Dexmedetomidine and Fentanyl as an Adjuvant to Intrathecal Isobaric Ropivacaine for Surgery of Fracture Neck Femur; A Randomized, Double-Blind Comparison

Background: Subarachnoid block (SAB) using isobaric ropivacaine provides rapid and reliable anesthesia with good muscle relaxation for lower limb surgeries. Fentanyl and dexmedetomidine are used as adjuvants to prolong intraoperative and postoperative analgesia. This study was done to compare their efficacy as an adjuvant to intrathecal ropivacaine for surgeries of fracture neck femur, as no such study has been done previously. Materials and Methods: In this randomized, double-blind comparative study, 74 patients undergoing surgery for a fracture neck femur under SAB were randomly distributed into two groups. Group RD received 2.5 ml isobaric ropivacaine 0.75% (18.75 mg) with five ?g of dexmedetomidine in 0.5 ml NS, and group RF received 2.5 ml isobaric ropivacaine 0.75% (18.75 mg) with 25?g Fentanyl (0.5ml) intrathecally. Block characteristics, hemodynamic changes, and other side effects were compared. Statistical analysis was done using SPSS Version 21.0 statistical analysis software. Results: Time to onset of sensory block was earlier in group RD than in group RF (5.27?0.77 vs. 6.27?0.87 min). The total duration of sensory block, motor recovery by one level, complete motor recovery, and duration of motor block were significantly higher in the dexmedetomidine group. The mean rescue analgesic requirement was significantly higher in group RF than in group RD. In contrast, the time to first rescue analgesia was significantly later in group RD (292?16.75 vs. 190.41?12.93 min). Conclusion: Dexmedetomidine produces earlier onset of sensory block, prolonged duration of sensory and motor blocks, and prolonged postoperative analgesia as compared to fentanyl when added as an adjuvant to ropivacaine for SAB.