Study of efficacy and safety of intravenous Dexmedetomidine infusion as an adjuvant to Bupivacaine spinal anaesthesia in Abdominal hysterectomy

BACKGROUND: The present study was designed to study the efficacy of dexmedetomidine by continuous intravenous infusion on various characteristics of spinal blockade especially in terms of duration of sensory and motor blockade, post operative analgesia, sedation and various side effects. MATERIALS AND METHODS: Sixty American Society of Anaesthesiologists (ASA) physical status I/II patients undergoing abdominal hysterectomy under spinal anesthesia were randomized into two groups of 30 each. Twenty minutes after subarachnoid block with 3 ml of 0.5% hyperbaric bupivacaine, patients in group BD received a loading dose of 1 μg/kg of dexmedetomidine intravenously by infusion pump over 20 min followed by a maintenance dose of 0.5μg/kg/h till the end of surgery, whereas patients in group B received an equivalent quantity of normal saline. RESULTS: The time taken for regression of motor blockade to modified Bromage scale 0 was significantly prolonged in group BD (238±24.13 min) compared to group B (193.4±3.11 min) (P < 0.001). The duration of sensory blockade (218.4±20.99 min vs. 165.9±23.50 min) were significantly prolonged in group BD compared to group B (P < 0.001). According to Ramsay sedation score, In Group BD 3.33% of patients had sedation score of 2, 30% of patients had sedation score of 3, 56.66% of patients had sedation score of 4, 10% of patients had sedation score of 5.In Group B all 100% patients had sedation score of 2. Time to first request for postoperative analgesic was prolonged in groupBD than in group B (P < 0.001). CONCLUSION: Intravenous dexmedetomidine significantly prolongs the duration of sensory and motor block of bupivacaine spinal anesthesia. It also provides excellent intraoperative sedation and postoperative analgesia.