Dexmedetomidine as an Intrathecal Adjuvant with Hyperbaric Bupivacaine for Lengthy Lower Limb Orthopaedic Surgeries: A Randomized Double Blinded Case Control Study

Abstract

Background: Spinal anesthesia is efficient but of limited duration. Intrathecal dexmedetomidine prolongs the sensory and motor blockade of bupivacaine. This study has been designed to evaluate the addition of 10 μg of dexmedetomidine to 0.5% hyperbaric bupivacaine 4 ml intrathecally for elective lower limb orthopaedic surgeries. Aims & Objectives: To evaluate the onset and duration of sensory and motor block, the effect on hemodynamics, postoperative analgesia, and adverse effects of intrathecal dexmedetomidine with 0.5% hyperbaric bupivacaine.
Patients & Methods: This is a randomized double blinded study. Forty patients classified in ASA I & II scheduled for elective lower limb orthopaedic procedures expected to extend more than 3 hrs were studied. Patients were allocated into two groups of 20 each. Group B (n=20) received 0.5 % bupivacaine 20 mg only. Group D (n=20) received intrathecal 0.5% bupivacaine 20 mg + dexmedetomidine 10 μg. Onset and duration of the sensory block, motor block, hemodynamics, pain, and sedation were assessed intraoperatively and postoperatively for 24 hrs. The incidences of adverse effects were determined. Results: There was significant difference between the two groups as regards to spinal block characteristics. The mean duration of motor block in Group B and D were 195.5 and 385.5 min, respectively. The mean duration of sensory regression to L1 in Group B and D were 167.5 and 358.5 min, respectively. Time to 2-segment regression in Group B and D were 79.5 and 132.5 min, respectively. The mean duration of analgesia in Group B and D were 223.5 min and 326.5 min, respectively. The patients in Group D had significant prolongation of the motor and sensory block (P < 0.001). Conclusion: Intrathecal dexmedetomidine in the dose of 10 μg significantly prolongs the anaesthetic effects of hyperbaric bupivacaine and can be beneficial in surgeries of long duration, precluding the need for an epidural or general anesthesia.