A comparative study of 0.375% bupivacaine with midazolam and 0.375% bupivacaine for brachial plexus block in upper limb surgeries

Abstract

Background: Brachial plexus block is useful as a sole regional anesthesia technique or as an adjunct to general anaesthesia for providing ideal operating conditions in upper limb surgeries. Adjuvants to local anesthetics for brachial plexus block may enhance the quality and duration of analgesia. Midazolam, a water-soluble benzodiazepine, is known to enhance the effect of local anesthetics. Methods: A prospective, randomized, single blinded study was conducted on 100 ASA Grade I or II adult patients undergoing elective upper limb surgeries under single injection supraclavicular brachial plexus block. Patients were randomly divided into two groups. Group I (n = 50) - 30mL of 0.375% Bupivacaine and Group II (n = 50) - 30mL of 0.375% Bupivacaine and preservative free Midazolam 0.05 mg/kg was used . Onset time and duration of sensory and motor blockade were recorded. Haemodynamic variables (i.e., Heart rate, Blood pressure and Oxygen saturation), Sedation scores and rescue analgesic requirements were recorded for 24 hr postoperatively. Results: The onset and duration of sensory and motor block was significantly faster in Group II compared to Group I (p< 0.05). The duration of sensory and motor block was significantly longer in Group II compared to Group I (p < 0.05). Rescue analgesic requirements were significantly less in Group II compared to Group I (p< 0.05) . Haemodynamics did not differ between groups in the post-operative period. Conclusion: Midazolam (0.05mg/kg) when used as an adjuvant to 0.375% Bupivacaine in brachial plexus block potentiated onset of sensory and motor block, and improved postoperative analgesia without any adverse events.