Reference range 520 Author criteria 3782 Reference range 2760 Reference range 119 Not stated 412


Action limits Reference range


0.5

0.6 0.2 0.0 0.0

2.1 0.0

0.4 0.0

1.68

1.50

2.14

1.01

0.85

0.62

0.83

1.00

Percent of all Total Percent of tests that number of tests that are influence LRþ LR patients abnormal management (CI) (CI)

Estimated based on 18% incidence of abnormal result. Complications ¼ cardiac, metabolic, and wound.


2001 Prospective

Dzankic et al [8]

Prospective Retrospective Retrospective Retrospective Prospective

1991 1991 1995 1999 1999


1985 Retrospective 1987 Retrospective

Velanovich [53]a Narr et al [29] Perez et al [49] Skenderis et al [54] Haug and Reifeis [50]

Kaplan et al [21] Turnbull and Buck [12] Charpak et al [4] Sanders et al [9]

Study


Table 8 Elevated serum glucose values G.W. Smetana, D.S. Macpherson / Med Clin N Am 87 (2003) 7–40 23

24


ture does not, however, allow a firm recommendation about the value of such screening. Hepatic tests Patients with advanced liver disease and cirrhosis have a marked increase in the risk of postoperative complications and death. The risk increases with increasing severity of liver disease, as classified by the Child-Pugh criteria. For example, among patients with cirrhosis undergoing abdominal surgery, mortality rates for Child-Pugh class A, B, and C are 10%, 31%, and 76%, respectively [30]. But few data exist to suggest that asymptomatic elevations of transaminases or alkaline phosphatase in patients without known liver disease imply a surgical risk. Relatively few studies of routine preoperative testing have evaluated the value of hepatic enzyme determinations. Table 9 summarizes the existing literature. No studies have reported the incidence of adverse events in patients with normal or abnormal hepatic enzyme results. Only 0.4% of all routine preoperative hepatic enzyme tests were abnormal. In only 0.1% of cases did this finding lead to a change in perioperative management, usually cancellation of surgery and further diagnostic evaluation. No study attributed excess morbidity to the finding of an abnormal hepatic enzyme, but specific incidences were unavailable. Clinically unsuspected abnormal hepatic enzyme levels are less frequent than other potentially routine preoperative tests. Given the very low incidence of abnormalities that influence management, we do not recommend routine testing of transaminases or alkaline phosphatase before surgery. A recent observation, however, suggests that measurement of serum albumin, often considered a liver function test, predicts postoperative morbidity. Gibbs et al prospectively studied 54,215 veterans undergoing major noncardiac surgery [31]. Mortality for patients increased from less than 1% for patients with a serum albumin of 4.6 gms/dL to 28% for patients with a serum albumin level of 60 years with an ASA class 3 with pre-existing pulmonary disease undergoing major surgery [42]. Charpak et al developed a selective protocol for ordering preoperative chest radiographs using similar criteria [43]. Their protocol recommended preoperative chest radiographs for patients with lung disease, cardiovascular disease, cancer, emergent surgery, current smoking history in patients >50 years of age, immune suppression, or a lack of a prior examination in immigrants. Though 52% of all radiographs were abnormal, only 4 of 271 (1.5%) unindicated radiographs impacted on patient management. In the report of Gagner and Chiasson, only 3% of patients age 50 years had an abnormal routine chest radiograph, whereas abnormal films were present in 30% of patients over age 50 years [44]. Ninety-two percent of abnormal chest radiographs could have been predicted on the basis of symptoms or a history of known cardiopulmonary disease. In the 5 studies in our review that allow a subset analysis of patients 40 years, women > 50 years, known CAD, diabetes, or hypertension Age > 50 years, known cardiac or pulmonary disease, symptoms or exam suggest cardiac or pulmonary disease

36


Using protocols and policy to influence testing Most institutions have established minimal criteria for routine preoperative testing. Thus, facility policies often require the physician caring for the patient to obtain a minimal set of tests before surgery. In many settings, assurance that the tests are complete is the responsibility of support staff for the surgeon or anesthesiologist. If tests are not obtained before surgery, the patient’s surgery may be delayed; hence, most physicians are compliant with these policies. The establishment of an up-to-date policy regarding preoperative testing has been shown to decrease inappropriate ordering. In one study, the frequency of tests ordered decrease from 23% to 55% and without apparent increase in complication rates [83]. We are hopeful that this article will inform those who develop policy to ensure the creation of a rationale set of minimum standards at each facility and encourage institutions to implement local evidence-based guidelines and policy regarding preoperative testing. The ASA recently published a practice advisory for preanesthesia evaluation [47]. The advisory supports our recommendation that physicians should not order routine preoperative tests, and that testing should be selective based on the history, physical examination, known comorbidities, and type of planned procedure. Summary In this article, we have shown that almost all ‘‘routine’’ laboratory tests before surgery have limited clinical value. Clinicians should order only a small number of routine tests based on age as noted in Table 13. Selective use of other preoperative tests should be based on history and physical examination findings that identify subgroups of patients who are more likely to have abnormal results. In general, clinicians should order tests only if the outcome of an abnormal test will influence management. When an abnormal test results from such testing, it is critical that physicians document their thinking about the result. Most routine preoperative tests are neither expensive nor risky. For this reason, clinicians can have a low threshold for ordering these tests in patients for whom the frequency of abnormalities is increased compared with a healthy population. We believe that physicians should not be criticized for selective test ordering before surgery. Physicians and institutions recommending routine preoperative testing for all patients provide no clinical value to their patients at considerable cost. References [1] Macpherson D. Preoperative laboratory testing: should any tests be ‘‘routine’’ before surgery? Med Clin N Amer 1993;77:289–308.


37

[2] Schein O, Katz J, Bass E, et al. The value of routine preoperative testing before cataract surgery. N Engl J Med 2000;342:168–75. [3] Roizen MF. More preoperative assessment by physicians and less by laboratory tests. N Engl J Med 2000;342:204–5. [4] Charpak Y, Blery C, Chastang C, et al. Usefulness of selectively ordered preoperative tests. Med Care 1988;26:95–104. [5] Macpherson DS, Snow R, Lofgren RP. Preoperative screening: value of previous tests. Ann Intern Med 1990;113:969–73. [6] Fletcher RH, Fletcher SW, Wagner EH. Clinical epidemiology. The essentials,. 3rd edition. Baltimore: Williams & Wilkins; 1996. [7] Sackett DL, Haynes RB, Guyatt GH, et al. Clinical epidemiology. A basic science for clinical medicine,. 2nd edition. Boston: Little, Brown, and Company; 1991. [8] Dzankic S, Pastor D, Gonzalez C, et al. The prevalence and predictive value of abnormal preoperative laboratory tests in elderly surgical patients. Anesth Analg 2001;93: 301–8. [9] Sanders DP, McKinney FW, Harris WH. Clinical evaluation and cost effectiveness of preoperative laboratory assessment on patients undergoing total hip arthroplasty. Orthopedics 1989;12:1449–53. [10] Faris PM, Spence RK, Larholt KM, et al. The predictive power of baseline hemoglobin for transfusion risk in surgery patients. Orthopedics 1999;22(suppl):s135–40. [11] Rohrer M, Mechelotti M, Nahrwold D. A prospective evaluation of the efficacy of preoperative coagulation testing. Ann Surg 1988;208:554–7. [12] Turnbull JM, Buck C. The value of preoperative screening investigations in otherwise healthy individuals. Arch Intern Med 1987;147:1101–5. [13] Peterson P, Hayes TE, Arkin CF, et al. The preoperative bleeding time test lacks clinical benefit. College of American Pathologists’ and American Society of Clinical Pathologists’ position article. Arch Surg 1998;133:134–9. [14] Rodgers R, Levin J. A critical appraisal of the bleeding time. Sem Thromb Hemost 1990;16:1–20. [15] Suchman A, Mushin A. How well does the activated partial thromboplastin time predict postoperative hemorrhage? JAMA 1986;256:750–3. [16] Borzotta A, Keeling M. Value of the preoperative history as an indicator of hemostatic disorders. Ann Surg 1984;200:648–52. [17] Gross RJ, Babbott S. Evaluation of healthy patients and ambulatory surgical patients. In: Gross RJ, Caputo GM, editor. Medical consultation, 3rd edition. Baltimore: Williams & Wilkins; 1998. p. 32–3. [18] Rappaport S. Preoperative hemostatic evaluation: which tests, if any? Blood 1983;61: 229–31. [19] Hirsch IA, Tomlinson DL, Slogoff S, et al. The overstated risk of preoperative hypokalemia. Anesth Analg 1988;67:131–6. [20] Nally BR, Dunbar SB, Zellinger M, et al. Supraventricular tachycardia after coronary artery bypass grafting surgery and fluid and electrolyte variables. Heart Lung 1996;25: 31–6. [21] Kaplan EB, Sheiner LB, Boeckmann AJ, et al. The usefulness of preoperative laboratory screening. JAMA 1985;253:3576–81. [22] Lee T, Marcantonio E, Mangione C, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 1999;100:1043–9. [23] Eagle K, Berger P, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J Am Coll Cardiol 2002;39:542–53.

38


[24] Higgins TL, Estafanous FG, Loop FD, et al. Stratification of morbidity and mortality outcome by preoperative risk factors in coronary artery bypass patients. A clinical severity score. JAMA 1992;267:2344–8. [25] Anderson RJ, O’Brien M, MaWhinney S, et al. Mild renal failure is associated with adverse outcome after cardiac valve surgery. Am J Kidney Dis 2000;35:1127–34. [26] Becquemin JP, Chemla E, Chatellier G, et al. Perioperative factors influencing the outcome of elective abdominal aorta aneurysm repair. Eur J Vasc Endovasc Surg 2000;20: 84–9. [27] Kurki TS, Kataja M. Preoperative prediction of postoperative morbidity in coronary artery bypass grafting. Ann Thorac Surg 1996;61:1740–5. [28] Furnary AP, Zerr KJ, Grunkemeier GL, et al. Continuous intravenous insulin infusion reduces the incidence of deep sternal wound infections in diabetic patients after cardiac surgical procedures. Ann Thorac Surg 1999;67:352–62. [29] Narr BJ, Hansen TR, Warner MA. Preoperative laboratory screening in healthy Mayo patients: cost-effective elimination of tests and unchanged outcomes. Mayo Clin Proc 1991;66:155–9. [30] Patel T. Surgery in the patient with liver disease. Mayo Clin Proc 1999;74:593–9. [31] Gibbs J, Cull W, Henderson W, et al. Preoperative serum albumin level as a predictor of operative morality and morbidity. Arch Surg 1999;134:36–42. [32] Akin BV, Hubbell FA, Frye EB, et al. Efficacy of the routine admission urinalysis. Am J Med 1987;82:719–22. [33] Kroenke K, Hanley JF, Copley JB, et al. The admission urinalysis: impact on patient care. J Gen Intern Med 1986;1:238–42. [34] Lawrence VA, Gafni A, Gross M. The unproven utility of the preoperative urinalysis: economic evaluation. J Clin Epidemiol 1989;42:1185–92. [35] Goldman L, Caldera DL, Nussbaum SR, et al. Multifactorial index of cardiac risk in noncardiac surgical procedures. N Engl J Med 1977;297:845–50. [36] Dorman T, Breslow M, Pronovost P, et al. Bundle-branch block as a risk factor in noncardiac surgery. Arch Intern Med 2000;160:1149–52. [37] Tait AR, Parr HG, Tremper KK. Evaluation and efficacy of routine preoperative electrocardiograms. J Cardioth Vasc Anesth 1997;11:752–5. [38] Gold BS, Young ML, Kinman JL, et al. The utility of preoperative electrocardiograms in the ambulatory surgical patient. Arch Intern Med 1992;152:301–5. [39] Kannel WB, Abbott RD. Incidence and prognosis of unrecognized myocardial infarctions. N Engl J Med 1984;311:1144–7. [40] Bouillot J-L, Fingerhut A, Paquet J-C, et al. Are routine preoperative chest radiographs useful in general surgery? A prospective, multicentre study in 3959 patients. Eur J Surg 1996;162:597–604. [41] Archer C, Levy AR, McGregor M. Value of routine preoperative chest x-rays: a metaanalysis. Can J Anaesth 1993;40:1022–7. [42] Silvestri L, Maffessanti M, Gregori D, et al. Usefulness of routine preoperative chest radiography for anaesthetic management: a prospective multicentre pilot study. Eur J Anaesthesiol 1999;16:749–60. [43] Charpak Y, Blery C, Chastang C, et al. Prospective assessment of a protocol for selective ordering of preoperative chest x-rays. Can J Anaesth 1988;35:259–64. [44] Gagner M, Chiasson A. Preoperative chest x-ray films in elective surgery: a valid screening tool. Can J Surg 1990;33:271–4. [45] Narr BJ, Warner ME, Schroeder DR, et al. Outcomes of patients with no laboratory assessment before anesthesia and a surgical procedure. Mayo Clin Proc 1997;72: 505–9. [46] Bass EB, Steinberg EP, Luthra R, et al. Do ophthalmologists, anesthesiologists, and internists agree about preoperative testing in healthy patients undergoing cataract surgery? Arch Ophthalmol 1995;113:1248–56.


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[47] American Society of Anesthesiologists Task Force on Preanesthesia Evaluation. Practice advisory for preanesthesia evaluation. Anesthesiology 2002;96:485–96. [48] Johnson H, Knee-Ioli S, Butler TA, et al. Are routine preoperative laboratory screening tests necessary to evaluate ambulatory surgical patients? Surgery 1988;104:639–45. [49] Perez A, Planell J, Bacardaz C, et al. Value of routine preoperative tests: a multicentre study in four general hospitals. Br J Anaesth 1995;74:250–6. [50] Haug RH, Reifeis RL. A prospective evaluation of the value of preoperative laboratory testing for office anesthesia and sedation. J Oral Maxillofac Surg 1999;57:16–20; discussion 21–22. [51] Macpherson C, Jacobs P, Den D. Abnormal peri-operative haemorrhage in asymptomatic patients is not predicted by laboratory testing. S Afr Med J 1993;83:106–8. [52] Vitez TS, Soper LE, Wong K, et al. Chronic hypokalemia and intraoperative dysrhythmias. Anesthesiology 1985;63:130–3. [53] Velanovich V. The value of routine preoperative laboratory testing in predicting postoperative complications: a multivariate analysis. Surgery 1991;109:236–43. [54] Skenderis BS II, Rodriguez-Bigas M, Weber TK, et al. Utility of routine postoperative laboratory studies in patients undergoing potentially curative resection for adenocarcinoma of the colon and rectum. Cancer Invest 1999;17:102–9. [55] Mangano CM, Diamondstone LS, Ramsay JG, et al. Renal dysfunction after myocardial revascularization: risk factors, adverse outcomes, and hospital resource utilization. The Multicenter Study of Perioperative Ischemia Research Group. Ann Intern Med 1998; 128:194–203. [56] Hamdan AD, Pomposelli Jr FB, Gibbons GW, et al. Renal insufficiency and altered postoperative risk in carotid endarterectomy. J Vasc Surg 1999;29:1006–11. [57] Schemel WH. Unexpected hepatic dysfunction found by multiple laboratory screening. Anesth Analg 1976;55:810–2. [58] Wataneeyawech M, Kelly KA. Hepatic diseases: unsuspected before surgery. N Y State J Med 1975;75:1278–81. [59] Lawrence VA, Kroenke K. The unproven utility of preoperative urinalysis: clinical use. Arch Intern Med 1988;148:1370–3. [60] Bhuripanyo K, Prasertchuang C, Khumsuk K, et al. The impact of routine preoperative urinalysis in Srinagarind Hospital. Khon Kaen. J Med Assoc Thai 1995;78:94–8. [61] Adams JG Jr, Weigelt JA, Poulos E. Usefulness of preoperative laboratory assessment of patients undergoing elective herniorrhaphy. Arch Surg 1992;127:801–4; discussion 804– 805. [62] Muskett AD, McGreevy JM. Rational preoperative evaluation. Postgrad Med J 1986; 62:925–8. [63] Ferrer MI. The value of obligatory preoperative electrocardiograms. J Am Med Womens Assoc 1978;33:459–69. [64] Seymour DG, Pringle R, Shaw JW. The role of the routine preoperative chest x-ray in the elderly general surgical patient. Postgrad Med J 1982;58:741–5. [65] McKee RF, Scott EM. The value of routine preoperative investigations. Ann R Coll Surg Engl 1987;69:160–2. [66] Yipintsoi T, Vasinanukorn P, Sanguanchua P. Is routine pre-operative electrocardiogram necessary? J Med Assoc Thai 1989;72:16–20. [67] McCleane G, McCoy E. Routine pre-operative electrocardiography. Br J Clin Pract 1990;44:92–5. [68] Bhuripanyo K, Prasertchuang C, Viwathanatepa M, et al. The impact of routine preoperative electrocardiogram in patients age > or ¼ 40 years in Srinagarind Hospital. J Med Assoc Thai 1992;75:399–406. [69] Callaghan LC, Edwards ND, Reilly CS. Utilisation of the pre-operative ECG. Anaesthesia 1995;50:488–90. [70] Murdoch C, Murdoch D, McIntyre P, et al. The pre-operative ECG in day surgery: a habit? Anaesthesia 1999;54;907.

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[71] Rees A, Roberts C, Bligh A, et al. Routine preoperative chest radiography in noncardiopulmonary surgery. BMJ 1976;1:1333. [72] Loder R. Routine preoperative chest radiography. 1977 compared with 1955 at Peterborough District General Hospital. Anaesthesia 1978;33:972–4. [73] Tornebrandt K, Fletcher R. Preoperative chest x-rays in elderly patients. Anaesthesia 1982;37:901–2. [74] Rucker L, Frye EB, Staten MA. Usefulness of screening chest roentgenograms in preoperative patients. JAMA 1983;250:3209–11. [75] Wiencek RG, Weaver DW, Bouwman DL, et al. Usefulness of selective preoperative chest x-ray films. A prospective study. Am Surg 1987;53:396–8. [76] Boghosian S, Mooradian A. Usefulness of routine preoperative chest roentgenograms in elderly patients. J Am Geriatrc Soc 1987;35:142–6. [77] Mendelson DS, Khilnani N, Wagner LD, et al. Preoperative chest radiography: value as a baseline examination for comparison. Radiology 1987;165:341–3. [78] Umbach G, Zubek S, Deck H, et al. The value of preoperative chest x-rays in gynecological patients. Arch Gynecol Obstet 1988;243:179–85. [79] Tape TG, Mushlin AI. How useful are routine chest x-rays of preoperative patients at risk for postoperative chest disease? J Gen Intern Med 1988;3:15–20. [80] Sommerville TE, Murray WB. Information yield from routine pre-operative chest radiography and electrocardiography. S Afr Med J 1992;81:190–6. [81] Ishaq M, Kamal RS, Aqil M. Value of routine pre-operative chest X-ray in patients over the age of 40 years. J Pak Med Assoc 1997;47:279–81. [82] Bellan L. Preoperative testing for cataract surgery. Can J Opthalmol 1994;29:111–4. [83] Mancuso CA. Impact of new guidelines on physicians’ ordering of preoperative tests. J Gen Intern Med 1999;14:166–72.

Med Clin N Am 87 (2003) 41–57

Perioperative medication management Donna L. Mercado, MD, FACPa,*, Brent G. Petty, MDb a

Medical Consultation Program, Baystate Medical Center, Tufts University School of Medicine, 759 Chestnut Street, Springfield, MA 01199, USA b The Johns Hopkins University School of Medicine, 1300 Maywood Avenue, Baltimore, MD 21204, USA

The management of a patient’s usual medications in the preoperative period is often a difficult and perplexing problem. Among the challenges faced by the physician when managing medication issues for surgical patients are the patient’s response to the stresses of surgery, the patient’s underlying diseases and the degree of control afforded by ongoing treatment, and the likelihood of some period where oral treatment is not an option. In addition, there are few controlled trials regarding perioperative medication discontinuation and resumption, so decisions regarding management are often made based on manufacturer’s recommendations, consensus, or anecdotes. This article will attempt to provide data, when available, for adjusting medications in the perioperative setting and will provide advice when data are lacking. Because some medications are known to influence surgical risk or surgical decisions (eg, antiplatelet agents, anticoagulants, some hormonal therapies, and herbal remedies), it is important to obtain a complete medication list from the patient, including over-the-counter medications and dietary supplements. Adjusting doses or discontinuing certain potentially complicating medications in advance of surgery is one obvious reason that elective procedures are less prone to complications than emergent procedures. Most medications are tolerated well through surgery and do not interfere with anesthetic administration. Therefore, most drugs should be continued through the morning of surgery unless totally unnecessary (eg, vitamins) or contraindicated (eg, herbal products). In particular, antihypertensive, anticonvulsant, and antipsychiatric medications should be given unless specifically contraindicated. * Corresponding author. E-mail address: [email protected] (D.L. Mercado). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 4 6 - 3

42

D.L. Mercado, B.G. Petty / Med Clin N Am 87 (2003) 41–57

For medications where therapeutic monitoring may provide important information regarding subtherapeutic or supratherapeutic doses, serum levels should be checked perioperatively (eg, digoxin, theophylline, phenytoin, and carbamazepine). Necessary medications can be given with a sip of water a few hours before surgery. Medications that are known to cause a withdrawal or rebound syndrome when held (eg, clonidine) should be continued throughout the perioperative period with as little interruption as possible. Cardiac drugs Drugs with long durations of action, such as digoxin and amiodarone, can be discontinued before surgery and restarted when the patient is able to eat. If necessary, intravenous doses of either digoxin or amiodarone could be used if the duration of inability to eat is extended or if their parenteral use is clinically indicated. Beta blockers used for patients with cardiovascular disease (as opposed to use in patients with migraine syndrome, for example) should not be discontinued abruptly before surgery. Observational data have shown an increased risk of perioperative infarction and death in patients with vascular disease whose beta blockers were discontinued [1]. If patients are not able to resume oral intake of beta-blockers soon after surgery, parenteral preparations such as esmolol or propranolol could be used. For patients who usually take oral nitrates, preoperative substitution of nitroglycerin ointment or patches is not reliable because of the likelihood of poor intraoperative absorption. The severity and stability of the patients’ angina, plus their usual dose of oral nitrates, will influence the assessment of whether intravenous nitroglycerin may be needed. Perioperative and intraoperative events (eg, ST depressions on ECG monitor) may influence the anesthesiologist to start intravenous nitroglycerin, and postoperative titration and switch to outpatient agents will require ongoing assessment of response. In the postoperative period, transdermal nitroglycerin via ointment or patch is an alternative to either intravenous or oral nitrates. Patients who regularly take antiarrhythmic drugs should continue them as long as possible before surgery, but they can usually be discontinued for a few days and resumed when the patient is eating again. Class IA agents, such as quinidine, procainamide, and disopyramide, are used with much less frequency than in years past. Parenteral procainamide is available for the patient whose continued treatment with this agent would be considered essential during the perioperative period. More recent antiarrhythmics, such as flecainide or sotalol, do not have an alternative, nonoral dosing route. For patients who take these agents for atrial arrhythmias (eg, atrial fibrillation or atrial flutter) and develop problems with these rhythms perioperatively, ventricular rate control could be attempted using intravenous diltiazem, beta blockers, or digoxin. For patients who take chronic outpatient medication for a history of monomorphic ventricular tachycardia and


43

who then develop a recurrence while nil per os (NOS) perioperatively, procainamide or amiodarone can be used parenterally. For polymorphic ventricular tachycardia, lidocaine or amiodarone are options. Especially important in these patients is the need to assure normal serum magnesium, potassium, and calcium, because deficiences of these cations can contribute to ventricular irritability. Antihypertensives Overall, the large variety of nonoral agents available to control perioperative and intraoperative hypertension provides sufficient options to handle blood pressure elevations when patients cannot take their usual antihypertensives after the morning-of-procedure dose. Nevertheless, there may be hazards in introducing new agents preoperatively with unpredictable response in the individual patient in order to achieve ‘‘normal’’ blood pressure. In the perioperative period, mild degrees of elevated blood pressure may be acceptable and would be preferable to causing autonomic instability or volume depletion in the effort to maximize blood pressure control. Sudden cessation of treatment with clonidine has been associated with worrisome, even dangerous, rebound hypertension. Using alternative parenteral agents or the clonidine patch may avoid acute hypertension. Such parenteral agents include esmolol, propranolol, hydralazine, diltiazem, and nitrates. Rebound hypertension also may occur after stopping guanfacine (TenexÒ, AH Robins Co., Richmond, VA), another alpha 2-adrenergic agonist, but it occurs with less frequency and later (after 2–4 days) with guanfacine, presumably because of its longer half-life. Pulmonary drugs This group of drugs consists primarily of those used to treat asthma and/ or chronic obstructive lung disease. Patients using inhalers can use them up to immediately before surgery and can resume them soon after surgery. This applies to inhaled steroids, beta agonists, and anticholinergic agents. If patients develop bronchospasm before they can resume their inhalers, then nebulized or parenteral beta agonists can be used. Because thoracic or abdominal surgery reduces lung function even in patients with normal lungs, some authorities favor nebulizers over metered-dose inhalers in the immediate postoperative period for asthmatic patients undergoing such surgeries. Another parenteral alternative is aminophylline, but both parenteral beta agonists and theophylline may cause tachycardia, hypertension, or ventricular arrhythmias. Intravenous steroids may be necessary if the bronchospasm does not respond to bronchodilators. Little is known about the implications of stopping leukotriene inhibitors, such as zafirlukast (AccolateÒ, AstraZeneca Pharmaceuticals, Wilmington, DE) or montelukast (SingulairÒ, Merck and Co., West Point, PA), or

44


lipoxygenase inhibitors, such as zileuton (Zyflo FilmtabÒ, Abbott Laboratories, Abbott Park, IL), before surgery. There are no parenteral formulations of these drugs. Because there are no known interactions between these agents and anesthetics, consider continuing them through the morning of surgery. The treatment of exacerbations of chronic obstructive pulmonary disease (COPD), which may be associated with surgery involving intubation, can follow the same principles employed for treating spontaneous acute exacerbations [2]. Diabetes Patients requiring insulin for usual management of their diabetes can generally be managed with perioperative glucometer testing and slidingscale regular insulin. Whether to use a morning dose of longer-acting insulin or to continue use of bedtime glargine insulin the night before surgery depends on how long the patients will be fasted before surgery, the severity of their diabetes, the timing of administration of intravenous solutions containing dextrose, and how soon the patients are likely to resume eating after surgery. For example, with outpatient surgery or diagnostic procedures performed under conscious or deep sedation, a common practice is to reduce the morning-of-procedure dose of long-acting insulin to 50% of the usual dose, and then use glucometer readings and sliding-scale insulin as needed to control periprocedure serum glucose. For diabetic patients adequately treated with oral agents, the drugs should be held on the morning of surgery, with sliding-scale insulin supplementation as needed. One important exception is metformin, which has been associated with the development of lactic acidosis, although rare. Metformin should be discontinued for at least 1 day before surgery and restarted after 2–3 days when it is certain that no acute renal dysfunction has developed perioperatively. In general, oral agents should be held postoperatively until patients are eating again. Antiplatelet agents and anticoagulants Aspirin inhibits platelet cyclooxygenase with subsequent irreversible platelet dysfunction. Because it takes 7–10 days to renew the circulating pool of platelets, traditional recommendations are to stop aspirin 7–10 days preoperatively. Although aspirin has been known to increase intraoperative bleeding, there is little evidence for any significant increased morbidity or mortality [3,4]. One study showed increased use of transfusions in patients undergoing coronary artery bypass grafting (CABG) but no increase in length of stay [4]. It is prudent to stop aspirin at least 7 days before surgery where possible, especially for surgeries in which excess bleeding would cause significant complications, such as vascular procedures, neurosurgery, and


45

certain ophthalmologic procedures. It is especially important to stop aspirin in alcoholic patients, as they often have underlying platelet dysfunction secondary to alcohol. Aggrenox, which is composed of aspirin and dipyridamole, should be stopped 7–10 days in advance of surgery because of its aspirin component. The dipyridamole has a half-life of about 10 hours and has a reversible effect on platelets [5]. The nonsteroidal anti-inflammatory COX-1 agents cause reversible inhibition of platelet cyclooxygenase. When possible, they should be stopped 1–3 days preoperatively depending on their individual half-lives. Drugs like ibuprofen and indomethacin have shorter half-lives (2–5 hours) and can be stopped 1 day before surgery, whereas naproxen and sulindac have longer half-lives (12–17 hours) and should be stopped 3 days before. The newer nonsteroidal anti-inflammatory drugs (NSAIDs), the COX-2 inhibitors, have little or no effect on platelets. All NSAIDs can have adverse effects on renal function; this effect may be accentuated in the perioperative period, which is another reason for holding these drugs perioperatively. The COX-2 inhibitors should be held at least 2–3 days before surgery because of the potential renal issues [5]. Clopidogrel (PlavixÒ, Sanofi-Synthelabo Inc., New York, NY) and ticlopidine (TiclidÒ, Parcor) are structurally similar agents that irreversibly inhibit platelet aggregation, probably by blockade of adenodiphosphate (ADP) binding to its receptor on the surface of platelets [6]. Because of the increased frequency of drug interactions, thrombotic thrombocytopenic purpura, and severe neutropenia with ticlopidine, its use has decreased in favor of clopidogrel. For elective procedures, both agents should be stopped 7 days preoperatively because of their irreversible effect on platelets. Cilostazol (PletalÒ, Otsuka America Pharmaceutical, Inc., Rockville, MD) is a phosphodiesterase inhibitor that has both antiplatelet and vasodilatory actions. Because its action on platelets is reversible, and because it has a fairly short half-life (11–13 hours) [5], it can be stopped 3 days before surgery. One would think intuitively that it is always best to discontinue oral anticoagulants before any surgical procedure, or to at least reduce the dose to allow nearly normal coagulation. Though this is generally true, data show that cataract surgery, using current techniques, can be performed safely with the International Normalized Ratio (INR) in the therapeutic range. In fact, the studies suggest that, with cataract surgery, the risk of systemic complications from discontinuing warfarin is greater than the risk of perioperative bleeding. Antiplatelet agents, on the other hand, can increase perioperative complications of cataract surgery and should be discontinued preoperatively as described above. The use of unfractionated heparin and low-molecular-weight heparins for prophylaxis of perioperative thromboembolic complications is covered in another section. But one issue regarding stopping and restarting these perioperative medications deserves comment here. A worrisome and serious complication of deep venous thrombosis (DVT) prophylaxis with

46


low-molecular-weight heparins is spinal hematoma with epidural anesthesia or analgesia [7]. This problem is most likely to occur when inserting or removing the epidural catheter. Interestingly, patients who undergo epidural anesthesia in the presence of antiplatelet agents are not at increased risk for epidural hematoma compared with patients not taking these agents. Patients receiving warfarin appear to be at intermediate risk. Recommendations regarding the time of epidural catheter manipulation in relation to doses of anticoagulants and antiplatelet agents are provided in Table 1 [8–12]. Osteoporosis agents As the population ages, and as osteoporosis awareness increases, an increasing number of patients will present for surgery while taking medications for this condition. Raloxifene (EvistaÒ, Eli Lilly and Co., Indianapolis, IN) is a selective estrogen receptor modulator (SERM) that mediates decreased resorption of bone and decreased bone turnover via binding to estrogen receptors [13]. Because it has been shown to increase risk of thromboembolic events, it should be stopped at least 1 week preoperatively for surgeries associated with a moderate to high risk of DVT, and not restarted until the patient is fully mobile postoperatively [5]. Tamoxifen, which is structurally similar, has a similar risk of DVT, but, before discontinuing it perioperatively, the patient’s oncologist should be consulted to discuss the risk/benefit ratio. Estrogen is used by millions of women both to alleviate premenopausal symptoms and to prevent and treat osteoporosis. The use of hormone replacement therapy is associated with an increase in thromboembolic events by threefold [14]. This phenomenon is even more dramatic in the perioperative setting. The Heart and Estrogen/progestin Replacement Study (HERS) in 2763 postmenopausal women found that the risk for deep venous thrombosis increased approximately 6-fold for patients admitted for hip fracture, 18fold for other types of lower extremity fracture, and 5-fold for nonfracture surgeries within 90 days of surgery [15]. For elective surgery, it is unclear how far in advance of surgery estrogen should be held to decrease this risk; some have suggested stopping 4 weeks preoperatively [16]. After surgery, the risk for DVT decreases when the patient is fully ambulatory, although the HER study showed an increased risk for 90 days postoperatively [15]. Alendronate (FosamaxÒ, Merck and Co., Inc., West Point, PA) is a bisphosphonate that inhibits osteoclast-mediated bone resorption. Because of its possible upper gastrointestinal (GI) side effects (esophagitis, esophageal erosions, and ulcers), there are specific guidelines regarding its administration. Patients must take it with 6–8 oz of water at least 30 minutes before ingesting the first beverage, food, or medication of the day, and then remain upright for 30 minutes. Given the difficulty for hospitalized patients to comply with the requirement to remain upright, it is best held in the perioperative period. Calcitonin (MiacalcinÒ, Novartis, East Hanover, NJ) is

None None None None None

PT

PT

None None

None

aPTT

Lab tests necessary prior to discontinuation of epidural catheter

Immediately Immediately Immediately Immediately Immediately

Immediately

12–24 hours At least 24 hours after catheter removal Immediately

At least 2 hours after epidural catheter removal, providing clinical monitoring checks are within normal limits, including no apparent bleeding Immediately

Time interval before therapy may be re-instituted after catheter removed

Abbreviations: aPTT, partial thromboplastin time; INR, International Normalized Ratio; NSAIDS, nonsteroidal anti-inflammatory drugs; PT, prothrombin time.

Low Low Low Low Low

Low-moderate

Prothrombin time (PT) INR 70 years, acute cholecystitis, nonfunctioning gall bladder, obstructive jaundice, or common duct stones. e After appropriate diet and catharsis, one gram each at 1 PM, 2 PM, and 11 PM the day before an 8 AM operation. f Morbid obesity, esophageal obstruction, decreased gastric acidity, or decreased gastrointestinal motility. g Urine culture positive or unavailable, preoperative bladder catheter, transrectal prostatic biopsy. h Patients with previous pelvic inflammatory disease, previous gonorrhea, or multiple sex partners. i Divided into 100 mg 1 hr before the abortion, and 200 mg 1 hr after. j Active labor or premature rupture of membranes. (Adapted from Antimicrobial prophylaxis in surgery. Med Lett Drugs Ther 2001;43:92–97; with permission.)

a

Vascular: arterial repair, prosthetic material, abdominal aorta Vascular: groin incision, leg amputation for arterial insufficiency

Cefoxitin 1–2 gm IV, or cefotetan 1–2 gm IV, or cefazolin 1–2 gm IV Ampicillin-sulbactam 1.5–3 gm IV or clindamycin 600–900 mg IV, plus gentamicin 1.5 mg/kg IV or cefazolin 1–2 gm IV Cefazolin 1–2 gm IV or vancomycinc 1 gm IV Topical drops over 2–24 hours: gentamicin, or tobramycin, or ciprofloxacin, or ofloxacin, or neomycin-gramicidin-polymyxin B Subconjunctival: cefazolin 100 mg Cefazolin 1–2 gm IV or vancomycinc 1 gm IV Cefazolin 1–2 gm IV, or cefuroxime 1.5 gm IV, or vancomycinc 1 gm IV Cefazolin 1–2 gm IV or vancomycinc 1 gm IV

Enteric gram-negative bacilli, anaerobes, enterococci, group B strep Oral anaerobes, enteric gram-negative bacilli, staphylococci

Gynecologic/obstetric: hysterectomy: vaginal or abdominal Head and neck: with incision through oral or pharyngeal mucosa

H.G. Weed / Med Clin N Am 87 (2003) 59–75 65

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H.G. Weed / Med Clin N Am 87 (2003) 59–75

first-trimester abortion in high-risk women, and may decrease infection risk in all women undergoing therapeutic abortion [41]. Head and Neck Prophylactic intravenous antimicrobials decrease surgical site infections after head and neck surgeries involving incision through the oral or pharyngeal mucosa [42]. Preferred antimicrobials for prophylaxis in cleancontaminated head and neck surgeries should have activity against the gram-positive and gram-negative aerobic bacteria, and the anaerobic bacteria found in the oropharynx, and include combinations such as ampicillinsulbactam (UnasynÒ), and clindamycin plus gentamicin [43,44]. Rinsing the surgical site with antimicrobials does not further decrease the infection rate [45]. Antimicrobial prophylaxis is not indicated for endoscopic sinus surgery without nasal packing [46]. Neurologic Antimicrobial prophylaxis can decrease infection rates after craniotomy [47–49]; however, some have argued that only high-risk patients, such as those undergoing repeat tumor resection benefit adequately [50]. Antimicrobial prophylaxis is probably not indicated for routine lumbar discectomy; however, it might benefit patients undergoing spinal procedures that are prolonged or involve fusion or foreign materials [51]. Ophthalmic procedures Although prophylactic 1% chloramphenicol ophthalmic ointment can prevent corneal ulcer in rural patients with corneal abrasion [52]. and ciprofloxacin ophthalmic solution can concentrate on corneal defects [53], there are no well-controlled trials of antimicrobial prophylaxis in ophthalmic surgery. Nonetheless, because postoperative endophthalmitis is a severe complication, antimicrobial eye drops are appropriate for procedures that invade the globe, and subconjunctival antimicrobials may be appropriate for high-risk patients [54,55]. As with all surgeries, antiseptic surgical setting and technique are the foundation of infection prophylaxis [56]. Orthopedic procedures Antimicrobial prophylaxis prior to surgery reduces the incidence of both early and late surgical site infection after joint replacement, and after repair of both open and closed fractures [57,58]. Antimicrobial prophylaxis is probably not indicated for either diagnostic or therapeutic, routine arthroscopic surgery [59]. It is reasonable to offer antimicrobial prophylaxis to patients with prosthetic joints who are undergoing invasive dental work and are at high risk for prosthetic joint infection [60]. Risk factors for prosthetic joint infection include recent joint placement (less than 1 year), rheumatoid arthritis, gross dental infection (eg, abscess), prolonged invasive dental work (more than 1 hour), and, possibly, diabetes mellitus and immunosuppressive


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corticosteroid treatment. Nonetheless, prosthetic joint infection from dental work is rare and the risks of prophylactic antimicrobial treatment probably outweigh the benefits for most patients with prosthetic joints. Thoracic procedures There is limited information on the efficacy of antimicrobial prophylaxis for noncardiac chest procedures; however, it is accepted practice to use prophylactic cephalosporin. There is a correlation between the antimicrobial susceptibilities of bacteria isolated from the lung prior to pulmonary resection, the prophylactic antimicrobial used, and the occurrence of postoperative infection [61]. Antimicrobial prophylaxis is not indicated for chest tube insertion to treat nontraumatic conditions such as spontaneous pneumothorax but is indicated for closed-tube thoracostomy after major chest trauma [62]. Urologic Prior to most urologic procedures, prophylactic antimicrobials are not indicated for patients with sterile urine; however, preoperative sterilization of the urine is indicated for patients with indwelling urethral catheters or bacteriuria. A prophylactic antimicrobial is indicated prior to transrectal prostate biopsy [63]. A single dose of ciprofloxacin is effective and commonly used; however, trimethoprim-sulfamethoxazole is similarly effective [64]. Vascular procedures Antimicrobial prophylaxis is not indicated for carotid endarterectomy or brachial artery repair; however, cephalexin decreases the incidence of postoperative surgical site infection after arterial repair, and after vascular surgeries in the abdomen or legs [65]. The implantation of prosthetic material is a risk factor for infection, and most practitioners use prophylactic antimicrobials for all vascular surgeries involving prosthetic material.

