RESUMEN
Background: Both dexamethasone and dexmedetomidine are commonly used local anaesthetic adjuvants in brachial plexus block to enhance the blocking effect. However, it is unclear which of the two drugs is more effective in a brachial plexus block. This article compares the effects of dexamethasone and dexmedetomidine combined with local anaesthetics in brachial plexus block through meta-analysis, availing information for current practice and future research. Methods: We conducted a search of the PubMed, Embase, Cochrane Library, and Web of Science databases to identify studies investigating the effects of dexamethasone and dexmedetomidine combined with local anaesthetics on brachial plexus block. The databases were searched from their inception to October 2021. Clinical randomized controlled trials were included. Two researchers independently conducted literature screening. The Cochrane System Review Manual was adopted for literature quality evaluation, whereas Stata 14.0 software aided in the meta-analysis. The duration of analgesia was the primary outcome indicator; whereas, the secondary outcome indicators included the duration of sensory block and motor block. Results: Seven articles were analysed, including 465 patients. Compared to the dexmedetomidine group, the dexamethasone group exhibited longer durations of analgesia (WMD = 111.29, 95% CI: 16.49-206.10, P = 0.021), sensory block (WMD = 173.20, 95% CI: 86.69-259.71, P < 0.0001), and motor block (WMD = 121.03, 95% CI: 12.87-229.20, P = 0.028). Conclusion: The present meta-analysis results affirm that dexamethasone is a better local anaesthetic adjuvant in brachial plexus block that enhances the blocking effect. Nevertheless, the existing heterogeneity warrants additional large-scale, multicentre, high-quality randomized controlled trials in the future for further verification and to provide more reliable clinical evidence.