REVIEW URRENT C OPINION

Preanesthesia evaluation for ambulatory surgery: do we make a difference? Jennifer Hofer, Esther Chung, and Bobbie J. Sweitzer

Purpose of review Ambulatory surgery is considered low risk; however, both surgery-related and patient-related factors combine to determine the overall risk of a procedure. The preanesthesia evaluation is useful to gather information and determine whether additional testing or medical optimization is necessary prior to surgery with the goal to prevent adverse events and improve outcomes. Recent findings Recent literature focused on the preanesthesia evaluation provides guidelines for patient-centered testing. Routine, protocolized preoperative testing is expensive and has not shown to improve outcomes. The preanesthesia visit is useful for patient evaluation, not specifically testing, but for the synthesis of information, medical optimization, additional targeted testing if indicated, assessment of risk, and plan for perioperative management. Summary Current literature supports a preanesthesia visit that focuses on individual patient evaluations and patientdirected effective interventions. This is in contrast to the previous routine, protocolized preoperative preparations. The challenge for anesthesiologists lies in understanding both surgery-specific and patientspecific risk factors, and targeting interventions to optimize the outcomes. Keywords obstructive sleep apnea and ambulatory surgery, postoperative nausea and vomiting, preanesthesia evaluation, preanesthesia testing, preoperative cardiac evaluation, preoperative testing and ambulatory surgery

INTRODUCTION Recently, there have been several publications addressing the controversy over preoperative assessment and testing. Although outpatient procedures are considered low risk, patients who undergo these procedures may be American Society of Anesthesiologists physical status (ASA PS) classification 1, 2, 3, or 4. Ambulatory surgical patients may have a variety of medical conditions varying in severity and control. Medical optimization prior to the procedure may be beneficial if the patient has poorly controlled comorbidities. The preoperative evaluation screens patients, guides additional tests and interventions to decrease morbidity and mortality, and may suggest outcomes from surgery. In 2012, the American Society of Anesthesiologists published an updated preanesthesia evaluation practice advisory [1 ]. The report consists of recommendations supported by the current literature, and the consensus is consistent with the previous reviews. The article states there is ‘insufficient evidence to identify explicit decision &

parameters or rules for ordering preoperative tests. . .. However, consideration of selected clinical characteristics [cardiovascular disease, respiratory disease] may assist the anesthesiologist when deciding to order, require, or perform preoperative tests’. The practice advisory offers guidelines for testing rather than a standardized protocol.

PREANESTHESIA TESTING: ROUTINE, TARGETED, OR NONE Day surgery appears safe [2]. In a Danish multicenter study evaluating more than 57 000 ambulatory The University of Chicago Medicine, Chicago, Illinois, USA Correspondence to Bobbie J. Sweitzer, MD, Professor of Anesthesiology and Critical Care and Medicine, Director, Anesthesia Perioperative Medicine Clinic, The University of Chicago Medicine, 5841 South Maryland Avenue, MC 4028, Office A202, Chicago, Illinois, USA. Tel: +1 773 834 8959; fax: +1 773 834 2307; e-mail: [email protected]. edu Curr Opin Anesthesiol 2013, 26:669–676 DOI:10.1097/ACO.0000000000000006

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Ambulatory anesthesia

KEY POINTS  Although outpatient surgeries are considered low risk, identification of appropriate candidates for ambulatory surgery requires the assessment of comorbidities and evaluation of patients’ physical status.  Preoperative assessments serve to screen, evaluate, test if indicated, and medically optimize patients preoperatively with the goal to reduce morbidity and improve outcomes.  The preanesthesia visit is useful for patient-directed, targeted interventions rather than protocolized routine preoperative preparations.

surgical procedures in ASA PS 2 and 3 patients, serious morbidity was low, and there was a very low rate of return hospital visits within 30 days of the procedure (1.21%). In this cohort, 24 patients died within 30 days of surgery because of any cause, compared to an expected 40 deaths without surgery if matched for age and sex. This suggests there is a lower rate of death in those having ambulatory surgery and that patient selection is good. Because ambulatory surgery is considered well tolerated, routine preoperative testing is under scrutiny [3 ]. In a National Surgical Quality Improvement Program (NSQIP) review, patterns of preoperative testing and their association with postoperative complications were evaluated. Testing was associated with higher ASA PS, older age, hypertension, ascites, bleeding disorders, systemic steroids, or scheduled laparoscopic surgery. Of 46 977 patients who had preoperative tests, 54% of patients with no NSQIP comorbidities received at least 1 test, 52% had a hematology test, 42% chemistries, 20% liver function tests, 15% coagulation labs, and 8% of patients had all 4 tests, in spite of no comorbidities. Abnormal results were found in 61% of patients. 15.3% of patients had tests on the day of the procedure; yet, surgery proceeded despite the majority having an abnormal result [3 ]. The rate of serious complications [reintubation, pulmonary embolus, myocardial infarction (MI), stroke, bleeding, and death] was 0.3%, and postoperative complications were not associated with preoperative testing or abnormal results. The conclusions of the study are consistent with previous publications that demonstrate excess ordering of preoperative tests, no interventions after abnormal results, rare changes in management (60) and selective testing (ordering an ECG for a patient with an arrhythmia detected on examination or a history of syncope). Guidelines to limit variation in testing &&