Bacterial Endocarditis The rationale for antimicrobial prophylaxis Endocarditis is an uncommon yet life-threatening infection. It usually occurs in people with abnormal or prosthetic heart valves and requires bacteremia with organisms that can reside on the valves. The source of the bacteremia can be inapparent or can be caused by a focal infection such as cellulitis, an abscess, or pneumonia. Some surgical and dental procedures can produce transient bacteremia, and, though the great majority of endocarditis is not attributable to an invasive procedure [66], periprocedure antimicrobials are administered to patients at risk with the goal of reducing the risk for this serious complication. Under the aegis of The American Heart Association, a panel of experts has devised recommendations for the use

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of antimicrobial prophylaxis to reduce the risk of bacterial endocarditis after invasive procedures [6]. Despite these guidelines, antibiotic prophylaxis against endocarditis is frequently both overused and underused [67]. At risk patients Patients at high risk for endocarditis include those with prosthetic valves, prior endocarditis, or complex cyanotic heart disease (Table 2). Patients at moderate risk include those with congenital cardiac malformations other than complex cyanotic heart disease; with rheumatic and other acquired structurally abnormal valves; hypertrophic cardiomyopathy; and with mitral valve prolapse including an abnormal, regurgitant mitral valve (Table 2). Patients at no greater risk than the general population include those with isolated secundum atrial septal defects, surgically repaired atrial and ventricular defects (more than 6 months after successful repair), surgically repaired patent ductus arteriosus (more than 6 months after successful repair), prior coronary artery bypass, implanted cardiac pacemakers and defibrillators, and benign murmurs (Table 2). At risk procedures Any procedure involving infected tissue at the surgical site is associated with a significant risk of bacteremia. Upper aerodigestive tract procedures Table 2 Patient risk categories for endocarditis High risk Prosthetic valves, including bioprosthetic and homograft valves Prior endocarditis Complex cyanotic heart disease Surgically constructed systemic-pulmonary shunts Moderate risk Congenital cardiac malformations other than complex cyanotic heart disease Rheumatic and other acquired, structurally abnormal valves Hypertrophic cardiomyopathy Mitral valve prolapse with a thickened or continuously regurgitant valve Low risk (no greater risk than the general population) Isolated secundum atrial septal defects Surgically repaired: atrial septal defects, ventricular septal defects, or patent ductus arteriosus (more than 6 months after successful repair) Prior coronary artery bypass Implanted cardiac pacemakers and defibrillators Prior Kawasaki’s disease or rheumatic fever without valve dysfunction Mitral valve prolapse without a thickened or continuously regurgitant valve Benign murmurs (Adapted from Dajani AS, Taubert KA, Wilson W, et al. Prevention of bacterial endocarditis. Recommendations by The American Heart Association. JAMA 1997;277:1794–1801; with permission.)


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associated with some risk of bacteremia include dental extractions and implants, tonsillectomy, rigid bronchoscopy, esophageal sclerotherapy and dilation, biliary tract surgery, and other procedures violating the oral or intestinal mucosa (Table 3). Procedures with negligible risk of bacteremia include restorative dentistry, local anesthetic injection, intracanal Table 3 Procedure risk categories for endocarditis in uninfected patients Upper aerodigestive tract procedures with some risk of bacteremia Procedures violating the oral, esophageal or intestinal mucosa, including: Prophylactic cleaning with anticipated bleeding Dental extractions and implants Periodontal surgery, scaling, planing, and probing Subgingival or intraligamentary periodontic manipulation or injection Endodontic surgery beyond the apex Initial placement of orthodontic bands, but not brackets Tonsillectomy—adenoidectomy Rigid bronchoscopy Esophageal sclerotherapy and dilation Biliary tract surgery including ERCP with biliary obstruction Upper aerodigestive tract procedures with negligible risk of bacteremiaa Restorative dentistry Local anesthetic injection not into dental ligaments Intracanal endodontistry Suture removal Adjustment of orthodontic appliances Endotracheal intubation Flexible bronchoscopy Tympanostomy tube insertion Transesophageal echocardiography Gastrointestinal endoscopy with or without biopsy Lower gastrointestinal and genitourinary tract procedures with some risk of bacteremia Prostate surgery Cystoscopy Urethral dilation Lower gastrointestinal and genitourinary tract procedures with negligible risk of bacteremiaa Vaginal hysterectomy Vaginal delivery Cesarean section Uterine dilation and curettage Therapeutic abortion Tubal ligation Insertion and removal of intrauterine devices Urethral catheterization ERCP ¼ endoscopic retrograde cholangiopancreatography. a Any procedure involving infected tissue at the surgical site is asociated with a significant risk of bacteremia. (Adapted from Dajani AS, Taubert KA, Wilson W, et al. Prevention of bacterial endocarditis. Recommendations by The American Heart Association. JAMA 1997; 277:1794–1801; with permission.)

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endodontistry, suture removal, adjustment of orthodontic appliances, endotracheal intubation, flexible bronchoscopy, tympanostomy, transesophageal echocardiography, and endoscopy without biopsy. Lower gastrointestinal and genitourinary tract procedures associated with some risk of bacteremia include prostate surgery, cystoscopy, and urethral dilation. Procedures with negligible risk include vaginal hysterectomy, normal vaginal delivery, cesarean section, uterine dilation and curettage, therapeutic abortion, tubal ligation, insertion and removal of intrauterine devices, and urethral catheterization (Table 3). Antimicrobials Antimicrobials used in endocarditis prophylaxis are aimed at the most likely causative organisms (Table 4). In upper aerodigestive tract procedures, viridians (alpha-hemolytic) streptococci are the most likely causative organisms, and in lower gastrointestinal and genitourinary tract procedures enterococci (Enterococcus faecalis) are the most likely causative organisms. Oral amoxicillin or intravenous ampicillin is usually the antimicrobials of choice. In upper aerodigestive tract procedures, alternative antimicrobials for penicillin-allergic patients include clindamycin, cephalexin, cephadroxil, azithromycin, and clarithromycin. Erythromycin is no longer listed as an alternative because of the availability of better-tolerated alternatives. In lower gastrointestinal and genitourinary tract procedures, vancomycin is the primary alternative to ampicillin. In the highest-risk patients undergoing lower gastrointestinal and genitourinary tract procedures, combination antimicrobial prophylaxis including gentamicin is used against enterococci because enterococci are frequently resistant to antimicrobials. Special considerations As with antimicrobial prophylaxis against postoperative infection, prophylaxis against endocarditis would be expected to be most effective if the antimicrobial is given within an hour prior to the procedure. Patients who chronically take antimicrobials, such as those who take penicillin for secondary prevention of rheumatic fever, may be colonized with bacteria resistant to penicillins. For these patients, it is appropriate to use an antimicrobial with a different mechanism of action than the one taken chronically. For example, for the patient who is taking penicillin to prevent rheumatic fever, either clindamycin or azithromycin would be an appropriate alternative. Summary The primary prophylactic measure against postoperative infection is antiseptic technique in patient preparation, during surgery, and in postoperative patient care. Antimicrobial prophylaxis against postoperative infection is not indicated for procedures with a low infection rate because the expected


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Table 4 American Heart Association Recommendations for Endocarditis Prophylaxis Upper Aerodigestive Tract Procedure with Some Risk of Bacteremia (Table 3) High- or moderate-risk patient (Table 2) No contraindication to penicillins: Oral: amoxicillin 2 gm PO 1 hr prior to the procedure Intravenous: ampicillin 2 gm IV 1/2 hr prior to the procedure Penicillins contraindicated: Oral: clindamycin 600 mg PO 1 hr prior to the procedure or cephalexin 2 gm PO 1 hr prior to the procedure or cephadroxil 2 gm PO 1 hr prior to the procedure or azithromycin 500 mg PO 1 hr prior to the procedure or clindamycin 500 mg PO 1 hr prior to the procedure Intravenous: clindamycin 600 mg IV 1/2 hr prior to the procedure or cefazolin 1 gm IV 1/2 hr prior to the procedure Lower gastrointestinal or genitourinary tract procedure with some risk of bacteremia (Table 3) High Risk Patient (Table 2) No Contraindication to Penicillins: ampicillin 2 gm IV 1/2 hr prior to the procedure plus Gentamicin 1.5 mg/kg IV 1/2 hr prior to the procedure and, 6 hr later Amoxicillin 1 gm PO, or ampicillin 1 gm IV Penicillins contraindicated: vancomycin 1 gm IV 1.5 hr prior to the procedure plus Gentamicin 1.5 mg/kg IV 1/2 hr prior to the procedure Moderate-risk patient (Table 2) No contraindication to penicillins: Oral: amoxicillin 2 gm PO 1 hr prior to the procedure Intravenous: ampicillin IV 2 gm 1/2 hr prior to the procedure Penicillins contraindicated: Vancomycin 1 gm IV 1.5 hr prior to the procedure (Adapted from Dajani AS, Taubert KA, Wilson W, et al. Prevention of bacterial endocarditis. Recommendations by The American Heart Association. JAMA; 1997, 277:1794– 1801, with permission.)

benefit of antimicrobial treatment is less than the risk of an adverse medication reaction. Antimicrobial prophylaxis has been demonstrated to be of greater benefit than risk in some procedures with higher infection rates; however, because the problem is complex and the data are limited, extrapolating these findings to the practitioner’s setting and the individual patient remains a challenge (Table 1). Although antimicrobial prophylaxis for bacterial endocarditis is not effective for most patients, the seriousness of the potential infection has driven

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the creation of guidelines recommending prophylaxis for at-risk patients undergoing at-risk procedures. Applying these guidelines appropriately could help to reduce unwarranted use of antimicrobials. In the prophylactic use of antimicrobials, as in many medical interventions, the difficulty is balancing the risks of the intervention with the potential benefits. Although we do not have either the randomized, controlled trials or the detailed, patient-specific information to estimate this balance precisely, there are general guidelines to help the clinician choose treatment for most patients.

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[18] Kaye K, Fraimow H, Abrutyn E. Pathogens resistant to antimicrobial agents. Epidemiology, molecular mechanisms, and clinical management. Infect Dis Clin North Am 2000;14:293–319. [19] Tanos V, Rojansky N. Prophylactic antibiotics in abdominal hysterectomy. J Am Coll Surg 1994;179:593–600. [20] Salkind A, Cuddy P, Foxworth J. The rational clinical examination. Is this patient allergic to penicillin? An evidence-based analysis of the likelihood of penicillin allergy. JAMA 2001;285:2498–505. [21] Solensky R, Earl H, Gruchalla R. Lack of penicillin resensitization in patients with a history of penicillin allergy after receiving repeated penicillin courses. Arch Intern Med 2002;162:822–6. [22] Phillips E, Louie M, Knowles S, et al. Cost-effectiveness analysis of six strategies for cardiovascular surgery prophylaxis in patients labeled penicillin allergic. Am J Health Syst Pharm 2000;57:339–45. [23] Li J, Markus P, Osmon D, et al. Reduction of vancomycin use in orthopedic patients with a history of antibiotic allergy. Mayo Clin Proc 2000;75:902–6. [24] Kriaras I, Michalopoulos A, Turina M, et al. Evolution of antimicrobial prophylaxis in cardiovascular surgery. Eur J Cardiothorac Surg 2000;18:440–6. [25] Burke J. The effective period of preventative antibiotic action in experimental incisions and dermal lesions. Surgery 1961;50:161–8. [26] Classen D, Evans R, Pestotnik S, et al. The timing of prophylactic administration of antibiotics and the risk of surgical-wound infection. N Engl J Med 1992;326:281–6. [27] Carrel T, Eisinger E, Vogt M, et al. Pneumonia after cardiac surgery is predictable by tracheal aspirates but cannot be prevented by prolonged antibiotic prophylaxis. Ann Thorac Surg 2001;72:143–8. [28] Coskun H, Erisen L, Basut O. Factors affecting wound infection rates in head and neck surgery. Otolaryngol Head Neck Surg 2000;123:328–33. [29] McDonald M, Grabsch E, Marshall C, et al. Single- versus multiple-dose antimicrobial prophylaxis for major surgery: a systematic review. Aust N Z J Surg 1998;68:388–96. [30] Da Costa A, Kirkorian G, Cucherat M, et al. Antibiotic prophylaxis for permanent pacemaker implantation: a meta-analysis. Circulation 1998;97:1796–801. [31] Cimochowski G, Harostock M, Brown R, et al. Intranasal mupirocin reduces sternal wound infection after open heart surgery in diabetics and nondiabetics. Ann Thorac Surg 2001;71:1572–8. [32] Kulling D, Sonnenberg A, Fried M, et al. Cost analysis of antibiotic prophylaxis for PEG. Gastrointest Endosc 2000;51:152–6. [33] Sharma V, Howden C. Meta-analysis of randomized, controlled trials of antibiotic prophylaxis before percutaneous endoscopic gastrostomy. Am J Gastroenterol 2000; 95:3133–6. [34] Dobay K, Freier D, Albear P. The absent role of prophylactic antibiotics in low-risk patients undergoing laparoscopic cholecystectomy. Am Surg 1999;65:226–8. [35] Higgins A, London J, Charland S, et al. Prophylactic antibiotics for elective laparoscopic cholecystectomy: are they necessary? Arch Surg 1999;134:611–3. [36] Tocchi A, Lepre L, Costa G, et al. The need for antibiotic prophylaxis in elective laparoscopic cholecystectomy: a prospective randomized study. Arch Surg 2000;135: 67–70. [37] Nathens A, Marchall J. Selective decontamination of the digestive tract in surgical patients: a systemic review of the evidence. Arch Surg 1999;134:170–6. [38] Yerdel M, Akin E, Dolalan S, et al. Effect of single-dose prophylactic ampicillin and sulbactam on wound infection after tension-free inguinal hernia repair with polypropylene mesh. Ann Surg 2001;233:26. [39] Kamat A, Brancazio L, Gibson M. Wound infection in gynecologic surgery. Infect Dis Obstet Gynecol 2000;8:230–4.

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[40] Chelmow D, Ruehli M, Huang E. Prophylactic use of antibiotics for nonlaboring patients undergoing cesarean delivery with intact membranes: a meta-analysis. Am J Obstet Gynecol 2001;184:656–61. [41] Sawaya G, Grady D, Kerlikowske K, et al. Antibiotics at the time of induced abortion: the case for universal prophylaxis based on a meta-analysis. Obstet Gynecol 1996;87: 884–90. [42] Weber R. Wound infection in head and neck surgery: implications for perioperative antibiotic treatment. Ear Nose Throat J 1997;76:790–1. [43] Callender D. Antibiotic prophylaxis in head and neck oncologic surgery: the role of gramnegative coverage. Int J Antimicrob Agents 1999;12:S21–5. [44] Rodrigo J, Alvarez J, Gomez J, et al. Comparison of three prophylactic antibiotic regimens in clean-contaminated head and neck surgery. Head Neck 1997;19:188–93. [45] Simons J. The role of topical antibiotic prophylaxis in patients undergoing contaminated head and neck surgery with flap reconstruction. Laryngoscope 2001;111:329–35. [46] Annys E, Jorissen M. Short term effects of antibiotics (Zinnat) after endoscopic sinus surgery. Acta Otorhinolaryngol Belg 2000;54:23–8. [47] Antimicrobial prophylaxis in neurosurgery and after head injury. Infection in Neurosurgery Working Party of the British Society for Antimicrobial Chemotherapy. Lancet 1994;344:1547–51. [48] Shapiro M, Wald U, Simchen E, et al. Randomized clinical trial of intra-operative antimicrobial prophylaxis of infection after neurosurgical procedures. J Hosp Infect 1986;8: 283–95. [49] Young R, Lawner P. Perioperative antibiotic prophylaxis for prevention of postoperative neurosurgical infections. A randomized clinical trial. J Neurosurg 1987;66:701–5. [50] Tenney J, Vlahov D, Salcman M, et al. Wide variation in risk of wound infection following clean neurosurgery. Implications for perioperative antibiotic prophylaxis. J Neurosurg 1985;62:243–7. [51] Dimick J, Lipsett P, Kostuik J. Spine update: antimicrobial prophylaxis in spine surgery: basic principles and recent advances. Spine 2000;25:2544–8. [52] Upadhyay M, Karmacharya P, Koirala S, et al. The Bhaktapur eye study: ocular trauma and antibiotic prophylaxis for the prevention of corneal ulceration in Nepal. Br J Ophthalmol 2001;85:388–92. [53] Eiferman R, Snyder J, Nordquist R. Ciprofloxacin microprecipitates and macroprecipitates in the human corneal epithelium. J Cataract Refract Surg 2001;27:170–2. [54] Gordon Y. Vancomycin prophylaxis and emerging resistance: are ophthalmologists the villains? The heroes? Am J Ophthalmol 2001;131:371–6. [55] Liesegang T. Perioperative antibiotic prophylaxis in cataract surgery. Cornea 1999;18: 383–402. [56] Tabbara K, al Jabarti A. Hospital construction-associated outbreak of ocular aspergillosis after cataract surgery. Ophthalmology 1998;105:522–6. [57] Boxma H, Broekhuizen T, Patka P, et al. Randomised controlled trial of single-dose antibiotic prophylaxis in surgical treatment of closed fractures: the Dutch Trauma Trial. Lancet 1996;347:1133–7. [58] Gillespie W, Walenkamp G. Antibiotic prophylaxis for surgery for proximal femoral and other closed long bone fractures. Cochrane Database Syst Rev 2001;CD000244. [59] Wieck J, Jackson J, O’Brien T, et al. Efficacy of prophylactic antibiotics in arthroscopic surgery. Orthopedics 1997;20:133–4. [60] Segreti J. Is antibiotic prophylaxis necessary for preventing prosthetic device infection? Infect Dis Clin North Am 1999;13:871–7. [61] Boldt J, Piper S, Uphus D, et al. Preoperative microbiologic screening and antibiotic prophylaxis in pulmonary resection operations. Ann Thorac Surg 1999;68:208–11. [62] Gonzalez R, Holevar M. Role of prophylactic antibiotics for tube thoracostomy in chest trauma. Am Surg 1998;64:617–20.


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[63] Taylor H, Bingham J. The use of prophylactic antibiotics in ultrasound-guided transrectal prostate biopsy. Clin Radiol 1997;52:787–90. [64] Isen K, Kupeli B, Sinik Z, et al. Antibiotic prophylaxis for transrectal biopsy of the prostate: a prospective randomized study of the prophylactic use of single dose oral fluoroquinolone versus trimethoprim-sulfamethoxazole. Int Urol Nephrol 1999;31:491–5. [65] Edwards WJ, Kaiser A, Tapper S, et al. Cefamandole versus cefazolin in vascular surgical wound infection prophylaxis: cost-effectiveness and risk factors. J Vasc Surg 1993;18:470–5. [66] Strom B, Abrutyn E, Berlin J, et al. Dental and cardiac risk factors for infective endocarditis. A population-based, case-control study. Ann Intern Med 1998;129:761–9. [67] Seto TB, Kwiat D, Taira D, et al. Physicians’ recommendations to patients for use of antibiotic prophylaxis to prevent endocarditis. JAMA 2000;284:68–71.

Med Clin N Am 87 (2003) 77–110

DVT prophylaxis and anticoagulation in the surgical patient Peter Kaboli, MD, MSa, Mark C. Henderson, MD, FACPb, Richard H. White, MD, FACPb,* a

Division of General Medicine, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA 52242, USA b Division of General Medicine, University of California—Davis, 4150 V Street/Suite 2400, PSSB, Sacramento, CA 95817, USA

To complete a comprehensive preoperative medical assessment prior to major surgery, the consultant must invariably address the issue of the prevention of postoperative thromboembolic complications. Venous thromboembolism (VTE), a term encompassing deep vein thrombosis and pulmonary embolism (PE), is one of the most common postoperative complications. In a study from Olmsted County, Minnesota, surgery was associated with an over twentyfold increase in the odds of being diagnosed with VTE [1]. In an analysis of over 2 million inpatient surgical procedures performed in California, 0.8% of cases were diagnosed with symptomatic VTE, 44% occurring during the hospitalization for surgery and the remainder within the first 3 months after surgery [2]. Overview of thromboembolism after surgery Scope of the problem Certain procedures, such as craniotomy for brain malignancy, are associated with a 3-month incidence of symptomatic VTE as high as 7.5% [3]. Because of the absence of reliable autopsy data, it is not clear how often fatal PE occurs after surgery. In a comprehensive study of patients undergoing total hip arthroplasty, Seagroatt estimated an excess of 0.7 deaths from PE for every 1000 operations during the first 90 days after surgery,

* Corresponding author. E-mail address: [email protected] (R.H. White). 0025-7125/03/$ - see front matter 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 4 4 - X

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compared with the ensuing 9-month period [4]. This compares with an estimated excess of 3.2 deaths/1000 from ischemic heart disease, 0.7 deaths/1000 from stroke, and an overall excess mortality of 6.5 deaths/1000 total hip operations. Thus, PE may account for 10% of all postoperative deaths following total hip arthroplasty. Fatal PE accounts for approximately 3–4% of all symptomatic VTE events [5]. For high-risk surgical procedures such as total hip arthroplasty, this translates to a rate of death caused by PE approximately 0.18–0.36% [6]. As discussed below, additional risk factors such as presence of a cancer, advanced age, and prolonged immobilization are likely to be associated with an increase in the incidence of fatal PE. Interpreting the literature The incidence of asymptomatic VTE is dramatically higher than that of symptomatic VTE, with asymptomatic VTE developing in 20–25% of patients after general surgery and 45–60% after orthopedic surgery involving the hip or knee [7]. Most clinical trials of thromboprophylaxis have evaluated a surrogate end point, venographic evidence of thrombosis, or asymptomatic VTE, primarily because the low incidence of symptomatic VTE events makes the sheer size and cost of conducting a sufficiently powered study prohibitive. Unfortunately, the precise relationship between the surrogate outcome of asymptomatic VTE and symptomatic VTE is not clear [8]. Most asymptomatic clots lyse spontaneously without treatment and they do not cause postphlebitic stasis or ulceration [9]. Fewer than one in eight venographically defined clots progresses to symptomatic VTE, although a somewhat higher proportion of proximal deep venous system clots become symptomatic compared with calf venous clots [7]. Relying on a one time ‘‘snapshot’’ of thrombosis using venography does not reflect the dynamic nature of clot formation and dissolution, a process that varies over time. For example, in one study of patients who had a negative venogram 7–10 days after total hip arthroplasty, 20% had a demonstrable clot 21 days later [10]. Unfortunately, the vast majority of thromboprophylaxis studies assess efficacy based on the incidence of asymptomatic VTE at one point in time [7]. The most valuable studies of thromboprophylaxis are those that demonstrate a significant reduction in hard end points such as incidence of symptomatic VTE or fatal PE. Implementing an optimal thromboprophylaxis regimen requires simultaneous assessment of the risks of VTE and the risks of bleeding. After combining these estimates with evidence-based knowledge regarding the efficacy and safety of various thromboprophylaxis modalities, one can make an appropriate treatment recommendation. If any recommendations are going to be followed, however, the consulting internist must also establish a working relationship with the surgeon and reach an agreement about: (1) the relative risks of bleeding and thrombosis for each prophylaxis regimen, and (2) the optimal duration of prophylaxis.


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Assessing the risk of VTE The risk of symptomatic VTE is directly related to: (1) the type of surgery being performed, (2) presence of other risk factors for VTE, (3) duration and extent of postoperative immobilization, and (4) use or nonuse of specific thromboprophylactic measures. Risk factors that have been shown to affect the incidence of postoperative venous VTE are outlined in Table 1. Age Essentially, all epidemiologic studies have shown that advancing age is a risk factor for incident VTE events, including postoperative VTE [1,11]. The incidence of VTE developing after surgery among patients less than 40 years old is quite low but rises linearly with age [12]. Table 1 Risk factors associated with venous thromboembolism (VTE) Risk factor

Effect

References

Age Ethnicity

Exponential increase in risk Asians have two- to three fold lower risk Major associated with up to six-fold higher riska Increased risk with pelvic, femur, leg fractures Three- to fourfold higher risk Increased risk

[1,11,143] [13]

Twofold higher risk Increase with BMI Higher risk

[18,2] [5,19] [21,146]

Increased, but absolute risk low Increased Increased

[16,17,147]

Type of surgery Trauma Previous VTE Varicosities or venous stasis changes Presence of a malignancy Obesity Left or right sided heart failure, COPD Thrombophilic disorder Stroke, immobilization Hematologic disorders: Polycythemia vera, essential thrombocytosis, paroxysmal nocturnal hemoglobinuria, others Medical disorders: nephrotic syndrome, inflammatory bowel disease, systemic lupus erythematosus, MI Pregnancy or estrogen use a

Increased, unknown magnitude

[2] [144,145] [2]

[148–151]

[152,153]

Some increase in risk

Major: neurosurgery, abdominal, thoracic, vascular, or orthopedic surgery on lower extremity. Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; MI, myocardial infarction; VTE, venous thromboembolism.

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Race/ethnicity Studies have shown that individuals with Asian/South Pacific Islander ethnicity have an approximately threefold lower risk of VTE, and this is also true for postoperative VTE [13]. Whether this simply reflects the lower prevalence of factor V Leiden and other thrombophilic disorders in this population is not known [14]. African Americans have a slightly higher relative risk of developing VTE compared with Caucasians, whereas Latinos appear to have a modestly lower risk of developing VTE [13]. Surgical procedure The particular surgical procedure is perhaps the strongest risk factor for developing VTE. We recently conducted a study of patients undergoing elective and urgent surgery in California [2]. Neurosurgery involving entry into brain or meningeal tissue and orthopedic surgery involving the hip (total or hemi-arthroplasty) was associated with the highest incidence of symptomatic VTE on the order of 6% and 3%, respectively. This compares with an incidence of approximately 0.3% following laparoscopic cholecystectomy or appendectomy. Other procedures associated with a substantially increased risk of VTE include major vascular surgery involving the aorta, iliac or arteries of the leg, general surgery involving removal of a portion of the small or large bowel, radical cystectomy, gastric bypass for obesity, and kidney transplantation. Surgical procedures associated with a very low risk of VTE include radical neck dissection, inguinal hernia repair, laparoscopic cholecystectomy, transurethral resection of the prostate, and thyroid or parathyroid surgery. Prior thromboembolism Prior VTE, particularly within the past 6 months, is a major risk factor for developing postoperative VTE, with an over three-fold higher relative risk [2]. This increased risk may reflect a higher propensity for a clot to form because of endothelial damage of the veins, or the presence of one or more underlying genetic or acquired thrombophilic conditions. Presence of a thrombophilic disorder The interplay between thrombophilic disorders and postoperative VTE has been clarified in recent years. In a large study of asymptomatic carriers of either factor V Leiden or activated protein C resistance, the absolute risk of manifesting VTE by age 65 years was small, on the order of 5–10%, but the relative risk of developing VTE was increased compared with noncarriers (relative risk [RR] ¼ 3.3, CI 1.7–6.1), particularly after surgery (RR ¼ 5.1, confidence interval [CI] 2.2–11.8) [15]. Other studies have confirmed these findings [16]. Based on these studies, it appears that the absolute risk of postoperative VTE among carriers is low (1 event per 100


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surgical procedures) and that patients should not be screened for inherited thrombophilic disorders prior to surgery. Presence of a lupus anticoagulant or anticardiolipin antibody in moderate or high titer among patients with no prior history of VTE is associated with a five to tenfold increase in the relative risk of developing VTE [17]. Patients with systemic lupus erythematosus plus either anticardiolipin antibodies or the lupus anticoagulant are probably at even higher risk for developing postoperative VTE. Cancer Presence of a malignancy is a potent risk factor that increases the risk of postoperative symptomatic VTE by at least twofold [2] and likely places such patients at increased risk for a longer period of time following the surgical procedure. Advanced clinical stage and pathology showing adenocarcinoma are strongly associated with VTE [18]. Obesity Obesity, defined as a body mass index (BMI) over 30, appears to confer an increased risk of symptomatic VTE, at least in patients undergoing total hip arthroplasty [5,19]. This may reflect a combination of greater physical restriction of venous outflow, higher right-sided cardiac filling pressures, decreased propulsion of blood because of reduced physical activity, or the presence of an underlying inflammatory state associated with obesity [20]. Another factor may be inadequate thromboprophylaxis. For instance, although the dose of heparin or low molecular weight heparin (LMWH) for treatment of VTE is adjusted for weight, the recommended dose for prophylaxis is usually fixed, which could potentially result in under-dosing. In addition, mechanical prophylaxis using pneumatic compression may be ineffective in obese individuals [19]. Medical conditions Congestive heart failure and chronic obstructive pulmonary disease (COPD) are associated with a higher incidence of VTE among hospitalized medical patients [21]. By extrapolation, it seems likely that these conditions also confer increased VTE risk in postoperative patients, with the mechanism being increased venous stasis. Immobilization-stasis Anything that leads to venous stasis likely increases the risk of VTE. Conversely, early mobilization of patients has been associated with a decreased relative risk of developing postoperative VTE [19,22]. Conditions such as marked obesity, stroke with hemiparesis, and prolonged bed rest in

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the hospital probably increase the risk of VTE by leading to increased venous stasis. Assessing the risk of bleeding Risk factors for bleeding have not been specifically defined in a large cohort of surgical patients. Factors likely to contribute to the risk of postoperative bleeding include: the type of surgery, the underlying problem leading to surgery (eg. cancer), the surgical technique, and other known bleeding risk factors. Widely appreciated bleeding risk factors during medical thromboprophylaxis include a known bleeding disorder, use of antiplatelet agents or nonsteroidal anti-inflammatory drugs (NSAIDs), previous gastrointestinal bleeding, cancer, and hepatic or renal insufficiency [23]. The relationship between age and bleeding risk during anticoagulant therapy has been noted in some studies [24,25] but not in others [24,26]. Risk stratification The American College of Chest Physicians (ACCP) criteria for VTE risk stratification are widely endorsed (Table 2). Patients are categorized on the basis of age, type of surgery, and presence or absence of additional thromboembolic risk factors. The obvious deficiencies of this schema are: (1) the Table 2 Risk stratification for thromboembolism after surgery Level of risk

Age (yrs)

Type of surgery

Additional Incidence of prox- Incidence risk factors imal DVT (%) of PE (%)

Low

40 40

Nonmajor Major Major

0.4

5 PVCs/min 5 at any time Suspected critical 20 AS — —

7

Other intraperitoneal or pleural Yes

— Aortic

3

3

5

Creatine > 1.5 2

—

— High-risk surgery

CVA DM requiring insulin Creatine > 2

— DM 3

—

—

—

—

1

1

1 1

Yes

Advanced age Procedure considered separately

Creatine > 2; Low functional capacity, uncontrolled systemic hypertension

Abnormal EKG, nonsinus rhythm Severe valvular disease CVA DM

Hemodynamically significant arrhythmias

(go to OR)

Minor (high intermediate, low risk)

Intermediate; minor

Minor Intermediate

Major

Minor

Major

Abbreviations: APC, atrial premature contraction; AS, aortic stenosis; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CHF, congestive heart failure; CVA, cerebrovascular accident; DM, diabetes mellitus; HX, history of; JVD, jugular venous distention; MI, myocardial infarction; OR, operating room; Pt, patient; PVC, premature ventricular contraction.

>70 yr Intraperitoneal, intrathoracic, aortic

Age Type of surgery

Other than nonsinus or APCs on last EKG > 5 PVCs/min at any time Valvular heart Important AS disease CVA — Diabetes — mellitus General pO250, status K3, abn AST, chronic liver disease, bedridden pt

Cardiac rhythm

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In a shift from risk indices to patient management, Eagle [20] and Vanzetto [21] each determined clinical variables to be used in deciding whether no testing, noninvasive testing, or coronary angiography should be done. The ACC-AHA [3] and ACP [4] guidelines included specific algorithms designed to guide whether additional cardiac testing or medical therapy was indicated before a patient could undergo surgery. Most recently, the ACC/ AHA has published an updated version of their original guidelines [1,2]. These will be discussed in more detail later. Approach to the patient History A detailed medical history is probably the most important factor in assessing a patient’s clinical risk of having a postoperative cardiac complication. Certain questions must be asked, and relevant information must be obtained regarding the patient’s current clinical status (Table 3). Age has been found to be an independent risk predictor in a number of studies and risk indices. The usual number that is quoted is over age 70; however, age represents a continuum for risk rather than the dichotomous variable. It is not age per se that predicts risk but rather the fact that age serves as a marker for decreased cardiac reserve and subclinical heart disease. In the most recent large study [22], age was not an independent risk Table 3 Approach to the surgical patient with cardiac disease History Age Prior cardiac disease (MI, angina, CHF, arrhythmias, valvular disease) Prior cardiac intervention (CABG, PCI) Prior cardiac evaluation (noninvasive test, angiography) Risk factors (HTN, DM, dyslipidemia, smoking) Associated diseases (PVD, CVA, CRI, COPD) Current status (chest pain, dyspnea) Functional capacity Medications Physical Exam Vital signs Carotid bruit JVD Murmur (AS, MS) or gallop (S3) Rales/wheezing Edema Peripheral pulses Neurologic deficit Abbreviations: CABG, coronary artery bypass grafting; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CRI, chronic renal insufficiency; HTN, hypertension; MI, myocardial infarction; MS, mitral stenosis; PCI, percutaneous coronary intervention; PVD, peripheral vascular disease.


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factor for cardiac complications of major noncardiac surgery after adjusting for other, more predictive, factors. History of any prior cardiac disease must be investigated: angina, myocardial infarction (MI), congestive heart failure or pulmonary edema, arrhythmias, or valvular heart disease. In patients with a confirmed history, the consultant needs to determine the severity and stability of angina, when a myocardial infarction occurred, and what if any cardiac work-up or intervention was done at that time or subsequently. Questions must be worded in a manner that a patient understands, rather than asking only if they had these diseases. Patients with a recent MI, unstable angina, Class III-IV angina, decompensated heart failure, or symptomatic aortic stenosis are at high risk for perioperative cardiac complications and should not undergo elective surgery without further evaluation or intervention. Mild stable angina (Class I-II), history of an old MI (with stable or no symptoms), and compensated CHF do not carry the same risk, and although these patients are at increased risk compared with patients with no cardiac disease, the absolute risk is lower. Such patients can usually undergo low- to intermediaterisk surgical procedures without further cardiac testing because the risk of coronary angiography and percutaneous coronary intervention (PCI) or preoperative coronary artery bypass grafting (CABG) would expose them to comparable or greater risks than the noncardiac procedure. First, do no harm. In the absence of known disease, the patient may have risk factors for CAD, and therefore the possibility of subclinical disease. These risk factors include diabetes mellitus, hypertension, dyslipidemia, and cigarette smoking. Diabetics, particularly those requiring insulin, are more likely to have vascular disease in general and are at increased risk for perioperative complications. Unless the patient has severe hypertension (stage 3), there is little evidence that it increases surgical risk. A patient may have other diseases associated with CAD and/or heart failure such as peripheral vascular disease, cerebrovascular disease, or renal insufficiency. The presence of coexisting respiratory disease such as chronic obstructive pulmonary disease should also be noted. It is important to ascertain and document the patient’s functional capacity, which also plays a role in the risk of postoperative complications. It is not enough to ask if the patient has chest pain or dyspnea without the knowledge of their usual daily activities or capabilities [23]. One should ask how many blocks a patient can walk and how many flights of stairs he or she can climb without symptoms, as well as what limits this activity. Patients who report being unable to walk four blocks or two flights had an increased risk of perioperative complications (cardiac and others), and this risk was inversely proportional to the number of blocks walked [24]. Similarly, the inability to climb two flights of steps was associated with an increased risk of cardiopulmonary complications in patients undergoing major thoracic, vascular, and abdominal surgeries [25].

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A complete list of medications and dosage, including prescription drugs, over-the-counter medications, and herbal preparations, should also be obtained. Physical examination The physical exam should be directed toward uncovering evidence of cardiac disease that the patient is unaware of as well as confirming findings suggested by the history. Vital signs will indicate the presence of hypertension, hypotension, tachycardia, bradycardia, various arrhythmias, and respiratory distress. The presence of jugular venous distension or an S3 gallop were significant predictors of postoperative cardiac complications in Goldman’s original risk index. Other evidence of congestive heart failure including rales and edema should be sought as well. The presence and significance of any cardiac murmurs should be evaluated. A carotid bruit, hemiparesis, pulsatile abdominal mass, or decreased peripheral pulses may suggest the presence of cerebrovascular or peripheral vascular disease. Electrocardiogram In addition to the history and physical exam, a preoperative ECG is usually the third component in routine cardiac risk evaluation; however, its findings rarely change perioperative management. The ECG should be evaluated for evidence of previous myocardial infarction, ischemia, arrhythmias, conduction defects, left ventricular hypertrophy, and nonspecific ST-T wave changes. The most important finding would be evidence of a silent MI, especially one that was not present on a recent prior ECG. The presence of left ventricular hypertrophy (LVH) serves as an indicator of more severe or long-standing hypertension and the possible existence of hypertensive heart disease. Many arrhythmias are detectable on physical examination, but conduction defects would otherwise go undetected. Significant ST segment depression (>0.5 mm) and left bundle branch block may be a markers of CAD, but there is no current evidence that such asymptomatic ECG findings increase perioperative risk in patients with or without known CAD. Previous cardiac work-up If the patient had undergone coronary evaluation in the past, it is important to obtain the results of any tests, including an exercise ECG, resting two-dimensional echocardiogram, stress thallium scan, dipyridamole thallium imaging, dobutamine stress echocardiogram, or coronary angiography. It is not enough to state that the test was normal or abnormal; full details are required.


