The relationship between cerebral oxygen saturation changes and postoperative cognitive dysfunction in elderly patients after coronary artery bypass graft surgery

Abstract

Objective: The aim of this study was to evaluate the predictive value of cerebral regional oxygen saturation (rSO(2)) in the occurrence of postoperative cognitive dysfunction (POCD) in elderly patients undergoing coronary artery bypass graft (CABG) surgery.

Design: A prospective study.

Setting: University hospital.

Participants: A total of 61 patients (84% male) with a mean age of 70.39 ± 4.69 on a waiting list for CABG surgery were enrolled in the study.

Intervention: A complete neurocognitive evaluation was performed 1 day before surgery as well as 4 to 7 days and 1 month after surgery. During surgery, rSO(2) was monitored continuously.

Measurements and main results: POCD was defined as a reduction of 1 standard deviation on 2 or more neuropsychologic indices. Forty-six patients (80.7%) developed early POCD, and 23 (38.3%) showed late POCD. Patients whose rSO(2) decreased to less than 50% during the surgery experienced more POCD 4 to 7 days after surgery (p = 0.04). In addition, a decrease of more than 30% from the patient's baseline rSO(2) was associated with POCD 1 month after surgery (p = 0.03).

Conclusion: Intraoperative cerebral oxygen desaturation is associated with early and late POCD in elderly patients. Cerebral oximetry is a promising tool in the prediction of subtle neuropsychologic deficits and further studies are needed.