Effect of dexmedetomidine on responses to endotracheal extubation during recovery from general anesthesia in patients with hypertension:a multicenter, randomized, blind, placebo-controlled clinical trial

Objective To evaluate the effects of dexmedetomidine on the responses to endotracheal extubation during recovery from general anesthesia in patients with hypertension in a muhicenter,randomized,blind,placebo-controlled clinical trial.Methods Five hundred and eighty ASA Ⅱ or Ⅲ patients with hypertension from 26 centers of both sexes,aged 18-64 yr,weighing 40-100 kg,scheduled for elective surgery under general anesthesia,expected surgery time 1-4 h,requiring endotracheal extubation after surgery,were randomly divided into 4groups (n =145 each):control group (group C) and different doses of dexmedetomidine group (group D1-3).Anesthesia was induced with iv injection of midazolam,fentanyl,propofol,and rocuronium or vecuronium.The patients were mechanically ventilated after tracheal intubation.Anesthesia was maintained with inhalation of sevoflurane and intermittent iv boluses of fentanyl and rocuronium or vecuronium.Dexmedetomidine 0.4,0.6 and 0.8 μg/kg (10 ml) were infused intravenously over 10 min starting from 30 min before the end of operation in groups D1-3,respectively.While the equal volume of normal saline was administered instead in group C.The patients were sent to postanesthesia care unit after extubaion.The time for recovery of spontaneous breathing,emergence time,time for recovery of orientation and time for Aldrete score ≥ 9 were recorded.The occurrence of adverse events and amount of vasoactive drugs used were also recorded.Results Compared with group C,the incidence of severe tachycardia and requirement for urapidil were significantly decreased in groups D1-3,and the incidence of severe hypertension was decreased in group D3 (P ＜ 0.05).There was no significant difference in the other indexes among the four groups (P ＞ 0.05).Conclusion Dexmedetomidine 0.8 μg/kg infused intravenously and slowly before the end of surgery can effectively inhibit the responses to endotracheal extubation during recovery form general anesthesia in patients with hypertension. Key words: Dexmedetomidine ;  Anesthesia recovery period ;  Hypertension ;  Hemodynamics ;  Postoperative complications