The effects of intravenous dexmedetomidine on spinal hyperbaric ropivacaine anesthesia

In this study we investigated the effects of intravenously administered dexmedetomidine on the duration of hyperbaric ropivacaine in spinal anesthesia, and the side effects. In a prospective, double-blind study, sixty ASA I-II patients were randomized to two groups of 30 individuals. All patients were administered hyperbaric ropivacaine (22.5 mg) for spinal anesthesia. Intravenous dexmedetomidine was administered in group I for 60 min, physiological saline at the same amount and duration was infused in group II. Measurements of mean blood pressure before and after the procedure revealed significant decreases in group I compared with group II after 20, 25, and 30 min. The times for two dermatomes regression of the blockade and complete resolution of motor blockade were significantly prolonged in group I. The sedation score in the dexmedetomidine group was significantly increased compared with controls. Atropine requirement was found to be significantly higher in group I than in group II. Our results show that intravenously administered dexmedetomidine prolonged the duration of spinal anesthesia, provided sufficient sedation, and had few side effects. Therefore, dexmedetomidine is appropriate during spinal anesthesia, if the anesthesiologist is alert for development of bradycardia.