Methods-This randomised study was designed to compare effects following intrathecal administration ofdifferent doses of dexmedetomidine with bupivacaine, in lower abdominal surgery patients. One hundred patients of American Society of Anaesthesiologists physical status I-II, scheduled for lower abdominal surgery under subarachnoid block, were randomly allocated to one of two groups. Each receiving spinal hyperbaric bupivacaine 15mg combined with dexmedetomidine 5mcg (group A) and dexmedetomidine 10mcg (group B). The onset and duration of sensory and motor blockade, regression of the same andduration of analgesia were noted.

Results- There was statistically significant difference in the onset time of the sensory and motor blockade and significant difference in the duration of sensory and motor blockade, prolonged in Groups B as compared to Group A. The time for rescue analgesic was significantly prolonged in Group B (327±24.6 minutes) as compared to Group A (254±18.6 minutes; P<0.0001).

Conclusion- Dexmedetomidine has a dose dependent effect on the onset, duration and regression of sensory and motor block when used as an adjuvant to bupivacaine in spinal anaesthesia. Dexmedetomidine also produces longer postoperative analgesia in patients undergoing lower abdominal surgeries.