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Preanesthesia evaluation for ambulatory surgery Hofer et al.

and reduce unnecessary tests whose abnormal results have limited clinical importance are more likely to be cost-effective and offer benefits to patients. Although routine testing has not shown to be beneficial, there is value in the preoperative assessment that goes beyond the laboratory checks and review of records. Preoperative evaluation can help with the risk stratification of patients with a high likelihood of complications. Surgical-related and patient-related factors interact to increase morbidity. Preoperative care can improve perioperative management. For example, the elderly benefit from preoperative assessments that consider the physiologic changes of aging and address thrombotic risk, pain control, delirium, and fluid management [8]. During the preoperative visit, if the patient is fully assessed and perioperative plans are actualized, improved outcomes may be realized.

CARDIOVASCULAR EVALUATION

Preliminary questions?

Cardiovascular risk assessment and management remain a priority among anesthesiologists. Each

year 50 000 patients experience a postsurgical MI among the 27 million patients who undergo noncardiac surgery [9,10]. Cardiac risk indices include the American College of Cardiology/American Heart Association (ACC/AHA), the Lee index, and the Erasmus model to guide perioperative management. A group from the UK summarizes the current status of preoperative cardiovascular evaluation of patients anticipating anesthesia and surgery [11 ]. They advocate a multidisciplinary approach with anesthesiologists, surgeons, and cardiologists working together. They specifically note that consensus guidelines from the ACC/AHA and European Society of Cardiology de-emphasize routine cardiac testing in favor of preoperative risk stratification based on the clinical assessment. A simplified stepwise approach to preoperative evaluation based on the authors’ interpretation of these consensus guidelines is shown in Fig. 1. Because most, if not all, ambulatory surgery is considered low risk, patients proceed to surgery without further cardiac testing as shown in Fig. 1 as long as the patient does not have an unstable &&

Urgent surgery needed? Surgery Low-risk surgery? Refer to cardiologist? Urgent revascularization

Unstable cardiac condition?

Assess functional capacity

Bad or unknown (≤ 4 MET)

Good (> 4 MET)

Intermediate-risk surgery

High-risk surgery

Risk factors?

≤2

≥3

Consider noninvasive testing (e.g. MPS/DSE)

No/mild/moderate ischemia

Medical optimization

Extensive ischemia

Consider revascularization

Surgery

FIGURE 1. Summary of the stepwise approach to preoperative cardiovascular risk evaluation. Data from [11 ]. &&

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Ambulatory anesthesia Table 1. Risk of myocardial infarction and cardiac death within 30 days after surgery Low risk 5%

Breast

Abdominal

Aortic/major vascular

Dental

Carotid

Peripheral vascular

Endocrine

Peripheral arterial angioplasty

Eye

Endovascular aneurysm repair

Gynecology

Head and neck

Reconstructive

Hip and spine

Orthopedic – minor

Transplant – lung/kidney/liver

Urology – minor

Urology – major

Data from [11

&&

].

cardiac condition as defined in the list below. Preoperative evaluation is guided by surgical risk, and the patient’s functional capacity and number of clinical risk factors. Even if one considers the ambulatory procedure to be intermediate risk (Table 1), patients proceed without further testing regardless of their functional capacity. The functional capacity only determines if medical optimization (e.g., betablockers, statins and aspirin) is indicated. There is some controversy about the risks and benefits of starting beta-blockers, especially in low-risk patients near or on the day of surgery. However, patients currently on beta-blockers should continue these. The authors also recommend that aspirin be continued and only be withheld if bleeding risks outweigh the cardiac risks. This article highlights the current understanding that the majority of perioperative cardiac events are because of stressinduced rupture of vulnerable atherosclerotic plaques triggering platelet aggregation, thrombosis and occlusion. Interestingly, these events often do not occur in the artery with the tightest stenosis. These findings are consistent with the failure of preoperative revascularization to either lower the perioperative event rate or long-term mortality (Table 2). Of special note is the high mortality rates associated with stent thrombosis if antiplatelet agents are prematurely discontinued (

Preanesthesia evaluation for ambulatory surgery: do we make a difference?

Ambulatory surgery is considered low risk; however, both surgery-related and patient-related factors combine to determine the overall risk of a proced...
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