A recent cluster randomized crossover trial conducted at 20 cardiac surgical centers across North America evaluated whether restricting benzodiazepine administration during open cardiac surgery could reduce the incidence of postoperative delirium. 

Published in JAMA Surgery, the research included 19,768 patients who underwent procedures between November 2019 and December 2022.

The investigators aimed to determine whether an institutional policy that restricted intraoperative benzodiazepines could lower the risk of delirium within 72 hours of surgery. Delirium was assessed using the Confusion Assessment Method–Intensive Care Unit and the Intensive Care Delirium Screening Checklist.

Out of the total patients, 9,827 surgeries occurred during restricted benzodiazepine periods, while 9,941 were performed under liberal policies. Delirium was reported in 14% of patients during restricted periods and 14.9% during liberal periods (adjusted odds ratio = 0.92; 95% confidence interval = 0.84-1.01; P = .07). No statistically significant difference was observed between the groups.

Adherence rates were high. Clinicians followed assigned benzodiazepine policies in 90.9% of cases during restricted periods and 93.2% during liberal periods. No patients spontaneously reported intraoperative awareness during either period.

Lead researcher Jessica Spence, MD, PhD, of the Population Health Research Institute in Hamilton, Ontario, Canada, and colleagues noted that while restricting benzodiazepines did not produce a statistically significant reduction in postoperative delirium, smaller clinically meaningful effects could not be ruled out.

"Given that smaller effect sizes cannot be ruled out, restriction of benzodiazepines during cardiac surgery may be considered," Spence and colleagues explained in their article. 

The researchers were not able to control for perioperative benzodiazepine administration or intraoperative awareness, which relied on patient self-reporting. Further research is needed "to determine whether restricting intraoperative benzodiazepines at the patient level can reduce the incidence of postoperative delirium," they concluded.

A full list of disclosures is available in the study.