Effect of dexmedetomidine combined anesthesia on postoperative delirium in elderly patients undergoing hip joint replacement

Objective To investigate the effect of dexmedetomidine combined anesthesia on postoperative delirium in the elderly patients undergoing hip joint replacement.Methods One hundred and sixty ASA Ⅱ or Ⅲ patients,aged 75-85 yr,with a body mass index of 20-25 kg/m2,scheduled for elective total hip joint replacement under general anesthesia,were randomly divided into 2 groups (n =80 each):sevoflurane-fentanyl control group (group C) and dexmedetomidine-sevoflurane-fentanyl group (group D).Dexmedetomidine was intravenously infused at 0.2 μg· kg-1 · h-1 until the end of operation after a loading dose of 0.6μg/kg over 15 min before induction of anesthesia in group D,while the equal volume of normal saline was infused in group C.Anesthesia was induced with iv injection of fentanyl 2-4 μg/kg and etomidate 0.1-0.3 mg/kg at 5 min after the end of administration of the loading dose.Tracheal intubation was facilitated with cisatracurium 0.15 mg/kg and the patients were mechanically ventilated.Anesthesia was maintained with target-controlled inhalation of sevoflurane (the end-tidal concentration 1％-3％) and intermittent iv boluses of fentanyl 0.05 mg.BIS was maintained at 40-60 during operation.The consumption of etomidate,fentanyl,and sevoflurane,agitation during emergence from anesthesia,and postoperative delirium within 24 h after operation were recorded.Results Compared with group C,the consumption of etomidate,fentanly,and sevoflurane was significantly reduced and the incidences of agitation during emergence from anesthesia and postoperative delirium within 24 h after operation were significantly decreased in group D (P ＜0.05).Conclusion Dexmedetomidine combined anesthesia can reduce the occurrence of postoperative delirium in the elderly patients undergoing hip joint replacement. Key words: Dexmedetomidine; Anesthesia,general; Aged; Delirium; Postoperative complication