Epidural analgesia with bupivacaine does not improve splanchnic tissue perfusion after aortic reconstruction surgery

Inadequate splanchnic tissue perfusion is relatively common during and after aortic surgery. We hypothesized that vasodilation caused by thoracic epidural analgesia improves splanchnic blood flow and tissue perfusion after aortic surgery. In this prospective, randomized, controlled study, we studied 20 patients undergoing elective aortic-femoral or aortic-iliac reconstruction surgery. Gastric and sigmoid colon mucosal PCO2 and pH were measured during surgery. An epidural bolus of bupivacaine 40 mg followed by infusion of 15 mg h-1 was started after operation in 10 patients. After operation, splanchnic blood flow and gastric and sigmoid colon mucosal PCO2 and pH were measured before and 2 h after the start of epidural analgesia. During surgery, the gastric mucosal-arterial PCO2 difference remained stable, whereas the sigmoid mucosal-arterial PCO2 difference increased during aortic clamping but returned to pre-clamping values after declamping. After operation, epidural analgesia had no effect on gastric or sigmoid mucosal-arterial PCO2 differences or on splanchnic blood flow.