A comparative study of 0.5% bupivacaine and 0.5% bupivacaine with dexmedetomidine for spinal anaesthesia in lower limb orthopaedic surgery

Background and objectives: Bupivacaine is the commonly used drug for spinal anaesthesia. To improve upon the quality of analgesia and prolong the duration of its action, many adjuvants have been tried.Intrathecal dexmedetomidine has potent central antinociceptive properties with analgesic effect at spinal level. Low doses of dexmedetomidine have shown effectiveness in intensifying spinal anaesthesia. So dexmedetomidine along with local anaesthetics improves the quality of intraoperative analgesia and also provide postoperative pain relief for longer duration. Objective: To evaluate the effects of adding dexmedetomidine to hyperbaric bupivacaine for lower limb orthopaedic surgeries. Methodology: 75 ASA grade I/II patients aged between 18 - 50 years undergoing elective lower limb orthopaedic surgeries were selected and divided into three groups of 25 each. Group “A” 0.5% hyperbaric bupivacaine 15 mg + 0.5ml of normal saline. Group “B” 0.5% hyperbaric bupivacaine 15 mg+5 µg Dexmedetomidine. Group “C” 0.5%hyperbaric bupivacaine15mg+Dexmedetomidine 7.5µg. Total volumes in all groups are kept constant at 3.5ml. Parameters: Onset and duration of sensory and motor block, Duration and quality of analgesia, perioperative hemodynamic parameters were assessed. Results: The onset of sensory and motor blockade was faster in group C than in group B than in group A. Duration of sensory block and analgesia was significantly prolonged in group C and Group B so also was the duration of motor block. There was no significant hemodynamic changes in all the three groups. Conclusion: Dexmedetomidine potentiates bupivacaine spinal anaesthesia by improving the quality of intra operative and post-operative analgesia.