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Clinical risk assessment Based on these items, the consultant should be able to identify whether the patient is in a low-, intermediate-, or high-risk group. In general, patients in low-risk groups require no further evaluation prior to surgery. Noninvasive testing in this group is unlikely to yield useful information as the likelihood of a positive test is low, and positive tests may frequently be false-positives. Previous guidelines have recommended against noninvasive testing in high-risk patients but in favor of routine noninvasive testing in intermediate-risk patients as identified by clinical criteria. The rationale was that high-risk patients did not need further risk stratification but rather should be considered directly for coronary angiography and revascularization, whereas noninvasive testing would help dichotomize intermediate risk patients into low-risk (no further intervention required) or high-risk (angiography) groups [26]. More recent data on the benefit of perioperative beta blockers has led to a major change in the incremental value of noninvasive testing, with our recommendation that it be used selectively in patients whose risk despite beta blockers is sufficiently high that coronary revascularization would be considered seriously. The ACC and ACP guidelines created algorithms to facilitate preoperative cardiac assessment and assist the consultant in deciding whether to proceed directly to surgery or to order further investigations or therapy. ACC-AHA guidelines Initially published in 1996 [3], the ACC/AHA guidelines were recently updated (2002) [1,2] to include additional data supporting much of the original document but also new information on beta-blockers, arrhythmias, and coronary evaluation and interventions. The ACC algorithm (Fig. 1) employs a strategy, using the urgency of surgery, history of previous coronary evaluation or treatment, clinical risk predictors, surgery-specific risk, and a patient’s functional capacity. Clinical predictors are classified as major (unstable coronary syndromes; recent MI (7–30 days), unstable angina, Class III-IV angina, decompensated CHF, significant arrhythmias, and severe valvular heart disease); intermediate (stable Class I-II angina, prior MI (>30 days), compensated or prior CHF, diabetes mellitus, and renal insufficiency (creatinine >2.0); and minor (advanced age, abnormal EKG, nonsinus rhythm, low functional capacity, prior cerebrovascular accident [CVA], and uncontrolled hypertension). Functional capacity was defined as poor (7–10 METS) based on evaluation of the patient’s daily activity. A cutoff of 4 METS was used as the dividing line between adequate and inadequate exercise capacity for purposes of decision-making in the algorithm. The ability to climb at least one flight of stairs carrying a bag of groceries, walk up a hill, or walk on level ground at 3–4 mph should indicate a functional capacity 4 METS.

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Fig. 1. Stepwise approach to preoperative cardiac assessment. Reprinted with permission from the American College of Cardiology. Journal of the American College of Cardiology 2002;39:542–53.

Surgery-specific risk as grouped by high, intermediate, or minor risk procedures (with cardiac risk >5%, 1–5%, or 180) [4,12, 14,15] and surgery type (abdominal aortic aneurysm resection and peripheral vascular surgeries) [12]. The severity of the blood pressure elevation, duration of control, use of antihypertensive medications, presence of end

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organ damage, or unusual etiology (eg, pheochromocytoma) may also influence risk of developing perioperative hypertension or hypotension. Of note, mild to moderate hypertension has not been found to be an independent predictor of major postoperative cardiac complications [6]. But patients with a systolic blood pressure of >140 mm Hg or diastolic blood pressure of >90 mm Hg at the time of hospital admission who were subsequently normotensive during hospitalization were at risk for a significant hypertensive response during endotracheal intubation [16]. Perioperative hypertension can occur during and after surgery, often in situations causing increased sympathetic stimulation that lead to adrenergic-mediated vasoconstriction. Intraoperative etiologies include laryngoscopy and intubation, inadequate (‘‘too light’’) anesthesia, surgical incision and manipulation, fluid overload (iatrogenic), ventilatory inadequacy, or use of vasopressors. Postoperatively, extubation, emergence and arousal from anesthesia, pain, hypothermia with shivering, hypoxia or hypercarbia, or intravascular volume overload can precipitate a hypertensive response, as can withdrawal from standing preoperative antihypertensive medications, especially beta blockers and clonidine. Other etiologies potentially responsible for postoperative hypertension developing 24–48 hours after surgery include the failure to restart the patient’s usual preoperative antihypertensive medication, decreasing effect or dose of analgesics and sedatives, and mobilization of fluids from the extravascular space. Treatment Investigators have confirmed the value of effective preoperative blood pressure control among patients with established hypertension [12,17], and experts therefore recommend that antihypertensive medications be continued during the perioperative period [4]. It is important to avoid withdrawal of beta blockers and clonidine because of a potential rebound increase in heart rate and blood pressure. Of note, the blood pressure-lowering effect of anesthetic induction is increased in patients chronically treated with angiotensin converting-enzyme (ACE) inhibitors and in patients given angiotensin II (AII) receptor antagonists [18]. These patients may require vasopressin-system agonists if the hypotension does not respond to sympathomimetic agents. There are no expert consensus guidelines to hold the dose of ACE inhibitors, AII receptor antagonists, or diuretics on the morning of surgery, although some practitioners might do so. Clinicians should remember, however, the potential benefits of continuing ACE inhibitor and AII receptor antagonist therapy in maintaining control of hypertension and/ or preventing exacerbation of congestive heart failure. Oral agents may need to be changed to parenteral or transdermal routes perioperatively until the resumption of oral intake. Additional information about specific antihypertensive medications can be found in the chapter on perioperative medication management.


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Initial treatment of postoperative hypertension should focus on reversing precipitating factors, such as pain, hypervolemia, hypoxia, hypercarbia, and hypothermia. If this fails or the patient has significant cardiovascular disease or has undergone neurosurgery, antihypertensive therapy may be instituted. True hypertensive emergencies are uncommon after noncardiac surgery and are defined as situations requiring immediate blood pressure reduction (although not necessarily to normal) to limit or prevent target- organ damage. These situations will usually require treatment with a parenteral antihypertensive agent, as would be done in the nonsurgical setting.

Congestive heart failure Epidemiology, diagnosis, and etiology Congestive heart failure (CHF) is increasing in prevalence in the U.S. population, affecting 6–10% of individuals older than age 65 [19]. The presence of CHF by history [20], physical signs (including a third heart sound or jugular venous distension [6] or including crackles on lung exam) [7], or a diagnosis of alveolar pulmonary edema by chest radiography [7] has been associated with an increased risk of perioperative cardiovascular complications. It is important to determine the etiology of CHF to direct treatment properly. Most processes result in left ventricular systolic dysfunction (70%) versus those causing diastolic dysfunction (30%). CHF may be caused by myocardial dysfunction related to ischemia, infarction, hypertension, valvular and pericardial disease, and cardiomyopathy. Arrhythmias, either tachycardic or bradycardic, may also precipitate perioperative CHF. Noncardiac causes of perioperative CHF that increase demand for cardiac output include anemia, fever, and hypoxia. The risk for postoperative CHF appears to be greatest immediately after surgery and then for 24–48 hours afterward. Initial postoperative risk may be caused by intraoperative fluctuations in blood pressure, myocardial ischemia, fluid administration, sympathetic stimulation, cessation of positive-pressure ventilation, and hypoxia. Subsequent risk may relate to reabsorption of interstitial fluid, myocardial ischemia, and potentially from effects of withdrawal from long-term preoperative oral CHF medications in patients whose medications have been held. Treatment Patients with active signs or symptoms of CHF preoperatively should have their medical therapy optimized, eg, through diuresis and afterload reduction. Studies have assigned a higher risk of perioperative cardiac complications in patients with pulmonary edema within 1 week of surgery [7], so it is recommended that elective surgery be postponed for at least 1 week after a patient’s CHF has been stabilized [21].

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Perioperative right heart catheterization Relatively few controlled studies have evaluated pulmonary artery catheterization (PAC) in relation to clinical outcomes. A recent randomized trial of PAC placement in elective vascular surgery patients showed no difference in complication rate, overall length of stay, or in surgical intensive care unit length of stay [22]. A case-control analysis of a subset of 215 matched pairs of patients who did and did not undergo right heart catheterization (RHC), adjusted for propensity of RHC and type of procedure, showed that patients who underwent RHC had an increased risk of postoperative CHF (odds ratio [OR] 2.9; 95% confidence interval [CI] 1.4–6.2) and of major noncardiac events (OR 2.2; 95% CI 1.4–4.9) [52]. But a recent randomized multicenter controlled trial of PAC use in 1994 patients age 60 or more who were classified as American Society of Anesthesiologists (ASA) class 3 or 4, and who underwent urgent or elective major surgery (abdominal, thoracic, major vascular, or orthopedic), showed no statistically significant difference in in-hospital mortality between the control (7.7%) and PAC (7.8%) groups (Chi-square P ¼ 0.918) [24]. The ASA has published guidelines on PAC insertion that focus on the inter-relationship between 3 variables: patient disease (clinical evidence of significant cardiovascular disease that would include recent CHF, significant left ventricular dysfunction, critical aortic stenosis, unstable angina, recent myocardial infarction (MI) or myocardial ischemia, pulmonary dysfunction, hypoxia, renal insufficiency, or other conditions associated with hemodynamic instability), surgical procedure (procedures associated with an increased risk of complications from hemodynamic changes, including damage to the heart, kidneys, lungs, or brain, such as those associated with significant intraoperative and postoperative intravascular fluid shifts, substantial changes in preload or afterload, and significant risk of perioperative myocardial ischemia), and practice setting (the physician must be skilled in the insertion of the PAC and educated in the interpretation of PAC data, and there must be adequate technical support provided by nursing staff and ancillary services) [25]. The American College of Cardiology/American Heart Association guidelines provide recommendations with a similar focus on appropriate patient- and surgery-specific risks [4]. In summary, we concur with the expert panels that PAC use should be determined on an individual patient basis according to unique hemodynamic risks presented by the patient’s underlying disease processes and the nature of the proposed procedure. Cardiomyopathy It is most important to determine the etiology of the cardiomyopathy before noncardiac surgery, as the disease process may be more likely to cause systolic or diastolic dysfunction. Hypertrophic obstructive cardiomyopathy (HOCM) presents particular challenges to patient management. Reduction of blood volume, decreased systemic vascular resistance, and


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increased venous capacitance may cause a reduction in left ventricular volume and thereby potentially increase a tendency to outflow obstruction [4]. Conversely, patients may be at increased risk of diastolic dysfunction from decreased compliance of the hypertrophied ventricle, and aggressive perioperative fluid administration may lead to increased left ventricular end diastolic pressure and increased pulmonary capillary pressure, causing alveolar pulmonary edema. Two small retrospective studies have assessed the incidence of adverse cardiac events in patients with HOCM undergoing noncardiac surgery. Thompson et al [26] reviewed 35 patients with asymmetric septal hypertrophy (ASH) who underwent general surgical procedures (specific information on surgery type was not provided). There were no perioperative cardiac deaths, and the one patient who sustained an MI and developed CHF had preoperative two-vessel coronary disease. The most common complications were atrial dysrhythmias requiring treatment (14%) and hypotension requiring vasoconstrictors (13%). A subsequent retrospective study of an echocardiographic database identified 77 patients with ASH on echocardiography within 24 months of surgery. Thirty-five patients underwent intra-abdominal or intrathoracic surgery (designated major surgery), and 42 patients underwent minor surgeries. Important predictors of adverse outcome were: type of surgery (major versus minor, P < 0.05), longer duration of surgery (P < 0.01), and increased intensity of hemodynamic monitoring (no monitoring versus intra-arterial versus right atrial versus pulmonary artery catheter, P < 0.05). Neither echocardiographic features–including magnitude of resting left ventricular outflow tract gradient and left ventricular dysfunction–nor history of prior MI were associated with adverse cardiac events. There were no perioperative deaths and one patient suffered a MI and ventricular tachycardia requiring emergent cardioversion. Twenty-five percent of patients experienced stable dysrhythmia (ie, not requiring urgent cardioversion), sixteen percent had CHF, fourteen percent had transient hypotension, and twelve percent developed myocardial ischemia [27]. In summary, common adverse events for patients with hypertrophic obstructive cardiomyopathy include perioperative CHF, myocardial ischemia, stable dysrhythmias, and transient hypotension, and appear to be associated with intra-abdominal or intrathoracic surgery and longer duration of surgery. The incidence of death and/or myocardial infarction is quite low, however.

Arrhythmias and conduction disorders Epidemiology and clinical significance Cardiac arrhythmias are common in the perioperative period, and most are benign. Early studies noted that transient perioperative arrhythmias occurred in 60–80% of patients, most of which were caused by transient

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bradyarrhythmias and premature atrial and ventricular depolarizations. The risk indices developed by Goldman and Detsky both included supraventricular and ventricular arrhythmias as clinical risk predictors for postoperative cardiac complications. Newer guidelines do not consider hemodynamically insignificant arrhythmias to be significant risk factors as more recent studies found that asymptomatic ventricular arrhythmias were not associated with an increase in postoperative cardiac complications; however, their presence in the perioperative period may unmask underlying cardiopulmonary disease and should provoke a search for myocardial ischemia, drug toxicity, or metabolic derangements [4]. Hypercapnea, hypoxia, hypokalemia, acidosis, and anemia increase arrhythmogenic potential, especially when they develop in association with general anesthesia [28]. A recent study of 4181 patients 50 years or older who had major nonemergent noncardiac procedures and were in sinus rhythm preoperatively found that 317 patients (7.6%) developed supraventricular arrhythmia (SVA). Atrial fibrillation (4.1%) and supraventricular tachycardia (3.7%) without discernible P waves were the most common types of SVA. Multiple regression analysis identified several independent correlates of SVA, most notably surgery type [intrathoracic surgery (OR 9.2) and abdominal aortic aneurysm repair (OR 3.9)], history of supraventricular arrhythmia (OR 3.4), significant valvular disease on physical examination (murmur grade 3, OR 2.1), history of asthma (OR 2.0), premature atrial complexes on the preoperative ECG (OR 2.1), and ASA Class 3 or 4 (OR 1.4) [23]. Patients with perioperative acute major cardiac and noncardiac (including bacterial pneumonia, bacteremia, pulmonary embolism, gastrointestinal bleeding, and cerebrovascular accident) events had an increased risk of perioperative SVA, and SVA was associated with a 33% increase in length of stay after adjustment for other clinical data (P < 0.001). A recent 2-year retrospective review of 13, 696 noncardiac, nonthoracic surgeries at one hospital identified 51 (0.37%) patients who developed atrial fibrillation within 30 days of surgery. Median age was 74 years, 59% of cases occurred in abdominal and vascular surgeries, and atrial fibrillation most commonly occurred on postoperative day 1. Two thirds of these patients had at least one of the following risk factors: hypertension, prior atrial fibrillation not present at the time of surgery, valvular heart disease, or myocardial infarction. Other common predisposing factors were positive fluid balance, hypokalemia, hypomagnesemia, and hypoxemia. Six patients (12%) remained in atrial fibrillation upon hospital discharge, thirty-six (71%) were discharged on new antiarrhythmic medications, and six patients (12%) died [29]. Therefore both of the above studies note that perioperative atrial fibrillation is associated with a significant impact on morbidity and length of stay. Though complex ventricular ectopy is common during and after surgery, serious symptomatic or sustained ventricular arrhythmias are rare. Kuner et al. noted that 95 out of 154 patients undergoing surgery had 195 episodes of cardiac arrhythmia, but only 5 patients had ventricular tachycardia [30]. Patients at risk of


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developing significant perioperative ventricular arrhythmias usually have structural heart disease with depressed ventricular function [28]. Common causes of acute ventricular arrhythmias in the perioperative period include acute myocardial ischemia, hypoxemia, hypokalemia, hypomagnesemia, and central venous catheters [31]. Management The presence of an arrhythmia in the perioperative setting should lead the clinician to evaluate the patient carefully for underlying cardiopulmonary disease, ongoing myocardial ischemia, drug toxicity, or metabolic derangements [4]. In atrial fibrillation, the patient’s hemodynamic stability and the presence of myocardial ischemia or congestive heart failure dictate whether the initial goal of therapy should be to restore sinus rhythm with direct current (DC) cardioversion, or to control the ventricular response rate if the arrhythmia is well tolerated [31]. Acute rate control of atrial fibrillation may best be achieved by intravenous infusion of diltiazem, with esmolol and verapamil available as alternative intravenous agents. Beta blockers, however, are the most effective agent for controlling the ventricular response during atrial fibrillation [32], and they have been shown to accelerate the conversion of postoperative supraventricular arrhythmias to sinus rhythm as compared with diltiazem [33]. Digoxin’s slow rate of onset limits its effectiveness for acute rate control, but it is still the drug of first choice for ventricular rate control in patients with decompensated heart failure because of its positive inotropic effect. It may best be used in addition to a beta blocker or calcium channel blocker [31]. Amiodarone has been proven to be effective in preventing postoperative atrial fibrillation in cardiac surgery (as have beta blockers) [34], and may be a more effective prophylactic agent in patients with prior atrial fibrillation. In addition, amiodarone is likely the most effective drug for maintaining sinus rhythm after cardioversion from atrial fibrillation [31]. In summary, the ACC/AHA recommends that physicians have a low threshold at which they institute prophylactic beta blocker therapy in patients at increased risk of developing a perioperative or postoperative arrhythmia (including those in whom arrhythmias are present during the preoperative evaluation) [4]. Two recent studies have demonstrated that beta blocker therapy can reduce the incidence of postoperative arrhythmias [35,36] in patients undergoing thoracic surgery (ie, a high-risk population). As mentioned above, hemodynamically significant ventricular arrhythmias occur rarely. Neither asymptomatic ventricular premature contractions nor asymptomatic hemodynamically insignificant nonsustained ventricular tachycardia (VT) require medical therapy in the perioperative period [31], although serum potassium, magnesium, and calcium levels must be monitored and carefully managed. Patients with nonsustained VT require a prompt evaluation for the presence of structural heart disease, for if the patient has evidence of prior myocardial infarction or of depressed left

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ventricular systolic function, an electrophysiologic study must be considered [31,37]. Sustained ventricular tachycardia or ventricular fibrillation (VF) in the perioperative period should be treated according to Advanced Cardiovascular Life Support (ACLS) protocol [38,39]. These guidelines allow the use of biphasic defibrillators, vasopressin in place of epinephrine, and amiodarone. After the patient is stabilized, a thorough evaluation for reversible causes is undertaken, and the patient must be evaluated for the presence of underlying structural heart disease [31]. If no precipitating causes are found, the patient should undergo electrophysiologic study and may require implantable cardioverter-defibrillator (ICD) placement, as the AVID study found that 3-year survival with ICD placement was superior to antiarrhythmic drugs in patients who had been resuscitated from near-fatal VF or who had undergone cardioversion from sustained VT [51]. Bradyarrhythmias and conduction disorders Patients with sinus bradycardia do not necessarily have sinus node dysfunction. Asymptomatic patients with persistent marked sinus bradycardia not readily explained by alterations in autonomic tone should, however, be evaluated further by assessing their response to atropine (0.02 mg/kg) or to exercise. Increase in heart rate to 90 or greater suggests that sinus node function is normal and that heart rate will increase appropriately during surgery. Atropine should be avoided in patients with angina at rest or with minimal exercise, glaucoma, or with symptoms consistent with bladder outlet obstruction [28]. Several studies, both from the 1970s and the 1990s, have shown that patients with bifascicular block [40] or left bundle branch block (BBB) with a prolonged PR interval [41] have an extremely low risk of developing complete heart block in the perioperative period, and, therefore, do not merit prophylactic preoperative temporary pacemaker insertion. Severe bradycardia with or without hemodynamic compromise requiring medical therapy has, however, been found to occur in about 8 percent of these patients [41]. Transthoracic pacing units should be readily available, especially in patients with pre-existing left BBB who require perioperative pulmonary artery catheterization (PAC), as complete heart block may develop in up to 8.5% of these patients receiving PAC [25]. Implanted pacemakers and ICDs Guidelines for implantation of cardiac pacemakers and antiarrhythmia devices have been recently published [42], and the indications in the perioperative setting are usually similar to those in the nonoperative setting. The main perioperative management issues with these devices have related to the potential for electrical magnetic interference with an implanted device from electrocautery or cardioversion. The electrical current generated by


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electrocautery or cardioversion can cause a variety of temporary or permanent responses by the implanted device, including: (1) resetting to a back-up, reset, or noise-reversion pacing mode; (2) inhibition of pacemaker output; (3) increase in pacing rate caused by activation of the rate-responsive sensor; (4) ICD firing caused by activation by electrical noise; or (5) myocardial injury at the lead tip that may cause failure to sense and/or capture [4]. The probability for adverse interaction has been reduced by the almost-universal use of bipolar electrocautery leads (which reduces the probability of electrical-magnetic interference), and improved pacemaker and ICD design [43]. Though no formal guidelines for the perioperative management of pacemakers and ICDs have been developed, the following general recommendations can be made: (1) pacemaker rate-responsive modes and ICDs should be programmed off during surgery; (2) current path (electrode tip to ground plate) should be arranged as far away as possible from the pulse generator; (3) pulse oximetry or peripheral pulse should be monitored to follow heart rate during electrocautery, as QRS complexes may not be seen; (4) electrocautery should not be applied directly over the pacemaker pulse generator; (5) electrocautery on or near the lead tip should be avoided because this may cause burning of the lead-tissue interface; and (6) if pacemaker inhibition is detected by the absence of pacing, a magnet may be applied over the pulse generator [31]. If there is any question regarding ICD or pacemaker function perioperatively, consultation with the cardiologist should be obtained, with a low threshold to interrogate the ICD or pacemaker before and after the surgical procedure.

Valvular heart disease Despite the decreasing incidence of rheumatic fever in developed countries, medical consultants continue to frequently encounter patients with various forms of valvular heart disease in the context of perioperative medical consultation. Lee et al [8] noted a 4% prevalence of history or physical examination showing significant valvular heart disease in 4315 patients undergoing elective major noncardiac procedures in a tertiary-care teaching hospital. Careful cardiac auscultation is therefore an essential element of the preoperative assessment, as this maneuver often identifies valvular abnormalities that necessitate specific precautions and perioperative interventions. In the context of perioperative medical assessment, the most important considerations relating to valvular disease are (1) whether severe aortic stenosis is present; (2) whether the identified valvular problem is associated with cardiac dysfunction and congestive heart failure; and (3) whether the combination of valve lesion and type of surgery dictate a need for endocarditis prophylaxis. Severe aortic stenosis (AS) has consistently been identified to be a risk factor for adverse outcome after noncardiac surgery. AS was the most

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heavily-weighted prognostic factor for predicting the occurrence of adverse cardiac events in the Detsky cardiac risk index [7]. In the study by Goldman et al [6], the proportion of patients with AS experiencing adverse cardiac events was 17.3%, whereas Detsky et al reported a similarly high rate of events. These early studies led many to conclude that patients with severe AS should generally not undergo elective noncardiac surgery, and experts recommend that patients with severe and symptomatic AS undergo aortic valve replacement prior to elective yet necessary noncardiac surgery [4]. This recommendation causes difficulties, however, when the noncardiac surgical procedure is relatively urgent, or when patients are not candidates for (or refuse) aortic valve replacement. Fortunately, Raymer and Yang [44] and Torsher et al [45] have more recently demonstrated that patients with even severe aortic stenosis can undergo noncardiac surgery with adverse event rates that approach those of patients without aortic stenosis (9% major complication rate similar to controls in the Raymer study, and 7% mortality rate in the Torsher study that included emergency surgeries and a patient cohort with more severe aortic stenosis), provided that the care providers— and especially the anesthesiologist—are aware of the presence of aortic stenosis. With advance knowledge, the anesthesiologist can carefully select anesthetic agents and vasopressor agents, and can use invasive arterial blood pressure monitoring to closely follow intraoperative blood pressures. The key thus is advance knowledge of the presence of severe aortic stenosis, generally achieved through a combination of careful clinical examination for signs of severe stenosis (slow rate of rise of the carotid pulse, mid-tolate peak intensity of the murmur, decreased intensity of the second heart sound, and maximal murmur intensity at the second right intercostal space) [46,47] and judicious use of echocardiography when clinical examination is indeterminate. Mitral stenosis, mitral regurgitation, and aortic regurgitation can similarly be detected through careful auscultation with or without supporting echocardiography. Once these valvular conditions are detected, it is then important to assess whether the valvular disease is associated with clinical evidence of congestive heart failure and ventricular dysfunction. More severe forms of these valvular conditions can be managed as necessary to optimize cardiac function and reduce the risk for perioperative congestive heart failure. Specific management considerations include: (1) avoidance of tachycardia in mitral stenosis to maintain an adequate diastolic filling time; (2) judicious use of afterload reducing agents in both aortic regurgitation and mitral regurgitation to optimize cardiac function without causing excessive hypotension; and (3) avoidance of excessive intravenous fluid administration in all valvular conditions to limit risk of volume overload and associated congestive heart failure. For all forms of valvular heart disease, an assessment should be made regarding indications for antibiotic prophylaxis for prevention of endocarditis, as per the American Heart Association guidelines published in 1997 [48].


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Briefly, these guidelines dictate that the need for prophylaxis relates to both the cardiac abnormality and the type of surgical procedure. Endocarditis prophylaxis is discussed in the chapter on antibiotic prophylaxis of the surgical patient. An important caveat to these guidelines is that most cases of endocarditis are not attributable to an invasive procedure, and that there are no published randomized trials demonstrating that prophylaxis lowers the risk of developing endocarditis [48]. Nevertheless, the recommendations made in the American Heart Association guidelines are widely accepted as reasonable suggestions based on both sound observational data and expert opinion. Perioperative management of anticoagulation in patients with valvular heart disease, and specifically with a mechanical prosthetic valve, depends of the invasive nature of the procedure and on the risk of thromboembolism without anticoagulation. Experts recommend that patients undergoing minimally invasive procedures (eg, dental work, superficial biopsies) should have their international normalized ratio (INR) briefly reduced to the low or subtherapeutic range and resume their normal dose of oral anticoagulation immediately after the procedure [4]. Perioperative heparin therapy is recommended for patients in whom the risk of bleeding with oral anticoagulation is high, and/or the risk of thromboembolism without anticoagulation is also high (mechanical valve in the mitral position, Bjork-Shiley valve, recent [ 2 hours Pain control with General anesthesia parenteral narcotics versus epidural Not using analgesia neuroaxial blockade Use of long-acting neuromuscular blockade

Emergency surgery Surgery technique Open versus laparoscopic

Neurologic status Impaired sensorium CVA history Fluid status CHF history Renal failure Blood urea nitrogen Blood transfusion Immune status Chronic steroid use Alcohol use Diabetes Abbreviations: AAA, abdominal aortic aneurysm; ASA, American Society of Anesthesiologists; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; OSA, obstructive sleep apnea.

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respiratory failure (Table 2) [4,5]. Low serum albumin is associated with respiratory failure [4], as well as higher 30-day postoperative mortality and morbidity rates [11,16]. Moreover, mortality increases exponentially as albumin falls below 4.0 g/dL [16]. Dependent functional status, with respect to activities of daily living, is also associated with an increased risk of PPCs [4,5]. Patients with greater than 10% weight loss in the 6 months prior to surgery are at increased risk for respiratory failure and pneumonia [4,5]. Obese patients (body mass index greater than 27 kg/m2) undergoing abdominal surgery are at greater risk for developing atelectasis and pneumonia [9]. Among thoracic surgery patients, however, the risk of PPCs is not increased when stratified by body mass index [12]. The conflicting evidence about obesity as a risk factor reflects differences in the measurement of co-morbid conditions in prior studies [19]. Respiratory status Risk factors for PPCs related to respiratory status include chronic obstructive pulmonary disease (COPD), smoking, preoperative sputum production and pneumonia, dyspnea, and obstructive sleep apnea (Table 1). Stable patients with COPD may become unstable in the perioperative period because of the detrimental respiratory effects of surgery and anesthesia [2,3]. Among noncardiac surgery patients, active smokers within 2 weeks of surgery are at increased risk for respiratory failure [4], and those who smoked within 1 year of surgery are at increased risk for pneumonia [5] (Table 2). Among abdominal surgery patients, higher pack-years of smoking are associated with increased risk of PPCs in univariate analysis but are not statistically significant in multivariable analysis [10]. Preoperative sputum production [14] and preoperative pneumonia [4] are independent risk factors for PPCs among patients undergoing elective noncardiothoracic surgery. Dyspnea, at rest or on minimal exertion, is also associated with an increased incidence of respiratory failure [4]. Obstructive sleep apnea (OSA) is associated with an increased risk of PPCs. In OSA patients undergoing hip or knee replacement surgery, 39% of patients with OSA (versus 18% in the control group) develop a serious pulmonary or cardiac complication [20]. Common PPCs include acute hypercapnia and episodic hypoxemia, with the majority occurring within 24 hours postoperatively. Serious complications necessitating ICU transfer occur in 24% of patients with OSA versus 9% in the control group. Neurologic status Risk factors related to neurologic status associated with PPCs include impaired sensorium [4,5,9] and previous stroke [4,5]. Patients with impaired sensorium or stroke with residual deficit have an odds ratio of 1.5 for


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pneumonia risk and 1.2 for respiratory failure risk (Table 2). These patients are less mobile postoperatively leading to a higher risk of atelectasis. They are also unable to protect their airway leading to higher risks of aspiration pneumonia and respiratory failure. Fluid status Risk factors for PPCs associated with fluid status include congestive heart failure [4], acute renal failure [4,7,8], and blood transfusion [4,5,21]. Patients with these conditions are at increased risk for pulmonary edema and pleural effusions that may lead to atelectasis, pneumonia, and even respiratory failure. High and low blood urea nitrogen levels are associated with pulmonary complications [4,5], implying that careful fluid management is needed in high-risk patients. In addition, patients with primary pulmonary hypertension are particularly sensitive to volume changes and may be difficult to manage once acute right heart failure occurs [22]. Immune status Chronic steroid use is associated with an increased risk of postoperative pneumonia, but not respiratory failure (Table 2). The increased risk of pneumonia may be secondary to immune suppression from the steroid medications in addition to the impact of diseases treated with steroids such as rheumatoid arthritis. Patients with alcohol use (greater than 2 drinks per day) within 2 weeks of surgery have 20% increased odds of pneumonia and respiratory failure (Table 2). Chronic alcohol use may be associated with diminished B-cell mediated immunity leading to an increased risk of pneumonia. Patients with insulin-treated diabetes mellitus are at slightly increased risk for respiratory failure, but not for pneumonia (Table 2).

Operation-related risk factors Several operation-related risk factors including surgical incision site, type of surgery, and surgical technique are associated with increased risk for PPCs (Table 1). Though these risk factors may not be modifiable, they are important to identify a priori for risk stratification. Surgical incision site and type of surgery Operations with incision sites near the diaphragm, such as thoracic and upper abdominal surgeries, are associated with the highest risk for PPCs [19]. Perioperative changes in lung volumes and ventilation patterns can lead to hypoxemia and atelectasis [23,24]. Diaphragmatic dysfunction contributes to these perioperative changes, even with adequate pain relief [25,26]. Depending on the PPC definition used, PPC rates range from 10–40% for

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Table 2 Comparison of the risk factors included in The Postoperative Pneumonia and Respiratory Failure Risk Indices

Risk factors

Postoperative Pneumonia Risk Index (OR [95% CI])

Type of surgery AAA repair Thoracic Upper abdominal Neck Neurosurgery Vascular Emergency surgery General anesthesia

4.29 3.92 2.68 2.30 2.14 1.29 1.33 1.56

Age 80 years 70–79 years 60–69 years 50–59 years 50 years 70 years 60–69 years 60 years

5.63 3.58 2.38 1.49 1.00 — — —

Point value

Respiratory Failure Risk Index (OR [95% CI])

Point value

(3.34–5.50) (3.36–4.57) (2.38–3.03) (1.73–3.05) (1.66–2.75) (1.10–1.52) (1.16–1.54) (1.36–1.80)

15 14 10 8 8 3 3 4

14.3 8.14 4.21 3.10 4.21 4.21 3.12 1.91

(12.0–16.9) (7.17–9.25) (3.80–4.67) (2.40–4.01) (3.80–4.67) (3.80–4.67) (2.83–3.43) (1.64–2.21)

27 21 14 11 14 14 11 —

(4.62–6.84) (2.97–4.33) (1.98–2.87) (1.23–1.81) (referent)

17 13 9 4 — — — —

— — — — — 1.91 (1.71–2.13) 1.51 (1.36–1.69) 1.00 (referent)

— — — — — 6 4 —

Functional status Totally dependent Partially dependent Independent

2.83 (2.33–3.43) 1.83 (1.63–2.06) 1.00 (referent)

10 6 —

1.92 (1.74–2.11) 1.92 (1.74–2.11) 1.00 (referent)

7 7 —

Albumin < 3.0 g/dL > 3.0 g/dL

— —

— —

2.53 (2.28–2.80) 1.00 (referent)

9 —

1.92 (1.68–2.18) 1.33 (1.12–1.58)

7 3

1.37 (1.19–1.57)a —

— —

1.24 (1.08–1.42) — 1.72 (1.55–1.91)

2 — 5

1.19 (1.07–1.33)a 1.15 (1.00–1.33)a 1.81 (1.66–1.98)

— — 6

1.28 (1.17–1.42) —

3 —

— 1.24 (1.14–1.36)a

— —

—

—

1.70 (1.35–2.13)a

—

— — —

— — —

1.69 (1.36–2.09)a 1.21 (1.09–1.34)a 1.00 (referent)

— — —

Weight loss > 10% (within 6 months) Chronic steroid use Alcohol > 2 drinks/day (within 2 weeks) Diabetes—insulin treated History of COPD Current smoker Within 1 year Within 2 weeks Preoperative pneumonia Dyspnea At rest On minimal exertion No dyspnea


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Table 2 (continued )

Risk factors

Postoperative Pneumonia Risk Index (OR [95% CI])

Impaired sensorium History of CVA History of CHF Blood urea nitrogen < 8 mg/dL 8–21 mg/dL 22–30 mg/dL > 30 mg/dL Preoperative renal failure Preoperative transfusion (> 4 units)

Point value

Respiratory Failure Risk Index (OR [95% CI])

Point value

1.51 (1.26–1.82) 1.47 (1.28–1.68) —

4 4 —

1.22 (1.04–1.43)a 1.20 (1.05–1.38)a 1.25 (1.07–1.47)a

— — —

1.47 1.00 1.24 1.41

(1.26–1.72) (referent) (1.11–1.39) (1.22–1.64)

4 — 2 3

1.00 1.00 1.00 2.29

— — — 8

— 1.35 (1.07–1.72)

— 3

1.67 (1.23–2.27)a 1.56 (1.28–1.91)a

(referent) (referent) (referent) (2.04–2.56)

— —

Adapted from Arozullah AM, et al. Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Annals of Internal Medicine 2001;135:847–57, and from Arozullah AM, et al. Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. Annals of Surgery 2000;232(2):242–53; with permission. a Risk factor was statistically significant in multivariable analysis but was not included in the Respiratory Failure Risk Index.

thoracic surgery and 13–33% for upper abdominal surgery, compared with 0–16% for lower abdominal surgery [19]. Two validated multifactorial risk indices from the largest surgical cohort to date reinforce the importance of the incision location and type of surgery (Table 2). Type of surgery is the strongest predictor of PPCs in both The Postoperative Respiratory Failure Risk Index and The Postoperative Pneumonia Risk Index (Table 2) [4,5]. In these indices, abdominal aortic aneurysm repair, thoracic surgery, and upper abdominal surgery carry the highest risk, confirming results from previous smaller studies. In addition, neck, peripheral vascular, neurosurgery, and emergency surgery are independently associated with increased PPC risk. Neurosurgery and neck surgery may be associated with increased risk for perioperative aspiration pneumonia. Surgical technique Modifying the surgical approach or extent of surgery may reduce operative time and incision-related risk in high-risk patients. In addition, randomized trials indicate that some laparoscopic procedures, despite longer anesthesia time, have lower PPC risk compared with open procedures. The PPC rate for patients undergoing laparoscopic cholecystectomy is 2.7% versus 17.2% for those undergoing open cholecystectomy [27]. In a randomized

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trial of laparoscopic versus open fundoplication, laparoscopic fundoplication is associated with significantly better FEV1 and FVC, shorter hospital stay, and decreased need for analgesics [28]. In two small cohort studies of open versus laparoscopic colectomy, however, there is no difference in pneumonia rates, but there is shorter hospital stay in the laparoscopic group [29,30].

Anesthesia-related risk factors Though internists usually restrict recommendations to their area of expertise, knowledge of anesthesia-related risk factors can optimize patient care through improved communication between the medical, surgical, and anesthesia teams. General and spinal anesthesia are associated with reduction in vital capacity and functional residual capacity. Perioperative impairment of mucociliary clearance mechanisms can also increase the risk of postoperative infection [1]. The immediate postoperative period may be associated with hypoventilation from residual anesthetic effect and deep breathing impairment secondary to incision pain. These routine anesthesia-related changes do not typically result in clinical complications. Nevertheless, duration, route of administration, and type of anesthesia are risk factors for PPCs. Duration of anesthesia is a well-established risk factor for PPCs [15], with studies showing an increasing incidence of PPCs with longer anesthesia especially greater than 2–6 hours [3,6,14,31–34]. Route and type of anesthesia administration There is debate about the efficacy of regional (epidural or spinal) anesthesia versus general anesthesia in reducing PPCs. In a large observational study of over 9,000 elderly patients with hip fracture, 30-day mortality and pneumonia rates are similar between regional and general anesthesia groups [35]. Conversely, a meta-analysis of 16 hip fracture surgery trials found that regional anesthesia, compared with general anesthesia, is associated with decreased mortality at 1 month [36]. The ‘‘stress response’’ caused by general anesthesia increases sympathetic and neuroendocrine activity, but it may be attenuated with regional anesthesia delivered through spinal or epidural anesthesia [37]. A systematic review of 141 trials that randomized patients to epidural or spinal anesthesia (with or without general anesthesia) versus general anesthesia alone supports the use of epidural or spinal anesthesia [38]. Most trials included were published before 1991 with samples of less than 50 patients. The review finds that epidural or spinal anesthesia, compared with general anesthesia, is associated with a 40% reduction in postoperative pneumonia and nearly one third reduction in 30-day mortality. The incidence of deep venous thrombosis, pulmonary embolism, myocardial infarction, renal failure, transfusion requirements, and respiratory depression also decreases with regional anes-


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thesia. The authors conclude that the addition of regional anesthesia, not the avoidance of general anesthesia, imparts benefit. The increasing use of combined general and regional anesthesia as well as postoperative epidural analgesia may antiquate the debate about general anesthesia alone versus regional anesthesia alone [39]. Another anesthesia-related risk factor for PPCs is the use of long-acting neuromuscular blocking agents that result in hypoventilation [40]. A prospective, randomized trial compared the incidence of PPCs following the use of pancuronium (long-acting neuromuscular blocker) versus two intermediate-acting agents, atracurium and vecuronium [41]. The incidence of residual neuromuscular block was 26% in the pancuronium group versus 5.3% in the intermediate-acting group. In the pancuronium group, patients with residual block were approximately four times more likely to develop PPCs than patients without residual block. In the intermediate-acting group, the incidence of PPCs was not significantly different between those with or without residual block. Risk factors related to postoperative care Risk factors for PPCs related to postoperative care include nasogastric tube use and pain control using parenteral narcotics. In a systematic review of blinded studies predicting PPCs, postoperative nasogastric tube placement is one of only two predictors that are significant in more than one study [15]. One of these studies, however, has a small sample size (n ¼ 148) with only 16 PPCs and no independent validation of the findings [14]. Furthermore, the final multivariable model reported did not include age, type of surgery, smoking, or other potential confounding variables— making the positive association between nasogastric tube placement and PPCs suspect [14]. Contrary to these findings, pre-emptive gastrointestinal (GI) tract management, including intraoperative nasogastric tube placement, in patients undergoing elective thoracotomy decreases aspiration and respiratory mortality rates [42]. The benefit of preventing large-volume aspiration through nasogastric tube placement may outweigh the risks of ineffective coughing and oropharyngeal aspiration in high-risk patients. Pain control is particularly important for patients with incisions close to the diaphragm. Though adequate pain control improves deep breathing, resulting in decreased atelectasis and pneumonia, narcotic pain medications may increase aspiration risk through GI slowing and also increase the risk of PPCs by reducing the ventilatory response to hypoxia and hypercapnia [43]. In a retrospective review of elective abdominal aortic aneurysm repairs, patients receiving an epidural catheter for postoperative pain control have significantly fewer pulmonary and cardiac complications than those receiving standard parenteral opioid analgesia [44]. In addition, patients receiving epidural analgesia have fewer ICU days, less intubation time, and lower hospital charges compared with the standard treatment group [44].

