EEG-Guided Anaesthetic Administration Does Not Prevent Postoperative Delirium in Older Adults

By Denise Baez

Electroencephalography (EEG)-guided anaesthetic administration does not decrease the incidence of postoperative delirium in older patients undergoing major surgery, according to a study published in JAMA.

“In this randomised study involving 1,232 patients aged 60 years and older undergoing major surgery, postoperative delirium occurred in 26.0% of the EEG-guided anaesthetic group and in 23.0% of the usual care group — a difference that was not statistically significant,” reported Troy S. Wildes, MD, Washington University School of Medicine, St. Louis, Missouri, and colleagues.

An interesting and unexpected finding was that the EEG-guided anaesthesia group had a lower 30-day mortality rate than the usual care group (4 [0.65%] vs 19 [3.07%] deaths).

The researchers undertook the study because excessive general anaesthesia has been associated with postoperative delirium. They hypothesised that if anaesthetic concentration is closely monitored during surgery, then there would be a decrease in postoperative delirium.

The ENGAGES study included older adults who were undergoing major surgery (cardiac and non-cardiac surgery) at Barnes-Jewish Hospital, St Louis, Missouri, between January 2015 and May 2018.

Delirium occurred 1 to 5 days after surgery in 157 of 604 (26%) patients who were randomised to receive EEG-guided anaesthesia, compared with 140 of 609 (23%) patients who were randomised to receive usual anaesthetic care (P = .22).

Anaesthetic concentration was significantly lower in the EEG-guided group than the usual care group (0.69 vs 0.80 minimum alveolar concentration).

There were no cases in either group of intraoperative awareness.

Postoperative nausea and vomiting was reported in 7.8% of patients in the EEG-guided group and in 8.9% of patients in the usual care group. Serious adverse events occurred in 20.2% and 21.0%, respectively.

“These findings do not support the use of electroencephalography-guided anaesthetic administration for the prevention of postoperative delirium among older adults undergoing major surgery,” the authors concluded.