Ultrasound guided supraclavicular brachial plexus block using plain ropivacaine and ropivacaine with additives

Context: Ultrasound (US) guided supraclavicular brachial plexus block (SBPB) provides predictable dense blockade. Inclusion of additives to local anaesthetics alters the quality of blockade. Aim: To assess the block characteristics of ropivacaine alone and with additives in US guided SBPB. Materials and Methods: Prospective, double blinded randomized controlled trial. Sixty patients undergoing elective upper limb surgeries under SBPB were randomly allocated to one of 3 groups: Group RR (who received 30ml of 0.5% ropivacaine), Group RD (30ml of 0.5% ropivacaine with 1 µg/kg of dexmedetomidine) and Group RM (30ml of 0.5% ropivacaine with 50µg/kg of midazolam). After administration of block with above drugs, the block characteristics were assessed every 3mins till onset of complete blockade, every 30mins for 6hrs, then hourly for 24hrs. Apart from sensory and motor blockade, sedation score was also assessed. Results: The duration of blockade (min) was significantly longer in Group RD (907 ± 205) compared to Group RR (597 ± 101) and Group RM (605 ± 188). There was no difference among the groups with respect to onset of sensory and motor blockade. The sedation scores were significantly higher in Group RD (median = 3) and Group RM (median = 2). Conclusion: Addition of dexmedetomidine to ropivacaine in ultrasound guided supraclavicular brachial plexus block prolongs both sensory and motor blockade. Both dexmedetomidine and midazolam when added to ropivacaine produce significant sedation.