Anesthesia Dose and Delirium

In this issue of JAMA, Deschamps and colleagues report results of the Electroencephalographic Guidance of Anesthesia to Alleviate Geriatric Syndromes-Canada (ENGAGES-Canada) trial. ENGAGES-Canada compared rates of postoperative delirium among 1140 patients 60 years or older undergoing cardiac surgery who were randomly assigned to 1 of 2 strategies to prevent excessive dosing of inhaled general anesthetics: electroencephalogram (EEG)-guided dosing vs usual care, in which anesthesia dose was guided by expired anesthesia gas levels and hemodynamic measurements. Although some previous studies have found an association between deep general anesthesia and postoperative delirium, it remains unknown whether using EEG guidance to minimize time with intraoperative EEG suppression—a marker of deep anesthesia—might reduce delirium compared with usual care.