Publication:

A comparative study of two doses of intrathecal dexmedetomidine 10 mcg and 15 mcg as adjuvants to 0.5% hyperbaric bupivacaine for abdominal hysterectomy: a randomized, prospective, double blind study

Background Neuraxial adjuvants have been used with local anaesthetics to avoid intraoperative pain, prolong the duration of anaesthesia, and avoid side effects and to provide adequate postoperative analgesia. Dexmedetomidine, a highly selective α2-agonist drug, is being routinely used nowadays as a neuraxial adjuvant. The aim of this study was to compare two doses of dexmedetomidine in terms of efficacy in prolonging the subarachnoid block as well as safety.

Methods In this prospective, randomized, double-blind, controlled study on 90 ASA I/II patients undergoing elective abdominal hysterectomy patients were randomly allocated to one of the three groups of 30 each, to receive subarachnoid block with 3.4 ml of 0.5% hyperbaric Bupivacaine along with either normal saline (S) or dexmedetomidine 10 µg (D 10) or dexmedetomidine 15 µg (D 15) and onset and duration of motor and sensory block were monitored along with two segment regression times, postoperative VAS scores and analgesic requirements and occurrence of any untoward effects.

Results Dexmedetomidine significantly decreased the onset times of sensory and motor blocks, prolonged time to two segment regressions, prolonged regression of motor and sensory blocks and time to first rescue analgesic in postoperative period. There was reduction in requirement of analgesics in both the dexmedetomidine groups. Effects were more pronounced in D 15 group than D 10 group. All three group patients were stable haemodynamically with only an insignificant number of patients having bradycardia and hypotension in the D 15 group.

Conclusions Thus dexmedetomidine prolongs the 0.5% hyperbaric Bupivacaine spinal anaesthesia duration. Prolongation of anaesthesia is in a dose dependent manner and groups are comparable in terms of safety profiles.