Study objective: To evaluate the efficacy of perioperative dexmedetomidine (DEX) administration for preventing delirium in adults after non-cardiac surgery.
Design: Systematic review and meta-analysis of randomized controlled trials (RCTs).
Interventions: Perioperative administration of DEX to prevent delirium in adults following non-cardiac surgery.
Measurements: The incidence of postoperative delirium (POD).
Methods: The databases of PubMed, Embase and Cochrane Central Register were searched from inception to Mar 4, 2021 for all available RCTs that assessed DEX for POD in adults after non-cardiac surgery. Risk ratio (RR) with a 95% confidence interval (CI) was calculated for dichotomous data. Standardized mean difference (SMD) was calculated for continuous data. Risk of bias was assessed using the second version of the Cochrane risk-of-bias tool for RCTs (RoB 2.0), and the level of certainty for main outcomes were assessed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology.
Main results: Thirteen studies, including the meta-analysis with a total of 4015 patients (DEX group: 2050 patients; placebo group: 1965 patients), showed that DEX significantly reduced the incidence of POD in adults after non-cardiac surgery compared with control group (RR: 0.60; 95%CI: 0.46 to 0.77, P = 0.0001, I2 = 55%, GRADE = moderate). Meanwhile, there was a statistical difference by the subgroup analysis between the mean age ≥ 65 years group and the mean age <65 years group. There were no statistical differences in length of hospital stay following surgery (SMD: -0.36; 95%CI: -0.80 to 0.07, P = 0.1, I2 = 97%, GRADE = low) and all-cause mortality rate (RR:0.57; 95%CI: 0.25 to 1.28, P < 0.17, I2 = 0%, GRADE = moderate) compared with placebo group. However, Meta-analysis showed that DEX administration significantly resulted in intraoperative bradycardia when compared with placebo group (RR: 1.39; 95%CI: 1.14 to 1.69, P = 0.0009, I2 = 0%, GRADE = high), and as well as intraoperative hypotension (RR: 1.25; 95%CI: 1.11 to 1.42, P = 0.0004, I2 = 0%, GRADE = high).
Conclusion: This systematic review and meta-analysis suggests that perioperative administration of DEX could significantly reduce the incidence of POD in patients elder than 65 years following non-cardiac surgery. However, there was no definite evidence that perioperative DEX could reduce the incidence of POD in patients younger than 65 years of age after non-cardiac surgery. In addition, perioperative DEX administration was associated with an elevated risk of bradycardia and hypotension.