Coronary artery bypass grafting using two different anesthetic techniques: Part I: Hemodynamic results

Hemodynamic changes were studied during two different anesthetic techniques in 54 patients undergoing coronary artery bypass grafting (CABG). All patients had normal to moderately impaired left ventricular function and were randomly assigned to two groups. In 27 patients, high thoracic epidural analgesia (TEA) with bupivacaine 0.375% plus sufentanil 1:200,000 (ie, 5 micrograms/mL) was used in combination with general anesthesia with midazolam/N2O; in the other 27 patients, general anesthesia (GA) with midazolam and sufentanil was used. After induction of epidural analgesia, heart rate and mean arterial pressure (MAP) decreased. Changes in cardiac index, systemic vascular resistance, and pulmonary capillary wedge pressure were not observed, whereas the stroke volume index increased significantly. After induction of intravenous anesthesia MAP decreased (20%) in both groups. During the pre-bypass period, metaraminol was used in 7 of 27 patients in the GA group and in 5 of 27 patients in the TEA group to treat hypotension. Inotopic drugs were used in 5 patients in the GA group and in none in the TEA group to treat a low CO. Ten GA patients and 4 TEA patients developed hypertension after sternal spread and the GA patients required more nitroprusside. Four GA patients developed electrocardiographic evidence of prebypass ischemia and, therefore, more nitroglycerin was needed for treating myocardial ischemia. More sodium nitroprusside was needed in the GA group during cardiopulmonary bypass (CPB) and the post-bypass period to treat hypertension with a high SVR. In conclusion, hemodynamic stability was more pronounced in the TEA than the GA group before and after CPB.