Comparison of effects of dexmedetomidine and clonidine as adjuvant to bupivacaine 0.25% in ultrasound guided supraclavicular brachial plexus block

Abstract

Background: Ultrasound guided brachial plexus block is the preferred technique for surgeries on upper limb. Adjuvants are usually added to peripheral nerve blocks to increase their analgesic efficiency and duration. We compared analgesic effects of dexmedetomidine 1mcg/kg and clonidine 1mcg/kg as adjuvant to a low volume of bupivacaine in USG guided supraclavicular brachial plexus block.Methods: A prospective, randomized controlled, double blind study planned after permission from institutional ethics committee. Sixty ASA grade I, II patients, 18-60 years undergoing upper limb orthopedic surgery included. Group 1 (Control group) received 20 ml of 0.25% bupivacaine. Group 2 (Dexmedetomidine group) received 20ml of bupivacaine + dexmedetomidine (10 ml of 0.5% bupivacaine + 1µg/kg of dexmedetomidine, diluted with 0.9% NS to 20 ml) Group 3 (Clonidine group) received 20 ml of 0.25 bupivacaine + clonidine (10ml of 0.5% bupivacaine+1µ g/kg of clonidine, diluted with 0.9% NS to 20 ml) in USG guided supraclavicular brachial plexus block. Continuous variables analyzed with analysis of variance or Kruskal-Wallis test and categorical variables with Fisher’s exact test.Results: Pain free period was 864.90±357.16 minutes: dexmedetomidine group; 584.59±172.38 minutes: clonidine group, 431.78±138.40 minutes: control group with p< 0.001. VRS (verbal rating score) was significantly higher in control group as compared to dexmedetomidine at 4 hours but the pain scores were comparable between all the groups after 8 hours of block.Conclusions: Dexmedetomidine as an adjuvant to bupivacaine provides prolonged anaesthesia, better pain relief in early postoperative period with haemodynamically stable, calm patients compared to clonidine and control group.