Deciding the Better Dose- A Prospective Randomized Double Blind Study of Two Different Doses of Perineural Dexmedetomidine in Axillary Brachial Block

Abstract

Background: Axillary brachial plexus block is generally regarded as the safest and reliable technique for forearm and hand surgeries. Dexmedetomidine, a potent alpha (α)-2-adrenergic receptor agonist when used as an additive in any peripheral nerve block can improve quality of block and postoperative analgesia, though uncertainity prevails regarding the dose in patients undergoing hand and forearm surgeries. Methods: In this prospective, randomized, comparative, double blind study, 80 patients were included. Each participant fulfilling the inclusion criteria then received axillary brachial plexus block using 15cc 2% lignocaine with adrenaline (1:200000)and 0.5% bupivacaine 5cc mixed with dexmedetomidine either 0.5 µg /kg (group A) or 1 µg /kg ( group B)in 2cc normal saline. Duration of post-operative analgesia was the primary outcome. Result: Duration of analgesia was significantly prolonged in group B (493.77±115.62 min) compared to group A (434.62±45.18 min, P <0.01). Conclusion: Between the two doses of dexmedetomidine, block characteristics and analgesia obtained were better with higher dose (1 µg/kg) but chances of side effects like bradycardia increased. Hence 0.5 µg/kg can be a better dose with improved block characteristics yet negligible side effects. Keywords: Brachial plexus block, Dexmedetomidine Perineural, Peripheral nerve stimulator, Ultrasonography