COMPARISON OF DEXMEDETOMIDINE VERSUS FENTANYL AS ADJUVANTS TO BUPIVACAINE IN SUPRACLAVICULAR BRACHIAL PLEXUS BLOCK: A PROSPECTIVE RANDOMIZED COMPARATIVE STUDY

Abstract

Background: The supraclavicular approach to blockage of nerves around the brachial plexus is a commonly used technique for upper extremity surgical procedures. The performance of the procedure can be graded as either ‘reliable’ or ‘unreliable’ depending on whether the nerve block worked out. Long-acting local anaesthetic agents such as bupivacaine give satisfactory analgesia and some degree of prolongation of pain relief. Adjuvant agents added to the local anaesthetic may improve the quality and duration of the supraclavicular nerve block and possibly improve postoperative analgesia, fentanyl and dexmedetomidine being studied as adjuvants for the use of local anaesthetics. The object of the study reported here was to investigate the relative efficacy and safety of these agents as adjuvants compared to each other and in combination with local anaesthetics. Objectives: The aim of this study was to compare the use of dexmedetomidine and fentanyl with bupivacaine for pain relief among persons with a supraclavicular brachial plexus block. The comparison of dexmedetomidine and fentanyl assesses the effect on onset of sensory (pain) block and motor (muscle) block and duration, the effectiveness of postoperative pain medications, stability during surgery, greater comfort from sedation, and adverse effects. Methods: This was a prospective, randomized trial conducted over a one year period involving one hundred patients going for elective surgery of their upper extremities. The patients were randomized into groups of fifty patients each receiving a brachial plexus block using supraclavicular brachial plexus block placement by ultrasound based approach. The patients in group D received a combination of bupivacaine and dexmedetomidine while patients in group F received bupivacaine and fentanyl. The primary outcomes studied were time to the onset of sensory and motor block, and duration of post-operative analgesia. Secondary outcomes included the length of sensory and motor blocks; intra-operative/post-operative hemodynamic parameters, sedation scores and side effects. Results: At baseline, demographic and clinical characteristics were similar between groups. In dexmedetomidine group the sensory and motor block developed was faster and individual's sensory block, motor block, and duration of post-operative pain relief Latency was longer than that in control group. Although hemodynamic variable were stable for both group during preoperative and postoperative periods, there was a trend to greater frequency of milder sedation in the dexmedetomidine group than in the control group. The overall incidence of adverse events was low and the incidence of adverse events was similar for both groups. Conclusion: Patients who underwent surgery on the upper limbs with a supraclavicular brachial plexus block will benefit from added dexmedetomidine rather than fentanyl to their bupivacaine. The addition of dexmedetomidine significantly extends duration of analgesia from the brachial plexus block and provides added reduction of pain after surgery with safety and hemodynamic stability.