Study: Postoperative delirium less likely with ephedrine than phenylephrine

Editor's Note

Using phenylephrine as an intraoperative vasopressor could lead to higher risk of postoperative delirium compared to ephedrine, according to findings published in the April issue of Anesthesiology.

Posted online last September, these findings confirm researchers’ original hypothesis. “The treatment of intraoperative hypotension with phenylephrine may impair cerebral perfusion through vasoconstriction, which has been linked to postoperative delirium,” they write. The observational study also showed correlation between the level of delirium risk and the does of phenylephrine.

The multicenter hospital registry study focused on 103,094 hospitalized adults undergoing general anesthesia for noncardiac, non-neurosurgical procedures between 2008 and 2020 at two tertiary academic healthcare networks in Massachusetts. Of that total, 78,982 (76.6%) patients received phenylephrine, and 24,112 (23.4%) patients received ephedrine during surgery; 770 patients (0.8%) developed delirium within 7 days—an outcome associated with the administration of phenylephrine in adjusted analyses.

A keyword and manual chart review-based approach in a subset of 45,465 patients further validated these findings. Additionally, fractional polynomial regression analysis further indicated a dose-dependent effect of phenylephrine.

Based on these results, the researchers recommend clinical trials to determine whether favoring ephedrine over phenylephrine for treating intraoperative hypotension can reduce the risk of postoperative delirium.