Efficacy of premixed versus sequential administration of dexmedetomidine as an adjuvant to intrathecal hyperbaric bupivacaine in lower limb surgery

Abstract

Objective: To evaluate the efficacy of intrathecal hyperbaric bupivacaine premixed with dexmeditomidine compared with sequential administration in separate syringes on block characteristics, haemodynamic parameters, side effect profile and postoperative analgesic requirement.
Trial design: This was a prospective, randomised clinical study.
Method: Sixty orthopaedic patients scheduled for elective lower limb surgery under spinal anaesthesia were divided into two groups to receive either intrathecal hyperbaric bupivacaine 12.5 mg premixed (Group P) with dexmeditomidine 10 μg (diluted to 0.5 ml with normal saline) or by sequential administration in separate syringes (Group S).
Outcome: Block characteristics, haemodynamic parameters, side effect profile and postoperative analgesic requirement were compared in both groups. 
Results: Time to achieve T10 spinal level was significantly less in group S (4.467 +  0.973 min) compared with group P (5.5 + 1.167 min). Similarly, patients in group S achieved Modified Bromage III earlier (6.1 + 1.296 min) than group P (7.5 + 1.333 min), p-value 0.0001. 
Conclusion: Dexmeditomidine given sequentially in a separate syringe as adjuvant to intrathecal hyperbaric bupivacaine can result in faster onset of both sensory and motor block and prolongs the duration of spinal anaesthesia, minimises clinically significant side effects and reduces the postoperative analgesic requirement.