Comparison of Dexmedetomidine In Ultrasound-Guided Supraclavicular Brachial Plexus Block Versus Intramuscular Administration In Upper Limb Surgeries

Dexmedetomidine is known to prolong sensory and motor blockade by local anesthetics. In this study we compared the efficacy of dexmedetomidine given intramuscularly and perineurally as an additive to supraclavicular brachial plexus block. Sixty-two patients requiring upper limb surgeries were randomly assigned to two groups. All patients received 2% lidocaine (10 mL) + 0.5% levobupivacaine (10 mL) + normal saline (5 mL). In the perineural group (PN), 0.5 µg/kg dexmedetomidine was administered perineurally in the block whereas in the intramuscular group (IM), 0.5 µg/kg dexmedetomidine was administered intramuscularly in the blocked arm. Onset and duration of sensory and motor blockade, time taken to request analgesia, sedation, and overall patient satisfaction were noted. Onset of sensory blockade occurred at 5 min in both groups. Onset of motor blockade (mean ± SD) occurred at 16.93 ± 6.91 min and 17.25 ± 6.93 min, in Group PN and Group IM, respectively. Sensory blockade (mean ± SD) lasted for 773.71 ± 222.6 min and 701.29±233.34 min, while motor blockade (median) lasted for 275 and 300 min in Group PN and Group IM, respectively. The onset and duration of blockade were comparable between the two groups. Onset and duration of brachial plexus block are comparable whether dexmedetomidine is given perineurally or intramuscularly as an adjunct to local anesthetic.