Applied Evidence

Preoperative evaluation: A time-saving algorithm

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Our preop evaluation method combines the latest guidelines and tools to help you avoid unnecessary testing and complete the process in one visit.




› Recommend that patients quit smoking 8 weeks before surgery; keep in mind, though, that quitting closer to the date of surgery does not increase the risk of complications. A
› Use the online American College of Surgeons/National Surgical Quality Improvement Program surgical risk calculator to estimate a patient’s surgical risk. C
› Send a patient directly to surgery if he or she has an estimated cardiac risk <1% or <2 risk factors of the Revised Cardiac Risk Index. B

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series

About 27 million Americans undergo surgery every year1 and before doing so, they turn to you—their primary care physician—or their cardiologist for a preoperative evaluation. Of course, the goal of this evaluation is to determine an individual patient’s risk and compare it to procedural averages in an effort to identify opportunities for risk mitigation. But the preoperative evaluation is also an opportunity to make recommendations regarding perioperative management of medications. And certainly we want to conduct these evaluations in a way that is both expeditious and in keeping with the latest guidelines.

Current guidelines for preoperative evaluations are less complicated than they used to be and focus on cardiac and pulmonary risk stratification. While a risk calculator remains your primary tool, elements such as smoking cessation and identifying sleep apnea are important parts of the preop equation. In the review that follows, we present a simple algorithm (FIGURE 12-6) that we developed that can be completed in a single visit.

Preoperative evaluation algorithm image
Cardiac assessment: A risk calculator is the primary tool

Cardiac risk estimation is perhaps the most important element in determining a patient’s overall surgical risk. But before you begin, you'll need to determine whether the preoperative evaluation of the patient is best handled by you or a specialist. Current guidelines recommend preoperative evaluation by a specialist when a patient has certain conditions, such as moderate or greater valvular stenosis/regurgitation, a cardiac implantable electronic device, pulmonary hypertension, congenital heart disease, or severe systemic disease.2

If these conditions are not present (and an immediate referral is not required), you can turn your attention to the cardiac assessment. The first step is to determine which cardiac risk calculator you’d like to use. In its comprehensive guideline on perioperative cardiovascular evaluation, the American College of Cardiology/American Heart Association (ACC/AHA) recommends the use of one of the 2 calculators described below.2

Revised Cardiac Risk Index. The most well-known cardiac risk calculator is the 6-element Revised Cardiac Risk Index (RCRI) (TABLE 1).7 Published in 1999, the RCRI was derived from a cohort of 2800 patients, verified in 1400 patients, and has been validated in numerous studies.2 Each element increases the odds of a cardiac complication by a factor of 2 to 3, and more than one positive response indicates the patient is at high risk for complications.7

Preoperative evaluation: A time-saving algorithm image
ACS NSQIP surgical risk calculator. A newer risk calculator was put forth by the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP).8 This calculator is Web-based and available at: Derived from over 1.4 million patients and stratified by 1557 surgical codes, it consists of 22 questions that relate to the patient’s medical history and the planned surgical procedure. A previous cardiac event is defined as a myocardial infarction or cardiac arrest. The only numerical inputs are height and weight, which are used to calculate body mass index. The output of the calculator includes a comparison of the patient’s risk to the average risk of complications in 11 areas, including cardiac, pulmonary, surgical site infections, and overall risks such as death, serious complications, and discharge to nursing or rehabilitation.

While a risk calculator remains your primary tool, elements such as smoking cessation and identifying sleep apnea are important parts of the equation.

The ACS NSQIP risk calculator has been criticized because it has not been validated in a group separate from the initial patient population used in its development.2 Another criticism is the inclusion of the American Society of Anesthesiologists' (ASA) classification of the overall health of the patient, a simple yet subjective and unreliable method of patient characterization.2

Choosing a calculator. The ACS NSQIP calculator may be more useful for primary care physicians because it provides individualized risks for numerous complications and is easy to use. The output page can be printed as documentation of the preoperative evaluation, and is useful for counseling patients about reconsideration of surgery or risk-reduction strategies. The RCRI is also simple to use, but considers only cardiac risk. Although the RCRI has been validated in numerous studies, the ACS NSQIP was derived from a more substantial 1.4 million patients.

Revised Cardiac Risk Index image


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