Effect of Dexmedetomidine as an Adjuvant to 0.75% Ropivacaine in Interscalene Brachial Plexus Block Using Nerve Stimulator: A Prospective, Randomized Double-blind Study

Background: Ropivacaine, a newer local anesthetic (LA), has been increasingly used nowadays in different concentrations for peripheral nerve blocks. It has lesser cardiac toxicity and higher safety margin when compared to bupivacaine. Dexmedetomidine, a novel α2agonist, is widely used as adjuvant to LA in peripheral nerve blocks to decrease the time of onset and increase the duration of the block. In this study, we evaluated the effect of dexmedetomidine as an adjuvant with 0.75% ropivacaine for interscalene brachial plexus block using nerve stimulator. Aim: This study aims to know the effect of using dexmedetomidine as an adjuvant to 0.75% ropivacaine in interscalene brachial plexuses block using nerve stimulator. Settings and Designs: Sixty patients scheduled for elective orthopedic surgery of the upper limb under interscalene block were considered in this prospective randomized controlled double-blind study. The study population was randomly divided into two groups with thirty patients in each group by using computerized randomization. Materials and Methods: Group R received 30 ml of 0.75% ropivacaine with 0.5 ml normal saline and Group RD received 30 ml of 0.75% ropivacaine with 50 μg of dexmedetomidine. The onset of sensory and motor blocks, duration of sensory and motor block, and patient satisfaction score were observed. Results: Both the groups were comparable in demographic characteristics. The onset of the sensory and motor block is earlier and statistically significant in Group RD (P < 0.05) when compared to Group R. The duration of sensory and motor blockade were significantly prolonged in Group RD (P < 0.0001). Conclusion: Addition of dexmedetomidine to 0.75% ropivacaine in interscalene brachial plexus block significantly shortened the time of onset of the block and prolongs the duration sensory and motor blockade.