The Effects of Bispectral Index–Guided Anesthesia on Postoperative Delirium in Elderly Patients: A Systematic Review and Meta-Analysis

Postoperative delirium (POD) is a form of delirium that affects patients who have undergone surgical procedures and anesthesia, usually peaking between 1 and 3 days after their operation. The aim of this meta-analysis was to determine whether monitoring of depth of anesthesia may influence the incidence of POD. A systematic literature search was conducted on studies that reported POD in elderly patients (>60 years old) who underwent surgery. This meta-analysis was carried out using random-effects model. Compared with control group, intraoperative bispectral index (BIS) monitoring reduced POD (odds ratio 1.32, 95% confidence interval 1.11–1.57, P = 0.001, I2 = 51%). In the mixed-surgery group, compared with the control group, BIS monitoring decreased the incidence of POD (odds ratio 1.24, 95% confidence interval 1.07–1.44, P = 0.004, I2 = 61%). There was also no significant difference in the incidence of POD among patients who underwent cardiac, colon, and orthopedic surgeries. BIS monitoring during surgery can reduce the incidence of POD in elderly patients. Whether BIS monitoring may reduce the incidence of POD in a single type of surgery needs further study.