Intraoperative myocardial ischemia in peripheral vascular surgery: general anesthesia vs combined sciatic and femoral nerve blocks.

摘要

STUDY OBJECTIVE: The aim of this study was to compare the frequency of intraoperative myocardial ischemia in lower extremity vascular surgery with general anesthesia vs regional anesthesia via combined sciatic and femoral nerve blocks. DESIGN: This is a prospective, randomized study. SETTING: This study was set at an academic medical center. PATIENTS: The study included 50 patients scheduled for elective lower extremity vascular surgery. INTERVENTIONS: Patients in group 1 received balanced general anesthesia, whereas patients in group 2 received combined sciatic and femoral nerve blocks with 40 mL of 0.375% bupivacaine. Monitoring included a radial artery catheter and multilead, dual-channel electrocardiogram with computerized ST-segment analysis. Blood pressure and heart rate variations were maintained within 10% of preoperative values by adjusting anesthetic depth, fluid replacement, and vasoactive drug dosages. MEASUREMENTS AND MAIN RESULTS: An ST-segment depression of at least 1 mm or elevation of at least 2 mm lasting for more than 1 minute was considered a significant episode of myocardial ischemia. Intraoperative hemodynamic data and the frequency of significant ST-segment change episodes were recorded. The number of patients with ischemic episodes and the total number of these episodes were lower in group 2 than in group 1 (1 patient vs 7 patients, P = 0.02; and 2 vs 14 episodes, P = 0.04). No significant difference was found between groups 1 and 2 regarding systolic or diastolic arterial pressures, or heart rate. CONCLUSION: Compared with general anesthesia, combined sciatic and femoral nerve blocks reduce the frequency of intraoperative myocardial ischemia in patients undergoing lower extremity vascular surgery.