Abstract
The use of cerebral oximetry to guide intraoperative management has been shown to improve patient outcomes in cardiac surgery. This pilot trial assessed the feasibility of performing a similar study of outcome in patients over the age of 70 years undergoing non-cardiac surgery. Patients over the age of 70 years undergoing total knee or hip arthroplasty or bowel resection surgery were randomly assigned to have cerebral oximetry values monitored (intervention group) or not monitored (control) while under general anaesthesia. Indicators of proof of concept were: rate of complications, rate of cerebral desaturation, relationship between cerebral desaturation and complications, and anaesthetist response to cerebral desaturation. Forty patients were recruited and randomised to a control group (n=20) or an intervention group (n=20). The proportion of the study population who had a complication was 40% (95% confidence interval [CI] 26% to 55%). Cerebral desaturation (<75% of baseline) occurred in only two patients (5.0% (CI 1.4% to 16%)), one in each group, and neither of those patients recorded a complication. Changes to anaesthetic management on the basis of cerebral oximetry values occurred in only two patients in the intervention group (10% (CI 2.8% to 30%)). Maintenance of cerebral oximetry values appeared to be closer to baseline in the intervention group than in the control group but this difference was not significant (P=0.15). Our results indicated that complications occurred frequently in the study population but did not appear to be associated with cerebral desaturation events. These findings do not support a larger intervention study using the current study population.