The Role of Dexmedetomidine as an Additive to Intravenous Regional Anesthesia: A Systematic Review and Meta-analysis.

Abstract

BACKGROUND\nIntravenous Regional Anesthesia (IVRA) is a reliable and cost-effective anesthetic method for minor surgical procedures to the extremities. Limitations of this block include tourniquet discomfort, short duration of anesthesia and absence of post-operative analgesia. Dexmedetomidine has been used as an adjuvant in order to minimise these negative characteristics with inconclusive results.\n\n\nAIMS\nThe aim of this study was to perform a systematic review of the existing evidence on the role of dexmedetomidine as an additive to Intravenous Regional Anesthesia (IVRA) in upper limb surgery.\n\n\nSTUDY DESIGN\nThe databases searched were MEDLINE, Embase, PubMed, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials databases and clinicaltrials.gov (1990-2019). Seven randomized controlled trials (RCTs) were included.\n\n\nMETHODS\nWe analysed duration of analgesia, onset time of sensory and motor block, intraoperative tourniquet pain scores, incidence of tourniquet pain, need for rescue analgesia, intraoperative rescue analgesia consumption, sedation scores, postoperative pain scores and anesthesia quality.\n\n\nRESULTS\nIntraoperative analgesia duration (MD 11.08 minutes; 95% CI 5.42, 16.75; p< 0.0001) was longer and sensory block onset time (MD -2.10 minutes; 95% CI -3.345, -0.86; p=0.00009) was shorter in the dexmedetomidine group. Anesthesia quality scores (MD 0.58; 95% CI 0.47, 0.70; p<0.00001) and postoperative sedation scores (MD 1.03; 95% CI 0.88, 1.24; p< 0.00001) were significantly higher. There was significant reduction in intraoperative rescue analgesia consumption (MD -19.70 mg; 95% CI -24.15, -15.26; p<0.00001) in the dexmedetomidine group. The risk of tourniquet pain, as well as postoperative pain scores were lower in favor of dexmedetomidine. The addition of dexmedetomidine to IVRA slightly increased the risk of sedation. A limitation of our study is that some of the interesting outcomes derive from a small number of RCTs.\n\n\nCONCLUSION\nThe addition of dexmedetomidine to IVRA ameliorates the block s characteristics and carries low risk of potential side effects.