The Effect of Midazolam and Dexmedetomidine Sedation on Block Characteristic Following Spinal Bupivacaine: A Randomized Comparative Study

BACKGROUND: Dexmedetomidine is widely used as an adjunct to general as well as regional anesthesia. AIMS: This study was conducted to compare and evaluate the synergistic effect of single intravenous (i.v.) bolus dose of dexmedetomidine with midazolam on spinal block duration, analgesia, and sedation in patients undergoing infra-umbilical surgeries. SETTINGS AND DESIGN: Prospective, randomized, comparative, and double-blinded study. MATERIALS AND METHODS: One hundred patients between 18 and 60 years of age of American Society of Anesthesiologists physical status I and II posted for elective infra-umbilical surgery under subarachnoid block were randomly divided into two groups (Group D and Group M). Patients of Group D received i.v. dexmedetomidine 0.5 μg.kg(−1) and of Group M received i.v. midazolam 0.05 mg.kg(−1) as premedication 5 min before spinal anesthesia over 10 min. Vital parameters, Ramsay sedation score, level of sensory and motor block, recovery time for sensory blockade, postoperative numerical rating scale, time of requirement of the first dose of postoperative rescue analgesic, and duration of analgesia were recorded and analyzed. STATISTICAL ANALYSIS: Chi-square test, t-test, and analysis of variance test were applied to analyze data using SPSS package for Windows. RESULTS AND CONCLUSION: Premedication with single i.v. dexmedetomidine prolonged the duration and increased the maximum upper level of only sensory component of spinal anesthesia (6.42 ± 3.21 vs. 4.8 ± 1.21 thoracic segments higher than with midazolam sedation). This property can be beneficial in preventing undesirable prolongation of motor block and facilitating early ambulation in shorter duration of infra-umbilical surgeries. In addition, dexmedetomidine slowed the regression of sensory block and increased the time of the first request of analgesic.