Background: Changes in local anesthetics temperature may influence the characters of the peripheral nerve block. The effect of warmed bupivacaine on supraclavicular brachial plexus block has not yet been evaluated.
Objectives: This study was designed to evaluate the influence of warming bupivacaine 0.5% on the characteristics of supraclavicular plexus block in adult patients undergoing orthopedic surgery below the mid-arm. The primary objective was the time to onset of sensory block. The secondary objectives were the time to onset of motor block, the duration of sensory and motor blocks, and the time to the first analgesic requirement.
Study Design: Randomized, double-blind, controlled trial.
Setting: University hospital setting.
Methods: Ninety patients who underwent elective or emergency orthopedic surgery below the mid-arm were included in this study. Patients were randomly allocated into 2 groups and received ultrasound-guided supraclavicular brachial plexus block. Group I received 30 mL 0.5% bupivacaine at 23°C. Group II received 30 mL bupivacaine 0.5% warmed to 37°C. The onset of sensory and motor blocks, postoperative pain severity, the duration of sensory and motor blocks, and the time to the first analgesic requirement were evaluated in all patients.
Results: The warm bupivacaine group had a significantly accelerated onset time of sensory and motor block. The duration of sensory and motor block and the time to first requirement for analgesia were significantly longer in the warm bupivacaine group. Moreover, it significantly reduced the postoperative analgesics consumption.
Limitations: Postoperative assessment of the offset of the sensory and motor blocks of the individualized nerves was inaccessible, in addition to a small sample size.
Conclusions: Warming bupivacaine 0.5% to 37°C improves the characteristics of supraclavicular plexus block. It promotes rapid onset of sensory-motor block and provided better quality of postoperative analgesia.