Preoperative Assessment, Risk Evaluation and Optimization
Core Concepts
The preoperative assessment must establish the patient's functional capacity, comorbid disease, airway risk, and the urgency of surgery. Know the ASA physical status classification and the revised cardiac risk index (RCRI), and understand that functional capacity is best estimated by the ability to climb two flights of stairs or perform 4 METs. Understand the role of cardiopulmonary exercise testing in high-risk patients.
Risk Indices
Know the RCRI components: ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, renal insufficiency (creatinine >2 mg/dL), and high-risk surgery. Know the Gupta perioperative risk calculator and the concept of the surgical Apgar score.
Optimization
Understand the perioperative management of diabetes (avoid long-acting sulfonylureas, hold metformin if contrast or renal impairment), the management of anticoagulants and antiplatelets, and the indications for preoperative cardiac testing. Know that routine stress testing is not indicated for asymptomatic patients undergoing low-risk surgery.
Traps
Questions frequently test whether a patient needs further cardiac testing before surgery, and the answer hinges on functional capacity and the RCRI. Another common trap is the belief that all patients on beta-blockers should have them started preoperatively; initiation should not be routine in beta-blocker-naive patients because of the risk of stroke and hypotension. Also know the difference between preoperative evaluation and preoperative testing.
Worked Example
A 68-year-old with diabetes and prior MI, able to climb two flights of stairs, scheduled for elective hernia repair. RCRI is 2 (ischemic heart disease, insulin-treated diabetes), but surgery is low risk and functional capacity is good, so no further cardiac testing is indicated. Continue beta-blockers and statins, and optimize glucose control.