An Evaluation of the Efficacy of adding Clonidine as Adjuvant to Bupivacaine as Compared to Dexmedetomidine as Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Blocks for Upper Limb Surgeries

BACKGROUND AND OBJECTIVES: Alpha-2 agonists are mixed with local anaesthetic agents to extend the duration of spinal, extradural and peripheral nerve blocks. We compared clonidine and dexmedetomidine as an adjuvant to local anaesthetic agent in supraclavicular brachial plexus block with respect to onset and duration of sensory and motor block and duration of analgesia. AIM OF THE STUDY: To evaluate the efficacy of adding Clonidine as an adjuvant to Bupivacaine as compared to Dexmedetomidine as adjuvant to Bupivacaine in supraclavicular brachial plexus blocks for upper limb surgeries, with regards to the following parameters: a) Onset of sensory block, b) Duration of sensory block, c) Onset of motor block, d) Duration of motor block, e) Haemodynamic changes (heart rate, NIBP, SPO2), f) Level of sedation and complications (if any). METHODS: Sixty ASA I and II patients scheduled for elective upper limb surgeries under supraclavicular brachial plexus block were divided into two equal groups in a randomized, double- blinded fashion. Group C received clonidine 1 μg/kg and Group D received dexmedetomidine 1 μg/kg added to bupivacaine 0.25% (40ml). Onset and recovery time of sensory and motor block and duration of analgesia were studied in both the groups. RESULTS: Duration of sensory block and motor block was 224.50±32.70 and 307.70±34.91min, respectively, in group C, while it was 414.63±70.35 and 489.16±72.80 min, respectively, in group D. There was no statistically significant difference in onset of sensory block. Onset of motor block in group C was 5.66 ±1.39 minutes. Onset of motor block in group D was 5.40±1.88 minutes. Onset of motor block in group D is faster than group D; this difference was statistically significant. ‘p’ value < 0.005. The duration of analgesia (time to requirement of rescue analgesia) in group D was 455.96±71.34 min, while in group C, it was 263.10±40.53 min. Statistically, this difference was significant (P=0.001). CONCLUSION: We conclude that addition of 1 μg/kg of dexmedetomidine to 0.25 % bupivacaine accelerates the onset of sensory and motor block, prolongs the duration of sensory and motor block and the time for rescue analgesia with mild sedation without any adverse effects, when compared to clonidine as an adjuvant to bupivacaine in supraclavicular brachial plexus blocks for upper limb surgeries