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Other methods for controlling postoperative pain and reducing PPCs include fascial infiltration of local anesthetic at incision closure and intercostal block. However, neither method is consistently found to reduce PPCs. In a randomized, controlled trial of elective laparotomy patients, fascial infiltration of bupivacaine (long-acting local anesthetic) fails to show any benefit over controls in atelectasis rate, change in vital capacity or expiratory reserve volume, or total analgesic amount taken [45]. In patients undergoing biliary surgery through a subcostal incision, those receiving intercostal blocks have a PPC rate of 6% compared with 11% for those given centrally acting analgesics [46]. In the same study, however, patients with a midline incision receiving intercostal blocks have a higher rate of PPCs.

Risk indices for preoperative assessment Risk indices are used routinely for preoperative cardiac risk assessment. Similarly, several risk indices predict PPCs, including modified versions of indices originally developed for predicting mortality, cardiac complications, or wound infections [47,48]. These indices are limited to specific types of surgery, rarely validated in independent samples, and combined pulmonary complications with different clinical implications into a single outcome [47–49]. Using data from a large, multi-center, observational study, Arozullah et al developed and validated separate risk indices and scoring systems for predicting postoperative pneumonia and respiratory failure [4,5]. The large sample size enables the investigators to examine many potential risk factors simultaneously and to validate their findings in independent samples. The risk factors in The Postoperative Pneumonia and Respiratory Failure Risk Indices, their associated odds ratios, and assigned point values are displayed in Table 2. These risk indices can provide preoperative PPC risk estimates using the scoring system and risk class assignment displayed in Table 3. Table 3 Risk class assignment by Postoperative Pneumonia and Respiratory Failure Risk Index Scores

Risk class

Postoperative Pneumonia Risk Index (point total)

Predicted probability of pneumonia (%)

Respiratory Failure Risk Index (point total)

Predicted probability of respiratory failure (%)

1 2 3 4 5

0–15 16–25 26–40 41–55 > 55

0.2 1.2 4.0 9.4 15.3

0–10 11–19 20–27 28–40 > 40

0.5 2.2 5.0 11.6 30.5

Adapted from Arozullah AM, et al. Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Annals of Internal Medicine 2001;135:847–57, and from Arozullah AM, et al. Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. Annals of Surgery 2000;232(2):242–53; with permission.


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The main limitation of these risk indices is that they are developed and validated using observational and retrospective chart review data from Veterans Administration hospitals. The patients are predominantly male and have high levels of comorbid conditions so that the risk indices may not generalize to healthier populations. Although risk factors such as age and smoking are likely to be significant risk factors in women, risk index calibration may not accurately predict PPC risk in this population. The validation of these risk indices in independent patient samples, however, provides some confidence in their usefulness for providing reasonable estimates of preoperative risk.

Preoperative testing Chest radiography As discussed in an earlier article, routine preoperative chest roentgenograms in healthy adults add minimal incremental value to a thorough history and physical for predicting PPCs and rarely change perioperative management. Whereas chest roentgenograms do not improve preoperative risk assessment, they may provide baseline findings useful for postoperative care in chronic lung disease or frail, elderly patients when a history is difficult to obtain. Arterial blood gas analysis Routine arterial blood gas analysis does not appear to improve preoperative pulmonary risk assessment. Small case series identify hypercarbia as a risk factor for the development of PPCs [50,51]. But these patients may be identified as high risk by other factors that do not require arterial blood gas analysis. A systematic review of blinded studies does not find hypercarbia to be a useful predictor of PPCs [15]. Pulmonary function testing The role of pulmonary function testing in risk assessment prior to noncardiothoracic surgery is not clear. Spirometry flow rates that are commonly measured include forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Spirometry accurately diagnoses airflow obstruction and its severity [52] despite variability in flow rates and substantial individual day-to-day variability [53]. Though patients with significant obstructive lung disease have more PPCs compared with normal patients, individual pulmonary function test abnormalities do not predict PPC risk. Pulmonary function tests (PFTs) became a routine part of the preoperative evaluation because of the erroneous assumption that accurate diagnosis of COPD translates into improved preoperative risk assessment. One influential study shows an increased risk of PPCs among abdominal surgical patients with abnormal spirometry [54]. In spite of major limitations, including small

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sample size, lack of standard definitions for PPCs, and no blinding of outcome assessments, several subsequent studies recommend preoperative PFTs for patients undergoing elective abdominal surgery [55–58]. In a 1990 consensus statement, The American College of Physicians (ACP) recommends preoperative PFTs in patients undergoing lung resection, coronary bypass surgery, or upper abdominal surgery with a history of tobacco use or dyspnea, patients undergoing lower abdominal surgery if there were unexplained pulmonary disease with anticipated prolonged or extensive surgery, or patients undergoing head and neck or orthopedic surgery with unexplained pulmonary disease [59]. The aggregate expense of ordering routine PFTs can be wasteful. One economic analysis estimates that roughly 40% of PFTs ordered do not meet ACP guidelines [60]. Improving guideline adherence in ordering PFTs may provide potential annual savings of $29–100 million overall and $8–20 million for Medicare [60]. More recent studies about the utility of spirometry before abdominal operations reach conflicting conclusions. Studies concluding that spirometry is predictive of PPCs rely on univariate analysis without adequate adjustment for potential confounding risk factors [6,61,62]. One study demonstrates the value of spirometry in smokers with severe airflow obstruction, but only for predicting bronchospasm [63]. A critical review concludes that preoperative spirometry is not useful in predicting pulmonary complications after abdominal operations [18]. The review concludes that previous studies have important methodological flaws, including poor standardization, inadequate blinding of observers, selection bias, inadequate control for cointerventions, and inclusion of questionable clinical outcomes such as microatelectasis. In another systematic review, preoperative PFTs predict PPCs in only one out of five blinded studies [15]. Several studies demonstrate the superiority of clinical findings over PFTs in predicting PPCs. Two investigations of patients with severe COPD (FEV1 < 50% predicted) conclude that preoperative PFTs do not predict PPCs [2,32]. By contrast, overall general medical condition (described by ASA class) is helpful in predicting PPCs. One prospective study finds that PFTs are weakly predictive of PPCs, whereas chronic mucous hypersecretion is a stronger independent predictor [64]. In a case-control study of abdominal surgery patients, no component of spirometry predicts PPCs, though abnormal results of lung examination (decreased breath sounds, prolonged expiration, rales, wheezes, or rhonchi), abnormal chest radiograph, cardiac, and overall comorbidity are all significant risk factors for PPCs [10]. In summary, routine PFTs should not be ordered solely for risk assessment purposes prior to abdominal surgery or other high-risk surgeries. It is reasonable, however, to obtain preoperative PFTs for unexplained dyspnea or exercise intolerance, as recommended in the nonoperative setting. Preoperative PFTs may enhance postoperative management in patients with obstructive lung disease by providing measurement of baseline airflow obstruction, but PFTs do not appear to predict PPC risk.


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Risk reduction strategies A preoperative medical evaluation enables clinicians to recommend preoperative and perioperative risk reduction strategies. But the evidence available to support risk reduction strategies is limited compared with the evidence available regarding risk assessment for PPCs. Preoperative smoking cessation, perioperative lung expansion maneuvers, and postoperative analgesia are risk reduction strategies supported by some evidence. Clinically intuitive strategies for elective surgery include optimization of pulmonary function in patients with COPD and asthma, and delaying surgery for patients with acute exacerbations of chronic lung disease or upper respiratory infection. There is no clear role for prophylactic antibiotic use in preventing PPCs. Preoperative smoking cessation Conflicting evidence exists regarding the benefits and ideal timing for preoperative smoking cessation. Short-term smoking cessation reduces carboxyhemoglobin and nicotine blood levels, and results in gradual improvement in mucociliary function and upper-airway hypersensitivity [65–67]. Brief abstinence before surgery, however, is associated with a paradoxical increase in PPCs. One cohort study in veterans undergoing noncardiac surgery finds that smoking cessation within 1 month of surgery is not associated with a reduction in PPCs [68]. Current smokers who reduce smoking are almost seven times more likely to develop PPCs, with the greatest risk among those who reduce smoking closest to the surgery date. Another cohort study of 200 consecutive patients undergoing coronary artery bypass grafting finds that patients who smoke for 2 months or less prior to surgery have a fourfold increased risk of PPCs compared with those abstaining for longer than 2 months (57.1% versus 14.5%) [69]. Patients not smoking for more than 6 months have a rate similar to patients who never smoked (11.1% versus 11.9%). The rate of PPCs is highest in patients who stop smoking 2–4 weeks prior to surgery. The authors conclude that abstinence from smoking for greater than 8 weeks prior to coronary artery bypass grafting (CABG) is needed to reduce the incidence of PPCs. This study does not control, however, for many patient-related risk factors, and the most common PPCs are bronchospasm requiring bronchodilator therapy and respiratory secretions requiring more than the usual chest physical therapy or inhalation therapy. It is unclear if these complications are selflimited or progress to more serious complications. In a retrospective study of 288 consecutive patients who underwent pulmonary surgery, the incidence of PPCs is 43.6% for current smokers (smoking within 2 weeks), 53.8% for recent smokers (duration of smoke-free period of 2–4 weeks), 34.7% for ex-smokers (duration of smoke-free period >4 weeks), and 23.9% for never-smokers [70]. The risk of developing PPCs after abstinence for 10 weeks appears to be similar to that in never-smokers.

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After controlling for gender, age, PFTs, and duration of surgery, there is a trend toward increased PPC risk for current and recent smokers compared with never-smokers. But the most common PPC is air leak or effusion requiring chest tube drainage for >7 days, making the results less applicable to nonthoracic surgery patients. A randomized trial of 120 hip and knee replacement patients examines the effect of a smoking-cessation intervention on complications [71]. Patients are randomized 6–8 weeks before surgery to an intervention of counseling and nicotine replacement versus standard care with little or no information about risks of smoking and smoking cessation. The intervention group has significantly fewer complications overall, significantly fewer wound complications, trends toward fewer cardiac complications and need for second surgery, and significantly fewer hospital days on nonorthopedic services. As expected, the rate of PPCs is low with only one case of respiratory insufficiency in each group. The study does not address the question of the ideal time for preoperative smoking cessation. The paradoxical increase in PPCs observed with short-term abstinence or reduced smoking may be caused by ineffective sputum removal [68,69]. Reduced smoking may decrease bronchial irritation and the stimulus for coughing; at the same time, bronchial hypersecretion of mucus is still present or even transiently increased [68,69,72]. This cascade may result in increased sputum retention. An alternative explanation may be that sicker patients tend to quit smoking closer to surgery [5]. Thus, short-term abstinence may simply be a marker for higher comorbid burden. In conclusion, the preoperative evaluation presents an opportunity to discuss and encourage life-long smoking cessation. Short-term abstinence or reduced smoking may increase PPCs, although the evidence is marked by methodological limitations. Abstinence for at least 8 weeks prior to surgery probably decreases PPC risk. But clinicians and patients rarely have 8 weeks notice before surgery.

Perioperative lung expansion maneuvers One long-standing hypothesis is that collapsed areas of the lung provide a nidus for the development of PPCs [1]. Lung expansion maneuvers inflate collapsed areas of the lung and may prevent the development of PPCs. The literature on the efficacy of different types of lung expansion maneuvers is conflicting and difficult to interpret for several reasons: the lack of controlled trials; inadequate descriptions of control arms in controlled studies; inconsistency in administration of lung expansion techniques; and variability in the definition used for PPCs [1]. Lung expansion maneuvers include incentive spirometry and chest physical therapy consisting of various combinations of the following: deep breathing exercises, postural drainage, percussion and vibration, cough, suctioning, and mobilization. Other


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lung expansion maneuvers include intermittent positive pressure breathing (IPPB) and continuous positive airway pressure. Although incentive spirometry is used routinely, a systematic review of 48 studies concludes that current evidence does not support routine incentive spirometry for the prevention of PPCs following cardiac or abdominal surgery [73]. Thirty-five of the 48 studies have significant methodological flaws. Three of the eleven remaining studies evaluate short-term physiologic markers, eg, vital capacity, and do not demonstrate an improvement with incentive spirometry. The results of the remaining 8 trials are summarized in Tables 4 and 5. Although the authors conclude that the evidence does not support the use of incentive spirometry, it is noteworthy that the majority of studies do not include control groups. Rather, most studies compare incentive spirometry to other lung expansion maneuvers, and, for the most part, incentive spirometry is equal in clinical efficacy. The authors report that one study in the CABG population does have a control arm; however, the control group underwent early mobilization [74]. The other two arms of the study consist

Table 4 Incentive spirometry and cardiac surgery Trial

Comparison groups

Administration

Outcome

Result

Gale GD, et al [82]

IS (n ¼ 52) IPPB (n ¼ 57)

20 minutes qid

Atelectasis

No difference

Dull JL, Dull WL [74]

EM (n ¼ 16) EM þ IS (n ¼ 17) EM þ DB (n ¼ 16)

EM: bid IS/DB: 10 breaths qid

PPCs; PFTs

No difference

Stock MC, et al [83]

IS (n ¼ 12) CPAP (n ¼ 13) DBC (n ¼ 13)

15 min every 2 hrs during waking hours from 2nd to 72nd hr post extubation

PFTs

No difference

Matte P, et al [84]

Chest PT þ IS (n ¼ 30) Chest PTþ CPAP (n ¼ 30) Chest PTþ Bilevel PAP (n ¼ 30)

IS: 20 breaths every 2 hrs CPAP: 1 hr every 3 hrs Bilevel PAP: 1 hr every 3 hrs

PFTs; venous admixture

CPAP, Bilevel PAP superior to IS

Abbreviations: IS, incentive spirometry; IPPB, intermittent positive pressure breathing; EM, early mobilization (included ankle exercises, range of motion to all extremities, 3 maximal coughs, encouragement and assistance for turning side to side, sitting, or standing); DB, deep breathing; DBC, deep breathing and cough; CPAP, continuous positive airway pressure; Chest PT, chest physiotherapy, Bilevel PAP, bilevel positive airway pressure; PFTs, pulmonary function testing; PPCs, postoperative pulmonary complications. Adapted from Overend TJ, et al. The effect of incentive spirometry on postoperative pulmonary complications: a systematic review. Chest 2001;20(3):971–8; with permission.

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Table 5 Incentive spirometry and abdominal surgery Comparison groups

Administration

Outcome

Results

Celli BR, et al [75]

No treatment (n ¼ 44) IS (n ¼ 42) IPPB (n ¼ 45) DBE (n ¼ 41)

IS: 10 breaths (over 15 min) qid IPPB: 15 min qid DBE: 10 maneuvers qid

PPCs

IS, IPPB, DBE Better than no treatment IS, IPPB, DBE Equal in efficacy

Stock MC, et al [85]

CDB (n ¼ 20) IS (n ¼ 22) CPAP (n ¼ 23)

PPCs; PFTs

No difference

Schwieger I, et al [76]

No treatment (n ¼ 20) IS (n ¼ 20)

15 minutes every 2 hours during waking period IS: 150–200 breaths/day

PPCs

No difference

Trial

Rickstein SE, Chest PT þ IS et al [86] (n ¼ 15) Chest PT þ PEP (n ¼ 15) Chest PT þ CPAP (n ¼ 13)

Chest PT: BID IS/PEP/CPAP: 30 breaths every 1 waking hour

Radiography, CPAP and PEP Gas exchange, superior to IS Lung volumes

Adapted from Overend TJ, et al. The effect of incentive spirometry on postoperative pulmonary complications: a systematic review. Chest 2001;20(3):971–78; with permission.

of early mobilization, plus incentive spirometry or deep breaths. There are no significant differences among the three groups. There are two abdominal surgery studies including a control group [75,76]. One study of incentive spirometry versus no respiratory therapy in elective cholecystectomy finds no significant differences in PPCs [76]. Conversely, the second study finds that the use of incentive spirometry is associated with a reduction in PPCs following abdominal surgery [75]. Incentive spirometry use versus no respiratory therapy is also associated with decreased length of hospital stay in upper abdominal surgery. The proportion of smokers is higher, however, in the second study—implying that incentive spirometry may be beneficial only in high-risk patients undergoing abdominal surgery. Chest physical therapy appears to be beneficial for reducing PPCs depending on the type of surgery. Fagevik et al demonstrate the superiority of chest physical therapy, consisting of breathing exercises with pursed lips, huffing, and coughing hourly, and information about the importance of changing position in bed and early mobilization versus no respiratory therapy for upper abdominal surgery [77]. But there is no difference between chest physical therapy and no respiratory therapy in patients undergoing laparoscopic abdominal surgery [78].


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Intermittent positive pressure breathing assists patients in achieving an involuntary maximal inspiration but has the side effect of abdominal distension [75]. A meta-analysis evaluating incentive spirometry, deep breathing exercises, and intermittent positive pressure breathing after upper abdominal surgery finds that the three modalities are similar in efficacy and better than no respiratory therapy [79]. The definition of PPCs includes atelectasis or pneumonia, but if radiographic results are unclear or unavailable, a combination of historical and physical findings is used to define a PPC. Thus, some reported PPCs might be of limited clinical significance. Continuous positive airway pressure (CPAP) appears to be equally effective or better than these three modalities, with the advantage that it is effort-independent. CPAP is expensive, however, requires special equipment, and causes patient discomfort, gastric distension, hypoventilation, and barotrauma [80]. In summary, the use of incentive spirometry following abdominal surgery may reduce PPCs, particularly in high-risk patients. No specific lung expansion maneuver is clearly superior, but CPAP may be beneficial in patients unable to perform deep breathing exercises or incentive spirometry. Patient education in lung maneuvers initiated preoperatively is more effective in reducing pulmonary complications versus education initiated postoperatively [77,81]. Summary Preoperative risk assessment for postoperative pulmonary complications is essential when counseling patients about the risks of surgery because of their significant associated morbidity and mortality. There are many patient-related, operation-related, and anesthesia-related risk factors for the development of PPCs. Though many of these risk factors are not modifiable, they can be useful in evaluating preoperative risk, especially when combined into formal risk indices [4,5]. Preoperative risk assessment enables clinicians to target preoperative testing and perioperative risk reduction strategies to high-risk patients. Reducing PPC risk at the patient level will require a greater understanding of the impact of modifying risk factors through interventional trials. Reducing hospital PPC rates will require future research into the processes of care associated with PPCs through controlled observational and interventional trials. References [1] Brooks-Brunn JA. Postoperative atelectasis and pneumonia. Heart Lung 1995;24:94–115. [2] Kroenke K, Lawrence VA, Theroux JF, et al. Postoperative complications after thoracic and major abdominal surgery in patients with and without obstructive lung disease. Chest 1993;104:1445–51. [3] Wong DH, Weber EC, Schell MJ, et al. Factors associated with postoperative pulmonary complications in patients with severe chronic obstructive pulmonary disease. Anesth Analg 1995;80:276–84.

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Med Clin N Am 87 (2003) 175–192

Perioperative evaluation and management of the patient with endocrine dysfunction Robert L. Schiff, MDa,*, Gail A. Welsh, MDb a

General Medical Consult Service, Loyola University Medical Center, Maywood, IL, USA b Mayo Medical School, Rochester, MN, USA

Over the past two decades the worldwide prevalence of diabetes mellitus has steadily risen. In the United States, an estimated 16 million people have diabetes mellitus [1]. Factors contributing to the increased prevalence of diabetes include the proliferation of obesity, lower levels of physical activity, and the aging of the population. Individuals with diabetes mellitus often require surgery sometime during their life [2]. Physicians in many specialties are involved in the perioperative care of patients with diabetes mellitus including internists, surgeons, anesthesiologists, and endocrinologists.

Diabetes mellitus and surgery Patients with diabetes mellitus who undergo surgery have an increased risk of developing perioperative complications [2,3]. They are particularly at greater risk for infectious, metabolic, electrolyte, renal, and cardiac complications during and after surgery [4–6]. The primary goal of perioperative care for the diabetic patient undergoing surgery is a safe and effective outcome without complications. Steps involved in achieving that outcome include the preoperative evaluation, a plan for managing diabetes during surgery, and postoperative diabetic care. The timing of the surgery is also important, particularly when other medical conditions coexist with diabetes (eg, cardiac, renal, or infectious problems). Communication and coordination of care between the internist or endocrinologist and the surgical team (surgeon and anesthesiologist) are often important for achieving a safe outcome.

* Corresponding author. E-mail address: rschiff@lumc.edu (R.L. Schiff). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 5 0 - 5

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Perioperative metabolic changes Many metabolic changes occur during surgery that have an effect on diabetes mellitus. With the onset of anesthesia and surgery, there is an increase in the secretion of epinephrine, norepinephrine, cortisol, and growth hormone [2,7]. The extent of the metabolic changes is related to the type of surgery, the length of surgery, and the stress of surgery. Whether the surgery is an elective or emergent procedure also affects the extent of metabolic changes. Epinephrine, norepinephrine, cortisol, and growth hormone are all insulin antagonists and cause insulin resistance at the tissue level. In addition, epinephrine causes a decrease in insulin secretion [2,6]. All of these metabolic changes contribute to hyperglycemia during and after surgery. The stresses of anesthesia and surgery also cause an increase in gluconeogenesis. There is mobilization of gluconeogenesis precursors, including amino acids, free fatty acids, and glycerol [7,8], and an increase in the metabolic rate during surgery. There is also a net protein catabolism during and after surgery [6]. These perioperative changes can result in poor control of blood glucose, ketosis, and acidosis [2,7]. Factors that affect the extent of the endocrine and metabolic changes during and after surgery include the type of diabetes, preoperative diabetic control, the magnitude of the surgery, and perioperative complications. Patients with diabetes mellitus are also at risk for hypoglycemia in the perioperative period. Hypoglycemia in the anaesthetized or sedated diabetic patient may be unrecognized if appropriate glucose monitoring is not done. Factors that may contribute to perioperative hypoglycemia in patients with diabetes mellitus include prolonged fasting, hypoglycemic medications, inadequate nutritional therapy, sedation, and postoperative gastrointestinal problems (eg, vomiting, gastroparesis, and ileus). Ramifications of perioperative hyperglycemia One of the most important consequences of perioperative hyperglycemia is impaired wound healing. Phagocytic function of granulocytes is adversely affected by hyperglycemia, particularly when blood glucoses are greater than 250 [9]. Collagen synthesis is suppressed by hyperglycemia when glucose levels are higher than 200mg/dL. Granulocyte chemotaxis is also decreased by hyperglycemia. The higher prevalence of vascular disease and renal disease in patients with diabetes mellitus also contributes to the greater frequency of postoperative wound infections [6]. Impaired wound healing contributes to the increased rate of postoperative infections in patients with diabetes mellitus. These infections, including wound infections, skin infections, pneumonia, and urinary tract infections, are a major cause of morbidity, accounting for about two thirds of all postoperative complications [10] and 20% of all postoperative deaths [11] in patients with diabetes. There is evidence from in vitro studies that hyperglycemia impairs wound healing. The best method for tightly controlling diabetes mellitus during


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major surgery is with a continuous IV insulin and glucose infusion [7,12,13]. Is there evidence that better control of diabetes in the perioperative period decreases morbidity or mortality? At this time, there are no prospective studies that document better perioperative outcomes from tighter control of diabetes mellitus. Some retrospective studies show that higher glucose levels perioperatively are associated with an increased risk of infection in patients with diabetes mellitus [5,14]. A recent prospective study randomly assigned 1548 critically ill patients admitted to a surgical intensive care unit to intensive insulin therapy or conventional insulin therapy [15]. Only 13% of these patients had a history of diabetes mellitus. Two thirds of the patients had undergone cardiothoracic surgery. In the intensive insulin therapy group, an insulin infusion was started if the blood glucose level exceeded 110 mg/dL, and, in the conventional insulin therapy group, it was started if the blood glucose exceeded 215 mg/dL. Patients in the intensive insulin group had a mean A.M. blood glucose of 103 mg/dL, and in the conventional insulin group it was 153 mg/ dL [15], but hypoglycemia occurred in 5% of the intensive insulin group compared with 1% in the conventional group. The 12-month mortality rate for the intensive insulin therapy group was 4.6% which was significantly lower than the 8.0% mortality rate for the conventional insulin group. The intensive insulin therapy group had 46% fewer episodes of septicemia and a 34% lower in-hospital mortality rate [15]. A retrospective study of 411 adults with diabetes mellitus who had coronary artery bypass surgery divided these patients into four quartiles based on their mean postoperative blood glucose levels [14]. Mean postoperative blood glucose levels ranged from 121–206 mg/dL in quartile 1 to 253–352 mg/dL in quartile 4. One hundred patients (24.3%) developed one or more postoperative infections. In adjusted risk models (adjusting for confounding variables such as age and comorbid conditions), those patients in the higher postoperative glucose quartiles had an increased risk for postoperative infections [14]. Another retrospective study examined the incidence of deep sternal wound infections in diabetic patients undergoing open heart surgery before and after instituting a continuous intravenous insulin infusion protocol [4]. Their control group included 968 patients who received sliding scale subcutaneous insulin and had a mean glucose of 206 on postoperative day 1. The study group of 1499 patients received a continuous intravenous insulin infusion and had a mean glucose of 176 on postoperative day 1. Institution of the continuous intravenous insulin infusion protocol resulted in a significant decrease in the incidence of deep sternal wound infections to 0.8%, compared with the rate of 1.9% in the subcutaneous insulin therapy group [4]. Preoperative evaluation The objectives for the preoperative assessment of patients with diabetes mellitus include evaluation of the status of their diabetes, identifying other

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medical problems, consideration of the type of surgery planned to assess the surgical risk, and measures to minimize the risk of surgery. It is important to identify both the type and duration of diabetes mellitus. Patients with diabetes for more than 10 years are more likely to have complications from diabetes. The patient’s current therapy for diabetes should be ascertained including diet, oral medication(s) and doses, and any insulin therapy including the type and dose. The status of diabetes control should be assessed by evaluating recent blood glucoses and hemoglobin A1C. The patient should be queried about any complications from diabetes. Because patients with diabetes mellitus are at increased risk for coronary artery disease, a cardiac history should be obtained prior to surgery. The preoperative physical exam should include an evaluation of cardiovascular status including blood pressure, heart rate and rhythm, and a cardiac exam. An abdominal exam and neurologic exam should also be undertaken. Certain preoperative tests should be done for all patients with diabetes mellitus before surgery. A chemistry panel to evaluate electrolytes and renal function should be ordered before surgery. An electrocardiogram should be taken before any major surgery for patients with diabetes mellitus. Whether any additional tests are indicated would depend on the patient’s medical problems and the type of surgery planned. Management of diabetes during surgery How a patient’s diabetes will be managed during surgery is dependent on several patient specific issues and several surgical factors. Patient issues to consider include whether the patient is being treated with diet alone, with oral hypoglycemic agent(s), or with insulin as well as the degree of glycemic control. Surgery-specific factors to consider are the type of anesthesia (local, regional, or general) and whether major or minor surgery is scheduled. How long the patient is expected to be nil per os (NPO) should also be considered. For example, an early morning knee arthroscopy may enable the patient to eat lunch, whereas an early morning laparoscopic cholecystectomy may preclude a normal lunch. For patients who undergo minor surgery (eg, cystoscopy, dilation and curettage, laparoscopic hernia repair) therapy for diabetes mellitus should be modified (Table 1). Patients undergoing minor surgery whose diabetes mellitus is controlled with diet alone or with oral hypoglycemic agents usually do not need insulin during surgery. For all patients with diabetes mellitus, a bedside blood glucose should be checked preoperatively and every 1–2 hours during minor surgery. Patients who are taking oral hypoglycemic agents should omit these on the morning of surgery or 24–48 hours preoperatively if on metformin or chlorpropamide. These patients can restart their usual oral hypoglycemic medication when they are able to resume their usual diet. Diabetic patients controlled with oral hypoglycemic medications who undergo major surgery usually do not need insulin during surgery. Patients on oral


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Table 1 Management of diabetes mellitus during surgery

DM controlled with diet alone: DM controlled with oral meds: DM poorly controlled with oral meds: DM on insulin therapy:

Minor surgery

Major surgery

No insulin during surgery



Insulin may be required during surgery IV insulin infusion during surgery IV insulin infusion during surgery

Insulin may be required 1/2–2/3 of usual AM insulin SQ

Abbreviations: DM, diabetes mellitus; SQ, subcutaneous.

hypoglycemic medications with poorly controlled diabetes should receive an insulin and glucose infusion during major surgery (Table 1). Insulin-treated patients should have their insulin dose modified before minor surgery. One half to two thirds of their usual morning insulin can be given. Less insulin should be given (eg, one half their usual dose) if it is anticipated that they will be NPO past their noon meal. Their IV fluids during surgery should be D5W/0.45NS at 100cc/hr to prevent hypoglycemia. When they are able to resume their usual diet, they can restart their preoperative insulin treatment. Patients with diabetes mellitus on insulin who undergo major surgery should receive a continuous IV insulin and glucose infusion during surgery [7]. An insulin infusion is the best method to control glucose levels and can be easily adjusted depending on the stress of surgery, the length of surgery, and the patient’s insulin requirements [7,11]. There is a wide variation in how much insulin is needed during surgery for these patients ranging from 0.7–4.2 units of regular insulin/hr [11]. A continuous IV glucose infusion should also be given to prevent hypoglycemia and to provide a source of carbohydrate to minimize the risk for ketosis and acidosis during fasting and the stress of surgery. Potassium chloride should be included in the insulin and glucose infusion (Table 2) unless the patient has hyperkalemia or chronic renal failure. It is inappropriate to use only IV push insulin to manage diabetes perioperatively, because IV push insulin has a half-life of only 5–10 minutes [7]. IV insulin and glucose infusion When a patient is started on a continuous IV insulin and glucose infusion for surgery, the usual insulin and oral hypoglycemic medication(s) should be held on the morning of surgery. Prior to starting the infusion, a bedside blood glucose should be checked. One IV line should be used for the insulin and glucose infusion, and a second IV line for any other fluids, medications, and/or blood products that are needed during surgery. The IV insulin infusion should be started at 1.0 units/hr of regular insulin by infusion pump.

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Table 2 Protocol for perioperative IV insulin infusion

Check bedside blood glucose. Hold usual morning diabetes medications. Begin insulin and glucose infusion: 1. Discard first 50 mL of insulin infusion 2. Start insulin infusion at 1.0 units/hr of regular insulin by infusion pump 3. Start D5W/0.45NS with 20 meq of KCL at 100 cc/hr Maintain one IV line for insulin and glucose infusion, and a separate IV access for any fluids, blood products, or medications. Monitor bedside blood glucose every 1–2 hs before surgery and every 1 hr during surgery. Aim for glucose of 100–200 mg/dL by adjusting insulin infusion rate in 0.5 unit/hr increments.

The first 50–60 mL of the insulin infusion should be flushed through the plastic tubing and discarded because insulin binds to plastic tubing, and this will saturate the insulin binding sites on the plastic tubing. When the insulin infusion is started, the glucose infusion should also be started with 1000 cc of D5W/0.45NS with 20 mEq of KCL to run at 100cc/hr. The bedside blood glucose should be checked every 1–2 hours (every 1 hour during surgery) and adjusted to maintain a glucose of 100–200 mg/DL. The insulin infusion can be adjusted in 0.5 unit/hr increments. For example, if at 1 hour the glucose is 250 mg/dL, then the infusion rate should be increased to 1.5 units/hr. If at 1 hour the glucose is 70 mg/dL, the infusion rate should be decreased to 0.5 units/hr. The IV glucose infusion should be maintained during these adjustments at 100cc/hr. For a very low glucose (eg, 50mg/dL) 1 ampule of D50 should be given IV push and the insulin infusion rate should be decreased by 0.5units/hr. For patients undergoing open-heart procedures, the metabolic changes that cause hyperglycemia are accentuated [13]. Diabetic patients undergoing open-heart procedures will usually require higher hourly infusion rates of IV insulin. What are the advantages of continuous IV insulin infusion compared with giving subcutaneous insulin during surgery? The absorption of subcutaneous insulin may be erratic and highly variable during surgery. Continuous IV insulin has the flexibility to control diabetes better, whether the surgery and its peak stresses occur early in the morning, late in the morning, or later in the day. The IV insulin infusion can be easily adjusted in response to complications that occur during or after surgery and can be individualized to meet the insulin requirements of each patient. Diabetes therapy after surgery The metabolic and hormonal stresses of surgery persist during the early postoperative period after major surgery. These metabolic changes can continue for up to 4 days after major surgery [8,17] but are most pronounced on the day of surgery and the first postoperative day. While the patient remains NPO, the insulin and glucose infusion can be continued. The insulin


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and glucose infusion can usually be stopped when the patient begins eating, although they are often unable to initially tolerate their usual diet. Until their usual diet is tolerated, subcutaneous regular insulin can be given every 6 hours based on bedside blood glucoses. When a patient’s dietary intake improves, their usual insulin dosing (or a reduced long-acting insulin dose) can be resumed. Patients on oral hypoglycemic agents who require an insulin and glucose infusion can restart their oral hypoglycemic medications when they resume their usual diet.

Surgery in the hypothyroid patient Hypothyroidism affects many bodily systems that can influence perioperative outcome, including myocardial function, pulmonary ventilation, hemostasis, gastrointestinal (GI) motility, and free water balance. There are no randomized, prospective studies looking at surgical outcomes in hypothyroid patients versus controls. Older case studies reported intraoperative hypotension, cardiovascular collapse, and extreme sensitivity to narcotics, sedatives, and anesthesia in undiagnosed hypothyroid patients [18,19] There are also case reports of myxedema coma developing after surgery [20–22]. Thus for many years, expert opinion encouraged clinical and chemical euthyroidism prior to any surgery. Two retrospective case-matched control studies from the 1980s evaluated the hypothyroid patient undergoing surgery. Weinberg et al [23] reviewed anesthetic and surgical outcomes in 59 hypothyroid patients and 59 paired euthyroid controls. There were no differences between the groups in surgical outcome, perioperative complications, or hospital length of stay. There were also no differences in outcome among subsets of hypothyroidism determined by level of thyroxine, though only a few were severely hypothyroid. The authors concluded that there was no evidence to justify deferring needed surgery in patients with mild to moderate hypothyroidism, and insufficient evidence to make recommendations for patients with severe hypothyroidism. Another retrospective study by Ladenson et al [24] looked at perioperative complications in 40 hypothyroid patients compared with 80 matched controls. Hypothyroid patients had more intraoperative hypotension in noncardiac surgery and more heart failure in cardiac surgery. They also had more postoperative GI and neuropsychiatric complications and were less likely to mount a fever with infection. There were no differences between the groups in duration of hospitalization, perioperative arrhythmias, delayed anesthetic recovery, pulmonary complications, or death, however. Patients with mild to moderate hypothyroidism may undergo urgent or emergent surgery without delay. Elective surgery in patients with mild hypothyroidism is probably safe, though minor complications such as ileus, postoperative delirium, or infection without fever may occur. Elective surgery should be postponed for patients with moderate and severe hypothyroidism.

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Patients with severe hypothyroidism who require urgent or emergent surgery should be treated perioperatively with intravenous T3 or T4 and glucocorticoids. Definitions of mild, moderate, and severe hypothyroidism are often vague and vary between studies. A useful definition of a severely hypothyroid patient includes one with myxedema coma; one with severe complications of the disease such as delayed mentation, pericardial effusions, or heart failure; or one with very low levels of thyroxine [25]. Thyroid replacement can be started or continued in the patient with mild to moderate disease going to surgery, with the same schedule as therapy in the outpatient setting. Levothyroxine has a half-life of 5–9 days, and so doses can be missed for several days if the patient is not eating. Initiation of thyroid replacement in the patient undergoing cardiovascular surgery or catheterization has been controversial. The risk of precipitating or worsening unstable coronary syndromes with thyroid hormone conflicts with the concern that untreated hypothyroidism might worsen heart failure or hypotension in the cardiac surgery patient. Studies of cardiac patients found no adverse outcomes in cardiac patients going to surgery or catheterization without thyroid replacement [26,27]. The need for thyroid hormone replacement should be assessed in each patient on an individual basis, with the knowledge that most patients can begin their replacement after the cardiac intervention. Myxedema coma is a rare complication of surgery and should be considered in any patient who develops seizures, coma, unexplained heart failure, or hypothermia perioperatively. Undiagnosed hypothyroidism should be suspected in any postoperative patient with difficulty weaning from ventilatory support, unexplained heart failure, prolonged ileus, or postoperative delirium.

