Comparative study between the effect of intravenous or intrathecal dexmedetomidine on bupivacaine spinal block in lower abdominal surgery

Background and aim Dexmedetomidine has been shown to prolong spinal anesthesia and enhance postoperative analgesia when given intravenously or intrathecally. It is a highly lipophilic medication that is quickly absorbed into the cerebrospinal fluid and functions as an analgesic by connecting the spinal cord alpha-2-adrenergic receptor. It extends to sensory and motor paralysis induced by local anesthetics. In this study, we aimed to compare the analgesic effect of intravenous (i.v.) versus intrathecal dexmedetomidine on bupivacaine spinal block in lower abdominal surgery. Patients and methods This randomized double-blinded comparative study was carried out on 50 patients scheduled for lower abdominal surgery admitted to Al-Azhar University Hospital, Assiut, Egypt. They were equally divided into two groups. Results There was no significant difference between either group regarding hemodynamic measurements. Time to reach sensory and motor block was significantly earlier in the intrathecal group than i.v. group. Numerical rating scale was significantly lower at 3, 4, 5, 6, 7, and 8 h in the intrathecal group than i.v. group ( P <0.05) and was insignificantly different at postanesthesia care unit, 1, 2, 9, 10, 11, and 12 h between both groups. Time to first request rescue analgesia was significantly delayed in the intrathecal group than i.v. group, and the number of analgesic requirements were significantly lower in the intrathecal group than i.v. group. Conclusion In lower abdominal surgeries, intrathecal dexmedetomidine on bupivacaine spinal block was superior to i.v. dexmedetomidine as it provides earlier sensory and motor block, lower pain score and analgesic requirements, as well as delayed time to first request rescue analgesia.