Application of regional cerebral oxygen saturation monitoring in predicting postoperative delirium in elderly patients

Abstract

Objective To evaluate the application of regional cerebral oxygen saturation (rSO2) in predicting postoperative delirium (POD) in elderly patients. Methods A total of 140 elderly patients were enrolled in this study. The value of rSO2, mean arterial pressure (MAP), heart rate, pulse oxygen saturation (SpO2) and end-tidal carbon dioxide partial pressure (PETCO2) were monitored at the time of room entry (t0), double-lung ventilation during anesthesia induction (t1), double-lung ventilation during lateral position (t2), single-lung ventilation during lateral position (t3), and extubation after surgery (t4). Meanwhile, the baseline of rSO2, minimum rSO2 (rSO2min), mean rSO2 (rSO2mean) and maximum percentage drop in rSO2 (rSO2%max) were recorded. The patients were divided into a POD group (n=24) and a non-POD group (n=116), according to the definition of POD. The independent risk factors of POD were determined using multivariate Logistic regression, and receiver operating characteristic curve(ROC) analysis was performed to assess the accuracy of rSO2 in predicting POD. Results POD was present in 24 patients among 140 elderly patients (17.1%). At t3 point, the levels of rSO2 were significantly decreased in the POD group compared with the non-POD group (P 0.05). In the POD group, its age and rSO2%max were significantly higher than that in the non-POD group, while its rSO2min and rSO2mean were significantly lower than that in the non-POD group (P<0.05). Logistic regression analysis showed that, age and rSO2%max were the independent risk factors for POD. ROC curve showed that the area under receiver operating characteristic curve (AUC) of rSO2%max was 0.893 (95%CI 0.829-0.939) at a cutoff value of 15.59%. The specificity and sensitivity of rSO2%max in predicting POD were 79.31% and 91.67%, respectively. Conclusions rSO2%max is the independent risk factor for POD in elderly patients after surgery, and rSO2%max>15.59% is considered a potential predictor of POD. Key words: Regional cerebral oxygen saturation; Delirium; Elderly patients; Predictor