Perioperative dexmedetomidine and postoperative delirium in non-cardiac surgery: a meta-analysis

Background: To compare the effects of perioperative dexmedetomidine with placebo (or other sedation) on the rate of postoperative delirium in adult patients who underwent non-cardiac surgeries. Methods: A meta-analysis was performed on randomized, controlled trials. MEDLINE, the Cochrane Central Register of Controlled Trials, and Embase (to March 20, 2019) were searched for literature retrieval. The standardized primary outcome was postoperative delirium. We pooled risk ratios using a random-effects model. Results: From 10 trials with 2,286 total participants, we recorded 363 postoperative delirium events during the follow-up periods. Compared with the control group, patients in the dexmedetomidine group had a postoperative delirium relative risk of 0.53 [95% confidence interval (CI), 0.37-0.76]. When the dexmedetomidine infusion rate was higher than 0.2 mu g/kg/h, the relative risk of postoperative delirium reduced significantly by 34%, compared with other sedation methods (relative risk =0.66; 95% CI, 0.47-0.94; P=0.02), with no heterogeneity (I-2=31%, P=0.18). While it reduced by 62% when the dexmedetomidine infusion rate was lower than 0.2 mu g/kg/h (relative risk =0.38; 95% CI, 0.27-0.54). Conclusions: Compared to the placebo (or other sedation methods), perioperative dexmedetomidine sedation resulted in lower rates of postoperative delirium in adult patients who underwent non-cardiac surgery.