Does Brain Monitoring During Anesthesia Lower Delirium Risk? A New Look at 87 Trials
Families often ask me whether their parent will be "the same" after surgery. Postoperative delirium, a sudden stretch of confusion in the days after an operation, is one of the most common problems in older patients, and it can linger. One tool we have is a processed EEG monitor, a small sensor on the forehead that turns brain wave activity into a number that helps us judge how deeply asleep a patient is. A large review published October 30, 2026 in the Journal of Clinical Anesthesia pulled together the randomized trials on this question.
The study
The authors gathered 87 randomized trials with more than 30,000 adults having surgery, endoscopy, or dental procedures, and compared anesthesia guided by a processed EEG monitor with anesthesia given without one. They looked at how much anesthetic drug was used, how often delirium showed up within 10 days, and how quickly patients woke up and left the recovery room.
With EEG guidance, patients received less propofol and less inhaled anesthetic. The risk of delirium was about 27% lower (risk ratio 0.73, 95% CI 0.63 to 0.84). Patients also had their breathing tube out about 3 minutes sooner, woke about 2 minutes sooner, were oriented about 4 minutes sooner, and spent about 3 minutes less in the recovery room. The benefit was most consistent for the BIS monitor, which had the most trials behind it. Results for other brands were less certain because there were fewer studies.
How I read it
The direction of these findings matches what I see in the operating room. When I can watch the EEG, I tend to give less drug, especially to older and frailer patients who are easily overdosed by numbers on a chart built for healthy younger adults. Less drug and a smoother wake up make sense.
I would still read the delirium result with some caution. Pooling 87 trials means pooling very different patients, drugs, and ways of measuring delirium, and the authors note substantial variation between studies. Some of the largest and most carefully run single trials of EEG guidance in older adults did not show a clear drop in delirium, so a pooled estimate can look more confident than any one good trial. It is also worth knowing that the review was funded by Medtronic, which makes the BIS monitor, and that several authors have ties to the company. That does not make the work wrong, but it is part of the picture. The time savings, a few minutes per case, are real but modest.
What it means for practice here
For my patients in Casper, especially older adults having longer operations, I see processed EEG as a sensible and low risk part of a careful anesthetic. It helps me avoid giving more anesthetic than a patient needs. It is not a cure for delirium on its own. The things that matter alongside it are simple: keeping blood pressure steady, avoiding unnecessary sedatives like benzodiazepines, treating pain well, and getting glasses, hearing aids, and family back at the bedside as soon as we can.
Source
- Hormis A, Centimole Z, Saunders SJ, et al. Processed electroencephalogram-guided anesthesia and its impact on postoperative delirium and perioperative efficiency: a systematic review and meta-analysis. Journal of Clinical Anesthesia. Published online October 30, 2026;116:112351. doi:10.1016/j.jclinane.2026.112351. PMID 42962495. Abstract (PubMed)
This post is clinician commentary for educational discussion. It is not medical advice for any reader's personal care. Anesthesia and perioperative decisions should be made with the treating clinician based on the individual patient's circumstances.