Hemodynamic Evaluation of Thoracic Epidural Analgesia Combined with General Anesthesia in Coronary Artery Bypass Surgery

Abstract

BACKGROUND: High dose fentanyl anesthesia has been recommended for circulatory stability during coronary artery bypass grafting (CABG), but hypertension and tachycardia in response to noxious stimulation have been noted. The purpose of this study was to evaluate the hemodynamic effects of extensive thoracic epidural analgesia (TEA) combined with general anesthesia (GA). METHODS: The hemodynamic effects in CABG were evaluated in 30 patients. They were randomized into two groups ; the GA group receiving high dose fentanyl (50‐70 mcg/kg), the TEA group receiving 10 ml bupivacaine 5 mg ml 1 followed by 5 ml every two hours epidurally GA (N2O‐O2). The hemodynamic parameters were evaluated before induction of anesthesia, 20 minutes after induction of anesthesia, after sternotomy, and 30 minutes after end of cardiopulmonary bypass. RESULTS: Heart rate and mean arterial pressure were significantly lower after sternotomy in the TEA group compared to the GA group. Significant increase in cardiac index and decrease in central venous pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure were found after induction of anesthesia and sternotomy in the TEA group compared to the GA group. Especially, the pulmonary vascular resistance was significantly lower during all the period in the TEA group compared to the GA group. No differences were observed in stroke volume index, systemic vascular resistance, left ventricular stroke work index between two groups. CONCLUSIONS: The present study suggests a more effective blockade of the stress response during CABG with TEA than with GA. So, we consider that TEA could be used as an adjunctive anesthetic method during CABG. [By kind permission, KoreaMed, Korean Association of Medical Journal Editors.]