Clinical evaluation of intravenous dexmedetomidine and intravenous midazolam for hysterectomy under subarachnoid blockade with 0.5% hyperbaric bupivacaine

Abstract

Background The excellence of subarachnoid blockade (SAB) can be improved with a variety of adjuvants, used either intrathecally or intravenously. Objective The present study aimed to compare the clinical efficacy of intravenous dexmedetomidine with midazolam for hysterectomy under SAB with 0.5% hyperbaric bupivacaine. Materials and methods After approval, 90 adult consenting middle-aged female patients of American Society of Anesthesiologists (ASA) physical status I and II scheduled for hysterectomy under SAB were blindly randomized into three groups of 30 patients each, to receive either intravenous dexmedetomidine 0.5 μg/kg (group I) or intravenous midazolam 0.05 mg/kg (group II) or normal saline (group III), 20 min after the SAB. Patients were assessed for the onset and duration of sensory and motor blockade, maximum cephalic spread, and intraoperative hemodynamic changes as primary endpoints. The study also evaluated the sedation level and visual analogue scale score for postoperative pain as secondary outcome. Results Patients in the dexmedetomidine group showed a higher cephalic level of sensory blockade. Time for two dermatomes’ sensory regression (144.33±19.2 min) and duration of sensory analgesia (270.10±16.6 min) in the dexmedetomidine group was extended, with a statistically highly significant difference among the groups and no hemodynamic variability. Ramsay sedation score was higher in the dexmedetomidine and midazolam groups than in the saline group. Respiratory depression was not observed in any patient. The incidence of postspinal shivering was low in patients of the dexmedetomidine group. Conclusion Midazolam provided only sedation, whereas dexmedetomidine extended the duration of sensory analgesia of SAB, maintained hemodynamic stability, and also provided arousable sedation without respiratory depression.