Midazolam as an adjuvant in supraclavicular brachial plexus block

Abstract

Background&Ai  Brachial plexus block is a useful alternative to general anaesthesia. Postoperative analgesia is an added advantage. Midazolam, a water soluble benzodiazepine has been used by various routes to prolong analgesia. The present study was undertaken to assess the analgesic efficacy of midazolam with bupivacaine in brachial plexus block. A prospective, randomized, double blind study was done at Karnataka Institute of Medical Sciences (KIMS), Hubli (India), from 01 March 2008 to 01 March 2009, on 50 adult patients ofASA1 and 2, aged between 18-65 years and scheduled for various upper limb surgeries. Patients were divided into two groups of 25 each. Group B received 30ml of inj. bupivacaine 0.5% +2ml normal saline and group BM received 30ml of inj. bupivacaine 0.5% + inj. midazolam (preservative free) 0.05mg/kg. Patients were observed for sedation, respiratory depression, pulse rate,SBP, DBP, duration of motor block, duration of pain relief and occurrence of any complications. Post operative analgesia was significantly longer (805.04 175.75 min) in group BM, as compared to group B (502.24 52.68 min) with p value <0.001. Pain score was significantly low in group BM (mean 1.6), compared to group B (mean 4.92) at 12 hours postoperatively. Onset of sensory block was 8.36 3.58 min and 8.52 4.18 min in group B and groupBMrespectively with p value >0.05. Hence there was no statistically significant difference. Onset of motor block in group B was 9.96 5.69 min and in group BM 7.92 5.68 min. and p value was >0.05 min. Hence there was not statistically significant difference Mild respiratory depression and sedation occurred intraoperatively in groupBMwhich required no active intervention. Addition of midazolam 50mcg/kg to 30ml of bupivacaine 0.5% for supraclavicular brachial plexus block prolonged sensory blockade and post-operative analgesia without increasing the risk of adverse effects