Objective: To compare the analgesic effectiveness of Dexmedetomidine and Fentanyl as an adjuvant to 0.5% Bupivacaine in spinal anaesthesia for patients undergoing lower limb surgery.

Study Design: Randomized controlled trial.

Place & Duration:The study was conducted at department of Anesthesia, Shaheed Mohtarma Benazir Bhutto Institute of Trauma, Karachi for duration from 15thJuly2020 to 15thFebruary 2021.

Methods: In this study 52 patients of both genders undergoing lower limb surgeries were included. Patient’s ages were ranging from 20 to 70 years. All the patients were divided into two Groups. Group A included 26 patients and received Inj. Dexmedetomidine 10 μg in 0.5ml normal saline with 12.5mg of 0.5% hyperbaric bupivacaine, Group B had 26 patients and received 25mg fentanyl with 12.5mg of 0.5% hyperbaric bupivacaine. Time to achieve T10 blockade, time to first rescue analgesia were examined and compare between both groups. All the statistical data was analyzed by SPSS 24.0. P-Value <0.05 was significantly considered.

Results: Mean age of group A was 40.52±12.28 years and in group B it was 40.14±13.34 years. There were 18 (69.23%) male patients and 8 (30.77%) females in group A while in Group B 19 (73.08%) patients were male and 7 (26.92%) were females. No significant difference was observed between both groups regarding time to T10 blockade with p-value >0.05. A significant difference was found regarding time to rescue analgesia, in Group A it was 426.58±92.44 minutes and in Group B, it was 206.44±48.47 minutes (p-value <0.0001). Patients’ satisfaction was high in dexemedetomidine group as compared to fentanyl group.

Conclusion: Dexmedetomidine 10 μg with 0.5% bupvicaine showed better effectiveness regarding time to first rescue analgesia as compared to fentanyl. No significant difference was observed regarding time to sensory blockade between both medications.

Keywords: Dexmedetomidine, Fentanyl, Spinal Anaesthesia, Lower Limb Surgery, Sensory Block, Analgesia.