Hepatosplanchnic oxygenation is better preserved during mild hypothermic than during normothermic cardiopulmonary bypass

Purpose: To assess and compare the effects of normothermic and mild hypothe rmic cardiopulmonary bypass (CPB) on hepatosplanchnic oxygenation. Methods: We studied 14 patients scheduled for elective coronary artery bypa ss graft surgery who underwent normothermic (> 35 degreesC; group I, n = 7) or mild hypothermic (32 degreesC; group II, n = 7) CPB. After induction of anesthesia, a hepatic venous catheter was inserted into the right hepatic vein to monitor hepatic venous oxygen saturation (ShvO(2)) and hepatosplanc hnic blood flow by a constant infusion technique that uses indocyanine gree n. Results: The ShvO(2) decreased from a baseline value in both groups during CPB and was significantly lower at ten minutes and 60 min after the onset o f CPB in group I (39.5 +/- 16.2% and 40.1 +/- 9.8%, respectively) than in g roup II (61.1 +/- 16.2% and 61.0 +/- 17.9%, respectively; P < 0.05). During CPB, the hepatosplanchnic oxygen extraction ratio was significantly higher in group I than in group II (44.0 +/- 7.2% vs 28.7 +/- 13.1%; P < 0.05). Conclusion: Hepatosplanchnic oxygenation was better preserved during mild h ypothermic CPB than during normothermic CPB.