Perioperative dexmedetomidine reduces delirium in elderly patients after non-cardiac surgery: a systematic review and meta-analysis of randomized-controlled trials.

BACKGROUND

Delirium is a frequent postoperative complication in elderly patients after non-cardiac surgery. We performed this updated meta-analysis to ascertain more precisely the efficacy of dexmedetomidine (DEX) on the incidence of postoperative delirium (POD) in elderly patients after non-cardiac surgery.

METHODS

We searched PubMed, EMBASE, the Cochrane Library, Web of Science, and the Cumulative Index of Nursing and Allied Health Literature (CINAHL) from inception until February 24, 2019. In this meta-analysis, we included randomized-controlled trials comparing the effect of DEX vs normal saline (NS) or other anesthetic drugs on POD incidence in elderly (either ≥ 60 or ≥ 65 yr old) patients undergoing non-cardiac surgery. We performed subgroup analyses of the DEX dosing strategy (starting time, dose, and duration of administration, with or without loading dose) and the strategy of various control drugs. A random-effects model was used for all analyses.

RESULTS

We included 11 studies involving 2,890 patients in our meta-analysis. The pooled results of these studies revealed that DEX significantly reduced the incidence of POD (relative risk [RR], 0.47; 95% confidence interval [CI], 0.38 to 0.58; P < 0.001) compared with the control group. Meanwhile, the incidences of hypotension (RR, 1.20; 95% CI, 1.04 to 1.39; P = 0.01) and bradycardia (RR, 1.33; 95% CI, 1.08 to 1.63; P = 0.007) were increased in the DEX group. Subgroup analyses revealed a decrease in POD incidence when DEX was administered intraoperatively (RR, 0.43; 95% CI, 0.33 to 0.57; P < 0.001) and postoperatively (RR, 0.38; 95% CI, 0.27 to 0.54; P < 0.001) with a loading dose (RR, 0.49; 95% CI, 0.36 to 0.69; P < 0.001) compared with NS (RR, 0.49; 95% CI, 0.37 to 0.64; P < 0.001) and other anesthetic drugs (RR, 0.40; 95% CI, 0.26 to 0.60; P < 0.001). There were significant differences in the time to extubation (standardized mean difference, -0.60; 95% CI, -1.17 to -0.03; P = 0.04) and the length of hospital stay (mean difference, -0.50 days; 95% CI, -0.97 to -0.03; P = 0.04). The amount of data for the duration of mechanical ventilation and length of intensive care unit stay were insufficient to perform a meta-analysis.

CONCLUSION

Perioperative dexmedetomidine reduces the incidence of POD in elderly patients after non-cardiac surgery, but this comes at the cost of an increased incidence of hypotension and bradycardia.