Surgery in the patient with hyperthyroidism The effect of thyrotoxicosis on the heart carries perioperative risk for the hyperthyroid patient. T3 and T4 exert direct inotropic and chronotropic effects on cardiac muscle. Left ventricular ejection fraction may not increase normally during exercise, and increased cardiac output may limit cardiac reserves during surgery in the hyperthyroid patient. Atrial fibrillation is present in 10–20% of patients [28–31]. The greatest risk to the perioperative thyrotoxic patient is thyroid storm, a rare but life-threatening complication that presents with fever, tachycardia, and confusion and may quickly lead to cardiovascular collapse and death. It can occur in the inadequately treated or undiagnosed hyperthyroid patient during or soon after surgery [16,32]. Patients with mild hyperthyroidism can go to surgery with preoperative beta blockade [33], but elective surgery should be postponed in those with moderate to severe disease until they are euthyroid. Propranolol has been the beta-blocker of choice at doses of 10–40 mg q.i.d., though cardioselective beta-blockers can also be used. The latter may be better tolerated in


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patients with asthma. Longer acting beta-blockers such as atenolol taken before surgery may maintain adequate heart rate control until the patient is able to take oral medication postoperatively [34]. The thyrotoxic patient undergoing urgent or emergent surgery needs premedication with antithyroid agents, beta blockade, and possibly corticosteroids. Close perioperative assessment and management of cardiac function is essential. Antithyroid medications include thionamides, iodine, and iopanoic acid. The thionamides, methimazole, and propylthiouracil (PTU) block thyroid hormone synthesis. Iodine blocks release of T4 and T3 from the thyroid, and iopanoic acid blocks T4 to T3 conversion. Iopanoic acid contains iodine and thus also blocks release of thyroid hormone. Euthyroidism can be achieved in 3–8 weeks with thionamides alone. Methimazole reverses hyperthyroidism sooner than PTU. There are other published combination regimens that can prepare a patient more rapidly for urgent surgery in 10 days or less [35,36]. Adrenal reserve may be low in the thyrotoxic patient. If time does not allow for completely adequate preparation prior to emergent surgery in the patient with severe hyperthyroidism or if thyroid storm occurs, hydrocortisone can be given 100 mg every 8 hours. This will not only treat possible adrenal insufficiency but may block peripheral conversion of T4 to T3 as well. One study showed improved outcomes in patients with thyroid storm treated with corticosteroids [37]. Thyroid storm should be considered in any patient who develops fever, tachycardia, and confusion in the postoperative period. Laboratory values do not differ between thyrotoxicosis and decompensated hyperthyroid crisis, and treatment may need to start before results of thyroid function tests are available. Burch devised a point system based on cardiac, neuropsychiatric, and other physical findings to help with diagnosis [38]. Treatment of thyroid storm includes beta blockade, thioamides, iodinated contrast agents, iodine, and corticosteroids. Thioamides should be given at least 1 hour prior to iodine to prevent uptake of iodine by the thyroid as substrate for more hormone production. Methimazole and PTU are available rectally, and PTU can be given intravenously [39–41]. Supportive care in the intensive care unit (ICU) setting is essential and should include hydration, nutrition with glucose and vitamins, antipyretics, cooling blankets, and treatment of cardiac complications such as heart failure and atrial fibrillation that may develop. Acetaminophen is the antipyretic of choice, as aspirin may increase thyroid hormone concentrations by interfering with protein binding of T4 and T3.

Perioperative management of the patient with pheochromocytoma Rarely is communication between surgeon, anesthesiologist, and internist more vital than in the preoperative preparation and perioperative management of the patient with a pheochromocytoma. In case series before 1961,

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surgical mortality ranged from 24–45% [42]. Introduction of alpha adrenoreceptor blockade in the 1950s, improved anesthetic drugs and management, and better localization techniques from the 1970s onward are the probable reasons for significantly improved surgical outcome [43]. With appropriate medical preparation and an experienced anesthesiologist and surgical team, survival of excision of a pheochromocytoma is 93.3–100% [44,45]. Pheochromocytoma is an uncommon neuroendocrine tumor of the chromaffin cell that is a cause of less than 0.2% of hypertension [46]. The most common sign of the tumor is hypertension, which can be paroxysmal. The tumor’s intermittent catecholamine surges can cause a variety of symptoms, including headache, chest pain, palpitations, diaphoresis, dyspnea, anxiety, and dizziness. Surgical excision can prevent the life-threatening complications of hypertensive crises, stroke, arrhythmias, and myocardial infarction. Preoperative preparation Catecholamine excess causes vasoconstriction that leads to both hypertension and hypovolemia. Pheochromocytoma patients can die intraoperatively from severe hypertensive crisis or hypotension that leads to cardiovascular collapse. When tumor veins are ligated during surgery, the sudden drop in circulating catecholamines can lead to vasodilatation. The catecholamine output of the contralateral adrenal may be suppressed from previous catecholamine excess. In the hypovolemic patient, this can lead to hypotension, shock, and death. Alpha adrenergic blockade has been the cornerstone of preoperative preparation in the past, as it treats both hypertension and vasoconstriction and improves circulating plasma volume prior to surgery. After alpha-blockers are initiated, beta-blockers are added if not contraindicated by heart failure or asthma to prevent the reflex tachycardia associated with nonselective alpha-receptor blockade. Beta-blockers may also prevent perioperative arrhythmias and cardiac complications. Beta blockade should not be given alone in a patient with pheochromocytoma, as it augments effects of catecholamines at the alpha adrenoreceptors, blocks beta receptor-mediated vasodilatation in skeletal muscle, and can cause higher blood pressure. Particular attention should be paid to preoperative evaluation of myocardial function. Not only can long-standing hypertension cause left ventricular hypertrophy and dysfunction, but chronic catecholamine excess can cause cardiomyopathy. The intraoperative hypotension that often occurs after excision of the tumor can be refractory in the patient with low cardiac output [47]. Regimens vary among centers, but usually alpha blockade for at least 10– 14 days prior to surgery is recommended. Normotension (140/90) is a preoperative goal, and one anesthesia review recommended no blood pressure greater than 160/90 in the 24 hours prior to surgery [54]. A recent retrospective case-series review showed a correlation that approached statistical sig-


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nificance between the level of preoperative hypertension and perioperative complications [45]. The long-acting, nonselective alpha blocker phenoxybenzamine has been the past drug of choice. Doses are initiated at 5– 10 mg by mouth b.i.d. and increased by 10 mg every few days to a dose of 0.5–1 mg/kg/day or until blood pressure is controlled. The average dose is 40–80 mg per day. It has significant side effects including somnolence, orthostasis, and stuffy nose. If phenoxybenzamine is not tolerated, the selective alpha 1 receptor blockers prazosin, doxazosin, or terazosin can be used. One study showed that doxazosin did not cause the prolonged duration of postoperative hypotension that can occur with phenoxybenzamine [48]. Some authors recommend metyrosine (alpha-methyl-p-tyrosine) at doses of 1–4 mg per day in addition to alpha blockade. It competitively inhibits tyrosine hydroxylase, the rate-limiting step in catecholamine biosynthesis. Patients who received it in combination with alpha blockade had better blood pressure control, as well as less need for intraoperative antihypertensives and pressors compared with patients who were on alpha blockade alone [49,50]. Propranolol, metoprolol, and atenolol have all been recommended for beta blockade. They should be begun several days after alpha blockade and at least a few days prior to surgery. Liberalization of salt in the diet along with alpha blockade should expand plasma volume. Though some centers admit patients preoperatively for blood pressure management, at least one retrospective study has documented the safety of outpatient preoperative preparation [51]. A few authors have argued that alpha adrenergic blockers are not necessary for safe surgery. Half of 60 patients at one institution underwent excision without preoperative alpha blockade. There were no strokes or myocardial infarctions, and there was only one postoperative death, which was caused by a pre-existing cerebral tumor [52]. As calcium ion transport is essential for release of catecholamines from chromaffin cells, calcium channel blockers are used for control of blood pressure and preoperative preparation at some centers. There are several case reports and a French study of pheochromocytoma patients treated with calcium channel blockers alone [48,53] prior to surgery. In another study of 113 patients, those who received preoperative alpha blockade had more perioperative cardiovascular complications and required more perioperative fluid than those receiving calcium channel blockers [54]. Studies have shown no difference in intraoperative hemodynamics and blood loss between open versus laparoscopic approaches, and patients leave the hospital sooner with laparoscopic surgery [55]. Splenic injury and splenectomy can be a complication in an open anterior abdominal approach [45]. The postoperative patient may remain hypertensive up to 2 weeks after excision. If hypertension persists, urinary catecholamines should be checked to ensure no additional tumor remains. If catecholamines are normal, the patient may be one of about 25% of pheochromocytoma patients whose

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hypertension persists after surgical excision caused by other concomitant disease, such as essential or renal hypertension [56]. Because norepinephrine and epinephrine contribute to insulin resistance, hypoglycemia may develop and persist into the postoperative period once the tumor is removed [57]. Glucose should be included in perioperative fluids, and blood sugars should be monitored frequently intraoperatively and postoperatively. Of course, those patients who undergo bilateral adrenalectomy for bilateral disease will need steroid replacement. Partial bilateral adrenalectomies are being done more frequently in patients with bilateral disease to prevent the need for lifelong replacement, but these patients need to be monitored closely for recurrent disease [58].

The patient on chronic glucocorticoids Surgery is a physiologic stress that activates the hypothalamic-pituitaryadrenal (HPA) axis and results in increased corticotropin (ACTH) and cortisol secretion. Exogenous glucocorticoids can suppress the HPA axis, and the patient on chronic glucocorticoids may not produce sufficient levels of ACTH and cortisol during and after surgery to meet physiologic needs. Adrenal insufficiency with hypotension and shock may occur. The evidence that this does in fact occur is mainly anecdotal. There are a few case studies, however, that show confirmed clinical and biochemical evidence of intraoperative adrenal insufficiency in patients who did not receive perioperative glucocorticoids after stopping them shortly before surgery [59]. To prevent this life-threatening complication, supplemental glucocorticoids (‘‘stress dose’’ steroids) are given perioperatively to those patients with documented or presumed HPA axis suppression. Two questions need to be answered by the provider caring for the patient on chronic glucocorticoids who is going to surgery: Is it likely that the patient’s dose and duration of glucocorticoid therapy has caused HPA suppression? If the patient is suppressed, what dose of supplemental glucocorticoids should be given? Suppression of the HPA axis There is wide variability in HPA suppression in patients on exogenous glucocorticoids that in general does not correlate well with age, sex, duration, or amount of dose. Nevertheless, it seems fairly clear from studies that oral glucocorticoids equivalent to less than 5 mg of prednisone in a single morning dose for any duration of time, alternate day short-acting glucocorticoids (cortisone, hydrocortisone, prednisone, prednisolone, or methylprednisolone) given in a morning dose, and any dose of glucocorticoids given for less than 3 weeks do not cause clinically significant suppression of the HPA axis [60– 62]. By contrast, any patient who has taken more than 20 mg of prednisone or its equivalent per day for more than 3 weeks or who is clinically cushingoid


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has probable suppression of the HPA axis [63]. HPA suppression in patients on intermediate regimens is much more variable and may depend on individual rates of drug metabolism and clearance [62,64]. Superpotent topical steroids at doses of 2 g per day have caused HPA axis suppression in patients [65,66]. HPA suppression can occur in patients treated with inhaled corticosteroids at doses of.0.8 mg/day or more of fluticasone propionate, though clinically significant adrenal insufficiency is rare [67,68]. The duration of functional HPA axis suppression after glucocorticoids have been stopped is debatable. Older studies showed delayed biochemical recovery on tests of pituitary and adrenal function up to 1 year after cessation of glucocorticoids [69,70], but the clinical importance of these test results is unclear. Because of these studies, however, most anesthesia and endocrine texts recommend perioperative supplemental glucocorticoids in patients who have had HPA axis suppressive doses of glucocorticoids within 1 year of surgery. Testing the HPA axis Patients who are on intermediate doses of glucocorticoids or who cannot give a good history of dose, duration, or tapering of therapy can undergo testing of the HPA axis if there is sufficient time to do so before surgery. Because the high dose (250 lg) ACTH stimulation test is supraphysiologic, response to it may mask a partially suppressed adrenal gland, and many now recommend the low dose (1 lm) ACTH stimulation test for assessment of the HPA axis [71]. Patients may have a normal response to surgical stress despite laboratory evidence of HPA suppression. In two studies, patients on chronic steroids were given their usual daily glucocorticoid dose but no glucocorticoid supplementation while hospitalized for surgery or medical illness. HPA suppression was evaluated with an ACTH stimulation test. No patient with an abnormal ACTH test developed clinical adrenal insufficiency [72,73]. The studies raise interesting questions, and some have used them to argue that supplemental glucocorticoids are unnecessary. The number of patients studied was small, however, and for now, the data are insufficient to discount the ACTH test or its results in surgical patients. Supplemental glucocorticoid regimens Because the status of the patient’s HPA axis is often uncertain, the decision to give perioperative supplemental glucocorticoids must weigh the risk of additional glucocorticoids in the perioperative period against the likelihood of adrenal insufficiency developing without them. Glucocorticoids have many side effects that can affect surgical outcome, including hypertension, fluid retention, psychiatric disturbance, increased risk of infection, gastrointestinal bleeding, impaired wound healing, and hyperglycemia. One

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way to mitigate the risks of additional glucocorticoids is to give the lowest protective dose for the shortest period of time necessary. Older regimens for glucocorticoid replacement included high doses of up to 300 mg of hydrocortisone per day for several days. A consensus paper [59] recommended that clinicians replace glucocorticoids only in amounts equivalent to the normal physiologic response to surgical stress, which in turn depends on the type and duration of surgery. ACTH and cortisol rise during induction of anesthesia, surgery, extubation, and recovery from anesthesia [74]. Up to 200–500 mg of cortisol can be secreted per day during severe stress but rates of more than 200 mg per day in the 24 hours after surgery are rare [59], Cortisol levels may average 50–75 mg per day for 1–2 days in a moderate stress surgery and 100–150 mg per day for 2–3 days for major stress surgery [75]. Table 3 makes specific recommendations on supplemental glucocorticoids based on likely HPA axis suppression and the anticipated stress of surgery. As the physiologic stress of local anesthesia or minor surgery is low, Table 3 Perioperative supplemental glucocorticoid regimens

No HPA axis suppression: 1. Less than 5 mg of prednisone or equivalent per day for any duration 2. Alternate-day single morning dose of short-acting glucocorticoid of any dose or duration 3. Any dose of glucocorticoid for less than 3 weeks Rx: Give usual daily glucocorticoid dose during perioperative period HPA axis suppression documented or presumed: 1. More than 20 mg of prednisone or equivalent per day for 3 weeks or more 2. Cushingoid appearance 3. Biochemical adrenal insufficiency on low-dose ACTH stimulation test 1. Minor procedures or local anesthesia Rx: Give usual glucocorticoid dose before surgery No supplementation 2. Moderate surgical stress Rx: 50 mg IV hydrocortisone prior to induction of anesthesia, 25 mg hydrocortisone every 8 hours thereafter for 24–48 hours, then resume usual dose 3. Major surgical stress Rx: 100 mg IV hydrocortisone prior to induction of anesthesia, 50 mg hydrocortisone every 8 hours for 48–72 hours, then resume usual dose HPA axis suppression uncertain: 1. 5–20 mg of prednisone or its equivalent for 3 weeks or more 2. 5 mg of greater of prednisone or its equivalent for 3 weeks or more in the year prior to surgery 1. Minor procedures or local anesthesia Rx: Give usual glucocorticoid dose before surgery No supplementation 2. Moderate or major surgical stress Check low-dose ACTH stimulation test to determine HPA axis suppression or Give supplemental glucocorticoids as if suppressed. Abbreviations: ACTH, adrenocorticotropic hormone; HPA, hypothalamic–pituitary–adrenal axis.


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patients need take only their usual daily glucocorticoid dose prior to these procedures. If a patient’s daily glucocorticoid dose is equivalent to the target cortisol levels of the surgery, no supplemental glucocorticoids are necessary. Though it is common to do so, it is not necessary to taper supplemental glucocorticoids over the duration of time they are given [59]. Topical and inhaled corticosteroids can suppress the HPA axis but rarely cause clinical adrenal insufficiency. These patients do not need supplemental glucocorticoids prior to surgery. Finally, it is important to remember that supplemental glucocorticoids may need to be resumed or continued at higher doses or for longer periods of time if the patient develops a significant postoperative complication such as infection or infarction. Summary Whenever possible, endocrine disorders should be identified and evaluated prior to surgery. A plan for perioperative management of diabetes should be based on the type of diabetes, what diabetes medications are taken, the status of diabetes control, and what type of surgery is planned. Perioperative management of diabetes must include bedside glucose monitoring. Patients with mild hypothyroidism can safely proceed with elective surgery. Elective surgery should be postponed for patients with moderate or severe hypothyroidism. Patients who have mild hyperthyroidism can undergo elective surgery with preoperative beta blockade. Elective surgery should not be done on patients with moderate or severe hyperthyroidism until they are euthyroid. Patients with pheochromocytoma need to be identified and properly treated before surgery to prevent perioperative cardiovascular complications. Patients who take endogenous steroids should have the status of their HPA axis determined prior to surgery. If the patient is undergoing moderate or major surgical stress and has documented or presumed HPA suppression, then stress doses of steroids should be give perioperatively. References [1] Harris MI, Flegal KM, Cowie CC, et al. Prevalence of diabetes, impaired fasting glucose, and impaired glucose tolerance in U.S. adults. Diabetes Care 1998;21:518–24. [2] Hirsch IB, McGill JB. Role of insulin in management of surgical patients with diabetes mellitus. Diabetes Care 1990;13:980–91. [3] Stagnaro-Green A. Perioperative glucose control: does it really matter? The Mount Sinai Journal of Medicine 1991;58:299–304. [4] Furnary AP, Zerr KJ, Grunkemeier GL. Continuous intravenous insulin infusion reduces the incidence of deep sternal wound infection in diabetic patients after cardiac sugical procedures. Ann Thorac Surg 1999;67:352–62. [5] Pomposelli JJ, Baxter JK, Babineau TJ, et al. Early postoperative glucose control predicts nosocomial infection rate in diabetic patients. Journal of Parenteral and Enteral Nutrition 1998;22:77–81.

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[6] Scherpereel PA, Tavernier B. Perioperative care of diabetic patients. Eur J Anaesthesiol 2001;18:277–94. [7] Hirsch IB, McGill JB, Cryer PE. Perioperative management of surgical patients with diabetes mellitus. Anesthesiology 1991;74:346–59. [8] Naito Y, Tamai S, Shingu K, et al. Responses of plasma adrenocorticotropic hormone, cortisol, and cytokines during and after upper abdominal surgery. Anesthesiology 1992; 77:426–31. [9] Gallacher SJ, Thomson G, Fraser WD, et al. Neutrophil bactericidal function in diabetes mellitus: evidence for association with blood glucose control. Diabet Med 1995;12:916–20. [10] DiPalo S, Ferrari G, Castoldi R, et al. Surgical septic complications in diabetic patients. Acta Diabetol Lat 1988;25:49–54. [11] Schiff RL, Emanuele MA. The surgical patient with diabetes mellitus: Guidelines for management. J Gen Intern Med 1995;10:154–61. [12] Pezzarossa A, Taddei F, Cimicchi MC. Perioperative management of diabetic subjects: subcutaneous versus intravenous insulin administration during glucose-potassium infusion. Diabetes Care 1988;11:52–8. [13] Thomas DJB, Hinds CJ, Rees GM. The management of insulin dependent diabetes during cardiopulmonary bypass and general surgery. Anaesthesia 1983;38:1047–52. [14] Golden SH, Peart-Vigilance C, Kao WHL. Perioperative glycemic control and the risk of infectious complications in a cohort of adults with diabetes. Diabetes Care 1999;22: 1408–14. [15] Van Den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in critically ill patients. N Engl J Med 2001;345:1359–67. [16] Strube PJ. Thyroid storm during beta-blockade. Anaesthesia 1984;39:343–6. [17] Goschke H, Bar E, Girard J, et al. Glucagon, insulin, cortisol, and growth hormone levels following major surgery: their relationship to glucose and free fatty acid elevations. Horm Metab Res 1978;10:465–70. [18] Abbott TR. Anaesthesia in untreated myxoedema. Br J Anaesth 1967;39:510–4. [19] Kim JM, Hackman L. Anesthesia for untreated hypothyroidism: report of three cases. Anesth Analg 1977;56(2):299–302. [20] Appoo JJ, Morin JF. Severe cerebral and cardiac dysfunction associated with thyroid decompensation after cardiac operations. J Thor Card Surg 1997;114(3):496. [21] Catz B, Russell S. Myxedema, shock and coma. Arch Intern Med 1961;108:407–17. [22] Holvey DN, Goodner CJ, Nicoloff JT, et al. Treatment of myxedema coma with intravenous thyroxine. Arch Intern Med 1964;113:89–95. [23] Weinberg AD, Brennan MD, Gorman CA. Outcome of anesthesia and surgery in hypothyroid patients. Arch Intern Med 1983;143(5):893–7. [24] Ladenson PW, Levin AA, Ridgway EC, et al. Complications of surgery in hypothyroid patients. Am J Med 1984;77(2):261–6. [25] Bennett-Guerrero E, Kramer DC, Schwinn DA. Effect of chronic and acute thyroid hormone reduction on perioperative outcome. Anesth Analg 1997;85(1):30–6. [26] Drucker DJ, Burrow GN. Cardiovascular surgery in the hypothyroid patient. Arch Intern Med 1985;145(9):1585–7. [27] Myerowitz PD, Kamienski RW, Swanson DK, et al. Diagnosis and management of the hypothyroid patient with chest pain. J Thorac Cardiovasc Surg 1983;86(1):57–60. [28] Forfar JC, Muir AL, Sawrers SA, et al. Abnormal left ventricular function in hyperthyroidism. N Engl J Med 1982;307:1165–70. [29] Klein I, Ojamaa K. Mechanisms of disease: thyroid hormone and the cardiovascular system. N Engl J Med 2001;344(7):501–9. [30] Sawin CT, Geller A, Wolf PA. Low serum thyrotropin concentration as a risk factor for atrial fibrillation in older patients. N Engl J Med 1994;331:1249–52. [31] Woeber KA. Thyrotoxicosis and the heart. N Engl J Med 1992;327:94–7. [32] McArthur JW, Rawson RW, Means JH, et al. Thyrotoxic crisis. JAMA 1947;132:868.


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Med Clin N Am 87 (2003) 193–210

Perioperative care of the patient with renal failure Anthony J. Joseph, MDa,*, Steven L. Cohn, MD, FACPb a

Division of Nephrology, State University of New York, Downstate Medical Center, 450 Clarkson Avenue, Box 52, Brooklyn, NY 11203, USA b Division of General Internal Medicine, State University of New York, Downstate Medical Center, 450 Clarkson Avenue, Box 68, Brooklyn, NY 11203, USA

Chronic kidney disease is increasingly prevalent in the United States [1]. The Third National Health and Nutrition Examination Survey from 1988 to 1994 estimated that 8 million individuals had moderate to severe chronic kidney disease characterized by a glomerular filtration rate (GFR) lower than 60 mL/min/1.73m2 [1]. According to the 2001 report of the U.S. Renal Data System (USRDS), moreover, the point prevalent count of patients with end-stage renal disease (ESRD) on December 31, 1999, was 328,695 [2]. As the number of Health Maintenance Organizations (HMOs) has escalated, general practitioners and internists have become the central or main physicians for many suffering from chronic kidney disease and ESRD. Additionally, surgeons, intensivists, and hospitalists care for people who undergo surgery—one of the most common therapeutic interventions associated with acute renal failure (ARF). For example, 27% of the 748 cases of ARF reported by Liano and Pascual were thought to originate in the postoperative period [3]. Because of the complexity and pervasiveness of renal failure, it is important that non-nephrologists be acquainted with perioperative care in those afflicted with this disorder. This article addresses the prevention of postoperative ARF as well as the perioperative care of ESRD patients undergoing surgery.

* Corresponding author. E-mail address: [email protected] (A.J. Joseph). 0025-7125/03/$ - see front matter 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 5 2 - 9

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A.J. Joseph, S.L. Cohn / Med Clin N Am 87 (2003) 193–210

Postoperative acute renal failure Epidemiology ARF is broadly defined as a sudden deterioration of renal function resulting in retention of nitrogenous wastes including urea and creatinine [4]. In many reports, the definition of ARF is based on serum creatinine which is a poor marker of renal function. The degree of creatinine elevation necessary to fulfill the diagnosis of ARF varies among authorities. For some researchers, ARF is present when there is a 25–50% increase in the serum concentration from baseline. Irrespective of a lack of consensus on the definition of ARF, two important facts should be remembered. Firstly, preexisting chronic kidney disease is a strong risk factor for the development of ARF [5–7]. Secondly, significant impairment of renal function, characterized by creatinine levels >1.5–3.0 mg/dL, introduces a serious risk that imposes a major threat to patients who have had surgery [8–10]. Chertow et al reported that acute renal failure requiring renal replacement therapy occurred in 1.1% of 42,773 individuals from 43 Veterans Affairs (VA) medical centers who had cardiac surgery [5] and 0.6% of 87,078 general surgery patients from the National VA Surgical Risk Study [11]. ARF is independently associated with early mortality following cardiac surgery, even after adjustment for comorbidity and postoperative complications. For example, the first aforementioned study also revealed that the 30day mortality for subjects with acute renal failure was 63.7% compared with 4.4% for those with normal renal function (P < 0.0001) [5]. Furthermore, in a recent report by Conlon et al. analyzing data from 2672 patients undergoing coronary artery bypass grafting (CABG), 211 (7.9%) individuals developed surgery-induced ARF. The mortality for patients who contracted ARF was 14% (odds ratio 15, P ¼ 0.0001) compared with 1% among those without ARF. In addition, mortality for CABG patients who received some form of dialysis was 28% (odds ratio 20, P ¼ 0.0001) as opposed to 1.8% among people who did not require renal replacement therapy [12]. Pathophysiology Usually, postoperative ARF is categorized as prerenal, intrinsic or renal, and postrenal. This classification may prove useful in determining the physiologic mechanism responsible for the GFR reduction or in establishing a differential diagnosis. Prerenal ARF results from diminished renal perfusion caused by volume depletion and/or hypotension. Intraoperative hormonal changes, secondary to stimulation of the sympathetic nervous system and renin-angiotensin-aldosterone axis, compromise GFR by inducing afferent arteriolar renal vasoconstriction. Simultaneously, angiotensin II modulates its own vasoconstrictive impact by stimulating renal release of prostaglandins. In the postoperative period, decreased glomerular perfusion may be caused by volume depletion, redistribution of extracelluar fluid or cardiac


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malfunction as in myocardial infarction, congestive heart failure, and tamponade [13,14]. As indicated by several reports, people with the renal or intrinsic type of ARF have diminished baseline GFR because of diabetes, hypertension, or vascular disease. Sustained hypotension and volume depletion, prolonged cardiopulmonary bypass or supra-aortic clamping time, sepsis, and nephrotoxin exposure (aminoglycosides, radiocontrast materials, myoglobin, hemoglobin) may precipitate acute renal failure [5–7,9,15–20]. Postrenal ARF occurs because of tubular obstruction exemplified by sulfonamide and acyclovir crystals or bladder dysfunction [21]. Pelvic or ureteral obstruction caused by blood clots, sloughed papillae, and retroperitoneal hematoma causes ARF only when bilateral or unilateral in a patient with a single functioning kidney. Clinical and laboratory evaluation The approach to patients with postoperative ARF necessitates a thorough history and chart review and a comprehensive physical examination in combination with key laboratory measurements such as complete blood count with leukocyte differential, metabolic panel, coagulation profile, microscopic urinalysis, and urine electrolytes. Focused history and record analysis provide important information about volume depletion, hypotension, cardiopulmonary bypass or supraaortic clamping time, arrhythmia, and exposure to endogenous (myoglobin, hemoglobin) and exogenous (drugs) nephrotoxins. A good physical examination yields valuable clues. Skin inspection for rash, purpura, livedo reticularis, gangrene, and digital cyanosis provides clues to raising the diagnosis of acute interstitial nephritis, renal artery, or atheromatous embolism. A thorough evaluation of the cardiovascular and volume status is the most important facet in the diagnosis and management of ARF, as prerenal azotemia is a correctable condition. Assessing daily fluid intake, output, and body weights is valuable when estimating volume status. Heart rate and blood pressure should be measured in the supine and seated with dangled legs positions whenever possible. Careful evaluation of heart and lungs is paramount. The care of severely ill people with sepsis, peripheral edema, third-spacing losses, or underlying heart disease may require insertion of a Swan-Ganz catheter to measure capillary wedge pressure, cardiac output, and systemic vascular resistance. Abdominal palpation may reveal upper quadrant tenderness secondary to ureteral obstruction or renal infarction, as well as a palpable bladder caused by a blocked bladder catheter or prostatic enlargement. Look for leg edema and muscle tenderness from rhabdomyolysis. Occasionally, patients manifest signs of uremic encephalopathy including confusion, stupor, coma, and seizures. Note that altered mental status is also one of the signs of systemic atheroembolism. Elevation of BUN and serum creatinine concentration is the hallmark of renal failure. In cases of prerenal azotemia and in some patients with

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obstructive uropathy, the serum BUN/creatinine ratio is elevated above 20:1 because of enhanced reabsorption of urea. Urinalysis (UA) is the most important test in the diagnostic work up of ARF. A normal UA is compatible with prerenal and postrenal azotemia, whereas the presence of many brown granular casts, renal tubular epithelial cells signals the possibility of ischemic or nephrotoxic ARF. A dipstick reading strongly positive for heme pigments in the absence of a significant number of red blood cells suggests rhabdomyolysis or intravascular hemolysis. Eosinophiluria discerned by Hansel’s stain associated with fever, rash, and peripheral eosinophilia are typical manifestations of acute interstitial nephritis [22]. The combination of eosinophiluria and ARF following an arteriographic procedure or in a patient with peripheral vascular disease evokes the diagnosis of atheroembolic renal disease. The fractional excretion of sodium (FENa), calculated from a random urine specimen, is a useful tool in this setting [23]. FENa (%) is defined as: {(Urine [Na] /Plasma [Na]) ‚ (Urine [Cr]/Plasma [Cr])} 100. An FENa < 1% favors the diagnosis of prerenal azotemia whereas, in acute tubular necrosis, it is usually >1%. There are exceptions, however. For example, some subjects with ARF secondary to severe burns or underlying liver disease have a FENa < 1%. Conversely, a patient with prerenal azotemia caused by administration of a loop diuretic may have a FENa > 1% [23]. The creatinine clearance can be quickly estimated by using the CockcroftGault equation [24]: For men: (140-age) lean body mass (kg) ¼ creatinine clearance in mL/min 72 serum creatinine (mg/dL) For women: 0.85 value for men For men, lean body mass (LBM) ¼ 106 lb for the first 60 inches, then 6 lb for each additional inch of height. For women, LBM ¼ 100 lb for the first 60 inches, then 5 lb for each additional inch of height. Severe renal dysfunction may exist in presence of a normal serum creatinine. Consider the case of an 85-year-old woman who weighs 48 kgs and has a serum creatinine of 1.3 mg/dL. The estimated creatinine clearance by the Cockroft-Gault formula is 24 mL/min, which is compatible with severe renal failure. Renal ultrasonography usually detects dilatation of the collecting system and ureters when obstructive uropathy causes ARF. Prevention of postoperative acute renal failure The high mortality rate of postoperative ARF, particularly after cardiac surgery, makes prevention a key objective in the overall management of this renal disease. Before surgical interventions, particularly those capable of inducing renal ischemia, one must identify potential risk factors such as volume depletion, hypotension, sepsis, nephrotoxin exposure, obstructive jaun-


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dice, and pre-existing chronic kidney disease. Elective surgery should be delayed until those abnormalities are improved. Correction of certain risk factors reduces the threat and ameliorates the consequences of this devastating complication, meaning postoperative ARF. Chertow et al have designed a preoperative renal risk stratification for subjects scheduled to have coronary artery bypass grafting. The goal is not to withhold or advise against required cardiac surgery, but to target high-risk patients for interventions [5]. Volume depletion and hypotension must be corrected promptly. If persistent, they can induce renal ischemia and tubular cell apoptosis with tubular obstruction of sloughed papillae [25]. Sepsis, by causing hypotension, direct renal vasoconstriction, and release of cytokines can provoke postoperative ARF [26]. Hospital-acquired infections should be prevented and treated whenever possible with non-nephrotoxic drugs [27,28]. Acute renal failure secondary to aminoglycoside nephrotoxicity occurs in 10–20% of patients given these drugs [18]. For most patients, it should not be difficult to avoid aminoglycosides. Nonsteroidal anti-inflammatory drugs (NSAIDs), including ketorolac, a parenteral compound, can cause hemodynamically-mediated ARF by inhibiting the synthesis of prostaglandins which act to preserve renal blood flow and GFR in subjects with volume depletion, pre-existing renal insufficiency, congestive heart failure, and liver cirrhosis [29,30]. Selective cyclooxygenase (COX)-2 inhibitors, like other NSAIDs, must be used cautiously or not at all in patients with predisposing diseases [31]. Because of their inhibitory effect on the efferent arterioles, angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockade (ARB) drugs may worsen ARF and should be withheld. Radiocontrast nephrotoxicity, perhaps caused by alterations in nitric oxide production and direct toxic effects of contrast agents, is another major cause of ARF [32,33]. Prevention, which is the best treatment for this type of kidney disease, includes avoidance of contrast media in at-risk subjects whenever possible, minimization of contrast load, and hydration before and after radiographic procedure [34,35]. A highly encouraging report indicates that pretreatment with N-acetylcysteine may protect against radiocontrastinduced nephropathy [36]. In the postoperative period, effort should be made to diagnose ARF early, eliminate causative agents, and prevent further insults. For example, we should be alert for tamponade caused by large pericardial effusion after cardiac surgery. Immune complex-mediated glomerulonephritis secondary to visceral abscesses subsides with drainage and appropriate antibiotherapy [27]. Early and aggressive hydration followed by mannitol and sodium bicarbonate infusion may minimize pigment-induced ARF, complicating major vascular surgery [37,38]. Obstructive uropathy can be easily treated by relieving the obstruction. Throughout the world, physicians including nephrologists have employed several pharmacologic maneuvers with the hope of preventing or improving

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ARF, precluding the need for dialysis, and reducing mortality. At this date, no hard data has proven their efficacy in humans, and some may even be harmful. Brown et al, in a controlled and randomized trial, showed that a high dose of furosemide (3 g) given intravenously or orally over 24 hrs prevented or reversed oliguria in 24 of 28 patients of the test group versus 2 of 27 of the control group, but the number of dialyses, duration of renal failure, and mortality were not different in the two groups. Moreover, deafness occurred in two individuals given furosemide and was permanent in one [39]. Many physicians believe that low-dose dopamine affects the outcome of ARF. Recently, Bellomo et al, in a multicenter, randomized, double-blind, placebo-controlled study of 328 patients admitted to 23 intensive care units, found that low-dose dopamine conferred no significant protection from renal dysfunction. There was no difference between the dopamine and placebo groups in peak serum creatinine concentration during treatment (245 versus 249 micromol/L; P ¼ 0.93), in the number of patients whose creatinine level exceeded 300 micromol/L (56 versus 56; P ¼ 0.92), or who required renal replacement therapy (35 versus 40; P ¼ 0.55) [40]. Another group of researchers, in a well-designed trial, concluded that dopamine and furosemide did not have any renoprotective effect during cardiac surgery. Their study suggested, furthermore, that furosemide caused renal dysfunction [41]. Improvement in renal function and histopathology in laboratory animals with renal failure, treated atrial natriuretic peptide (ANP), and prompted the study of anaritide, a synthetic form of ANP, in patients with ARF. The Auriculin Anaritide Acute Renal Failure Study Group conducted a multicenter, randomized, double-blind, placebo-controlled trial of anaritide in 504 critically ill patients with acute tubular necrosis. Study subjects received a 24-hour intravenous infusion of either anaritide or placebo. The primary end point was dialysis-free survival for 21 days after treatment. The rate of dialysis-free survival was not different in the two groups (43% in the anaritide group versus 47% in the placebo group, P ¼ 0.35). In a subgroup of 120 subjects with oliguria, dialysis-free survival was 27% in the anaritide group and 8% in the control group (P ¼ 0.008). Conversely, nonoliguric patients had inferior survival with anaritide, 48% versus 59% dialysis-free survival with placebo, P ¼ 0.03 [42]. A similarly designed trial, enrolling only patients with oliguric acute renal failure, failed to confer any advantage to anaritide [43]. At this time, ANP and its synthetic form, anaritide, are not employed in the management of acute renal failure. Beside conservative management of ARF complications, renal replacement therapy is widely utilized to manage patients with fluid overload, electrolyte abnormalities, particularly hyperkalemia, or acid-base perturbation. Because the mortality rates of ARF have remained elevated, several clinical trials have examined the role of membrane biocompatibility, timing, type, and adequacy of renal replacement therapy on clinical outcomes. At this


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writing, none of those dialysis-related variables have been securely linked to improved survival in people affected by ARF [44,45]. Frequently, the decision as to which membrane or technique for dialysis is selected depends on patients’ condition, costs, and local circumstances such as the availability of an on-site (in the ICU) skilled nurse for hemodialysis and/or a nephrologist familiar with continuous renal replacement therapy. Whether or not dialysis adequacy has an impact on survival of patients with postoperative ARF, erring in favor of too much dialysis is preferred. Perioperative care of ESRD patients According to the 2001 report of the U.S. renal data system, diabetes and hypertension in 1999 were listed as the chief causes of end-stage renal disease in North America, accounting for 68.2% of incident ESRD patients funded by Medicare [2]. Hypertensive and especially diabetic individuals suffering from ESRD have serious comorbid conditions such as myocardial dysfunction, coronary artery, and peripheral vascular diseases. Furthermore, the loss of renal reserve hampers their ability to handle fluids, sodium, and acid loads, eliminate potassium, and excrete and/or metabolize medications including antibiotics, analgesics, and anesthetics. Consequently, they may be unable to compensate for normal stresses of surgery. For instance, hyperkalemia resulting from blood products, muscle trauma, hemolysis, metabolic acidosis, and hematoma resorption occurs frequently after surgery. People with ESRD are immunosuppressed and more susceptible to infections. An imprecise number of uremic patients furthermore have bleeding diathesis secondary to platelet dysfunction. Therefore, it is not surprising that individuals with ESRD have an increased surgical morbidity and mortality whose rates vary according to the burden of associated ailments, and the type and emergent nature of the operation. Kellerman, analyzing data from eight studies, reported that the overall mortality of ESRD patients undergoing general surgery was approximately 4%, ranging from 0–47% in emergency cases [13]. The morbidity rate was 54%, varying from 12–64%. In another review involving 13 studies, the same author indicated mortality and morbidity rates were 10% and 46%, respectively, in patients undergoing cardiac surgery [13]. Clinical and laboratory evaluation Perioperative care of people with known ESRD begins with an in-depth interview, physical examination, electrocardiogram, and screening laboratory tests including a blood count, metabolic panel, serum magnesium, and phosphorus levels, as well as a coagulation profile. The initial goal is detect comorbid conditions that might adversely impact morbidity and mortality perioperatively. Typically, ESRD patients scheduled to have surgery may become symptomatic with coronary artery disease or myocardial dysfunction,

