Impact of monitoring cerebral oxygen saturation on the outcome of patients undergoing open heart surgery

Aims and Objectives: We studied the usefulness of regional cerebral oxygen saturation (rSO(2) ) monitoring during cardiopulmonary bypass (CPB) and evaluated effects of cerebral oxygen desaturation on the postoperative neurological outcome. Materials and Methods: 100 patients were randomly allocated to either control or intervention group. In the control group rSO(2) was recorded continuously, but the attending anesthesiologist was blinded. In the intervention group specific interventions were initiated in case of cerebral desaturation. Neurocognitive testing was done using a simplified antisaccadic eye movement test (ASEM) and mini-mental state examination (MMSE). Data was analyzed using Chi-square test, and unpaired t-test. Results: In both the groups rSO(2) declined during CPB. The decrease in rSO(2) was significant (P < 0.001) in the control group compared to the intervention group. In the intervention group the rSO(2) mainly responded to an increase in mean arterial pressure. The area under the curve below threshold rSO(2) was significantly more (P < 0.0001) in the control group compared to intervention group and a significant decrease in the MMSE and ASEM scores occurred in control group at one week and three months postoperatively. Conclusions: Monitoring of rSO(2) during CPB can significantly decrease the incidence of postoperative neurocognitive decline.