EFFECTIVE VOLUME OF LOCAL ANAESTHETIC FOR ULTRASOUND-GUIDED INFRACLAVICULAR BRACHIAL PLEXUS BLOCK: A PROSPECTIVE RANDOMIZED CONTROL TRIAL

Abstract

Background: Upper limb fractures are a common orthopedic condition requiring surgical intervention, often performed under general anesthesia or regional anesthesia via a brachial plexus block. Ultrasound-guided infraclavicular brachial plexus block (ICB) is widely used for procedures involving the distal humerus, elbow, forearm, and hand due to its efficacy and safety. However, the optimal volume of local anesthetic for effective ICB remains uncertain. This study compares the efficacy of 25ml and 30ml of 0.5% ropivacaine in ultrasound-guided ICB. Aim: To evaluate the quality of anesthesia, onset, and duration of postoperative analgesia using 25ml and 30ml of 0.5% ropivacaine in ultrasound-guided infraclavicular brachial plexus block. Materials and Methods: A randomized controlled trial was conducted on 60 patients undergoing upper limb surgery below the mid-humerus at R.L. Jalappa Hospital and Research Centre. Patients were randomly allocated into two groups: Group A received 25ml of 0.5% ropivacaine, and Group B received 30ml of 0.5% ropivacaine. The onset and duration of sensory and motor block, postoperative analgesia, and visual analog scale (VAS) scores were analyzed using appropriate statistical methods. Results: The onset of sensory and motor block was comparable between the groups (p>0.05). However, Group B exhibited a significantly longer duration of sensory (12.9±1.6 min vs. 10.9±3.0 min, p<0.05) and motor block (13.5±2.4 min vs. 10.2±3.0 min, p<0.05). Group B also demonstrated prolonged analgesia (14.13±1.22 hours vs. 12.77±2.45 hours, p<0.05) and lower VAS scores at multiple postoperative time points. Conclusion: While 30ml of 0.5% ropivacaine provides longer sensory and motor block duration and superior postoperative analgesia, 25ml remains a viable alternative with a comparable onset, adequate anesthesia, reduced toxicity risk, and cost-effectiveness. It is recommended in cases where early motor recovery and resource optimization are priorities.