Dexmedetomidine as Adjuvant to Lower Doses of Intrathecal Bupivacaine for Lower Limb Orthopedic Surgeries

BACKGROUND: Dexmedetomidine, an α(2) adrenergic agonist, has been found to be a useful adjuvant to local anesthetics. It has been found to produce satisfactory block with lower doses of spinal bupivacaine. AIM: The aim of this study is to compare the difference in spinal block characteristics and hemodynamic effects of 7, 8, and 9 mg hyperbaric bupivacaine combined with 5 μg dexmedetomidine and to find out the optimum dose that would provide satisfactory block and hemodynamic stability for lower limb orthopedic surgeries. SETTINGS AND STUDY DESIGN: This was a prospective, observational study. MATERIALS AND METHODS: Ninety patients undergoing lower limb orthopedic surgeries were allocated to three groups of thirty each. Group A received 7 mg, Group B 8 mg and Group C 9 mg 0.5% hyperbaric bupivacaine along with dexmedetomidine 5 μg. The spinal block characteristics, hemodynamic stability, and side effects were compared. STATISTICAL ANALYSIS: The quantitative variables were compared using ANOVA test and the qualitative variables using Chi-square test. RESULTS: All three groups had satisfactory anesthesia and analgesia. The onset of analgesia was slower and peak sensory level lower in Group A. The onset of motor block, time to attain peak sensory levels, duration of analgesia, maximum pain scores, and requirement of rescue analgesics were comparable among groups. Duration of motor block and time of regression of sensory level were more in Group C. Hemodynamics and sedation scores were comparable. CONCLUSION: Dexmedetomidine with lower doses of bupivacaine produces satisfactory anesthesia without hemodynamic instability. A dose of 7 mg bupivacaine with 5 μg dexmedetomidine may be sufficient for orthopedic surgeries.