Effect of remimazolam on postoperative delirium in elderly patients undergoing major abdominal surgery: a randomized controlled Trial

Background: Older patients are at a high risk of postoperative delirium (POD), and the choice of general anesthesia may affect postoperative cognitive outcomes. As a new type of benzodiazepine, remimazolam has wide application prospects in clinical anesthesia owing to its rapid onset, non-organ metabolism, and low respiratory and circulatory depression. This study aimed to compare the effect of propofol-based versus remimazolam-based general anesthesia on the incidence of delirium after major abdominal surgery in older adults. Patients and Methods: A total of 370 older adults (≥ 65 to < 90 years old) scheduled to undergo major abdominal surgery (> 2 h) were randomized to receive propofol or remimazolam-based general anesthesia. Trained investigators assessed delirium within 5 days postoperatively using the Confusion Assessment (CAM) or Confusion Assessment Intensive Care Unit (CAM-ICU) scale. The incidence of delirium between the two groups was compared using protocol and intention-to-treat (ITT) analyses. Results: There was no significant difference in the incidence of POD between the two groups (per-protocol: 29 [17.1%] vs. 34 [19.7%]; OR [95%]: 1.189 [0.688-2.057], P = 0.578). In subgroup analysis, age ≥ 75 years interacted with the intervention (Odds Ratio [95% CI]: 2.700 [1.118 to 6.521], interactive P < 0.001). The incidence of hypotension was lower in the remimazolam group (Odds Ratio [95% CI]: 0.460 (0.262-0.807), P = 0.009). There were no significant differences in pain scores or other adverse events between the two groups ( P > 0.05). Conclusions: Our study, combined with the literature, suggests that remimazolam does not increase the risk of POD in older patients compared with propofol. Larger studies are required to confirm or rule out this effect. Given the safety profile and wide availability of remimazolam, this is worth investigating; with the passage of time and the expansion of many people, the choice of general anesthetic strategy for special populations may be more instructive.