Buprenorphine for postoperative analgesia: Axillary brachial plexus block versus intramuscular administration in a placebo-controlled trial

BACKGROUND AND AIMS: Peripheral administration of opioids has been suggested for prolongation of regional analgesia. This prospective, randomized, double-blind placebo-controlled study was undertaken to compare the effect of regional (axillary brachial plexus block [ABPB]) versus intramuscular (IM) buprenorphine (2 μg/kg) in adults. MATERIAL AND METHODS: Seventy-five adults undergoing upper limb surgery received ABPB with local anaesthetic (15 ml 0.5% bupivacaine, 15 ml 2% lignocaine with adrenaline 1:200,000, 9 ml normal saline [NS]). In addition, regional group RB (n = 25) received buprenorphine 2 μg/kg in ABPB and 1 ml NS IM. Systemic Group SB (n = 25) received 1 ml NS in ABPB and buprenorphine 2 μg/kg IM. Group C (n = 25) received 1 ml NS in ABPB and IM. Onset, duration of sensory and motor block, hemodynamic parameters, sedation score, pain scores using visual analog scale, duration of postoperative analgesia, rescue analgesic (RA) requirement, adverse events, and patient satisfaction were noted. RESULTS: Demographics, onset and duration of sensory, motor block were similar. RB group had longest duration of analgesia (20.61 ± 1.33 h) compared to SB (10.91 ± 0.90 h) and control group (5.86 ± 0.57 h) (P < 0.05 RB vs. SB/C and SB vs. C). RA requirement was highest in the control group and least in RB group (P = 0.000 RB vs. SB/C and SB vs. C). SB group had a maximum number of side effects (P = 0.041, SB vs. RB/C). Patient satisfaction was highest with group RB (P < 0.05 RB vs. SB/C, and P = 0.06 SB vs. C). CONCLUSION: Buprenorphine 2 μg/kg in axillary plexus block provides significantly prolonged analgesia with less RA requirement and greater patient satisfaction compared to IM administration. This is highly suggestive of action on peripheral opioid receptors.