Effect of clonidine as adjuvant in bupivacaine-induced supraclavicular brachial plexus block: A randomized controlled trial

Objective: Clonidine has been used as adjuvant to local anesthetics in order to extend the duration of analgesia in various regional and central neuraxial blocks. It is previously reported that clonidine added to bupivacaine increases analgesia duration in brachial plexus block. We evaluated the effect of this combination in supraclavicular brachial plexus block for upper limb orthopedic procedures.

Materials and methods: A randomized double-blind placebo controlled trial was done with 70 patients of American Society of Anesthesiologists Grade I or II status undergoing upper limb orthopedic procedures. Group A (n = 35) patients received 25 ml of 0.5% bupivacaine and 0.2 ml (30 mcg) clonidine, whereas group B (n = 35) received 25 ml of 0.5% bupivacaine and 0.2 ml normal saline through a supraclavicular approach for brachial plexus block. Vital parameters were recorded 10 min prior to block placement and every 3 min thereafter till the end of the procedure. Onset and duration of both sensory and motor blocks and sedation score were recorded. All patients were observed in postanesthesia care unit and received tramadol injection as soon as they complained of pain as rescue analgesic. Duration of analgesia was taken as the time from placement of block till injection of rescue analgesic.

Results: Analgesia duration was 415.4 +/- 38.18 min (mean +/- standard deviation) in Group A (clonidine) compared to 194.2 +/- 28.74 min in Group B (control). No clinically significant difference was observed in heart rate, blood pressure, and oxygen saturation. Sedation score was higher in the clonidine group.

Conclusion: Addition of a small dose of clonidine to 0.5% bupivacaine significantly prolonged the duration of analgesia without producing any clinically important adverse reactions other than sedation.