Block Characteristics and Sedation Profile of Dexmedetomidine Added to Intrathecal Hyperbaric Bupivacaine in Subarachnoid Block

Open Access

Abstract

Background: Dexmedetomidine, a selective α2-adrenergic agonist, has emerged as a useful adjuvant to intrathecal local anaesthetics to improve block characteristics and prolong postoperative analgesia. However, the optimal dose that balances efficacy and safety remain uncertain. Objective: To evaluate the block characteristics and sedation profile of dexmedetomidine added to intrathecal hyperbaric bupivacaine in subarachnoid block. Methods & Materials: This prospective randomized controlled study was conducted at Dhaka Medical College Hospital over six months. Sixty ASA I–II patients undergoing elective lower abdominal and lower limb surgeries were randomly allocated into three groups (n=20 each). Group A received 3 µg, Group B 5 µg, and Group C 10 µg dexmedetomidine along with 0.5% hyperbaric bupivacaine. Onset and duration of sensory and motor block, hemodynamic parameters, sedation (Ramsay Sedation Scale), and postoperative analgesia (VAS) were assessed. Statistical analysis was performed using SPSS version 22.0, with p<0.05 considered significant. Results: The onset of sensory block was significantly faster and duration was prolonged in Group C, followed by Group B and Group A (p<0.05). Motor block characteristics showed no significant difference. Postoperative pain scores were significantly lower in Groups B and C, indicating better analgesia. Sedation scores were higher in Groups B and C (p<0.05). Hemodynamic parameters remained stable overall, though higher incidence of bradycardia and hypotension was observed in Group C. Conclusion: Intrathecal dexmedetomidine enhances sensory block and prolongs analgesia in a dose-dependent manner. A dose of 5 µg provides an optimal balance between efficacy, sedation, and hemodynamic stability.