Assessment of differential brachial plexus block using ropivacaine in intraoperative conscious patients: A randomized control trial

Background: During orthopaedic surgical procedures such as trigger finger repair or tendon repair, differential nerve block (DNB) can permit intraoperative assessment of adequacy of surgery. The current study was undertaken to compare the efficacy and safety of 0.15% ropivacaine and 0.1285% ropivacaine in producing DNB for hand surgeries. Methods: This was a randomized controlled trial of 40 participants, aged 18-60 years, either gender, ASA I/II requiring hand or forearm surgery. Participants were randomized to receive 25 ml of either 0.15% (Group R15) or 0.1285% ropivacaine (Group R1285). Onset of sensory and motor block, requirement of additional analgesia or general anaesthesia for surgery was noted. Results: DNB was achieved in 18/20 (90%) patients in Group R15 and in 10/20 (50%) patients in Group R1285 (P=0.057). In group R15, mean time to achieve DNB was 15.26 +/- 3.5minutes and it was12.78 +/- 5.6 minutes in R1285 group (P=0.165). Mean duration of DNB was 15.52 +/- 3.7 minutes among R15 and 18.89 +/- 3.3 minutes among R1285 (P=0.027). Duration of surgery was 20 minutes in both groups. Two patients (10%) in each group developed full motor block and 8 (40%) patients among R1285 needed general anaesthesia. Conclusion: Differential block sufficient to permit surgery of short duration is possible with both concentrations but success rate is higher with 0.15% ropivacaine.