This study was conducted to assess the effects of IV dexmedetomidine on sensory, motor, haemodynamic parameters and sedation during subarachnoid block. 50 ASA I and II patients, aged 18 to 55years, either sex, scheduled for elective surgeries under spinal anaesthesia, with duration more than 2 hours were included in the study with their informed consent and after approval of research, ethics committee. The patients were randomly allocated into two groups, Group A received IV dexmedetomidine 1mcg/kg bolus over 10 min prior to spinal anaesthesia, followed by an infusion of 0.5 mcg/kg/h for the duration of the surgery. Group B received similar volume of normal saline infusion. Time for the onset of sensory and motor blockade, cephalad level of analgesia and duration of analgesia were noted. Sedation scores using Ramsay Sedation Score (RSS) and haemodynamic parameters were assessed. Demographic parameters, duration and type of surgery were comparable. Significant changes were observed in onset, duration of sensory blockade, two segment regression and duration of motor blockade in group A while onset of motor blockade was insignificant. There was clinically and statistically significant decrease in heart rate and blood pressures in Group A. The mean intraoperative RSS was higher in Group A.  Administration of IV dexmedetomidine during spinal anaesthesia hastens the onset of sensory block and prolongs the duration of sensory and motor block with satisfactory arousable sedation.

Keywords: Dexmedetomidine, intravenous, spinal anaesthesia, supplementation.

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