Effect of dexmedetomidine infusion on characteristics of spinal anesthesia with hyperbaric bupivacaine: A randomized controlled trial

Dexmedetomidine is a highly selective and potent α2 agonist having both sedative and analgesic properties. This study was aimed to assess the effects of intravenous dexmedetomidine on sensory, motor, haemodynamic parameters and sedation during subarachnoid block (SAB) with 0.5% hyperbaric bupivacaine. Sixty patients undergoing infraumbilical and lower limb surgeries were allocated into 2 groups, group D (n=30) received dexmedetomidine infusion at the rate of 0.5 µg/kg/h over an hour prior to SAB and continued till the end of surgery whereas patients in group C (n=30) received similar volume of normal saline infusion for the same duration. Onset of sensory block was 63.77 ± 7.42 s in group D compared with 126.2 ± 12.83s in group C. Two segment regression time was 177.03 ± 11.64 min in group D and 85.67 ± 10.32 min in group C and analgesia duration was 287.67 ± 14.84 min in group D and 149 ± 13.16 min in group C. Onset of motor block was 3.95 ± 0.65 min in group D and 4.5 ± 0.62 min in group C. Motor blockade duration was prolonged in group D compared with group C. There was significant difference between the groups in respect to block characteristics. Administration of intravenous dexmedetomidine during SAB hastens the onset and prolongs the duration of sensory and motor block. It also provides conscious sedation and additional analgesia.