A Comparison between Intrathecal Dexmedetomidine and Fentanyl as an Adjuvant to Hyperbaric Bupivacaine in Spinal Anaesthesia for Lower Limb Surgeries - A Double Blind Controlled Study

Introduction Various adjuvants have been used with local anesthetics in spinal anaesthesia to avoid intraoperative visceral and somatic pain and to provide prolonged postoperative analgesia. Dexmedetomidine, a highly selective 2 adrenergic agonist has evolved as a panacea for various applications and procedures in the perioperative and critical care setting. It is also emerging as a valuable adjunct to regional anaesthesia and analgesia, where gradually evolving studies can build the evidence for its safe use in central neuraxial blocks. Objectives This study was aimed to evaluate the onset and duration of sensory and motor block, hemodynamic responses, postoperative analgesia, and adverse effects of dexmedetomidine or fentanyl when given intrathecally with hyperbaric bupivacaine. Methodology 150 patients of ASA class I and II scheduled for lower limb surgeries were studied. Patients were randomly allocated to receive either 12.5 mg 0.5 % hyperbaric bupivacaine plus 5 g dexmedetomidine (Group D, n = 75) or 12.5 mg 0.5 % hyperbaric bupivacaine plus 25 g fentanyl (Group F, n = 75) intrathecally. Results Patients in Group D had a significantly longer sensory and motor block time than patients in Group F. The sensory regression time to S1 was 447.541.2 min in group D and 179.920.14min in group F (Pless than0.0001). The time for rescue analgesia was 402.360.06min in group D and 15029.6 min in group F (Pless than0.0001). Conclusion Intrathecal dexmedetomidine is associated with prolonged motor and sensory block, hemodynamic stability, and reduced demand for rescue analgesics compared to fentanyl.