The Effect on Outcome of Adding Magnesium Sulphate to Bupivacaine in the Ultrasound-guided Supraclavicular Brachial Plexus Block Anesthesia

Abstract

This study evaluated the motor and sensory block durations and the postoperative analgesic effects of adding Magnesium Sulphate to Bupivacaine HCL for Ultrasound-guided supraclavicular brachial plexus block. Sixty ASA I-II patients subjected to elective forearm or hand surgery were randomly divided equally into 1 of 2 groups depending upon the local anesthesia (LA) solution used to receive either 23 mL of bupivacaine HCL 0.5% plus 2 mL normal saline (group B) or 23 mL of bupivacaine HCL 0.5% plus Magnesium Sulphate 100 mg diluted with 2mL normal saline (group BM). Motor and sensory block durations were evaluated until the return of normal motor and sensory function. The degree of pain was assessed during the surgery period and 24 hours postoperatively. The results of this study showed that Magnesium Sulphate provided significantly longer motor block duration (329.33 ± 86.54 min vs 237.46 ± 62.91 min, P = 0.001) and significantly longer sensory block duration (356.00 ± 117.02 min vs 278.00 ± 87.23 min, P = 0.005) when compared with bupivacaine alone. Furthermore, the patients in the Magnesium Sulphate group achieved significantly (P < 0.001) lower values of Visual Analogue Scale (VAS) of pain between the periods from 4 to 12 hours postoperatively. There was significantly less diclofenac consumed (mg) in the Magnesium Sulphate group. The patients in the Magnesium Sulphate group reported significantly higher rates of good sleep quality on the first postoperative night (75%) compared with the patients in the bupivacaine group (25%). Also, the patient satisfaction was significantly higher in the Magnesium Sulphate group compared with the bupivacaine group (75% vs 25%). We concluded that Magnesium Sulphate 100 mg to bupivacaine HCL extended the motor and sensory block durations, provided more effective postoperative analgesia with improvement in the sleep quality of the first postoperative night, and provided better patient satisfaction compared to bupivacaine HCL alone.