Background: Postoperative delirium is a major debilitating complication for patients and is associated with poor outcomes. Previous studies have suggested that excessive general anesthesia may lead to postoperative delirium. Electroencephalography (EEG)-based monitors have been administered in clinical practice in an attempt to deliver appropriate anesthesia. The aim of this updated meta-analysis was to evaluate the current body of research concerning the effects of EEG-based monitor on postoperative delirium.
Methods: We conducted a meta-analysis of randomized controlled trials of the effect of processed EEG monitor on postoperative delirium as the primary outcome. The search was performed in CENTRAL, MEDLINE, and EMBASE, with no language restrictions from inception until June 23, 2019. Two independent reviewers screened records and full-text articles for inclusion. Data extraction and risk-of-bias assessment were conducted by 3 independent reviewers. Random-effects models were used to calculate combined-effect estimates. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence.
Results: Of 5904 records screened, 5 studies met our inclusion criteria, including 3612 patients. Meta-analysis revealed no significant effect of EEG-based monitors on postoperative delirium (risk ratio [RR], 0.79; 95% confidence interval [CI], 0.60-1.05; I = 73%). The results showed a statistically significant reduction in intensive care unit (ICU) length of stay (3 studies, weight mean difference [WMD] -0.29 days; 95% CI, -0.53 to -0.05) in patients with EEG monitored. EEG-guided anesthesia did not have a statistically significant difference in all-cause mortality (3 studies, RR, 0.63; 95% CI, 0.31-1.29) and hospital length of stay (4 studies, WMD -0.61 days; 95% CI, -1.34 to 0.11). Few studies investigated the effects of EEG-guided anesthesia on perioperative major nonneurological complications and did not come up with promising results.
Conclusions: The current evidence is not sufficient to support the prevention effects of EEG monitor on postoperative delirium. More robustly designed and well-conducted studies with emphasis on this matter are warranted.