Efficacy of dexmedetomidine on postoperative nausea and vomiting: a meta-analysis of randomized controlled trials

Purpose: Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on PONV. Methods: Two researchers independently searched PubMed, Embase and Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs). The meta-analysis was performed with Review Manager. Results: Eighty-two trials with 6,480 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative nausea (Risk Ratio (RR) = 0.61, 95% confidence interval (CI): 0.50 to 0.73) and vomiting (RR = 0.48, 95% CI: 0.36 to 0.64) compared with placebo, with an effective dose of 0.5 mu g/kg (RR = 0.46, 95% CI: 0.34 to 0.62) and 1.0 mu g/kg (RR = 0.29, 95% CI: 0.12 to 0.75), respectively. The antiemetic effect can only be achieved intravenously, not epidurally or intrathecally. The efficacy of dexmedetomidine was similar to that of widely used agents, such as propofol, midazolam etc., but better than opioid analgesics. Moreover, application of dexmedetomidine reduced intraoperative requirement of fentanyl (Standard Mean Difference = -1.91, 95% CI: -3.20 to -0.62). Conclusions: The present meta-analysis indicates that dexmedetomidine shows superiority to placebo, but not to all other anesthetic agents on PONV. And this efficacy may be related to a reduced consumption of intraoperative opioids.