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fluid and electrolyte abnormalities, hypotension or uncontrolled hypertension, anemia, and a bleeding diathesis. Therefore, the main objective is to correct or improve those disorders before and/or after surgery. Prevention of infections, adjustment of medications, and glycemic control should also be a concern. Cardiac evaluation Cardiac disease is the leading cause of death in both diabetic and nondiabetic patients with ESRD. It accounts for almost 50% of deaths among prevalent ESRD patients whose cardiovascular mortality rates are approximately 10–20 times that of the general population [2,46]. Coronary artery disease (CAD), the key factor in the pathogenesis of cardiac disease, is common among ESRD patients, with a prevalence close to 40% [46]. Congestive heart failure, with a prevalence of 40% among hemodialysis and peritoneal dialysis patients, is an independent predictor of death [46]. Beside coronary artery disease, left ventricular hypertrophy whose prevalence is 75% also constitutes a risk factor for the development of CHF [46]. Clearly, cardiovascular disease can complicate perioperative care in individuals with renal failure. For the general population, clinicians integrate information from the history, physical examination, and electrocardiogram in order to develop an initial estimate of perioperative risks. In people affected by chronic renal disease, defining a cardiovascular risk profile based on clinical variables is difficult. Although many subjects with both kidney failure and coronary artery disease have a typical history of exertional dyspnea and angina or hypotension-induced chest pain during dialysis, 23–40% have silent ischemia documented by Holter monitoring on and off dialysis [47,48]. Several researchers found, furthermore, that approximately 75% of their diabetic patients with angiographically significant CAD were asymptomatic [49,50]. The inverse situation, namely angina without CAD, is also common. Rostand et al indicated that 47% of their patients complaining of angina had trivial or absent coronary artery occlusion [51]. Assessing functional capacity in ESRD patients is often impossible because of anemia or dialysis-induced weakness, diabetic neuropathy, claudication, or joint and bone pain secondary to renal osteodystrophy and amyloidosis. Also, clinical manifestations of CHF may be different in dialysis patients from those in other patient cohorts. Ultrafiltration, in very compliant subjects, minimizes fluid accumulation and negates the typical symptoms and signs of CHF. Intradialytic hypotension may be the only indication of left ventricular dysfunction [46]. These points should be kept in mind when evaluating ESRD patients. Because typical manifestations of cardiac disease may be lacking in ESRD patients, we have to turn to noninvasive tests such as echocardiography, thallium stress testing, dipyridamole thallium imaging, combined dipyridamole-exercise thallium scintigraphy, and dobutamine stress echo-


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cardiography. Echocardiography in 433 subjects at initiation of renal replacement therapy revealed that 15% had systolic dysfunction, 32% demonstrated left ventricular dilatation with preserved systolic function, and 74% displayed concentric left ventricular hypertrophy [52]. The practicability of exercise testing, even combined with thallium imaging, is limited because patients’ physical drawbacks or their inability to reach target heart rate. There are also concerns about difficulties in the interpretation of exercise electrocardiographic tracings in the presence of left ventricular hypertrophy (LVH). Additionally, though thallium stress imaging has a sensitivity of 90% for detection of CAD, its specificity is only 68% [53]. As an alternative to stress testing in ESRD patients, dipyridamole thallium imaging is hampered by widely varying sensitivities and specificities. In nonuremic subjects without diabetes, the sensitivity and specificity of myocardial perfusion imaging have been reported to be 79% and 76% [54]. For ESRD patients, sensitivity and specificity vary respectively from of 37% to 86% and from 73% to 79% [55]. Fortunately, a promising report indicates that the combination of dipyridamole and exercise thallium imaging may be more accurate in dialysis patients [56]. Dipyridamole-exercise thallium imaging and coronary angiography were both performed prospectively in 60 asymptomatic hemodialysis patients. The sensitivity, specificity, positive and negative predictive values, and overall accuracy of thallium imaging were 92, 89, 71, 98, and 90%, respectively. After a median follow-up of 2.8 years, the probability of surviving without a coronary event was significantly higher in patients with normal thallium image than in those with an abnormal test (adjusted risk ratio 9.2; P < 0.005) [56]. Dahan et al explain their findings by suggesting that dipyridamole is a less sensitive stimulus for detection of CAD than maximal exercise, but its use with submaximal exercise may be as accurate as maximal exercise alone. Dobutamine stress echocardiography (DSE) has been very valuable in finding CAD in renal transplant patients when the clinical event rate is used for test validation [57,58]. Conversely, DSE is an imperfect screening test when quantitative coronary angiography (QCA) is used to detect CAD. The sensitivity and specificity of DSE for CAD diagnosis were 52% and 74%, respectively, compared with QCA stenosis of 50% or greater; 75% and 71% compared with QCA stenosis >70%; and 75% and 76% for stenosis >75% by visual estimate [59]. The noninvasive detection of CAD in people affected by ESRD remains problematic. Coronary angiography, the gold standard for the diagnosis of CAD, is invasive and costly and cannot be used as a screening method. It should be reserved for people with a high risk of CAD and for those who would benefit from revascularization. For the general ESRD population, no published practice guidelines have been devised for perioperative cardiovascular evaluation for noncardiac surgery. De Lemos and Hillis, proposing a diagnostic management strategy for

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screening for renal transplantation, stratified their patients into groups with low, intermediate, and high risk [60]. Transplant candidates younger than 50 years, without diabetes or symptoms suggestive of CAD or CHF but with a normal EKG, had a low cardiovascular risk and did not require invasive cardiac evaluation. Individuals older than 50 years or diabetic without symptoms of CAD or CHF were at intermediate risk and should have noninvasive testing and subsequently coronary angiography if either dipyridamole thallium imaging or dobutamine echocardiography is positive. All high-risk patients, meaning those with symptoms of CAD, electrocardiographic evidence of previous myocardial infarction, or congestive heart failure should have cardiac catheterization before renal transplantation. This management strategy is derived from studies involving renal transplant candidates who are, in general, healthier than the rest of the ESRD population. Also, renal transplantation is an intermediate cardiac risk procedure. Although the ESRD patient may be able to tolerate the surgical procedure short-term, the long-term prognosis is equally important because of the limited availability of donor kidneys. In emergency cases, one has to weigh the benefits of the surgical procedure against the risk of a fatal or nonfatal cardiac event. Fluid and electrolyte management Whether or not dialysis has been initiated, euvolemia should be attained when ESRD patients are being prepared for surgery. For those individuals not on replacement therapy, a euvolemic state can be achieved with diuresis or hydration as appropriate. In other instances, euvolemia is securable with dialysis. Currently, there is no very good measure of adequacy for fluid removal in dialysis patients. In practice, notion of dry weight, the lowest weight tolerated without intradialytic symptoms or hypotension in the absence of overt fluid overload, is employed [61]. Subjects who have a stable dry weight with minimal fluid gain between treatments can undergo emergency surgery without dialytic therapy, provided there is no other indication for dialysis. Establishing the quantity of fluid to be removed is difficult when fluid overload is accompanied by muscle mass wasting or left ventricular dysfunction exists. Fluid overload is definitely an indication for preoperative dialysis. Cautious volume extraction is preferable to prevent unwanted bouts of intradialytic hypotension. Furthermore, excessive fluid loss may also worsen hypotension secondary to anesthesia-induced vasodilation. At times, ultrafiltration or dialysis must be offered postoperatively in patients receiving a large fluid volume during surgery. It is unusual to find major changes in serum sodium concentration in ESRD. Subjects receiving dialysis have an obvious and ready means for adjusting water surplus or deficit [62]. Hyperkalemia may occur before and after surgery. Dialysis is the treatment of choice in both instances when the serum potassium exceeds


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6 mEq/L. Medical treatment of hyperkalemia has to be initiated when surgery is emergent or dialysis is not readily available [62,63]. If the EKG shows signs of a dangerous arrhythmia, cardioprotection or membrane stabilization is accomplished by infusing 10 mL of calcium gluconate with ECG monitoring. Insulin is very effective in driving potassium into the cells of patients with renal failure by stimulating the activity of a Na-K-ATPase pump. Consequently, it increases the net movement of extracellular potassium into the intracellular fluid. Although glucose infusion induces endogenous insulin secretion, it is less effective in the management of hyperkalemia. Patients should be monitored carefully for hypoglycemia. b2-adrenergic agonists also shift potassium into the cells through Na-KATPase stimulation. Caution is warranted with b2-agonists because of the risk of tachycardia and arrhythmias which can be dangerous in patients with CAD or with the administration of anesthesia. Serum potassium reduction with sodium bicarbonate is negligible unless there is moderate or severe metabolic acidosis. b2-agonists, sodium bicarbonate, glucose, and insulin drive potassium from one milieu to another and correct hyperkalemia only temporarily. Removing a potassium surfeit is accomplished with sodium polystyrene sulfonate. Forty grams of the resin dissolved in 80 mL of sorbitol is a standard oral dose. Alternatively, 50–100 g in 200 mL of water is given as a retention enema. Oral or rectal dose of resin should be repeated every 2–4 hours. It is important to remember that the resin can cause intestinal necrosis, especially when it is given with sorbitol within the first week after surgery. Anemia and bleeding diathesis The ideal hemoglobin level for people with ESRD remains a controversial issue. The Anemia Work Group of the National Kidney FoundationKidney Disease Outcome Quality Initiative (NKF-K/DOQI) recommends that the hemoglobin level be maintained between 11 and 12 g/dL [64]. By consensus, transfusion is appropriate for people with hemoglobin levels of 8–10 g/dL when extensive surgery is contemplated or excessive blood loss is a possibility. For elective surgery, the target level of hemoglobin can be reached over weeks by increasing erythropoietin dose, adding intravenous iron if necessary, and by transfusion of packed red blood cells. Postoperative bleeding occurs for many reasons and a specific cause must be sought. Heparin-induced bleeding is unusual as the drug is withheld during dialysis on the day of surgery. During the postoperative period, dialysis patients undergo heparin-free dialysis for at least 24 hours. Uremic patients may have platelet dysfunction resulting in an increased bleeding tendency manifested by a prolonged bleeding time [65]. Individuals with a prior history of uremic bleeding must be treated before surgery. Dialysis, desmopressin (dDAVP, l-desamino-8-d-arginine vasopressin) administered intravenously or intranasally at a dose of 0.3 lg/kg, and cryoprecipitate are

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capable of stopping the bleeding [66]. Raising the hematocrit to 30% improves uremic bleeding [67]. Intravenous conjugated estrogens (0.6 mg/ kg) are an adequate alternative when they are given 4 or 5 days before surgery [68]. Hypotension and hypertension Hypotension or hypertension may afflict dialysis patients. Hypotension can be episodic and intradialytic or persistent [69]. The first type occurs in up to 20% of the dialysis population and is caused by several factors such as rapid or excessive fluid removal, left ventricular and autonomic dysfunction, low sodium concentrate, and intake of antihypertensive drugs before dialysis. Usually, the renal team corrects those abnormalities by adjusting the dry weight, increasing dialysate sodium concentration, and by employing steady ultrafiltration [69]. Treating anemia with erythropoietin, increasing the dialysate calcium concentration, and using cool temperature hemodialysis may improve cardiovascular performance in many dialysis patients [69]. Approximately, 5% of long-term patients suffer from persistent, chronic hypotension which limits fluid removal during hemodialysis. Midodrine, a selective alpha-1 adrenergic agonist, is useful in this condition [70]. During the postoperative period, hypotension may occur because hemorrhage, arrhythmia, pericardial tamponade, or sepsis. Appropriate treatment of the causative factor will improve hypotension. Fluid retention, augmented sympathoadrenal discharge, endothelin increase, and nitric oxide reduction likely represent the primary factors underlying the hypertension of renal failure [62,71]. Optimization of fluid status with dialysis and ultrafiltration lowers elevated blood pressure. Preoperative anxiety and withholding of antihypertensive drugs worsen hypertension. When fluid removal is not successful or dialysis cannot be performed immediately, labetalol, enalaprilat, or hydralazine can be administered intravenously. In the intensive care units, intravenous nitroprusside can be used for 1 or 2 days. Accumulation of thiocynate, a metabolite of nitroprusside, can occur and cause anorexia, disorientation, and toxic psychosis in ESRD patients. Drug therapy Adverse drug response occurs more frequently in uremic patients than in people with normal GFR [72]. Abnormalities of drug metabolism with renal failure consist of prolonged half-life of drugs and active metabolites excreted by the kidneys as well as changes in bioavailability, volume of distribution, and protein binding [73]. Adverse drug reactions can affect all organs including the failing kidneys. It is prudent to abstain from prescribing nephrotoxic drugs for subjects with renal failure. Some reports suggest that the presence of residual renal function is associated with a lower mortality risk in dialysis


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patients [74,75]. As a rule, before administering any drug to subjects with renal failure, one should determine if a dosage reduction is necessary or if a particular drug should be avoided. The American College of Physicians and the American Society of Internal Medicine published comprehensive guidelines for drug prescribing in renal failure. Medication dosing varies with the degree of renal failure, drug biotransformation, and type of renal replacement therapy [73]. Sedative premedication with benzodiazepines is advised only in reduced doses because chronic renal failure increases the free fraction of those preparations. For example, dialysis patients receiving alprazolam may develop psychomotor and memory abnormalities [76]. Meperidine, whose metabolite is normeperidine, can produce excitatory central nervous system effects including seizures and should be avoided [77]. Caution is warranted with morphine because its conjugation with glucuronic acid results in morphine-6-glucuronide which possesses opioid activity and is excreted by the kidney [78]. Fentanyl is metabolized in the liver, with only 7% excreted unchanged in the urine. It is moderately bound to plasma protein and its volume of distribution is large. Premedication with fentanyl is safe in ESRD [79]. Inhaled anesthetics proffer advantage over intravenous agents because they are eliminated primarily via the lungs and not the kidneys. Halothane, desflurane, and nitrous oxide can be administered to kidney failure patients [79]. Absence of significant change in protein binding and clinical effects of metabolites associated with hepatic metabolism make propofol a suitable agent for the induction of general anesthesia [80,81]. Succinylcholine, used without difficulty in people with renal failure, can cause hyperkalemia— particularly in traumatized, burned, or neurologically injured patients. Succinylcholine, in large doses, should be avoided as its metabolite, succinylmonocholine, is weakly active and excreted by the kidney [79]. Nondepolarizing muscle relaxants like atracurium are the blocking agents of choice for ESRD patients [79]. Antibiotic treatment is common during the perioperative period either for prophylaxis or treatment of infections. Some studies indicate that preoperative antibiotics reduce the risk of infections following vascular access procedures or peritoneal catheter placement [82,83]. The use of low-molecular-weight heparins remains controversial. Data concerning their pharmacokinetic and pharmacodynamic profiles in patients with renal failure are limited. It has been suggested that their doses be decreased by 50% when the GFR is lower than 10 mL/min [73]. Glycemic control Surgical stress and certain anesthetic agents stimulate the release of counter-regulatory hormones such as glucagon, growth hormone, cortisol, epinephrine, and norepinephrine, whose combined effect worsens insulin deficiency and resistance [84]. Consequently, hyperglycemia and even

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ketogenesis in type 1 diabetic patients may take place during or after surgery. Additionally, those receiving insulin or oral agents are at risk for hypoglycemia because of necessary preoperative fasting. The goal in managing diabetic uremic patients is to maintain plasma glucose levels between 150 and 200 mg/dL during surgery to protect against hypoglycemia [85]. After surgery, targeting blood glucose levels between 120 and 180 mg/dL reduces morbidity attributed to fluid and electrolyte imbalance, decreases the risk of infection, and perhaps accelerates the wound-healing rate [86]. In planning management, the type of diabetes and surgical procedure, the current therapeutic regimen, and degree of recent glycemic control are considered. Numerous protocols have been suggested for treating diabetic patients undergoing surgery. Generally, no intraoperative treatment is recommended for people treated with diet alone or diet and oral hypoglycemic agents if glycemic control is acceptable (80–200 mg/dL). Subjects receiving insulin or poorly controlled type 2 patients require insulin during the perioperative period. Preoperative insulin recommendations are complex. Key to proper management is reliance on frequent finger stick glucose measurements [85]. For early-morning procedures, insulin can be administered subcutaneously. Continuous insulin infusion is the most rational and physiologic approach for insulin-treated patients undergoing long, complex operative procedures or for people requiring surgery while in ketoacidosis [64,84– 87]. After outpatient surgery, a preoperative regimen can be reinstituted when patients resume eating. Diabetic control is difficult in those with gastroparesis or when surgical procedures interdict oral intake. Summary Preventing postoperative ARF, especially in subjects with pre-existing chronic kidney disease, and caring for ESRD patients undergoing surgery are challenging and best accomplished by a team comprised of primary care physician, nephrologist, cardiologist, surgeon, anesthesiologist, endocrinologist, and nutritionist. Elimination of risk factors for ARF whenever possible, as well as early diagnosis, may improve the outcome of this devastating illness. Drugs capable of preventing or changing the course of postoperative ARF may be available soon. For uremic patients, a comprehensive approach is necessary to minimize morbidity and mortality imposed by numerous comorbid conditions. References [1] NKF-K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, classification, and stratification. Am J Kidney Dis 2000;37(suppl 1):S1–S266. [2] United States Renal Data System. USRDS 2001 Annual data report: atlas of end-stage renal disease in the United States. Bethesda, MD: National Institute of Health, National Institute of Diabetes and Kidney Diseases; 2001.


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Med Clin N Am 87 (2003) 211–227

Surgery in the patient with liver disease Mohammed K. Rizvon, MBBSa,b,*, Calvin L. Chou, MD, PhDc,d a

Medical Consultation Service, Nassau University Medical Center, East Meadow, NY, USA b Department of Medicine, State University of New York at Stony Brook, Stony Brook, NY, USA c Department of Medicine, University of California, San Francisco, CA, USA d Medical Consultation Service, San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA

Patients with liver disease undergoing surgery face significant postoperative complications. The complex functions of the liver, perioperative stresses, and the unpredictable effects of medications and anesthesia in these patients make preoperative evaluation challenging. A preoperative risk assessment should take into consideration the type of liver disease, the degree of hepatic impairment, and the operative risks associated with the procedure. This article discusses the preoperative evaluation and perioperative management of patients with liver disease scheduled for nontransplant and noncardiac surgeries. Preoperative assessment Asymptomatic patients The preoperative evaluation of patients with liver disease begins with a careful history and physical examination. For many asymptomatic patients, this simple tool serves as a valuable screening test for patients with occult liver disease. Careful attention to history of prior surgeries, jaundice or blood transfusions, use of alcohol and other recreational drugs including use of intravenous drugs, sexual history, and a system review for liver disease including pruritus, easy fatigability, excessive bleeding after minor trauma, abdominal distention, and weight gain should be elicited. Physical * Corresponding author. Medical Consultation Service, Nassau University Medical Center, 2201 Hempstead Turnpike, East Meadow, NY 11554. E-mail address: [email protected] (M.K. Rizvon). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 5 3 - 0

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examination should focus on signs of liver disease, such as icterus, pallor, ascites, hepatomegaly, splenomegaly, testicular atrophy, palmar erythema, spider nevi, and gynecomastia. Any suspicion of liver disease should be investigated with blood testing for hepatic function, coagulation studies, electrolytes, and liver enzymes. Routine preoperative testing of liver function, however, is not recommended because of its questionable predictability and low prevalence [1]. In a series of 7620 elective surgical admissions, Schemel [2] found 11 patients with abnormal liver function tests. Elective surgery was canceled in all of these patients. Three patients developed clinical jaundice, but all 11 patients were subsequently found to have liver disease on further testing. Other studies reported significant liver disease on follow-up of asymptomatic patients with deranged liver tests [3,4]. In an older study [5], 12 of the 73 patients with postoperative liver dysfunction had unsuspected preoperative liver disease. Asymptomatic patients with significantly abnormal liver tests should have elective surgery postponed and investigated to reassess the perioperative risks. Acute and chronic hepatitis Most of the studies in acute hepatitis are old [6–9] and showed significant mortality following surgery in patients with liver disease (Table 1). It was common practice more than half a century ago to perform laparotomy for unexplained jaundice lasting more than 6 weeks [10]. A significant concern in these patients was the need to differentiate between medical and surgical causes of jaundice. Strauss et al [9] reported 13% mortality in 73 patients with subacute jaundice who underwent laparotomy for decompression of the common bile duct. Harville and Summerskill [8] reported a postoperative mortality of 10% in 42 patients who had laparotomy done for acute hepatitis. Some

Table 1 Risks of surgery in patients with hepatitis Investigators

Risk factors

Type of surgery

Mortality (%)

Strauss et al [9] Harville and Summerskill [8] Bourke et al [10] Greenwood et al [7]

Viral hepatitis Acute viral hepatitis

Biliary tract surgery Laparotomy

13 10

Hepatitis Alcoholic hepatitis

Laparotomy Open liver biopsy Percutaneous liver biopsy Major surgery

0 58 10

Giller et al [6] Powell-Jackson et al [11]

Alcoholic and viral hepatitis Viral hepatitis, alcoholic hepatitis, and chronic persistent hepatitis

Explorative laparotomy

42 100 in viral and alcoholic hepatitis, 43 in patients with chronic hepatitis


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studies reported higher mortalities. In one study [11] all patients with viral and alcoholic hepatitis died after exploratory laparotomy. Greenwood et al [7] reported a mortality of 58% following open liver biopsy and 10% after percutaneous liver biopsy in patients with acute alcoholic hepatitis. Bourke et al [10] reported no postlaparotomy deaths among 155 patients with various causes of jaundice, although only two of them had hepatitis. Fortunately, with the advent of more advanced laboratory testing and superior imaging techniques, many of these patients do not have to undergo major surgery. It is prudent to postpone elective surgeries during the acute phase of hepatitis and wait until transaminases have returned to the normal range. Patients with milder forms of chronic hepatitis (formerly chronic persistent hepatitis) tolerate surgery well. Runyon [12] reported operative mortality on 20 patients with chronic hepatitis. About two thirds of these patients had chronic active hepatitis, of which four had cirrhosis. There was no postoperative mortality or liver failure. In a recent study, patients with chronic hepatitis C who underwent laparoscopic cholecystectomy had no deaths or complications [13]. Alcoholic liver disease The complications of surgery in patients with alcoholic liver disease depend on the severity of liver pathology. Patients with fatty liver tolerate general surgery well, but patients with alcoholic hepatitis and cirrhosis have increased postoperative mortality and morbidity. In selected cases, preoperative liver biopsy is helpful in knowing both the liver pathology and the extent of steatosis. Elective surgery should be postponed in patients with acute alcoholic hepatitis until liver function tests have returned to normal. Patients with a history of alcohol abuse have increased postoperative complications, such as poor wound healing, infections, delirium, and bleeding. Patients should abstain from using alcohol to improve liver function or should be monitored carefully perioperatively for signs of alcohol withdrawal. Other problems in the perioperative period in these patients include drug interactions of alcohol with commonly administered agents, such as acetaminophen. Cirrhosis Patients with cirrhosis have altered hepatic blood flow [14] that worsens liver function and decreased metabolism of commonly administered drugs. Cirrhotic patients may have nutritional disorders; ascites; abnormal coagulation profile; renal dysfunction; and encephalopathy (or a significant risk of developing it) postoperatively. There are more data regarding postoperative complications in cirrhotics than in patients with other liver diseases (Table 2 [17,19,20,22–25,90,92–100]). Postoperative deaths and complications historically have been high, but better preoperative assessment and newer anesthetics and operative techniques show improving survival rates in these patients.

Biliary tract surgery Biliary tract

Various surgeries

Umbilical herniorrhaphy Abdominal surgery

Biliary tract Abdominal surgery

Colectomy

Trauma

Surgery for peptic ulcer disease (Billroth, total gastrectomy, suture, excision, total or partial vagotomies) Abdominal surgery Thoracotomy

Schwartz, 1981 [97] Aranha et al, 1982 [22]

Doberneck et al, 1983 [24]

Pescovitz, 1984 [96] Garrison et al, 1984 [17]

Cryer et al, 1985 [90] Aranha and Greenlee, 1986 [23]

Metcalf et al, 1987 [94]

Tinkoff et al, 1990 [98]

Lehnert and Herfarth, 1993 [93]

Jakab et al, 1993 [92] Ueda et al, 1994 [99]

Type of surgery

Investigators (publication year)

Table 2 Risks of non-laparoscopic surgery in patients with cirrhosis

21 0

54

30

15 83 if PT increased by 2.5 seconds 19.6 Emergency surgery: 45.8 13 Child’s A 10, B 31, C76 Emergency surgery: 57 21 67 Emergency surgery: 86 24

Mortality rate (%)

Child’s score, prothrombin time, and increased WBC Included Child’s C patients

Encephalopathy, ascites, hypoalbuminemia, decreased hemoglobin Ascites, elevated total bilirubin, prolonged PT, hx motor vehicle accident, multiple traumas, blunt abdominal trauma requiring laparotomy. Preoperative hemoglobin < 12g/dL, SBP < 100 mm Hg, prolonged PT, presence of portal hypertension. Unable to calculate Child’s score because of emergent nature of surgery.

Ascites, prolonged PT, low albumin < 3.5 mg/dL Ascites, prolonged PT, need for emergent surgery

Bilirubin > 3.5, alk phos > 70, increased PT > 2 s, increased PTT > 2s, emergency surgery, GI tract surgery, ascites, blood loss >IL, and postoperative complications 96 Total cases; emergent surgery associated with increased mortality Child class, increased bilirubin, decreased albumin, ascites, malnutrition, active infection, increased WBC, increased PT, increased PTT, need for emergency surgery

High bilirubin, blood transfusion, prolonged PT Increased PT > 2.5 s

Prognostic factors/comments

214 M.K. Rizvon, C.L. Chou / Med Clin N Am 87 (2003) 211–227

Abdominal surgeries

Abdominal surgeries

Trauma (emergent expl lap)

TURP

Mansour et al, 1997 [19]

Ziser et al, 1999 [20]

Wahlstrom et al, 2000 [100]

Nielsen et al, 2001 [95]

6.7

47

Child’s A 10 B 30, C 82 Emergency surgery: 50 11.6

28

Male sex; a high Child-Pugh score; ascites; a diagnosis of cirrhosis other than primary biliary cirrhosis (especially cryptogenic cirrhosis); elevated serum creatinine; COPD; infection; preoperative UGI bleeding; a high ASA severity status; a high surgical severity score; respiratory tract surgery; and the presence of intraoperative hypotension. 17 Patients; four times increased risk of mortality when compared with noncirrhotic control group. Advanced age, comorbidity, and acute admission

Encephalopathy, CHF, emergent surgery, infection, elevated total bilirubin, INR > 1.6, low albumin, elevated creatinine. Authors state that Child-Pugh classification was not a useful indicator, but all six patients in the study with Child’s class C cirrhosis died. Child’s class, emergent surgery, encephalopathy, ascites, and prolonged PT.

Adapted from Friedman LS, Maddrey WC. Surgery in the patient with liver disease. Med Clin North Am 1987;71:453–76; with permission [91]. Abbreviations: CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; GI, gastrointestional; INR, international normalized ratio; PT, prothrombin time; PTT, partial thromboplastin time; TURP, transurethral prostatic resection; UGI, upper gastrointestinal; WBC, white blood cell count.

Mixed (mostly abdominal but including CABG and orthopedic surgery

Rice et al, 1997 [25]

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Risks of surgery in patients with cirrhosis correlate well with the severity grading introduced by Child and Turcotte [15]. Five factors were found to be significant factors affecting mortality after portosystemic shunt surgery in patients with cirrhosis: (1) ascites, (2) albumin, (3) bilirubin, (4) encephalopathy, and (5) nutritional status. Three of the five prognostic factors (severity of ascites, nutritional status, and grade of encephalopathy), however, are subjective. In the absence of large prospective studies, Child’s classification [15] and the Child-Pugh [16] score are useful tools for preoperative assessment, which have been validated in a number of studies [17–20]. Two separate studies [17,19] done 13 years apart show that postoperative mortality is reproducibly linked to Child’s class: patients with class A cirrhosis have a postoperative mortality of 10%; patients with class B and C cirrhosis have mortality rates of 30% and 80%, respectively. Cirrhotic patients benefit from preoperative aggressive treatment of coagulopathy, ascites, and encephalopathy. Recent studies have shown the benefit of converting inoperable Child’s class C patients to Child’s B preoperatively with improved survival and no significant problems [21]. Coagulopathy is a common finding in patients with cirrhosis and needs to be corrected before surgery. Some studies have suggested a high mortality rate in patients with prolonged prothrombin time [17,22–24]. Cholestasis, malnutrition, and decreased hepatic synthesis of coagulation factors are some of the reasons for altered coagulation tests in these patients. Coagulopathy in these patients can be managed preoperatively with vitamin K administration; however, vitamin K does not correct the prothrombin time if there is decreased hepatic synthesis. In these cases, fresh frozen plasma infusions usually bring the prothrombin time to normal limits. Cryoprecipitate is helpful when vitamin K and fresh frozen plasma fail to reduce the prothrombin time to within three seconds of normal. Cirrhotic patients undergoing surgery may have encephalopathy preoperatively, or are at high risk of becoming encephalopathic in the postoperative period. In a retrospective study of 40 patients with chronic liver failure undergoing nonhepatic surgery, presence of encephalopathy was associated with a high risk of mortality (88%), even higher than emergent surgery (50%) [25]. Constipation, infection, upper gastrointestinal bleeding, uremia, alkalosis, and overuse of sedatives are known precipitating factors of encephalopathy. Prevention of encephalopathy by correction of electrolyte abnormalities, appropriate gastrointestinal prophylaxis, and restriction of sedatives in these patients is essential. Avoiding nephrotoxic agents, such as aminoglycoside antibiotics and nonsteroidal agents, is important in preventing renal dysfunction [26]. Ascites can affect postoperative course in a number of ways. It can cause respiratory compromise from poor lung expansion leading to atelectasis, hypoxia secondary to hepatopulmonary syndrome, and wound dehiscence [27]. Ascites should be managed aggressively preoperatively with diuretics and paracentesis. Ascitic fluid analysis is important to rule out spontaneous


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bacterial peritonitis, which is associated with a high postoperative mortality. Large-volume paracentesis can be done safely preoperatively with the simultaneous administration of albumin to minimize worsening of renal function. Intraoperative risks Patients with liver disease are particularly susceptible to anesthetic effects; unpredictable intraoperative hemodynamic factors; and deleterious effects of medications, especially sedatives and skeletal muscle relaxants. Administration of anesthesia by inhalational or spinal routes leads to decreased hepatic blood flow. Because the liver is endowed with dual blood supply, it is usually able to adapt to the altered blood flow. Experimental animal studies have shown that under conditions of stress, hepatic blood flow increases to compensate for reduced portal blood flow [28]. Patients with liver disease, especially cirrhotics, are unable to compensate adequately for this decrease in portal blood flow, which may result in postoperative hepatic dysfunction [14]. In addition to anesthetic agents, direct consequences of surgery, such as excessive bleeding, periods of hypotension, mechanical ventilation, application of positive end-expiratory pressure, and increased splanchnic resistance, can all cause decreased hepatic blood flow, leading to hepatic ischemia and postoperative liver dysfunction [29]. Hepatitis following administration of anesthetic agents has been well described in the literature. One of the most well-known complications, halothane-induced hepatitis, occurs rarely (1 in 35,000 exposures) [30]. Risk factors for complications following halothane administration are age over 60, obesity, multiple exposures to halothane, short intervals between exposures, bilirubin over 10 mg/dL, and prothrombin time longer than 20 seconds. Isoflurane rarely causes hepatitis and is the preferred agent in patients with liver disease. A number of factors can affect the metabolism of the drugs commonly used in the perioperative period. Hepatocellular dysfunction, cholestasis, altered drug binding caused by decreased serum albumin, and decreased blood flow can all delay metabolism of these drugs, prolonging their duration of action and formation of toxic metabolites. It is prudent to decrease the dose of narcotic analgesics, such as morphine and meperidine, by as much as 50% [31]. In addition, a decrease in pseudocholinesterases leads to enhanced activity and toxicity of neuromuscular blocking agents [30]. Specific conditions Improved outcomes in laparoscopic procedures There is increasing evidence to suggest that laparoscopic procedures, when compared with their open laparotomy counterparts, may decrease operative morbidity and mortality in patients with cirrhosis. Eight case

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series of laparoscopic cholecystectomy have been reported: seven studies reported no mortality in a total of 119 patients with cirrhosis who underwent laparoscopic cholecystectomies [21,32–38]. Three patients in one of these studies were originally classified as being Child’s class C (one of these died); all others were Child’s class A or B. One prospective study [39] examined cirrhotic patients undergoing open or laparoscopic cholecystectomy. Blood loss and wound infections were increased in patients undergoing the open procedure; however, no mortality in either group was reported. The immunologic function of cirrhotic patients postoperatively may partially explain these differences: when compared with patients having undergone open procedures, patients undergoing laparoscopic cholecystectomy exhibit increases in circulating CD3 and CD4 cells, and decreased circulating tumor necrosis factor-a and interleukin-1b [40]. In addition, four retrospective studies examining outcomes of laparoscopic cholecystectomy have compared patients with cirrhosis with healthy patients [41–44]. A comparable percentage of patients in both groups underwent conversion to open cholecystectomy. Patients with cirrhosis experienced a higher incidence of hemorrhage. Otherwise, morbidity and mortality in the groups were similar. Only one study included patients with Child’s class C cirrhosis, and one of these patients died [42]. Patients with cirrhosis also have an eightfold increased mortality risk when undergoing open appendectomy [45]. With laparoscopic appendectomy, however, they have significantly decreased wound infections, bleeding, hospital stay, and ratings of postoperative pain [46]. Hepatic resection Hepatectomy remains a therapeutic option in patients with hepatocellular carcinoma. Patients scheduled for hepatic resection, however, need specialized testing to assess the dynamic functions of the liver. Prognostic factors favoring lower morbidity and mortality in cirrhotic patients after hepatectomy include the following: Demographic factors Smaller (3.5 mm) was found in all the patients with acute acalculous cholecystitis. This study also showed the utility of serial ultrasound examinations in these patients in monitoring improvement or worsening thereby requiring surgical intervention. Many of these same findings associated with acalculous cholecystitis, however, are often found in critically ill patients not suspected of having acalculous cholecystitis [84]. Cholecystectomy in patients with acalculous cholecystitis is associated with high mortality and morbidity [85,86]. Patients benefit, however, from early surgical intervention. Surgical treatment within 48 hours of onset of symptoms is associated with 8% gallbladder wall perforation as opposed to 25% to 40% if surgery was done after 48 hours [87,88]. It is important that postoperative jaundice is evaluated methodically and treatment instituted early.

Summary Management of the surgical patient with liver disease begins with a careful preoperative assessment (Fig. 1). Any clues to liver disease on history and physical examination should be investigated to ascertain the cause of the clinical finding. More data on surgical patients with unexpected liver disease are

Fig. 1. Perioperative assessment of the patient with liver disease.

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now available [89]. Patients undergoing emergent surgery are at significant risk of developing liver dysfunction. Child’s class still correlates strongly to postoperative complications. Cornerstones of perioperative management in these patients are medical treatment of complications of chronic liver disease, such as ascites; coagulopathy; prevention of encephalopathy; and rapid treatment of dangerous postoperative complications, such as acute acalculous cholecystitis. Evolving knowledge of the effects of anesthesia, improving surgical techniques, and use of better diagnostic tests will help in the reduction of perioperative complications in these patients. References [1] Robbins JA, Mushlin AI. Preoperative evaluation of the healthy patient. Med Clin North Am 1979;63:1145–56. [2] Schemel WH. Unexpected hepatic dysfunction found by multiple laboratory screening. Anesth Analg 1976;55:810–2. [3] Hay JE, Czaja AJ, Rakela J, et al. The nature of unexplained chronic aminotransferase elevations of a mild to moderate degree in asymptomatic patients. Hepatology 1989;9: 193–7. [4] Hultcrantz R, Glaumann H, Lindberg G, et al. Liver investigation in 149 asymptomatic patients with moderately elevated activities of serum aminotransferases. Scand J Gastroenterol 1986;21:109–13. [5] Dykes MH, Walzer SG. Preoperative and postoperative hepatic dysfunction. Surg Gynecol Obstet 1967;124:747–51. [6] Giller S, Berliner S, Shoenfeld Y, et al. Surgery in patients with hepatitis. Med Interna 1981;19:211–5. [7] Greenwood SM, Leffler CT, Minkowitz S. The increased mortality rate of open liver biopsy in alcoholic hepatitis. Surg Gynecol Obstet 1972;134:600–4. [8] Harville DD, Summerskill WHJ. Surgery in acute hepatitis. JAMA 1963;184:257–61. [9] Strauss AA, Siegfried SF, Schwartz AH, et al. Decompression by drainage of the common bile duct in subacute and chronic jaundice: a report of 73 cases with hepatitis or concomitant biliary duct infection as cause. Am J Surg 1958;97:137–40. [10] Bourke JB, Cannon P, Ritchie HD. Laparotomy for jaundice. Lancet 1967;2:521–3. [11] Powell-Jackson P, Greenway B, Williams R. Adverse effects of exploratory laparotomy in patients with unsuspected liver disease. Br J Surg 1982;69:449–51. [12] Runyon BA. Surgical procedures are well tolerated by patients with asymptomatic chronic hepatitis. J Clin Gastroenterol 1986;8:542–4. [13] O’Sullivan MJ, Evoy D, O’Donnell C, et al. Gallstones and laparoscopic cholecystectomy in hepatitis C patients. Ir Med J 2001;94:114–7. [14] Crosti PF, Giovannelli CF, Bardi U, et al. Hepatic blood flow in cirrhosis. Lancet 1971;2:322. [15] Child CG, Turcotte JG. Surgery and portal hypertension. In: Child CG, editor. The liver and portal hypertension. Philadelphia: WB Saunders; 1964. p. 1–85. [16] Pugh RN, Murray-Lyon IM, Dawson JL, et al. Transection of the oesophagus for bleeding oesophageal varices. Br J Surg 1973;60:646. [17] Garrison RN, Cryer HM, Howard DA, et al. Clarification of risk factors for abdominal operations in patients with hepatic cirrhosis. Ann Surg 1984;199:648–55. [18] Isozaki H, Okajima K, Morita S, et al. Surgery for cholelithiasis in cirrhotic patients. Surg Today 1993;23:504–8. [19] Mansour A, Watson W, Shayani V, et al. Abdominal operations in patients with cirrhosis: still a major surgical challenge. Surgery 1997;122:730–5; discussion 735–6.

