Preoperative Preparation and Monitoring

Preoperative assessment and optimization of cardiac risk were previously discussed. It is extremely important that long-term cardiac and respiratory medications be given the morning of surgery. β-Blockers are most important because they have been shown to reduce the incidence of perioperative myocardial ischemia and subsequent cardiac morbidity.^{[58] [59] [60] [61]} I do not recommend that antiplatelet therapy (usually aspirin) be terminated preoperatively. Monitoring for lower extremity arterial revascularization should include an intra-arterial catheter that permits continuous blood pressure monitoring to optimize coronary artery perfusion, continuous blood pressure monitoring to optimize lower extremity graft perfusion, and blood sampling for diagnostic laboratory testing. A urinary bladder catheter is usually adequate for assessing intravascular volume and cardiac output, and central venous catheters are not necessarily helpful in routine cases. Central venous pressure monitoring should be considered for patients with significant renal dysfunction in whom intravascular volume should be carefully monitored and for patients with significantly impaired ventricular dysfunction or congestive heart failure. In these patients, a pulmonary artery catheter may be helpful, but given the relatively low potential for blood loss and third-space fluid losses with lower extremity vascular procedures, the pulmonary artery catheter is usually reserved for patients with active congestive heart failure or unstable angina. Our criteria for using invasive hemodynamic monitoring have been previously described.^[79] Computerized ST segment monitoring is helpful in monitoring for myocardial ischemia.