927

Chapter 25 - Preoperative Evaluation

Michael F. Roizen

RATIONALE

The ultimate goals of preoperative and preprocedure medical assessment of patients who are to undergo anesthesia care are to reduce the morbidity of surgery, to increase the quality but decrease the cost of perioperative care, and to return the patient to desirable functioning as quickly as possible. We include preprocedure in this assessment period because anesthesia care increasingly involves rendering the patient more comfortable during procedures that do not involve classic surgery. Traditionally, these goals have been facilitated by a preoperative meeting between the patient and the anesthesiologist. The meeting now has six specific purposes:

1. To obtain pertinent information about the patient's medical history and physical and mental conditions, in

   ---

   928

   order to determine which tests and consultations are needed
2. Guided by patient choices and the risk factors uncovered by the medical history, to choose the care plans to be followed
3. To obtain informed consent
4. To educate the patient about anesthesia, perioperative care, and pain treatments in the hope of reducing anxiety and facilitating recovery
5. To make perioperative care more efficient and less expensive
6. To utilize the operative experience to motivate the patient to more optimal health and thereby improve perioperative and/or long-term outcome

Reducing the patient's anxiety and obtaining informed consent are discussed in other chapters. Most data indicate that recovery occurs more quickly when the anesthesiologist allays the patient's concerns, informs the patient about what is to come, and plans postoperative pain therapy with the patient^{[1] [2] [3] [4] [5]} (also see Chapter 72 ). The next three functions of preoperative evaluation are closely related: the acquisition of a pertinent medical history, including information about physical and medical conditions.

No. 6 in this list—improving outcome by using interventions in a preoperative and preprocedure assessment clinic—perioperative and long-term outcome changes with aspirin, β-adrenergic receptor blocking agents, cholesterol management drugs, diet, exercise, immunization, smoking cessation, and other interventions instituted in a clinic or by a primary care physician that use the operative experience to motivate more optimal health for daily life—is relatively new: Can you change therapy now and into the immediate postoperative period and alter the perioperative outcome and/or long-term outcome? Rolled into this new function are three other questions:

Do you have enough time to initiate such that that change will make a positive outcome difference to the patient?

Do you have the time to motivate the patient to accept such?

Can you motivate the patient to initiate such?

These four questions affect the decisions about testing, consultation, and discussion of care plans with the patient and lead to patient education, setting expectations for the patient's postoperative pain therapy and recovery plan, and cost reduction, and possibly leading to a high quality of life long-term. This may impose an additional important function (some would say opportunity for the specialty and individual physician; some would say burden for the anesthesiologist) as perioperative physician motivating the patient. This function derives from the judgment and continuing data that show that a patient in optimal shape for daily living has a better perioperative and long-term outcome than one not in such shape. However, this function also requires the preoperative or preprocedure interview to be conducted earlier (days, not hours, prior to surgery) to have maximum effectiveness and places the perioperative physician into the mainstream of medical care. As medicine has evolved, perhaps nowhere has the mutation demanded of physicians been greater than in perioperative care.

Thus, major functions of preoperative and preprocedure evaluation—optimizing patient health before surgery and/or planning the most appropriate perioperative management—improve perioperative and long-term outcome—reduce perioperative costs. Data supporting this claim are substantial, but indirect; studies of perioperative morbidity over five decades repeatedly show that preoperative patient conditions and perioperative optimization of care are significant predictors of postoperative morbidity.^{[6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70]} Specifically, less severe manifestations of adverse preoperative conditions are associated with lower perioperative morbidity and mortality ( Table 25-1 and Fig. 25-1 ).

These data strongly imply (some would say prove) that preoperative treatment or alteration of such conditions and habits such as congestive heart failure, diabetes, cardiovascular demand reduction, blood vessel inflammation, physical inactivity, and smoking, to name only a few, can reduce the severity of disease, improve patient quality of life and functioning, and thus reduce perioperative morbidity and mortality. Moreover such changes have been shown to improve longer-term quality of life

929

Figure 25-1 Estimated risk of hospital mortality in relation to age, preoperative disease, and surgery. Elective surgery, top triangles; emergency surgery, bottom triangles. (From Pedersen T, Eliasen K, Henriksen E: A prospective study of mortality associated with anaesthesia and surgery: Risk indicators of mortality in hospital. Acta Anaesthesiol Scand 34:176, 1990.)

Preoperative consultations may initiate additional risk-modification tactics, such as reducing tachycardia^[5] or the stress on plaque,^{[31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42]} controlling hypertension,^{[51] [52] [53]} perioperative cessation of smoking,^{[54] [55] [56] [57]} nutritional fortification,^{[60] [61]} immunization,^[62] reducing inflammation in blood vessels,^{[43] [44] [45] [46] [47] [48]} and stamina/strength training,^{[63] [64] [65] [66] [67] [68] [69] [70]} and in this way may improve perioperative outcome. Preoperative evaluation produces other benefits as well. Patient education about perioperative care expectations can radically reduce the length of stay and costs ( Table 25-2 ) and, as previously mentioned, substantially improve quality of life.

