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

PURPOSE: To assess and compare the effects of normothermic and mild hypothermic cardiopulmonary bypass (CPB) on hepatosplanchnic oxygenation. METHODS: We studied 14 patients scheduled for elective coronary artery bypass graft surgery who underwent normothermic (>35 degrees C; group I, n=7) or mild hypothermic (32 degrees C; 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 hepatosplanchnic blood flow by a constant infusion technique that uses indocyanine green. 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 of CPB in group I (39.5 +/- 16.2% and 40.1 +/- 9.8%, respectively) than in group 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 hypothermic CPB than during normothermic CPB.