Depth of Anesthesia and Postoperative Delirium

In this article, we reviewed the association between depth of anesthesia and postoperative delirium. We also evaluated the evidence for intraoperative brain function monitoring to prevent delirium after surgery. Anesthetics produce profound neurochemical changes that may disrupt normal brain function and result in postoperative delirium. Brain function monitoring has emerged as a tool for titration of anesthetic delivery to avoid sedative drugs overdose and may prevent postoperative delirium. A meta-analysis of five existing trials showed that brain function monitoring significantly reduced the risk of delirium after surgery (odds ratio 0.56, 95 % confidence intervals: 0.40–0.77). However, the current evidence is still not definitive because of limited sample size and heterogeneity among studies. Future studies are required to evaluate different depths of anesthesia and postoperative delirium.