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[20] Ziser A, Plevak DJ, Wiesner RH, et al. Morbidity and mortality in cirrhotic patients undergoing anesthesia and surgery. Anesthesiology 1999;90:42–53. [21] D’Albuquerque LA, de Miranda MP, Genzini T, et al. Laparoscopic cholecystectomy in cirrhotic patients. Surg Laparosc Endosc 1995;5:272–6. [22] Aranha GV, Sontag SJ, Greenlee HB. Cholecystectomy in cirrhotic patients: a formidable operation. Am J Surg 1982;143:55–60. [23] Aranha G, Greenlee HB. Intra-abdominal surgery in patients with advanced cirrhosis. Arch Surg 1986;121:275–7. [24] Doberneck RC, Sterling Jr WA, Allison DC. Morbidity and mortality after operation in nonbleeding cirrhotic patients. Am J Surg 1983;146:306–9. [25] Rice HE, O’Keefe GE, Helton WS, et al. Morbid prognostic features in patients with chronic liver failure undergoing nonhepatic surgery. Arch Surg 1997;132:880–5. [26] Arroyo V, Gines P, Rimola A, et al. Renal function abnormalities, prostaglandins, and effects of nonsteroidal anti-inflammatory drugs in cirrhosis with ascites. An overview with emphasis on pathogenesis. Am J Med 1986;81:104–22. [27] Pavlidis TE, Galatianos IN, Papaziogas BT, et al. Complete dehiscence of the abdominal wound and incriminating factors. Eur J Surg 2001;167:351–4. [28] Hanson KM, Johnson PC. Local control of hepatic arterial and portal venous flow in the dog. Am J Physiol 1966;211:712–20. [29] Cooperman LH, Wollman H, Marsh ML. Anesthesia and the liver. Surg Clin North Am 1977;57:421–8. [30] Friedman LS. The risk of surgery in patients with liver disease. Hepatology 1999;29:1617–23. [31] Gholson CF, Provenza JM, Bacon BR. Hepatologic considerations in patients with parenchymal liver disease undergoing surgery. Am J Gastroenterol 1990;85:487–96. [32] Friel CM, Stack J, Forse RA, et al. Laparoscopic cholecystectomy in patients with hepatic cirrhosis: a five-year experience. J Gastrointest Surg 1999;3:286–91. [33] Gugenheim J, Casaccia M Jr, Mazza D, et al. Laparoscopic cholecystectomy in cirrhotic patients. HPB Surg 1996;10:79–82. [34] Lacy AM, Balaguer C, Andrade E, et al. Laparoscopic cholecystectomy in cirrhotic patients: indication or contraindication? Surg Endosc 1995;9:407–8. [35] Morino M, Cavuoti G, Miglietta C, et al. Laparoscopic cholecystectomy in cirrhosis: contraindication or privileged indication? Surg Laparosc Endosc Percutan Tech 2000;10: 360–3. [36] Saeki H, Korenaga D, Yamaga H, et al. A comparison of open and laparoscopic cholecystectomy for patients with cirrhosis. Surg Today 1997;27:411–3. [37] Sleeman D, Namias N, Levi D, et al. Laparoscopic cholecystectomy in cirrhotic patients. J Am Coll Surg 1998;187:400–3. [38] Yerdel MA, Tsuge H, Mimura H, et al. Laparoscopic cholecystectomy in cirrhotic patients: expanding indications. Surg Laparosc Endosc 1993;3:180–3. [39] Yerdel MA, Koksoy C, Aras N, et al. Laparoscopic versus open cholecystectomy in cirrhotic patients: a prospective study. Surg Laparosc Endosc 1997;7:483–6. [40] Lausten SB, Ibrahim TM, El-Sefi I, et al. Systemic and cell-mediated immune response after laparoscopic and open cholecystectomy in patients with chronic liver disease: a randomized, prospective study. Dig Surg 1999;16:471–7. [41] Angrisani L, Lorenzo M, Corcione F, et al. Gallstones in cirrhotics revisited by a laparoscopic view. J Laparoendosc Adv Surg Tech A 1997;7:213–20. [42] Clark JR, Wills VL, Hunt DR. Cirrhosis and laparoscopic cholecystectomy. Surg Laparosc Endosc Percutan Tech 2001;11:165–9. [43] Jan YY, Chen MF. Laparoscopic cholecystectomy in cirrhotic patients. Hepatogastroenterology 1997;44:1584–7. [44] Poggio JL, Rowland CM, Gores GJ, et al. A comparison of laparoscopic and open cholecystectomy in patients with compensated cirrhosis and symptomatic gallstone disease. Surgery 2000;127:405–11.


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[45] Poulsen LO, Thulstrup AM, Sorensen HT, et al. Appendicectomy and perioperative mortality in patients with liver cirrhosis. Br J Surg 2000;87:1664–5. [46] Tsugawa K, Koyanagi N, Hashizume M, et al. A comparison of an open and laparoscopic appendectomy for patients with liver cirrhosis. Surg Laparosc Endosc Percutan Tech 2001;11:189–94. [47] Shimada M, Rikimaru T, Sugimachi K, et al. The importance of hepatic resection for hepatocellular carcinoma originating from nonfibrotic liver. J Am Coll Surg 2000;191: 531–7. [48] Poon RT, Fan ST, Lo CM, et al. Improving survival results after resection of hepatocellular carcinoma: a prospective study of 377 patients over 10 years. Ann Surg 2001;234:63–70. [49] Wu CC, Yeh DC, Lin MC, et al. Improving operative safety for cirrhotic liver resection. Br J Surg 2001;88:210–5. [50] Nagasue N, Kohno H, Tachibana M, et al. Prognostic factors after hepatic resection for hepatocellular carcinoma associated with Child-Turcotte class B and C cirrhosis. Ann Surg 1999;229:84–90. [51] Takenaka K, Shimada M, Higashi H, et al. Liver resection for hepatocellular carcinoma in the elderly. Arch Surg 1994;129:846–50. [52] Ishikawa A, Fukao K, Tsuji K, et al. Trimethadione tolerance tests for the assessment of feasible size of hepatic resection in patients with hepatocellular carcinoma. J Gastroenterol Hepatol 1993;8:426–32. [53] Noguchi T, Imai T, Mizumoto R. Preoperative estimation of surgical risk of hepatectomy in cirrhotic patients. Hepatogastroenterology 1990;37:165–71. [54] Hemming AW, Gallinger S, Greig PD, et al. The hippurate ratio as an indicator of functional hepatic reserve for resection of hepatocellular carcinoma in cirrhotic patients. J Gastrointest Surg 2001;5:316–21. [55] Kato M, Sugawara Y, Orii R, et al. Lactate levels in cirrhotic patients undergoing liver resection. Hepatogastroenterology 2001;48:1106–9. [56] Orii R, Sugawara Y, Hayashida M, et al. Lactate is correlated with the indocyanine green elimination rate in liver resection for cirrhotic patients. Anesth Analg 2001;92: 1064–70. [57] Eguchi H, Umeshita K, Sakon M, et al. Presence of active hepatitis associated with liver cirrhosis is a risk factor for mortality caused by posthepatectomy liver failure. Dig Dis Sci 2000;45:1383–8. [58] Llovet JM, Fuster J, Bruix J. Intention-to-treat analysis of surgical treatment for early hepatocellular carcinoma: resection versus transplantation. Hepatology 1999;30: 1434–40. [59] Shirabe K, Shimada M, Gion T, et al. Postoperative liver failure after major hepatic resection for hepatocellular carcinoma in the modern era with special reference to remnant liver volume. J Am Coll Surg 1999;188:304–9. [60] Tanabe G, Sakamoto M, Akazawa K, et al. Intraoperative risk factors associated with hepatic resection. Br J Surg 1995;82:1262–5. [61] Kanematsu T, Furui J, Yanaga K, et al. A sixteen-year experience in performing hepatic resection in 303 patients with hepatocellular carcinoma: 1985–2000. Surgery 2002;131: S153–8. [62] Nagasue N. Liver resection for hepatocellular carcinoma: indications, techniques, complications, and prognostic factors. J Hepatobiliary Pancreat Surg 1998;5:7–13. [63] Didolkar MS, Fitzpatrick JL, Elias EG, et al. Risk factors before hepatectomy, hepatic function after hepatectomy, and computed tomographic changes as indicators of mortality from hepatic failure. Surg Gynecol Obstet 1989;169:17–26. [64] Midorikawa Y, Kubota K, Takayama T, et al. A comparative study of postoperative complications after hepatectomy in patients with and without chronic liver disease. Surgery 1999;126:484–91.

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Evaluation and management of anemia and bleeding disorders in surgical patients Barbara Armas-Loughran, MD, Rakhi Kalra, MD, Jeffrey L. Carson, MD* Division of General Internal Medicine, Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, 125 Patterson Street, Professional Building, 4th Floor, New Brunswick, NJ 08903, USA

Anemia is commonly encountered and blood transfusion is frequently administered in the perioperative setting. The goals in the evaluation of an anemic patient are to determine the cause of anemia, assess its physiologic impact during surgery, and determine the need for its correction. Clinicians also commonly encounter patients at risk of bleeding. This article reviews the preoperative evaluation of anemia, physiologic consequences of anemia, and observational and clinical trial studies evaluating the efficacy of transfusion, and provides recommendations on the use of transfusion in the perioperative period. Also described is the approach to patients at risk for bleeding.

Anemia and red blood cell transfusion The preoperative evaluation of the anemic patient The basic work-up of an anemic patient includes a detailed history and physical, complete blood count with indices, a reticulocyte count, peripheral smear, and stool guaiac. With this information, a differential diagnosis is quickly established and further testing can be done to determine the specific etiology. The history should focus on symptoms of bleeding, such as melena, hematochezia, hematemesis, hematuria, or significant blood loss during menses. Questions should be asked regarding a past medical history of anemia; need for blood transfusions; dietary habits; medications; and a history of * Corresponding author. E-mail address: [email protected] (J.L. Carson). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 5 4 - 2

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hematologic, liver, renal, or endocrine disorders. Family histories of anemia, splenectomy, or early onset cholelithiasis place congenital hemolytic disorders higher in the differential diagnosis. The physical examination should focus on the skin for jaundice, mucous membranes for pallor, and examination for hepatosplenomegaly. Stool and urine should be checked for occult blood loss. Once an acute bleed has been ruled out, the reticulocyte count and mean corpuscular volume are the most helpful indices in determining the cause of anemia. A hemolysis work-up is often indicated in patients with an increased reticulocyte count. This includes direct and indirect Coombs’ tests, lactate dehydrogenase, indirect and direct bilirubin, and haptoglobin levels. Iron deficiency and thalassemia are the most common causes of microcytic anemias. Ferritin, serum iron, and total iron-binding capacity should be ordered in these patients. Further work-up involves hemoglobin electrophoresis to determine hemoglobin A2 (in thalassemia minor) and a bone marrow biopsy to evaluate iron stores. Normocytic anemias are most commonly seen in neoplastic, chronic inflammatory, or infectious conditions. Work-up includes the aforementioned iron studies and an assessment of liver and renal function. Questions should also be asked regarding a history of medications or radiation that could lead to marrow suppression. Macrocytic anemias require an initial measure of vitamin B12 and folate levels. Further assessment might include thyroid function tests, liver function tests, and a bone marrow biopsy. Physiologic changes associated with anemia It is helpful to understand some of the important physiologic consequences of anemia when making decisions regarding the need for its correction. Physiologic changes in the anemic patient aim to preserve tissue oxygenation in the setting of decreased oxygen-carrying capacity. One adaptation to anemia is an increased production of 2,3-diphosphoglycerate, which causes a shift to the right in the oxyhemoglobin dissociation curve [1–3], increasing the oxygen delivered to the tissues at a given PO2. Anemia also affects cardiac output. Many well-controlled studies have demonstrated an inverse relationship between hemoglobin levels and cardiac output [4–6]. There are conflicting data, however, concerning the hemoglobin level at which this occurs. Studies have shown a threshold hemoglobin level for this inverse relationship that varies from 7 to 12 g/dL [4]. In the setting of normal cardiac function, increased cardiac output is thought to be mediated by increased sympathetic activity and decreased blood viscosity. As a result, myocardial contractility and venomotor tone are augmented, and left ventricular preload and afterload are increased and decreased, respectively [7]. The body’s cardiovascular and systemic response to acute blood loss is mediated by both the amount and rapidity of blood loss, and patient characteristics. The latter include age, comorbid illnesses, pre-existing volume

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status, hemoglobin values, and the use of medications that have cardiovascular or peripheral vascular effects. Laboratory studies that investigated the effect of normovolemic anemia on the coronary circulation have shown that, in the setting of a normal coronary circulation, there are few consequences with hemoglobin levels as low as 7 g/dL [8–10]. Evidence pertaining to transfusion in the perioperative setting Transfusion practices vary widely in the perioperative setting. Red blood cell transfusions are given to increase oxygen-carrying capacity. Two observational studies of orthopedic patients undergoing total hip and knee arthroplasty confirmed this variability [11,12]. Differences in transfusion practices have been attributed to several factors including lack of established transfusion guidelines [13], differences in the availability of autologous units for transfusions, and training differences between hospitals [14]. Risks and benefits must be weighed when making decisions and counseling patients regarding blood transfusions. Knowledge of the level of anemia at which blood transfusions prevent adverse outcomes is integral to the decision-making process. Studies in patients who declined blood transfusion provide important insights into the risk of anemia. In the largest consecutive series of patients who declined blood transfusion, the risk of postoperative mortality or morbidity rose as the preoperative hemoglobin fell below 10 g/dL and was substantially higher in patients with cardiovascular disease compared with patients without cardiovascular disease [15]. The risk was extremely high when the preoperative [15] and postoperative hemoglobin fell below 5 to 6 g/dL [16]. Two large observational studies evaluated the effect of anemia or transfusion practices in the perioperative setting [17,18]. The largest study involved a cohort of 8787 consecutive hip fracture patients who underwent surgical repair and who had postoperative hemoglobin levels less than 10 g/dL [17]. In this study hemoglobin levels as low as 8 g/dL did not seem to affect 30- or 90-day mortality, suggesting that this level might be safe in orthopedic surgery patients. Another study looked at 2202 patients undergoing coronary artery bypass graft surgery [18]. In this study patients were divided into three groups based on their hematocrit level when they entered the intensive care unit. The groups were designated as high (hematocrit 34%), medium (hematocrit 25% to 33%), or low (hematocrit 50 70–99

0.6 3.3 0.9

1.5 1.1 2.9

4 2.2 3.7

Clinical trials— asymptomatic patients ACAS CASANOVA

825 171

>60 50–90

0.4 1.2

1.9a 2.7

— 0.3

Clinical series—multisite Brook McCrory

1302 1160

Any Any

3 1.4

6.6a 3.4a

— —

NASCET VA Cooperative ECST

Stroke— minor (%)

MI (%) 0.9 2 NR

NR 0 1.7 2.1

a Reported combined major and minor stroke rate. Adapted from Arron MA, Lefevre F, Chadha V, Cohn SL. Perioperative medical evaluation and care of the patient undergoing neurosurgery. In: Batjer H, Loftus P, editors. Textbook of neurosurgery, Batjer edition. New York, NY: Williams & Wilkins; in press; with permission.

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with EKGs and serum troponin-I is often warranted for patients at high risk of ischemia, for those with perioperative hemodynamic instability, and for patients with postoperative symptoms consistent with ischemia. Although mild postoperative fluctuations in blood pressure are typically transient and benign, sustained systolic blood pressure above 180 to 220 mm Hg or diastolic blood pressure above 110 mm Hg has been associated with stroke and transient ischemic attack following CEA [16]. Given the consequences of marked postoperative hypertension, arterial pressure should be controlled before surgery, because preoperative blood pressure control predicts postoperative control. The hyperperfusion syndrome develops in a subset of patients, usually those who have had a long-standing, high-grade stenosis [15]. It is typically characterized by a severe, unilateral headache that improves with upright posture, and is thought to be precipitated by a sudden increase in blood flow to a chronically hypoperfused region of the brain. Although the syndrome is usually self-limited, cerebral edema, increased intracranial pressure, seizures, and hemorrhage may develop. Confirmation of the clinical impression of hyperperfusion can be sought by transcranial Doppler examination. Strict perioperative control of blood pressure is important for both the prevention and treatment of cerebral hyperperfusion. SAH and aneurysm Nontraumatic SAH is usually caused by the abrupt rupture of an intracranial aneurysm. Patients must be assessed quickly for aneurysm location and size, medically stabilized before aneurysm clipping, and closely managed postoperatively. The medical consultant can be most helpful regarding perioperative blood pressure control, the assessment and treatment of cardiac instability, and the management of hyponatremia and other fluid and electrolyte disorders. The treatment of hypertension requires immediate attention. Elevated postoperative blood pressure should first be addressed by providing adequate analgesia, oxygenation, ventilation, sedation, and laxatives. Blood pressure before clipping should be maintained within 5% to 10% of the patient’s premorbid values. If the patient’s prior blood pressure is not known, many experts recommend that systolic blood pressure should be kept below 150, diastolic blood pressure below 90 mm Hg diastolic, or a mean arterial pressure below 110 mm Hg [17]. Cardiac dysfunction following SAH includes dysrhythmias, heart failure, and ischemia. Large clinical series indicate that 50% to 100% of patients experience at least one ECG abnormality during the acute stage of SAH [18]. They can include peaked P waves, Q waves, increased QRS voltage, ST segment elevation or depression, peaked or inverted T waves, prolonged QT interval, large U waves, and rhythm disturbances [18]. EKG abnormalities, however, are usually transient and do not usually represent clinically significant cardiac dysfunction. Given the

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reduced specificity of electrocardiography following SAH, other diagnostic modalities must be used to detect cardiac dysfunction accurately. The troponin-I can be used in conjunction with ECG to help determine whether echocardiography or other testing is needed. Echocardiographically proved left ventricular dysfunction provides more definitive evidence of cardiac dysfunction following SAH. Echocardiography may reveal regional wall motion abnormalities caused by ischemia or global left ventricular dysfunction. In the setting of SAH, global dysfunction may be caused by previous left ventricular dysfunction, or may be the result of increased catecholamine production leading to diffuse myocardial damage [19], a condition also termed myocytolysis. The clinical significance of this finding is unclear. Spinal surgery Spinal surgery is most commonly performed on the cervical or lumbar regions. The most common indications for cervical spine surgery are spondylosis (42%); herniated disk (28%); trauma (17%); ossification of the posterior longitudinal ligament (5%); rheumatoid arthritis (4%); and tumor (4%) [20]. Mortality for cervical spinal surgery is low. Recent clinical series have reported a perioperative death rate of 0.8% in 4589 patients undergoing any cervical spine surgery [20] and a mortality rate of 0.13% among 10,416 patients undergoing routine cervical diskectomy [21]. Local injury to spinal nerves, nerve roots, or peripheral nerves occurs at a rate of 0.2% to 0.6% [21]. Factors influencing perioperative risk are the complexity and difficulty of the planned procedure, the duration of anesthesia, and the expected perioperative blood loss. Most lumbar operations are performed for intervertebral disk disease, spondylosis, spondylolisthesis, and vertebral fractures. Mortality following lumbar surgery is low, with recent series reporting mortality rates of less than 1% [22]. In general, most patients can undergo spinal surgery with acceptably low morbidity and mortality, but particular concern should be given to the elderly patient with multiple medical illnesses who is scheduled to undergo a prolonged and complex procedure. For patients undergoing prolonged operations or procedures that are expected to have a large amount of blood loss, volume status should be optimized preoperatively and monitored closely. Frequent electrolyte measurements may be warranted. Syndrome of inappropriate antidiuretic hormone (SIADH) secretion may develop in up to 5% of patients following spinal surgery [23], and is more common in patients undergoing spinal fusion, patients with large spinal deformities, and following operations with greater than usual blood loss. Medical evaluation before surgery for brain tumors Despite advances in chemotherapy and radiation therapy, surgery remains the preferred form of treatment for most primary brain tumors. The primary


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risk following surgery is for local neurologic complications, but these patients are also susceptible to a wide range of medical complications either caused by the surgery itself or as a result of impaired neurologic status. A significant number of patients undergoing surgery for brain tumors have intracranial hypertension preoperatively or postoperatively, and the medical consultant should be familiar with the treatments and complications of increased intracranial pressure. A variety of therapies are efficacious. Elevating the head above the level of the chest and limiting flexion or rotation of the neck facilitate venous outflow and reduce intracranial pressure [24]. Medications that reduce brain volume, such as corticosteroids, osmotic agents, and loop diuretics, are also effective. Reducing the arterial concentration of carbon dioxide and inducing an alkalosis through hyperventilation have important roles in treatment. Effective control of seizures is also of paramount importance [25]. Patients with increased intracranial pressure likely receive high doses of systemic corticosteroids preoperatively. This raises several important issues related to the potential for adrenal suppression and other complications of high-dose corticosteroid therapy. Patients undergoing craniotomy who have postoperative neurologic deficits are at a higher risk for aspiration and nosocomial pneumonia. In addition to cognitive status, the lack of an effective cough, dysphonia, and the lack of a gag reflex have been shown to be predictive of aspiration [26]. Aggressive aspiration precautions, lung expansion measures, and close attention to respiratory status are warranted in this situation.

Common issues in perioperative management DVT prophylaxis Patients with neurologic disease are at increased risk of developing DVT, largely because of the venous stasis induced by immobility. Patients undergoing neurosurgery may be at additional risk because of a secondary hypercoagulable state. The highest incidence has been reported in patients with stroke, spinal cord injury, and brain tumors, with respective rates for DVT of 42%, 42%, and 30% [27]. Multiple risk factors for DVT often coexist in these patients. In addition to the neurologic condition, other risk factors, such as advanced age, prolonged immobility, leg weakness, or a secondary hypercoagulability state, may be present. Mechanical methods seem to be effective in preventing DVT in the neurosurgical population and are often used as the sole method of prophylaxis. A recent review using pooled data from randomized trials estimated the risk reduction to be 60% for elastic stockings and 66% for intermittent pneumatic compression, as compared with 73% for low-dose unfractionated heparin (LDUH) [28]. Mechanical agents are not recommended, however, as single agents for patients with acute stroke or spinal cord injury. Anticoagulation with LDUH or low-molecular-weight heparin (LMWH) is indicated

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for patients with acute stroke or spinal cord injury, and LMWH is probably more efficacious in these settings. Anticoagulants remain controversial, however, for general prophylaxis of neurosurgical patients. Although the efficacy of these agents in reducing DVT has been well established in clinical trials, the risk of increased bleeding complications is less well defined. Some studies have reported no difference in central nervous system bleeding, whereas others have reported increased central nervous system bleeds with LMWH [28]. These clinical trials have not been powered to assess this uncommon, but potentially catastrophic, outcome accurately. It is difficult to assess accurately the risk-benefit ratio, and many surgeons continue to prefer mechanical means of prophylaxis. The recommendations for DVT prophylaxis in patients with neurologic disease [28,29] are to use LMWH for patients with acute ischemic stroke or spinal cord injury. For neurosurgery patients, prophylaxis with intermittent pneumatic compression, intermittent pneumatic compression plus elastic stockings, LDUH, or LMWH is acceptable. Combination therapy with mechanical and pharmacologic methods may be more effective than either alone, but are accompanied by the potential risk of anticoagulation. In general, prophylaxis should be started preoperatively and continued until the patient is ambulatory. Hypertension For patients with neurologic disease, blood pressure control is often of paramount importance. Guidelines for blood pressure control in the general surgical patient, however, are not generally applicable to the patient with neurologic disease. Patients with neurologic impairment may have areas of relative hypoperfusion and impaired cerebral autoregulation of blood flow. This makes them both more vulnerable to cerebral hypoperfusion and more likely to suffer serious consequences if it occurs. When autoregulation is impaired cerebral perfusion is dependent largely on the systemic perfusion pressure, and the maintenance of blood pressure in the optimal range may have a direct bearing on the adequacy of cerebral perfusion. As a result, more aggressive management of blood pressure is warranted, and often targeted to a specific desired range. Intravenous medications are usually used for their efficacy, rapidity of action, ease of titration, and because most patients hospitalized with neurologic disease are not able to take medications orally. There are a variety of available intravenous agents (Table 2). The choice of specific agent may depend on the disorder being treated, comorbidities, and individual preferences. The goals of blood pressure control may vary depending on the specific condition being treated and the local practice patterns. The premorbid blood pressure, if known, and the blood pressure on presentation can be used as guides for target blood pressure. For example, in the setting of an acute ischemic stroke, the target blood pressure in the first 24 hours should be a reduction of 20% to 25%


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Table 2 Intravenous antihypertensive drugs for postoperative neurosurgery patients Agent

Continuous infusion

Bolus

Dosage

Nitroprusside

Yes

No

Nicardipine

Yes

Yes

Initial: 0.5 lg/kg/min Infusion: 0.25–0.50 g/kg/min Bolus: 1–2 mg Infusion: 5–7 mg/h (gradual) 10–15 mg/h (more rapid) Loading dose: 500 lg/kg/min over 1 min Infusion: 50 lg/kg/min over 4 min Titrate: loading dose with increase of 50 lg/kg/min up to 200 lg/kg/min Immediate control: bolus of 1 mg/kg followed by 150 lg/kg/min 1.25 to 5 mg IV Q 6 h Bolus: 20 mg IV or approx 0.25 mg/kg Titration: 40–80 mg every 10 min up to a cumulative dose of 300 mg 5–10 mg IV Q 20 min 5–100 g/min

Esmolol

Yes

Yes

Enalapril Labetalol

No Yes

Yes Yes

Hydralazine Nitroglycerin

No Yes

Yes No

Onset of action

Titratable

Very rapid

Yes

Rapid

Yes

Rapid

Yes

Variable Rapid

No Yes

Rapid Very rapid

No Yes

Adapted from Arron MA, Lefevre F, Chadha V, Cohn SL. Perioperative medical evaluation and care of the patient undergoing neurosurgery. In: Batjer H, Loftus P, editors. Textbook of neurosurgery, Batjer edition. New York, NY: Williams & Wilkins; in press; with permission.

from the presenting pressure to preserve cerebral perfusion. In contrast, for a SAH the blood pressure should be reduced more aggressively, generally to a systolic blood pressure less than 150. Patients with a previous history of hypertension who are being evaluated for neurosurgery should be assessed for the presence of cardiac and other vascular disease. Elective operations are usually postponed if the preoperative diastolic blood pressure is greater than or equal to 110 mm Hg [24], but as previously noted, a lower threshold may be appropriate for patients undergoing neurosurgery, as it is for patients with underlying heart disease. This is particularly true for operations, such as CEA and craniotomy for brain tumors. Postoperative delirium Delirium is a confusional state that is characterized by an acute alteration in attention and cognition. It is relatively common in the postoperative setting, and more common in patients with neurologic disorders. Delirium can often go unrecognized, especially in the postoperative period when

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differences in attention may be thought to be related to anesthesia, pain, or pain medications [30]. Because delirium is associated with an increase in perioperative morbidity and mortality, prompt recognition and management may improve outcomes. In addition to the neurologic procedure and its potential complications, such as intracranial hemorrhage and cerebral edema, several other medical problems may precipitate or exacerbate delirium. Medications (especially anesthetics, analgesics, and psychoactive agents) and infections are probably the most common causes of mental status changes in hospitalized patients [31]. Metabolic derangements, such as hypoxemia, hypercarbia, hyperglycemia, and hyponatremia, are also frequent causes of postoperative delirium. Cardiac ischemia and pulmonary embolism may present in the postoperative period primarily as mental status changes. Patients with pre-existing dementia are particularly prone to postoperative mental status changes and may develop delirium as a result of alterations in sensory and environmental stimuli. In the preoperative evaluation, certain factors have been found to be predictors of postoperative delirium [31,32]. These include prior history of delirium, age greater than 70, pre-existing cognitive or functional impairment, abuse of alcohol or narcotics, and abnormal laboratory studies. Preoperative recommendations in those patients at risk may include delaying surgery until detoxification has been accomplished, providing treatment for underlying medical issues, and re-evaluating blood tests at a later time. The origin of delirium is often multifactorial and cannot be attributed to one definite cause. Potential complications related to the surgical procedure should be pursued actively and potentially serious cardiac or pulmonary disorders should be investigated. Metabolic and hemodynamic factors should be assessed carefully and any detected abnormalities corrected. Signs of infection should be sought diligently and treated appropriately. Any nonessential psychotropic drugs should be withheld. The role of sensory deprivation and other contributing aspects of the physical environment should be considered and modified whenever possible. Hyponatremia Hyponatremia is a common medical problem in patients with central nervous system injury. Although the SIADH secretion classically is associated with neurologic disease, cerebral salt wasting (CSW) also makes up a large number of cases of hyponatremia in this setting and may be unfamiliar to the medical consultant. Other less common medical causes of hyponatremia, such as adrenal insufficiency and hypothyroidism, are important to consider because they require specific treatment. A variety of medications, most prominent of which are the diuretics, can reduce serum sodium levels. Fluid overload states, such as cirrhosis, heart failure, and nephrotic syndrome, can cause secondary hyponatremia. Pseudohyponatremia from


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hyperglycemia, hypertriglyceridemia, and paraproteinemias should be considered. The major distinction that often must be made is between SIADH secretion and CSW. This distinction is important because the treatment for SIADH is fluid restriction, whereas the appropriate therapy for CSW is hydration and sodium replacement. CSW is defined as the renal loss of sodium induced by intracranial disease leading to hyponatremia and volume depletion. The serum and urine osmolalities and electrolytes may be similar in the two disorders, but volume status and the response to fluid and salt replacement differentiate CSW and SIADH. Hypovolemia may be recognized by significant weight loss, a negative fluid balance, or by physical and laboratory evidence of volume contraction. For example, orthostatic hypotension, hypokalemia, and prerenal azotemia are seen with CSW, but are virtually never seen in SIADH [33]. This clinical picture is more compatible with CSW than SIADH. Table 3 gives a summary of the features of each of these two syndromes.

Summary Patients with neurologic disease who require surgery present distinct issues and challenges for the medical consultant. Although it is not possible to offer a unified approach to neurologic patients, the primary care consultant should understand the clinical issues that are common to these patients, and the individual considerations necessitated by the nature of the neurologic disorder and the clinical characteristics of the patient. The preoperative evaluation combines elements of literature evidence on risk assessment with Table 3 Differentiating features of the CSW Syndrome and the SIADH secretion

Plasma volume Salt balance Signs or symptoms of dehydration Weight Pulmonary capillary wedge pressure Central venous pressure Hematocrit Osmolality BUN/Cr ratio Serum protein concentration Urine sodium concentration Serum potassium concentration Serum uric acid concentration

CSW

SIADH

fl Negative Present fl fl fl › › or normal › › ›› › or no change Normal

› Variable Absent › or no change › or normal › or normal fl or no change fl Normal Normal › fl or no change fl

Adapted from Arron MA, Lefevre F, Chadha V, Cohn SL. Perioperative medical evaluation and care of the patient undergoing neurosurgery. In: Batjer H, Loftus P, editors. Textbook of neurosurgery, Batjer edition. New York, NY: Williams & Wilkins; in press; with permission.

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a thorough understanding of the planned procedure and local practice patterns, and clinical judgment as to the estimated risk-benefit ratio. Perioperative management necessitates attention to many general principles of perioperative care, such as awareness of the potential for cardiopulmonary complications and the need for DVT prophylaxis. In addition, there are management issues for neurologic patients, such as blood pressure control and evaluation of hyponatremia, which may differ from other surgical patients. In these circumstances, the interaction of the neurologic condition with the medical condition and the implications of treatment on the underlying neurologic process also need to be considered. References [1] Landercasper J, Merz BJ, Cogbill TH, et al. Perioperative stroke risk in 173 consecutive patient with a past history of stroke. Arch Surg 1990;125:986–9. [2] Kam PCA, Calcroft RM. Peri-operative stroke in general surgery patients. Anaesthesia 1997;52:879–83. [3] Wong DHW. Perioperative stroke. Part I: General surgery, carotid artery disease, and carotid endarterectomy. Can J Anaesth 1991;38:347–73. [4] Sauve JS, Laupacis A, Ostbye T, et al. Does this patient have a clinically important carotid bruit? JAMA 1993;270:2843–5. [5] Biller J, Feinberg WM, Castaldo JE, et al. AHA Scientific Statement: guidelines for carotid endarterectomy. Circulation 1998;97:501–9. [6] Adams R, Victor M. Principles of neurology. 5th edition. New York: McGraw-Hill; 1993. p. 353–64. [7] Rudick RA, Cohen JA, Weinstock-Guttman B, et al. Management of multiple sclerosis. N Engl J Med 1997;337:1604–11. [8] Jones RM, Healy TEJ. Anaesthesia and demyelinating disease. Anaesthesia 1980;35: 879–84. [9] Goldman D, Brown F, Guarnieri D. Perioperative medicine. 2nd edition. New York: McGraw-Hill; 1994. p. 351–9. [10] Mattos MA, Modi JR, Mansour MA, et al. Evolution of carotid endarterectomy in two community hospitals: Springfield revisited – seventeen years and 2243 operations later. J Vasc Surg 1995;21:719–28. [11] European Carotid Surgery Trialists’ Collaborative Group. MRC European carotid surgery trial: interim results for symptomatic patients with severe (70–99%) or with mild (0–29%) carotid stenosis. Lancet 1991;337:1235–43. [12] Mayberg MR, Wilson SE, Yatsu F, et al. Carotid endarterectomy and prevention of cerebral ischemia in symptomatic carotid stenosis. JAMA 1991;266:3289–94. [13] North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991;325:445–53. [14] Brook RH, Park RE, Chassin MR, et al. Carotid endarterectomy for elderly patients: predicting complications. Ann Intern Med 1990;113:747–53. [15] Casanova Study Group. Carotid surgery versus medical therapy in asymptomatic carotid stenosis. Stroke 1991;22:1229–35. [16] Wong JH, Findlay JM, Suarez-Almazor ME. Hemodynamic instability after carotid endarterectomy: risk factors and associations with operative complications. Neurosurgery 1997;41:35–43. [17] Miller J, Diringer M. Management of aneurysmal subarachnoid hemorrhage. Neurol Clin 1995;133:451–78.


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[18] Mayer SA, LiMandri G, Sherman D, et al. Electrocardiographic markers of abnormal LV wall motion in acute SAH. J Neurosurg 1995;83:889–96. [19] Pollick C, Cujec B, Parker S, et al. Left ventricular wall motion abnormalities in subarachnoid hemorrhage: an echocardiographic study. J Am Coll Cardiol 1988;12:600–5. [20] Zeidman SM, Ducker TB, Raycroft J. Trends and complications in cervical spine surgery: 1989–1993. J Spinal Disord 1997;10:523–6. [21] Romano PS, Campa DR, Rainwater JA. Elective cervical discectomy in California: postoperative in-hospital complications and their risk factors. Spine 1997;22:2677–92. [22] Young HF. Complications of spinal surgery and trauma. In: Greenfield LJ, editor. Complications in surgery and trauma. 2nd edition. Philadelphia: JB Lippincott; 1990. p. 713–22. [23] Brown CA, Eismont FR. Complications in spinal fusion. Orthop Clin N Am 1998;29: 679–99. [24] Shapiro HM, Drummond JC. Neurosurgical anesthesia. In: Cucchiarra RF, Miller ED, Reves JG, et al, editors. Anesthesia. 4th edition. New York: Churchill Livingstone; 1994. p. 1897–946. [25] Thapar K, Rutka JT, Laws ER. Brain edema, increased intracranial pressure, vascular effects and other epiphenomena of human brain tumors. In: Kaye AH, Laws ER, editors. Brain tumors: an encyclopedic approach. Edinburgh: Churchill Livingstone; 1995. p. 163–89. [26] Arron MA, McDermott MM, Dolan N, et al. Management of medical complications associated with stroke. Heart Dis Stroke 1994;3:103–9. [27] Hamilton MG, Hull RD, Pineo GF. Venous thromboembolism in neurosurgery and neurology: a review. Neurosurgery 1994;34:280–96. [28] Geerts WH, Heit JA, Clagett CP, et al. Prevention of venous thromboembolism. Chest 2001;119(Suppl):1325–1755. [29] Clagett GP, Anderson FA, Geerts W, et al. Prevention of venous thromboembolism. Chest 1998;114:531S–60S. [30] Litaker D, Locala J, Franco K, et al. Preoperative risk factors for postoperative delirium. Gen Hosp Psychiatry 2001;23:84–9. [31] Francis J, Strong S, Martin D, et al. Delirium in elderly general medical patients; common but often unrecognized. Clin Res 1998;36:711A. [32] Marcantonio ER, Goldman L, Mangione CM, et al. A clinical prediction rule for delirium after elective noncardiac surgery. JAMA 1994;271:134–9. [33] Harrigan MR. Cerebral salt wasting: a review. Neurosurgery 1996;38:152–60. [34] Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). American College of Cardiology Web site. 2002. Available at: www.acc.org/ clinical/guidelines/perioi/update/periupdate_index.htm. Accessed June 10, 2002. [35] Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid stenosis. JAMA 1995;273:1421–8. [36] DeWeese JA, Rob CG, Satran R, et al. Surgical treatment for occlusive disease of the carotid artery. Ann Surg 1968;168:85–94.

