Effect of Intravenous Dexmedetomidine During General Anesthesia on Acute Postoperative Pain in Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background: Dexmedetomidine has been shown to have an analgesic effect. However, no consensus was reached in previous studies. Methods: Electronic databases such as PubMed, Embase, and Cochrane Central were searched for relevant randomized controlled trials (RCTs). The relative risk (RR) and weighted mean difference (WMD) were used to analyze the outcomes. Random-effects model was used for meta-analysis. Results: Compared to the normal saline group, patients using dexmedetomidine showed a significantly decreased pain intensity within 6 hours (WMD=−0.93, 95% CI −1.34 to −0.53) and at 24 hours after surgery (WMD=−0.47, 95% CI −0.83 to −0.11). Dexmedetomidine usage significantly reduced the cumulative opioids consumption at 24 hours after surgery (WMD=−6.76, 95% CI −10.16 to −3.35), decreased the rescue opioids consumption in post-anesthesia care unit (WMD=−3.11, 95% CI −5.20 to −1.03), reduced the risk of rescue analgesics (RR=0.49, 95% CI 0.33 to 0.71), and the interval to first rescue analgesia was prolonged (WMD=34.93, 95% CI 20.27 to 49.59). Conclusion: Intravenous dexmedetomidine effectively relieved the pain intensity, extended the pain-free period, and decreased the consumption of opioids during postoperative recovery of adults in general anesthesia.