Comparative evaluation of intrathecal dexmedetomidine and fentanyl in patients undergoing lower-limb surgery under spinal anesthesia

Background: Different adjuvants have been studied to enhance the quality and extend the duration of spinal anesthesia. The use of dexmedetomidine has been increased in recent times due to its analgesic and sedative properties. Aims and Objectives: To compare the intrathecal dexmedetomidine and fentanyl in patients undergoing lower-limb surgery under spinal anesthesia. Materials and Methods: Fifty patients (aged 20–50 years) of American Society of Anesthesiologists grades I and II undergoing elective lower-limb orthopedic procedures were included in the study. In group-D (n=25), 5 μg of intrathecal dexmedetomidine with 12.5 mg of 0.5% hyperbaric bupivacaine and group-F (n=25), 25 μg of intrathecal fentanyl with 12.5 mg of 0.5% hyperbaric bupivacaine. Results: There was a statistically significant difference in both the groups. The mean time for two-segment regression and regression of sensory block to L1 was slow with intrathecal dexmedetomidine as compared to those receiving intrathecal fentanyl. Furthermore, the mean total time of sensory and motor block was 342.80 min and 381.24 min, respectively, while patients receiving intrathecal fentanyl had a shorter mean time of sensory and motor block which was 190.24 min and 219.24 min, respectively (P: 0.015). Mean time for the rescue analgesia was also higher with dexmedetomidine than the fentanyl group. Conclusion: Both intrathecal fentanyl and intrathecal dexmedetomidine are safe and effective, but intrathecal dexmedetomidine offers several advantages such as faster onset of pain relief, prolonged duration of sensory and motor blockade, and longer time before requiring additional pain medication.