Med Clin N Am 87 (2003) 273–289

Perioperative care for the elderly patient Margaret M. Beliveau, MDa,*, Mark Multach, MDb a

Division of General Internal Medicine, Mayo Clinic, 200 First Street, South West, Rochester, MN 55905, USA b Division of General Internal Medicine, University of Miami School of Medicine, P.O. Box 016760 (M-841), Miami, FL 33101, USA

In 1927, as a young Professor of Surgery at Tulane Medical School, I taught and practiced that an elective operation for inguinal hernia in a patient older than 50 years was not justified. Alton Ochsner, MD

The perioperative management of the elderly has undergone major changes over the past eight decades. This has become increasingly the case with the dramatic shift in the population toward the elderly with the aging of the baby boom of the 1950s. The age group 65 years and older is the fastest growing segment in the United States, expected to comprise 20% of the population by 2025. Changes are increasingly apparent as the population ages and older patients are considered for surgery with greater frequency. In England, for example, surgical admissions for the elderly now outnumber nonsurgical admissions. One half of individuals over the age of 65 will undergo major surgery during their lifetime, with most procedures in patients in their sixth decade and beyond. The diseases for which surgery is performed, the surgical procedures performed, and the goals of the intervention also are changing with the aging of the surgical population. There is a pronounced shift from minor surgical procedures, trauma surgery, and surgery for nonmalignant disease to surgery for ocular, orthopedic, coronary artery, peripheral vascular, and neoplastic (especially pulmonary, colorectal, and genitourinary) diseases. Despite the rapidly increasing need for surgery in the elderly, a scarcity of literature exists studying the perioperative care of the elderly. Perioperative care becomes more complicated with age. The initial presentation of a surgical problem is more likely to be of greater severity. In the extreme, the presentation requires emergent surgery more frequently in the elderly (eg, * Corresponding author. E-mail address: beliveaufi[email protected] (M.M. Beliveau). 0025-7125/03/$ - see front matter Ó 2003, Elsevier Science (USA). All rights reserved. PII: S 0 0 2 5 - 7 1 2 5 ( 0 2 ) 0 0 1 5 5 - 4

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it is much more common to see intestinal obstruction as the surgical justification for surgery in colorectal cancer in the elderly compared with a younger population). Disease at presentation is more advanced, whether malignant (cervical or colorectal cancer); vascular (coronary artery or peripheral artery disease); or other (degenerative disease of the spine). As a result of these and other factors, the goal of the surgery is more often palliative than curative. Elderly patients for surgery are more likely to have surgery canceled for comorbid conditions after admission than a younger cohort. Hospitalizations for surgery are prolonged on average in the aged, independent of the presence of comorbid conditions. Evaluating the perioperative risk of these patients is very important. The study of perioperative assessment and care of the elderly patient has lagged behind the science of perioperative management in general. Much of the art of perioperative care in the elderly is extrapolated from literature on younger populations. The literature in perioperative care is primarily descriptive as opposed to outcome derived. The individual patient conditions’ contribution to surgical risk is related to a combination of physiologic changes associated with underlying diseases, combined to a lesser degree with age-related physiologic changes. Research over the past several decades has clarified perioperative risk factors, showing that age by itself is at most a minor risk factor for perioperative complication [1,2]. As one author has noted, ‘‘Increased risk, when present, is attributable to both normal aging, because of decreased physiologic reserve, and pre-existing disease or pathologic changes not uniformly seen in all geriatric patients.’’ The impact of age on surgical risk comes through a physiologic decrease in vital organ function, leading to a decreased ability to respond to perioperative stress. Functional status changes associated with aging seem to be more important risk factors in the elderly. Demographics Surgery is performed more frequently in the elderly (136 procedures per 100,000 aged 40 to 64 years and 190 per 100,000 over 65). One third of all surgeries in the United States are performed in patients 65 years and older. Age is less of a risk factor than several age-associated changes, including increased prevalence of chronic diseases; increased need for emergent surgery (eg, patients over the age of 65 are more than twice as likely to present for emergent surgery as younger patients, 37% versus 17%); and overall alterations in functional status in major organs. All of these factors combined lead to a sicker population presenting for surgery (eg, approximately 80% of patients over the age of 89 present with American Society of Anesthesiology class III) as evidenced by the identical mortality rates by American Society of Anesthesiology score independent of age (Table 1).


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Table 1 Age versus physical status % Mortality Age

I

II

III

IV

V

1–30 31–50 51–70 >70

6 2 1 0

8 11 8 5

22 25 29 25

28 37 39 45

36 25 23 25

Finally, the incidence of chronic diseases and disabilities is increased in the elderly. On average, a patient over the age of 74 has three disabilities or diseases. In patients over the age of 65, 20% present with no problems and 30% have more than three problems. Complicating this is the increased difficulty in the recognition of diseases in the elderly. One example is the assessment of cardiac disease that is complicated by the increased presence of silent ischemia, underreporting of symptoms, and decreased physical activity, among many factors obscuring the diagnosis. The physician must have heightened awareness of atypical presentations of disease (typical angina less commonly, atypical presentations become more common). Cardiovascular functional assessment is made more difficult as patients decrease activity. Even in nursing home–bound, inactive patients, however, risk in selected populations can be relatively low (2.3%). The pattern of atypical presentations is seen in many illnesses, both cardiac and those involving other organ systems.

Impact of age-related physiologic and anatomic changes Age-related changes lead to altered organ function. Although allowing normal day-to-day functioning, the impact of changes leads to decreased functional reserve of the individual. The individual’s response to stress is compromised. Several changes are of critical importance when discussing perioperative risk: cardiac, pulmonary, renal, and changes leading to altered pharmacology and pharmacokinetics. Cardiac The heart undergoes many changes. There is no inevitable decrement in rest cardiac function, in the absence of coexisting heart disease. However, cardiac output, in response to stressors is blunted. In part this is caused by a decreased responsiveness to catecholamines. Older patients have increased ectopy in the absence of cardiac dysfunction. Accompanying these physiologic changes are anatomic ones. There is an increase in ventricular mass (left ventricular hypertrophy); increased fibrosis within the myocardium and conduction system; and calcification of the

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aortic and mitral valve skeletons. Clinically this is manifested as congestive heart failure from diastolic dysfunction. The hypertrophied myocardium responds to decreased filling with decreased exercise tolerance; cough (especially dependent); dyspnea; and fatigue. Late in the process, the obliteration of the left ventricular cavity, with low filling volumes, may lead to symptoms of low cardiac output. Pulmonary The changes in the respiratory system include changes in the chest wall, respiratory musculature, and the lung parenchyma. The thorax becomes stiffer with age, increasing the work of breathing and decreasing lung volumes. The strength and endurance of the musculature decrease with age. Parenchymal changes include decreased ciliary function and number and interstitial stiffening. The clinical effect of these changes is a gradual decrease in PO2, increased dead space, and decreased expiratory volume and flow rate. The net result is an overall decline in pulmonary function. More important is the narrowing of the gap between tidal volume and closing volume, leading to increased risk of postoperative respiratory complications. Renal Renal changes include a decrease in numbers of functional units, and decreased functional status of the units (decreased blood flow and decreased glomerular filtration). These changes are primarily manifested in response to rapid volume changes rather than as baseline dysfunction. In fact, the traditional methods of estimating renal function (serum creatinine and creatinine clearance) typically overestimate actual values because of the decreased muscle mass. In the elderly, a more accurate estimate of renal function comes from the Crockroft-Gault equation (females, multiply by 0.85): ð140-ageÞ weightðkgÞ 72 serum creatinine Nutritional An increasingly important factor is nutritional status. Several studies have documented the negative effect of poor nutritional status on surgical outcome and complications. Other studies have documented an associated decrease in perioperative complications (although not in overall outcome) in patients undergoing oncologic procedures given nutritional supplementation for at least 1 week preoperatively. Laboratory abnormalities The prevalence of abnormal test results varies according to the test. Abnormalities of common laboratory tests occur in 0.5% to 15% in an


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asymptomatic, low-risk geriatric population. As in younger populations, the abnormalities found in this manner (asymptomatic polychemistry profile testing) do not correlate with a higher morbidity or mortality. Altered pharmacokinetics Changes occur in both the uptake and metabolic handling of drugs, which lead to an increased incidence of complications and toxicity. Included are changes in altered gastrointestinal motility and blood flow; renal function; decreased hepatic function and blood flow; decrease in serum drugbinding proteins; and altered volume of distribution (caused by decreased lean body mass and reciprocal increase in total body fat). Finally, as noted in cardiac changes, there may an altered receptor response to drugs.

Predicting and preventing postoperative complications Delirium Delirium is a clinical syndrome in which there is an acute disruption of attention and cognition. Up to 20% of elderly surgical patients experience delirium as a postoperative complication. Orthopedic surgery patients, especially those with hip fracture, may have an incidence of delirium of 28% to 60% [3,4]. The development of postoperative delirium has been associated with increased morbidity and mortality. Marcantonio et al [3] found that the development of delirium was associated with increased risk of major complications (myocardial infarction, pulmonary edema, pneumonia, respiratory failure, and so forth). In their study (as in many others) delirium was associated with an increased risk of death, increased length of stay, and an increased rate of discharge to long-term care facilities. Additionally, patients with hip fracture were found to have poor functional recovery at 1 month if delirium developed in the postoperative setting [5]. Although all elderly patients may be at some risk for the development of postoperative delirium, it may be possible to identify patients at highest risk preoperatively and focus interventions on this group. Marcantonio et al [3] developed a clinical prediction rule for postoperative delirium based on preoperative risk factors, including age, history of alcohol abuse, pre-existing cognitive dysfunction, pre-existing physical impairment, type of surgery, and the presence of metabolic abnormalities. Patients with three or more of these risk factors had a 50% risk of postoperative delirium. Evaluation of the elderly patient who develops delirium requires consideration of preoperative, intraoperative, and postoperative factors [4]. Preoperative factors include pre-existing dementia, polypharmacy, drug or alcohol use/abuse, metabolic derangements, and depression. All efforts should be made to correct metabolic abnormalities before surgery and anesthesia.

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Medication lists should be reviewed carefully and any unnecessary medications stopped. Patients should be questioned carefully about the use of overthe-counter drugs and supplements. Intraoperative factors that have been associated with postoperative delirium include the type of surgery and the anesthetic drugs used [4]. Among the highest-risk surgical procedures are cardiac surgery; hip fracture surgery (especially femoral neck fractures); and ophthalmologic surgery [5,6]. Anticholinergic agents have been associated with postoperative delirium. Barbiturates and benzodiazepines may also play a role. There seems, however, to be no increased risk when general anesthesia is compared with regional anesthesia [5,7]. Intraoperative hypotension or hypoxemia may also be risk factors for postoperative delirium. Postoperative causes of delirium may be similar to preoperative causes. Postoperative hypoxia and hypotension may contribute to delirium. Pain and pain medications, particularly meperidine, may also play a role. Other psychoactive agents (eg, benzodiazepines and sedatives) may be used more frequently postoperatively [8]. Sepsis and metabolic abnormalities need to be considered in this setting, as does myocardial infarction. Withdrawal from alcohol or drugs should be suspected in any patient with a preoperative history of use. Environmental changes and altered sensory input (decreased visual acuity because glasses are not available and decreased auditory acuity because hearing aids are not available) can contribute to the development of delirium, especially in patients with pre-existing cognitive impairment. There are many etiologic factors to consider in a patient with postoperative delirium. There are considerable data that help identify patients at risk [3,6,7]. Once these high-risk patients have been identified, one must be able to intervene to prevent the onset of delirium. Several studies have looked at measures designed to reduce the incidence of postoperative delirium [9– 12,20]. Most studies have focused on comprehensive, multidisciplinary geriatric assessment as a key component of reducing the incidence of delirium. This intervention must occur before the onset of delirium. Once delirium developed, the interventions were not as effective, although the severity may have been reduced [9]. Careful preoperative assessment, ongoing postoperative assessment, cautious use of medications, correction of metabolic abnormalities, and attention to environmental factors remain the most effective ways to prevent postoperative delirium. Comprehensive geriatric assessment and follow-up seems to be effective because it focuses on minimizing these risk factors. Postoperative confusion can be associated with significant consequences for the patient, the nursing staff, and the family. Once it has developed, etiologic factors should be identified quickly and corrected if possible. Any drugs that may be contributing should be stopped or decreased in dosage. Haloperidol or risperidone can be used to help manage behavior that may place the patient at risk for self-harm. Benzodiazepines should be used in patients suspected of having delirium tremens. Thiamine should also be


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given to these patients. Physical restraints may increase the risk of injury and should be avoided if possible. Patients need frequent orientation to time, place, and circumstances. Clocks and calendars may help with orientation. Lighting in the room should mimic day-night cycles. Glasses and hearing aids should be used if needed. Patients should be out of bed as soon as possible. These simple measures may help shorten the course and improve the outcome of postoperative delirium. Immobility Immobility can be devastating to an elderly patient who has recently undergone surgery. Multiple organ systems can be affected by immobility, including the skin, the cardiovascular system, the lungs, the musculoskeletal system, and the gastrointestinal and genitourinary tracts. In addition, there may be significant psychosocial consequences of prolonged bed rest. The elderly, however, may be more likely to be at bed rest postoperatively because of underlying frailty and debility; increased frequency of musculoskeletal problems (arthritis and muscle weakness); and increased caregiver time and expense required to encourage mobility. Pressure ulcers are a significant source of morbidity and mortality for postoperative patients. The elderly are particularly at risk. Hip fracture patients have a high incidence of pressure ulcers [13], and these ulcers are associated with an increased mortality. Although there are many studies of pressure ulcer development in hospitalized patients, there are surprisingly little data looking at the perioperative setting. Age, length of surgery, nutritional status, and type of surgery are all potential risk factors. In addition, emergency surgery and critical illness may increase risk. Shorter surgeries may actually increase the risk of pressure ulcers because careful pressure relief may be neglected [14]. Elderly patients, especially those with hip fractures, are at increased risk for osteoporosis. Bed rest increases that risk substantially. Zerwekh et al [15] studied the effects of bed rest on bone mineral metabolism. They found a significant increase in bone resorption by both biopsy and biochemical markers. There was no change in the rate of new bone formation, which led to a significant decrease in bone mineral density, especially at the greater trochanter. This could contribute to risk of future fractures and impair fracture healing if not corrected. Pulmonary risks associated with immobility include atelectasis, increased risk of aspiration and pneumonia, and increased risk of venous thrombosis and pulmonary embolism. Early ambulation is the most effective technique for reducing the risk of postoperative pulmonary complications. Cardiovascular deconditioning also occurs. This can be associated with a decrease in cardiac output, decreased stroke volume, or orthostatic hypotension. Cardiac atrophy is associated with a reduction in left ventricular size and distensibility, which alters the Starling mechanism [16].

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Immobility also has a number of metabolic effects, including negative nitrogen balance, decreased tissue sensitivity to insulin, and altered calcium metabolism [17]. Oral intake may be impaired by the anorexia induced by bed rest [16]. Confinement to bed or chair can also lead to sensory deprivation, loneliness, and depression, and may increase the risk of postoperative delirium. Immobility may also be associated with constipation and fecal impaction. This can create a vicious cycle of decreased oral intake and increased malnutrition. Mobilization can decrease the risk of constipation, impaction, and ileus. All of these potential complications can lead to only one conclusion: despite many factors that may impair mobility in elderly postoperative patients, these patients need an aggressive mobilization strategy that is multidisciplinary in nature. Physical and occupational therapists, nurses, physicians, family members, and most especially the patients themselves must participate in the mobilization program. Rehabilitation programs must start early and continue as long as is necessary for maximal functional recovery. Malnutrition In industrialized countries, the elderly are perhaps at most risk of being malnourished. Many elderly patients live on limited incomes. Many more have decreased access to transportation. These factors may limit availability of nutritionally valuable foods. Appetite is often decreased because of medications, alterations in taste and smell, coexisting medical illness, and decreased activity. Little is known about the requirements for vitamins, minerals, and trace elements in older people. Surgical disease (eg, gallbladder disease or abdominal ischemia) and preoperative testing may further increase the risk of preoperative malnutrition. Serum albumin can be used as a marker for malnutrition. Gibbs et al [18] showed that serum albumin levels were excellent predictors of 30-day postoperative mortality. This was true even for patients who were otherwise considered to be low risk. Malnutrition must be identified preoperatively. Elderly patients with preoperative malnutrition may develop protein-calorie malnutrition from the stress of surgery. Negative nitrogen balance depletes visceral protein stores. This leads to loss of muscle mass, which impedes efforts at postoperative rehabilitation and ambulation. This vicious cycle leads to increased risk of postoperative pulmonary complications and other consequences of immobility. Impaired immune response may lead to difficulty with wound healing. Prevention of malnutrition should begin preoperatively with identification of patients at highest risk. Nutritional status should be monitored and addressed from the first postoperative day. Elderly patients, especially those with pre-existing malnutrition, should not be allowed to ‘‘fall behind’’ nutritionally. Voluntary food intake should be monitored and nutritional supplements introduced promptly in patients with inadequate intake. Although


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nasogastric feeding is an attractive option, many patients tolerate it poorly. Oral supplementation, if monitored carefully, is probably adequate [16]. Parenteral feeding should be used only as a last resort for patients with altered gastrointestinal tract function. Elderly patients are particularly vulnerable to complications of parenteral feeding. Infections Postoperative infections are an important source of morbidity and mortality in elderly patients. The most common sites of postoperative infection are urinary tract infection, surgical site infection, and pneumonia [17]. Elderly patients may have diminished immune function, which predisposes them to infection, although there is little known about specific decreases in immunologic competence [17]. Urinary tract infection is almost always caused by prolonged catheterization. Elderly patients are at increased risk to be catheterized because of medication side effects; pre-existing incontinence; and decreased mobility, which impedes toileting. Symptoms of urinary tract infection in the elderly may be subtle. For example, postoperative confusion may be the first and only sign of a urinary tract infection. Avoidance of catheterization if possible and early removal of the catheter are the most important steps in preventing urinary tract infections postoperatively. Pneumonia is a leading cause of postoperative mortality in elderly patients. Vigorous pulmonary toilet and aggressive early mobilization are needed to decrease the risk of this complication. Additional risk is conferred by nasogastric tubes, dementia, and immobility. Malnutrition and impaired immune function may increase the mortality associated with postoperative pneumonia. Continence Incontinence is never a normal consequence of aging and should not be an accepted complication of surgery. Every effort should be expended to maintain continence perioperatively. The development of incontinence may prolong the length of stay or may result in an elderly patient entering a nursing home. Indwelling catheters should be removed as soon as possible postoperatively (or avoided altogether, if possible). Urinary retention can be managed with intermittent catheterization [19]. Factors that contribute to incontinence and urinary retention should be eliminated. Immobility, anticholinergic medications, intravenous fluids, delirium, constipation, and urinary tract infection may all be contributing factors. Systematic toileting and prompt responses to requests help maintain continence. Outcomes of surgery in the elderly As the population ages, we are faced with increasingly difficult and complex decisions about health care in elderly patients. Until recently, many

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patients were denied necessary surgical procedures (both elective and emergent) solely on the basis of chronologic age. Over the last two decades, significant insights have been gained into the risks faced by those over 65 who undergo surgery and anesthesia. It has been learned, first of all, that many of these patients can safely be treated surgically. At times, one needs to elucidate carefully the goals of the surgical procedure proposed. When discussing risks and benefits, one must consider not only the risks of the surgery but also the risks of no surgery [21]. Emergency surgery has clearly been associated with an increased risk of postoperative morbidity and mortality in all age groups, but particularly in the elderly [21]. Patients should be advised to have surgical disease managed electively to avoid the risk of complications that might require emergency surgery. Why are elderly patients at such increased risk? Is it age alone or are other issues at play? Comorbidities, such as diabetes, hypertension, heart disease, and arthritis, can contribute substantially to the risk of poor postoperative outcomes. Indeed, many studies [21–23] have suggested that other medical problems, which are more frequent with age, are responsible for the increase in perioperative complications seen in older patients. Polanczyk et al [24] recently demonstrated that age in and of itself was associated with an increase in perioperative complications and longer length of stay. The encouraging finding of this study was that overall perioperative mortality was quite low, even in patients over the age of 80. Magnuson et al [25] studied laparoscopic cholecystectomy in elderly patients. Their findings suggest that laparoscopic cholecystectomy for uncomplicated gallbladder disease could offer the same benefits to older patients that have become apparent in younger patients: decreased pain, shorter hospital stays, and earlier return of preoperative functional status. Because return to baseline functional status is particularly important in the elderly, laparoscopic cholecystectomy might offer even more benefit to this group. Elderly patients, however, were more likely to present with complicated gallbladder disease (acute cholecystitis, gallstone pancreatitis, and common bile duct stones), which is more likely to require conversion to open cholecystectomy. Unfortunately, many elderly patients with known gallstone disease were not offered surgical therapy until complications developed. This delay resulted not only in increased conversion to open procedures but also in increased perioperative morbidity and prolonged length of stay. Elective surgical therapy when possible may be the best way to improve perioperative outcomes in the elderly. Careful preoperative assessment and optimization of medical problems should allow elderly patients to take advantage of minimally invasive surgery with significantly less risk [26,27]. Cardiac and pulmonary complications are the most frequent causes of perioperative morbidity and mortality in the elderly. Particular attention should be directed toward minimizing these complications. A thorough history and physical examination is the cornerstone of preoperative risk assessment. Preoperative functional status is


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particularly important in the elderly. Physically fit, active patients, who can perform at least four metabolic equivalents (METS) of work, have decreased risk of perioperative complications. Unfortunately, many elderly patients have limitations on functional status because of musculoskeletal problems (eg, osteoarthritis). Cardiopulmonary fitness is more difficult to assess in this group. Elderly patients tend to have decreased cardiovascular reserve, although the degree of decline varies from individual to individual. The prevalence of coronary heart disease increases with age, as does the presence of other types of heart problems, such as valvular disease, congestive heart failure, and rhythm disturbances. Decreased reserve and increased disease contribute to an overall increased risk of perioperative cardiac complications in the elderly [24]. The optimal strategy for cardiac risk stratification in this age group is unclear. The American Heart Association and American College of Cardiology guideline cites age as a minor clinical predictor of perioperative risk. This guideline also focuses on functional status as a significant factor in preoperative risk stratification. Because this may be more difficult to ascertain in elderly patients, optimal preoperative testing is less clear. One may need to resort to nonexercise stress testing (eg, stress echocardiography) for moderate- and high-risk surgical procedures when functional capacity is unclear. Although one generally can identify higher-risk patients, strategies for risk reduction remain unclear. b-Adrenergic blockers seem to offer the most promise for decreasing perioperative cardiac risk. Whether other modalities are beneficial remains to be seen. Timing, dosage, and duration of therapy remain unknown. Elderly patients should be considered for b-blocker therapy unless a contraindication exists. Postoperative pulmonary complications can pose a significant threat to elderly patients. Age-related decline in pulmonary reserve and changes in pulmonary function caused by surgery and anesthesia increase risk of postoperative pulmonary complications. Abdominal and thoracic surgical procedures cause a decrease in vital capacity, functional residual capacity, respiratory muscle dysfunction and changes in chest wall mechanics. All of these changes increase the likelihood of early airway closure and atelectasis, which can lead to a ventilation-perfusion mismatch. The presence of pulmonary disease further increases the risk of postoperative pulmonary complications. Neurologic problems, such as stroke and dementia, increase the risk of aspiration. Preoperative pulmonary function tests, however, are rarely useful in predicting risk of postoperative pulmonary complications. As with cardiac risk, functional status is a more important predictor of postoperative pulmonary complications. Prevention is the key to minimizing the risk of postoperative pulmonary complications. Patients and their families should be educated preoperatively about the importance of deep breathing, coughing, incentive spirometry, and early postoperative ambulation. Smoking cessation should be encouraged, although optimal timing is unclear [28]. Patients with chronic obstructive pulmonary disease should be evaluated in a timely fashion to ensure

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that there is no evidence of acute exacerbation. Adequate postoperative analgesia should help with deep breathing, coughing, and early ambulation. Care must be taken, however, to avoid oversedation. Polypharmacy and alterations in drug metabolism may lead to an increased risk of perioperative complications. Multiple medications may precipitate or exacerbate postoperative delirium. Diuretic use can cause electrolyte disturbances, which in turn may increase the risk of postoperative delirium and cardiac arrhythmias. Drugs with anticholinergic effects may cause delirium or may precipitate urinary retention and constipation. Alterations in drug metabolism can occur at many sites. Age-related changes in renal and hepatic function all affect the absorption and metabolism of drugs. Older patients may have decreased absorption of medications because of decreased blood flow to the gastrointestinal tract and of alterations with gastric acidity. Gastric motility may be decreased, especially in patients with diabetes. Kidney function is subject to the same age-related decline as other organ systems. Serum creatinine may not rise, even with significant renal dysfunction, because of decreased muscle mass. Comorbidities, such as diabetes, hypertension, vascular disease, and congestive heart failure, may further impair renal function. Renal dose adjustment should be made in elderly patients, especially if the glomerular filtration rate is less than 80 mL/min. Nephrotoxic drugs should be avoided. Hepatic blood flow is responsible for drug delivery to the liver. Hepatic mass determines the availability of hepatic enzymes for drug metabolism. Both of these functions may be decreased with age. The metabolism and clearance of many drugs used perioperatively are affected by this decrease in hepatic function. Any drugs that are hepatically metabolized should be used with caution in the elderly. This is particularly true of benzodiazepines, which can have a prolonged half-life in this group of patients. Additionally, elderly patients can have a paradoxical response to benzodiazepines. Volume of distribution is also substantially altered in the elderly. Many older patients have decreased total body water and increased total body fat, with decrease in lean body mass. This can lead to an increased volume of distribution of fat-soluble drugs and a decreased volume of distribution of water-soluble drugs [17]. Serum albumin may be decreased and protein binding may be altered. Anticipation and avoidance are the key to minimizing the problems associated with polypharmacy. Medication lists should be reviewed carefully preoperatively. Patients should be questioned about the use of alcohol and over-the-counter medications and supplements. Medication regimens should be simplified as much as possible preoperatively. Any unnecessary or duplicated medicines should be discontinued. Where possible, drug levels should be checked preoperatively to avoid toxicity and ensure therapeutic efficacy. Patients and their families should be given clear written and verbal instructions about preoperative changes in their medication regimens.


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The do-not-resuscitate status in the perioperative setting More and more, elderly patients are being encouraged to make decisions about end-of-life care. As older patients become sicker, they need to think seriously about which life-prolonging measures they would consider appropriate and which they would like to avoid as noxious or overly burdensome [29]. Many elderly patients execute do-not-resuscitate (DNR) orders because of a combination of comorbidities rather than a single terminal illness. These patients should not be denied surgical procedures simply because of the existence of a DNR order. Institutional policies differ with respect to DNR policies in the operating room [31]. Some institutions require that DNR orders be suspended automatically during anesthesia. The assumption underlying this policy is that anesthesia is an iatrogenic situation and a cardiac arrest in this situation is potentially reversible. Proponents of this viewpoint argue that this is fundamentally different from allowing an underlying disease to ‘‘take its course.’’ This is an important consideration in this group of patients, who are more likely to undergo surgery to relieve pain or improve quality of life. Patients with DNR orders who suffered perioperative cardiopulmonary arrest were unlikely to survive to hospital discharge. There seemed to be no benefit in attempting to resuscitate a patient with a DNR order who suffered an arrest [31,32]. Are patients being denied surgical procedures because of the presence of a DNR order? The SUPPORT investigators [30] found that this was generally not the case, once other variables were adjusted for (estimate of 2-month survival, diagnosis, age, and severity of illness). What happens to the DNR order perioperatively? Clemency and Thompson [33] studied the attitudes of internists, anesthesiologists, and surgeons. Most anesthesiologists assumed that the DNR order was suspended in the perioperative period. Internists and surgeons underestimated this assumption. All three groups believed that the internist, surgeon, anesthesiologist, and patient should share the responsibility for defining the DNR status perioperatively. They also believed that this issue should not be decided by hospital policy. Although there are little data available, it seems that patients with preexisting DNR orders who undergo surgery do have a slightly increased risk of cardiopulmonary arrest intraoperatively or postoperatively [7]. Walker [33] has likened the DNR order to the Jehovah witness’s right to refuse blood transfusion. He notes that this refusal of treatment should not deny the patient the right to a surgical procedure. He advocates a more flexible approach to this problem. Patients and their physicians (surgeons, internists, and anesthesiologists) should enter into a dialogue about how the DNR order will be interpreted in the perioperative period. All risks and benefits should be discussed (and carefully documented). The patient’s preference, however, should determine the final outcome of this decisionmaking process.

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Role of the generalist in the perioperative management of the elderly patient As reviewed, the generalist has a vital role in the perioperative care of the elderly patient. Many functions are similar to those for all patients: 1. Assessing risk for perioperative complications: Specific disease-related risk Physiologic changes associated with aging 2. Developing a diagnostic or therapeutic plan for optimizing the patient’s physical status and minimizing risk 3. Developing a plan for monitoring for perioperative complications in patients at increased risk 4. Examining for the presence and status of other illnesses not necessarily related to perioperative risk 5. Developing a therapeutic plan for the perioperative management of these illnesses 6. Defining the risks and benefits for the individual patient, which may be significantly altered in the elderly as already discussed (relief of suffering or improvement in functioning and quality of life become more overriding issues rather than simply prolongation of life) 7. Becoming intimately involved as part of the team that follows-up maintaining patient functioning postoperatively and following discharge from the hospital

Summary As the population survives longer, surgery has become a much more common consideration. Preoperative management of these patients requires a working knowledge of changes associated with aging and the physiology of surgery and anesthesia. Using this information, patients can be clinically evaluated effectively and plans made for their perioperative care to minimize complications.

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[4] Marcantonio ER, Goldman L, Orav EJ, et al. The association of intraoperative factors wih the development of postoperative delirium. Am J Med 1998;105:380–384. [5] Parikh SS, Chung F. Postoperative delirium in the elderly. Anesth Analg 1995;80: 1223–32. [6] Dolan MM, Hawkes WG, Zimmerman SI, et al. Delirium on hospital admission in aged hip fracture patients: Prediction of mortality and 2-year functional outcomes. J Gerontol Med Sci 2000;55A:M527–M534. [7] Raja SN, Haythornthwaite J. Anesthetic management of the elderly: Measuring function beyond the immediate perioperative horizon. Anesthesiology 1999;91:909. [8] Marcantonio ER, Flacker JM, Wright RJ, et al. Reducing delirium after hip fracture: a randomized trial. J Am Geriatr Soc 2001;49:516–22. [9] Fisher BW, Flowerdew G. A simple model for predicting postoperative delirium in older patients undergoing elective orthopedic surgery. J Am Geriatr Soc 1995;43:175–8. [10] Williams-Russo P, Urquhart BL, Sharrock NE, et al. Postoperative delirium: predictors and prognosis in elderly orthopedic patients. J Am Geriatr Soc 1992;40:759–67. [11] Litaker D, Locala J, Franco K, Bronson DL, Tannous Z. Preoperative risk factors for postoperative delirium. General Hospital Psychiatry 2001;23:84–89. [12] Inouye SK, Bogardus ST, Baker DI, et al. The hospital Elder life program: a model of care to prevent cognitive and functional decline in older hospitalized patients. J Am Geriatr Soc 2000;48:1697–706. [13] Evans JM, Andrews KL, Chutka DS, et al. Pressure ulcers: prevention and management. Mayo Clin Proc 1995;70:789–99. [14] Stotts NA. Risk of pressure ulcer development in surgical patients: a review of the literature. Adv Wound Care 1999;12:127–36. [15] Zerwekh JE, Ruml LA, Gottschalk F, et al. The effects of twelve weeks of bed rest on bone histology, biochemical markers of bone turnover, and calcium homeostasis in eleven normal subjects. J Bone Miner Res 1998;13:1594–601. [16] Levine BD, Zuckerman JH, Pawelcyk J. Cardiac atrophy after bed-rest deconditioning: a nonneural mechanism for orthostatic intolerance. Circulation 1997;96:517–25. [17] Watters JM, McClaren JC. The elderly surgical patient. In: Wilmore DW, Cheung LY, Harken AH, et al, editors. American College of Surgeons Scientific American Surgery. New York: Scientific American; 1999. p. 2–31. [18] Gibbs J, Cull W, Henderson W, et al. Preoperative serum albumin level as a predictor of operative mortality and morbidity; results from the National VA Surgical Risk Study. Arch Surg 1999;134:36–42. [19] Delmi M, Rapin CH, Bengou AM. Dietary supplementation in elderly patients with fractured neck of the femur. Lancet 1990;335:1013–6. [20] Skelly JM, Guyatt GH, Kalbfleisch R, et al. Management of urinary retention after surgical repair of hip fracture. Can Med Assoc J 1992;145:1185–9. [21] Seymour DG, Pringle R. Postoperative complications in the elderly surgical patient. Gerontology 1983;29:262–70. [22] Berry AJ, Smith RB, Weintraub WS, et al. Age versus comorbidities as risk factors for complications after elective abdominal aortic reconstructive surgery. J Vasc Surg 2001; 33:345–52. [23] Vaz FG, Seymour DG. A prospective study of elderly general surgical patients: 1. Preoperative medical problems. Age Ageing 1989;18:309–15. [24] Polancyzk CA, Marcantonio E, Goldman L, et al. Impact of age on perioperative complications and length of stay in patients undergoing noncardiac surgery. Ann Intern Med 2001;134:637–43. [25] Magnuson TH, Ratner LE, Zenilman ME, et al. Laparoscopic cholecystectomy: applicability in the geriatric population. Am Surg 1997;63:91–5. [26] Fried GM, Clas D, Meakins JL. Minimally invasive surgery in the elderly patient. Surg Clin North Am 1994;74:375–87.

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[27] Efron DT, Bender JS. Laparoscopic surgery in older adults. J Am Geriatr Soc 2001;49: 658–663. [28] Bluman LG, Mosca L, Newman N, Simon DG. Preoperative smoking habits and postoperative pulmonary complications. Chest 1998;113:883–89. [29] Clemency MV, Thompson NJ. Do not resuscitate orders in the perioperative period: patient perspectives. Anesth Analg 1997;84:859–64. [30] Margolis JO, McGrath BJ, Kussin PS, et al. Do not resuscitate (DNR) orders during surgery: ethical foundations for institutional policies in the United States. Anesth Analg 1995;80:806–9. [31] Clemency MV, Thompson NJ. Do not resuscitate (DNR) orders in the perioperative period: a comparison of the perspectives of anesthesiologists, internists, and surgeons. Anesth Analg 1994;78:651–8. [32] Wenger NS, Greengold NL, Oye RK, et al. Patients with DNR orders in the operating room: Surgery, resuscitation, and outcomes. Journal of Clinical Ethics 1997;8:250–7. [33] Walker RM. DNR in the OR. JAMA 1991;226:2407–12.

Selected Readings del Guercio LRM, Cohn JD. Monitoring operative risk in the elderly. JAMA 1980;243:1350–5. Dzankic S, Pastor D, Gonzalez C, et al. Prevalence and prognostic value of abnormal laboratory tests in elderly surgical patients. Anesth Analg 2000;90:S166. Eagle KA, Brundage BH. AHA Task Force on Practice Guidelines. Guidelines for perioperative cardiovascular evaluation for noncardiac surgery: an abridged version of the report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. Mayo 1997;72:524–31. Ergina P, Gold S, Meakins J. Perioperative care of the elderly patient. World Journal of Surgery 1993;17:192–8. Evans JM, Fleming KC, Talley NJ, et al. Relation of colonic transit to functional bowel disease in older people: a population-based study. J Am Geriatr Soc 1998;46:83–7. Fisher BW, Flowerdew G. A simple model for predicting postoperative delirium in older patients undergoing elective orthopedic surgery. J Am Geriatr Soc 1995;43:175–8. Franco K, Litaker D, Locala J, Bronson D. The cost of delirium in the surgical patient. Psychosomatics 2001;42:68–73. Gerson MC, Hurst JM, Hertzberg VS, et al. Cardiac prognosis in noncardiac geriatric surgery. Ann Int Med 1985;103:832–7. Gerson MC, Hurst JM, Hertzberg VS, et al. Prediction of cardiac and pulmonary complications related to elective abdominal and noncardiac thoracic surgery in geriatric patients. Amer J Med 1990;88:101–7. Gerson MC, et al. Cardiac prognosis in noncardiac geriatric surgery. Med Clin N Am 1987; 71:569–82. Goldman L, Caldera DL, Nussbaum SR, et al. Multifactorial index of cardiac risk in noncardiac surgical procedures. N Engl J Med 1977;297:845–50. Hirsch CH. When your patient needs surgery: weighing risks versus benefits. Geriatrics 1995; 50:26–31. Hosking MP, Warner MA, Lobdell CM, et al. Outcomes of surgery in patients 90 years of age and older. JAMA 1989;261:1909–15. Inouye SK, Bogardus ST, Charpentier PA, et al. A multicomponent intervention to prevent delirium in hospitalized older patients. N Engl J Med 1999;340:669–76. Jackson CV. Preoperative pulmonary evaluation. Archives of Internal Medicine 1988;148: 2120–7. Kallis P, Unsworth-White J, Munsch C, et al. Disability and distress following cardiac surgery in patients over 70 years of age. Eur J Cardiothorac Surg 1993;7:306–12.


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Keating HJ III. Perioperative Care of the Older Patient. Clin Ger Med W.B. Saunders Company: August, 1990. Koruda MJ, Sheldon GF. Surgery in the Aged. Advances in Surgery 1991;24:293–331. Marcantonio ER, Flacker JM, Michaels M, Resnick NM. Delirium is independently associated with poor functional recovery after hip fracture. J Am Geriatric Soc 2000;48:618–24. Mehul R, Shah G, Aharonoff P, et al. Outcome after hip fracture in individuals ninety years of age and older. J Orthop Trauma 2001;15:34–9. MP H. Outcomes of surgery in patients 90 years of age and older. JAMA 1989;261:1909–15. O’Hara DA, Duff AM, Berlin JA, et al. The effect of anesthetic technique on postoperative outcomes in hip fracture repair. Anesthesiology 2000;94:947–57. Older P, Smith R. Experience with the preoperative invasive measurement of haemodynamic, respiratory and renal function in 100 elderly patients scheduled for major abdominal surgery. Anaesth and Intensive Care 1988;16:389–95. Older P, Smith R, Courtney P, et al. Preoperative evaluation of cardiac failure and ischemia in elderly patients by cardiopulmonary exercise testing. Chest 1993;104:701–4. Palda ZA, Detsky AS, et al. Clinical guideline, part I: guidelines for assessing and managing the perioperative risk from coronary artery disease associated with major surgery. Annals IM 1997;127:309–12. Palda ZA, Detsky AS. Clinical guideline, part II: perioperative assessment and management of risk from coronary artery disease. Annals IM 1997;127:313–27. Rodgers A, Walker N, Schug S, et al. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials. BMJ 321: 1493–7. Schein O, Katz J, Bass E, et al. The value of routine preoperative medical testing before cataract surgery. N Engl J Med 2000;342:168–75. Schrader LL, McMillen MA, Watson CB, et al. Is routin preoperative hemodynamic evaluation of nonagenarians necessary? J Am Ger Soc 1991;39:1–5. Seymour DG, Pringle R. A new method of auditing surgical mortality rates: Application to a group of elderly general surgical patients. Br Med J 1982;284:1539–42. Seymour DG, Pringle R. Surgical emergencies in the elderly: can they be prevented? Health Bull 1981;41:112–31. Seymour G. Medical Assessment of the Elderly Surgical Patient. Rockville, MD: Aspen Systems; 1986. Thomas DR, Ritchie CS. Preoperative assessment of older adults. JAGS 1995;43:811–21. Timiras P. Physiological Basis of Geriatrics. New York: MacMillan Publishing Company; 1988. U.S. Census Bureau Population Projections Program. Population division. Projections of the total resident population by 5-year age groups, and sex with special age categories: middle series. Washington DC: U.S. Census Bureau; 2000. Vanzetto G, et al. Additive value of thallium single-photon computed tomography myocardial imaging for prediction of perioperative events in prediction of perioperative events in clinically selected high cardiac risk patients having abdominal aortic surgery. Am J Cardiol 1996;77:143–8. Vaz FG, Seymour DG. A prospective study of elderly general surgical patients: II postoperative complications. Age and Aging 1989;18:316–26. Zenilman ME. Surgery in the nursing home patient. Surg Clinic N Am 1994;74:63–77.

Preoperative medical consultation

Evidence-Based Medical Consultation

Evidence-Based Medical Consultation, 1e

Preoperative Assessment and Management

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