Dexmedetomidine vs dexamethasone as an adjuvant to 0.5% ropivacaine in ultrasound-guided supraclavicular brachial plexus block

Background and Aims: Both dexmedetomidine and dexamethasone have individually been shown to be beneficial as an adjuvant to ropivacaine. We compared the efficacy of combination of ropivacaine with dexmedetomidine and ropivacaine with dexamethasone in ultrasound-guided supraclavicular brachial plexus (SCBP) block. Material and Methods: In this prospective randomised double-blind controlled trial, 60 ASA physical status I/II patients undergoing elective upper-limb surgery under ultrasound-guided SCBP block with 30 ml of 0.5% ropivacaine were randomised into three groups. Group 1 (n = 20) received 1 mu g/kg of dexmedetomidine, and group 2 (n = 20) received 8 mg of dexamethasone in addition to ropivacaine, while group 3 (n = 20) received only ropivacaine. The primary outcomes studied were onset and duration of sensory and motor block. Secondary outcomes included duration of analgesia, total analgesic consumption in 24 h postoperatively and quality of block. ANOVA and Chi-square test were used to compare results on continuous measurements and categorical measurements, respectively. Results: Onset of sensory and motor block was faster in group 1 (13.5 +/- 4.1 and 17.0 +/- 4.1 min) and group 2 (15.6 +/- 3.6 and 18.5 +/- 3.7 min) as compared to group 3 (20.1 +/- 5.3 and 24.9 +/- 5.6 min; P < 0.001). Block duration was significantly longer in group 1 and group 2 than in group 3. Duration of analgesia was prolonged in group 1 and 2 (1218.0 +/- 224.6 and 1128.0 +/- 207.5 min, respectively) as compared to group 3 (768.0 +/- 273.7 min; P < 0.001). Twenty-four hours analgesic consumption postoperatively was reduced in the two study groups. Conclusion: Both dexmedetomidine and dexamethasone when used as adjuvants to ropivacaine for SCBP block, block onset time, and prolong' block duration.