Objective To investigate the effect of intmopemtive intravenous penehyclidine hydrochloride on pulmonary function in patients undergoning thoracotomy.Methods Sixty ASA Ⅰ or Ⅱ patients aged 30-64 yr scheduled for elective radical esophagectomy for cancer were randomly divided into 2 group(n=30 each):penehyclidinc hydrochloride group and control group.Penehychdine hydrochloride 0.01 mg/kg(in nolmal saline 2 ml)was injected iv 20 min after opening the thoracic cavity in penehyclidine hydrochloride group.The equal vohlme of normal saline was injected iv in control group.Anesthesia was induced with fentanyl 2μg/kg,propofol 0.4μG/ml and rocuronium 0.6 mg/kg.The patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with remlfentanyl 0.1μg·min-1,propofol 2.0-2.5 μg/ml and intermittent iv injecfion of rocuronium.The use of remifentanyl and pmpofol was stopped 5 min before operation.Dynamic lung compliance (Cd) and peak airway pressure were monitored and recorded immediately before penehychdine hydrechlofide administration (T0) and at 3 min(T1),5 min(T2),10 min(T3),30 min(T4),1 h(T5),2 h (T6)after penehyclidine hydrochloride administration.Results There was no significant difference in Cd and peak airway pressure among different time points in control group(P>0.05).Cd was significantly higher,while peak airway pressure lower at T1-6 than at T0 in penehychdine hydrochlofide group(P<0.05).Cd wag significantly higher,while peak airway pressure lower at T1-6 in penehyclidine hydrochloride group than in control group(P<0.05) .Conclusion Intraoperative intravenous penehyclidine hydrochloride can improve the pneumodynamics and is helpful for ventilation in patients undergoing thoracotomy.