Can this process of preoperative assessment be accomplished in isolation by a primary care physician or internist? Although much of the process probably could be, a condition considered "optimal for daily life" (e.g., some degree of prerenal azotemia in the patient with congestive heart failure) may not be "optimal preoperative status" (at which time vasodilation may cause hypotension or permanent renal impairment or both). Furthermore, the process of preoperative evaluation and risk factor modification requires a broad knowledge of the content of scientific perioperative care and a deep understanding of the context in which that knowledge is applied. Understanding the context—the environmental, sociological, ethical, and team concepts and the economic influences—of perioperative care is almost as important as the technical knowledge upon which the practice of perioperative care rests. Thus, compulsive attention to the effects of planned perioperative maneuvers on patient physiology would be desirable—perhaps even necessary—if the benefit of such preplanning is deemed worth the cost. Furthermore, the perioperative time presents a more meaningful period to

930

Preoperative evaluation by a physician is not inexpensive. However, later sections of this chapter show how preoperative planning can be much less expensive than current practices because of the ability to order tests selectively and to use education and information tools to increase efficiency, to shorten the length of stay, to reduce the rate of cancellations, and to increase patient satisfaction. In addition, preoperative assessment can uncover hidden conditions that could cause problems both during and after surgery. In this way, the anesthesiologist is able to anticipate problems and plan therapy intended to prevent or minimize the effects of such problems.^{[5] [18] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70]}

A study at the University of Florida found that preanesthetic evaluations provided information leading to changes in care plans for more than 15% of all healthy patients (i.e., American Society of Anesthesiologists [ASA] physical status I and II patients), and for 20% of all patients in general.^[24] Care plans were changed because of information from observation and history: the most common conditions causing changes were gastric reflux, insulin-dependent diabetes mellitus, asthma, and suspected difficult intubation ( Table 25-3 ). However, the data did not indicate that these changes improved patient outcome. Nevertheless, practitioners seem to believe that the discovery of these conditions calls for a change in plans, which is usually implemented in a way that delays operating room (OR) schedules and increases costs. Examples of last-minute changes are administration of an H₂ -blocker 1 to 2 hours before, a β-blocker 1 hour before, and an oral antacid immediately before entry to the OR; the obtaining of equipment to measure blood glucose levels; the obtaining of a history of the patient's diabetic course and treatment from the primary care doctor as well as from the patient; the performance of fiberoptic laryngoscopy; or additional skilled help. Thus, even if preoperative evaluation were not to alter outcome to any great degree, its ability to reduce costs by reducing laboratory tests and delays in obtaining equipment or treatments perceived to be beneficial (and medicolegally required) would be substantial and would warrant its use.

Data from Stanford,^{[25] [26]} the University of Chicago,^{[5] [67] [68] [69]} the University of South Florida,^[27] the University of Rochester, ^[28] the University of Massachusetts,^[29] and community hospitals in London, Ontario,^[30] and in Australia^{[68] [69]} and elsewhere^{[39] [40] [41] [42] [43] [44] [45] [46] [47] [48]} confirm these cost and outcome advantages. Furthermore, a negative history and physical examination can lead to decreased resource utilization for healthy patients^[23] and for those with comorbid conditions but without risk factors requiring high intensity care.^[74] In addition, preoperative evaluation gives practitioners confidence that they will not be surprised by unexpected patient conditions and gives patients confidence that the health care system is responding to their individual conditions and is focused on their well-being in the perioperative period and beyond.

In the beginning, the preoperative assessment described above relied only on accurate history-taking and physical examination. In the 1960s, multiphasic screening laboratory tests were added to the process. This chapter evaluates the goals of preoperative medical assessment and the relative importance of history-taking, physical examination, and laboratory testing regarding the improvement of perioperative outcome but then goes beyond these knowledge-based steps.

Beginning with the first edition of Anesthesia in 1981, I have attempted to describe not only current practices but also the need for innovative change. In the first edition (before the use of diagnosis-related groups [DRGs] to establish fees, and before that cost-based push to reduce testing), I discussed the lack of benefit from nonselective laboratory testing. In the second edition (1986), I described how cost-benefit and benefit-risk analyses again pointed to the need to reduce the amount of laboratory testing. The third edition (1991) also came to a nontraditional conclusion: we needed to change the way we usually

931

Not surprisingly, in the fifth edition (1999), this chapter accentuated the need to develop consensus in making a preoperative clinic effective for all and to implement an effective electronic information system ("informatics") process. It also emphasized the dramatic benefits of instituting a functional preoperative clinic that has gone through the stages of efficient patient evaluation, appropriate test selection, and effective prerequisite education of the patient and that is organized in such a way that patient satisfaction is increased. The importance and benefits of adding patient education to these processes was also highlighted, as were the information services that make the process more efficient for all caregivers as well as for the patient. I now emphasize the metamorphosis of preoperative evaluation into a period that can motivate a higher quality of life and thereby improve long-term as well as immediate outcome.

I believe that just as the practice of anesthesia has changed during the past decade, the practice of preoperative evaluation also needs to change to ensure that the best

932

The difficulty is that we must obtain a thorough history far enough in advance to allow us to perform selected tests and to implement the necessary therapies and motivational strategies without disrupting surgical schedules and the patient's perioperative care plans. This must also be done far enough in advance to give the patient and his or her significant others time to plan for the options that have been selected.