Cerebral oximetry-guided anaesthesia and postoperative delirium in elderly patients undergoing off-pump coronary artery bypass grafting: a randomized controlled trial

While cerebral oximetry monitoring has been reported to reduce neurological dysfunction and hospital stay after cardiac surgery, its effect on postoperative delirium (POD) during off-pump coronary artery bypass grafting (CABG) remains underexplored. This study examines whether using cerebral oximetry to guide anaesthesia can reduce POD in patients aged ≥ 65 years undergoing off-pump CABG. This single-center, randomized trial enrolled 200 patients scheduled for off-pump CABG. Participants were randomly assigned (1:1) to either the intervention or control group using sealed envelopes prior to anaesthesia. In the intervention group, cerebral oxygen saturation was continuously monitored by cerebral oximetry. A desaturation event (a drop > 20% from baseline or an absolute regional cerebral oxygen saturation < 55% at either probe) triggered predefined intervention strategies. In the control group, cerebral oximetry data were blinded to clinicians, and patients received standard anaesthetic care. The primary outcome was the incidence of POD during the first 7 days after surgery. Secondary outcomes included the incidence of postoperative acute kidney injury and myocardial infarction, mechanical ventilation duration, intensive care unit (ICU) and hospital stay, and in-hospital mortality. A total of 200 patients were randomized and included in the final analysis. Delirium occurred in 14 patients (14.0%) in the intervention group versus 24 (24.0%) in the control group within the first 7 postoperative days (P = 0.104). Subgroup analysis showed a significantly lower incidence of delirium in older patients ( > 70 years) in the intervention group compared to the controls [5/47 (10.6%) vs. 11/31 (35.5%); P = 0.011], suggesting a possible interaction between cerebral oximetry-guided anaesthesia and advanced age. ICU and hospital stays were also markedly shorter in the intervention group. Cerebral oximetry-guided anaesthesia did not significantly reduce POD in patients aged ≥ 65 years undergoing off-pump CABG; exploratory analyses suggested a numeric reduction in those > 70 years. However, this observation requires prospective validation in a larger, adequately powered trial. ChiCTR2300068537 (Chinese Clinical Trial Registry), registered 22/02/2023.