<b>Effects of Three Different Doses of Intrathecal Dexmedetomidine Added to Bupivacaine on Effectiveness of Subarachnoid Block in Elective Caesarean Sections: A Prospective Randomized Double-Blind Study</b>

Background: Spinal anesthesia with hyperbaric bupivacaine is commonly used for elective cesarean section, but its limited postoperative analgesic duration and dose-related hemodynamic effects have encouraged the use of intrathecal adjuvants. Objective: To compare the effects of three doses of intrathecal dexmedetomidine added to bupivacaine on sensory and motor block characteristics, postoperative analgesia, and perioperative tolerability in elective cesarean section. Methods: This prospective, randomized, double-blind, four-arm clinical trial included 160 ASA I–II parturients aged 18–40 years undergoing elective cesarean section under spinal anesthesia. Participants were allocated equally to receive bupivacaine 10 mg with dexmedetomidine 5 µg, 7.5 µg, or 10 µg, or bupivacaine 10 mg alone. Sensory block onset to T6, sensory and motor block duration, Visual Analogue Scale-guided time to first rescue analgesia, hemodynamic parameters, sedation, and adverse events were assessed. Results: Sensory onset was fastest with 10 µg dexmedetomidine and slowest in the control group. Sensory and motor block durations were significantly prolonged in dexmedetomidine groups, while time to first analgesic request was longest with 10 µg dexmedetomidine. Conclusion: Intrathecal dexmedetomidine improved spinal block quality and postoperative analgesia, with 10 µg showing the greatest analgesic benefit.