Effects of dexmedetomidine on quality of emergence from general anesthesia in elderly patients undergoing orthopedic operation

Objective To evaluate the effects of dexmedetomidine on the quality of emergence from general anesthesia in the elderly patients undergoing orthopedic operation.Methods Sixty ASA Ⅰ -Ⅲ patients,aged ≥65 yr,undergoing elective orthopedic operation,were randomly assigned to one of 3 groups ( n =20 each):control group (group C) ; dexmedetomidine 0.25 μg/kg group (group D1 ) and dexmnedetomidine 0.50 μg/kg group (group D2).In groups D1 and D2,15 min befone anesthesia induction,dexmedetomidine 0.25 μg/kg and 0.50 μg/kg were infused over 15 min respectively,while the equal volume of normal saline 15 ml was given instead of dexmedetomidine in group C.After anesthesia induction,tracheal intubation was performed and the patients were mechanically ventilated.General anesthesia was used in the three groups.Flurbiprofen 1 mg/kg was injected intravenously immediately before skin incision.The time for recovery of spontaneous breathing,emergence time,extubation time,and adverse reactions were recorded.Pain was assessed with verbal rating scale (VRS) at 5 min after emergence from anesthesia.Results Compared with group C,the incidence of agitation,bucking,and adverse cardiovascular events and VRS score were significantly decreased,and the rate of effective analgesia was significantly increased in groups D1 and D2,and the emergence time and extubation time were significantly prolonged in group D2(P ＜0.05).Compared with group D1,the emergence time and extubation time were significantly prolonged in group D2(P＜0.05).There was no significant difference in VRS score,the rate of effective analgesia and the incidence of adverse renctions between groups D1 and D2(P＞0.05).Conclusion Ⅳ infusion of dexmedetomidine 0.25 μg/kg before induction of general anesthesia can effectively improve the quality of emergence from general anesthesia in the elderly patients undergoing orthopedic operation. Key words: Dexmedetomidine; Aged; Anesthesia,general; Anesthesia recovery period