A comparative study on the analgesic effects of clonidine and midazolam as an adjuvant to a mixture of local anaesthetics in supraclavicular brachial plexus block

Abstract

Introduction: With the rapid increase in traffic accidents, victims present for upper limb surgeries. Brachial plexus block is a good substitute to general anaesthesia. The aim of this study was to compare the analgesic effects of clonidine and midazolam as adjuvant to a mixture of local anesthetics in supraclavicular brachial plexus block. Material & Methods: A randomized prospective double blind study conducted at Department of Anaesthesiology in a Tertiary care teaching hospital over a period of 6 months on 60 ASA- I and ASA II patients who fulfilled the inclusion and exclusion criteria. They were divided into 2 groups of 30 each based on computer generated randomization table, Group C received 150 μgm clonidine +Inj lignocaine 2% with adrenaline 15ml+Inj bupivacaine plain (0.5%) 15ml and diluted to 40ml and Group M received Inj midazolam 50μgm/kg adjuvant to the same mixture of local anesthetics and diluted to 40ml. Both the groups were compared based on the onset of sensory & motor block, duration of sensory & motor block, sedation measured by sedation score (Culebras). Total duration of sensory & motor analgesia & post-operative VAS score was recorded. Results: Onset of sensory and motor block was earlier in Group C, even duration of analgesia was significantly prolonged in Group C (619.53 ± 77.58 min versus 508.73 ± 89.83 min. in group M, the p value being < 0.001). VAS score was 0 upto 3hrs in Group C and 0.5hr in group M. And the maximum sedation score seen in Group C was 3(Sedated and responding to mild stimulus). In Group M the maximum score noted was only 2 (Sedated and responding to verbal commands). Conclusion: Clonidine as an adjuvant in brachial plexus block for upper limb elective surgeries prolongs post-operative analgesia and also has high sedation score with no complications in either of the groups.