Article Type

Original Study


Background Dexmedetomidine was shown to improve bupivacaine spinal anesthesia. Objective The aim of this study was to compare between intrathecal and intravenous (i.v.) dexmedetomidine as an adjuvant to bupivacaine spinal anesthesia. Patients and methods Sixty ASA physical status I-II aged 20-60 years scheduled for lower abdominal surgery under spinal anesthesia were assigned randomly to two groups. The intrathecal group received intrathecal 15 mg hyperbaric bupivacaine with 5.0 μg dexmedetomidine, followed by an i.v. infusion of normal saline solution during surgery. The i.v. group received intrathecal hyperbaric bupivacaine 15 mg with 0.5 ml normal saline solution, followed by a loading dose of dexmedetomidine 0.5 μg/kg over 10 min and then a maintenance dose of 0.5 μg/kg/h during surgery. Assessment parameters were vital signs, spinal block, analgesia, sedation, and side effects. Results Blood pressure and heart rate values were lower in the i.v. group than in the intrathecal group. The intrathecal group had earlier sensory onset, higher peak sensory level, and prolonged sensory regression time to S1 dermatome (P < 0.001). The time to Bromage 3 motor block was comparable between both groups, but the regression time to Bromage 0 was prolonged in the intrathecal group (P < 0.001). The intrathecal group had a longer time to first analgesic request (P < 0.001) and less analgesic consumption than the i.v. group. The i.v. group had a higher intraoperative sedation level. The intrathecal group had fewer side effects than the i.v. group, but this was statistically insignificant. Conclusion As an adjuvant for spinal bupivacaine, intrathecal dexmedetomidine is superior to i.v. dexmedetomidine. It provides more stable hemodynamics, greater block augmentation, better analgesia, and fewer side effects including the intraoperative sedation score than the i.v. route.