Cerebral oxygenation is better during mild hypothermic than normothermic cardiopulmonary bypass

Purpose: Normothermic cardiopulmonary bypass (CPB) has been recently used i n cardiac surgery. However, there is a controversy whether there is a diffe rence in incidence of neurological disorder after coronary artery bypass gr aft (CABG) surgery between normothermic CPB and mild hypothermic CPB, In th is study, we assessed the effects of normothermia and mild hypothermia (32 degrees C) during CPB on jugular oxygen saturation (SjvO(2)). Methods: Twenty patients scheduled for elective CABG surgery were divided i nto two groups. Group 1 (n=10) underwent normothermic (>35 degrees C) CPB, and Group 2 (n=10) underwent mild hypothermic (32 degrees C) CPB. Alpha-sta t blood gas regulation was applied. After inducing anesthesia, a 4.0 French fibre optic oximetry oxygen saturation catheter was inserted into the righ t jugular bulb to monitor SjvO(2) continuously throughout anesthesia and su rgery. Results: The SjvO(2) in the normothermic group was decreased at 20 (41.5 +/ - 2.4%) and 40 min (43.8 +/- 2.8%) after the onset of CPB compared with con trol (53.9 +/- 5.4%, P < 0.05). However, there was no change in SjvO(2) in the mild hypothermic group during the study. No changes in jugular venous-a rterial differences of lactate or creatine phosphokinase isoenzyme BE were observed in two groups during the study. Conclusions: Cerebral oxygenation, as assessed by SjvO(2) was increased dur ing mild hypothermic CPB than during normothermic CPB.