Evaluation of the effect of intravenous dexmedetomidine on characteristics of spinal anaesthesia with hyperbaric bupivacaine

Abstract

Aims: A study was performed to evaluate the effect of intravenously administered dexmedetomidine just before spinal anaesthesia, on spinal block characteristics, postoperative analgesia, haemodynamics and sedation. Methods: Sixty patients, aged 18 - 50 years of either sex, ASA grade I & II, who were undergoing elective lower abdominal and lower limb surgeries under spinal anaesthesia with hyperbaric bupivacaine, were randomly allocated in to two equal groups of 30 patients each to recieve 20 ml of normal saline intravenously (group A) and intravenous dexmedetomidine 0.5 mcg/kg prepared in normal saline to a total volume of 20 ml (group D) over a 10 min period as a single dose just before spinal anaesthesia. Onset and duration of sensory blocks and motor blocks, highest sensory block level, time to 2 segment regression, duration of analgesia, perioperative haemodynamic parameters, VAS and sedation scores were assessed. Results: Both groups were comparable with regard to demographic data. The onset of sensory and motor block were significantly earlier in group D as compared to group A. Duration of motor block and analgesia were significantly longer in group D as compared to group A. Sedation score were significantly higher in group D. Though HR and NIBP were significantly decreased in group D, however all patients remained haemodynamically stable. Conclusion: Bolus dose of intravenous dexmedetomidine 0.5 µg/ kg administered just before spinal anaesthesia prolongs the duration of sensory – motor block and postoperative analgesia with arousable sedation.