Sedation during spinal anaesthesia : A comparison between Dexmedetomidine and midazolam infusion.

Objective: To study the effects of intravenous dexmedetomidine infusion and compare it with intravenous midazolam infusion during spinal anaesthesia (S/A) with regards to effect on psychomotor performance, memory and any side effect. Materials Methods: A prospective randomized double blind study was conducted on 60 patients of ASA I to III, scheduled for lower abdominal or lower limb surgery under S/A. All patients were randomly divided into two groups of 30 each; randomization was done by computer generated random numbers. In Group D, dexmedetomidine 1 μg/kg and In Group M, midazolam 0.04 mg/kg basal infusion for 10 min then S/A was given with hyperbaric bupivacaine (0.5%). After achieving required level of S/A; position given and then infusion of inj. Dexmedetomidine 0.5µg/kg/hr in group D and Inj. Midazolam 0.04mg/kg/hr by infusion started. Both psychomotor and memory test were performed before study drug infusion and after 1 and 4 hour of stoppage of infusion. Results: Thus, in both the groups, psychomotor performance was not significantly changed as compared to baseline at 1 hour and 4 hour after stoppage of infusion. There was significantly decreased in recall of picture, after 1 hour of study drug infusion in both the groups (anterograde amnesia); which was regained at 1 hour after stoppage of infusion. The mean time required to achieved sedation score (RSS) of 3 were statistically significant shorter in group D as compared to in group M (P 0.05). Conclusion: Thus, we conclude that, Dexmedetomidine provide rapid onset of arousable sedation without causing respiratory and cardiovascular depression. It provides anterograde amnesia with rapid recovery of psychomotor function.