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.