Post-operative Cognitive Dysfunction and the Change of Regional Cerebral Oxygen Saturation in Elderly Patients Undergoing Spinal Surgery

"Cognitive functioning was assessed with the following test: Korean Mini-Mental State Examination (K-MMSE) and visuomotor test of D-LOTCA battery.~Regional cerebral oxygen saturation was continuously monitored using the INVOS 5100 (somatics,Troy, MI) with bifrontal placement of two sensors before the induction of the anesthesia until the end of operation.~Baseline rSO2 was defined as the average saturation value over a 1 min period before induction of general anesthesia, beginning approximately 3 min after the sensors were applied in supine position. After the induction, baseline prone rSO2 was defined over a 5min period after the change of position.~There is no intervention were made according to rSO2 values. Physiologic variables including BIS, PaCO2,PaO2, glucose, electrolyte, hematocrit, HR, MAP, and nasopharyngeal temperature were measured every 1 hours during the surgery."