Effect Of Different Doses Of Butorphanol On The EC50 Of Propofol During Hysteroscopy

Objective:To explore the effect of different doses of butorphanol onEC50 of propofol during hysteroscopy.Methods:120 patients scheduled for hysteroscopy were randomized to A,B,C,and D groups,and normal saline,10,15,20 μg/kg butorphanol were administrated,respectively.We measured the EC50 of propofol preventing body movement according to Dixon’s up-and-down methodology.The anesthesia time,operation time,awaking time,and the dose of propofol were recorded.Patients’ SBP,DBP,HR,RR were measured at T0～T5 and their VAS score and OAA/S score at t0～t6 were noted.Other parameters were measured such as the incidence of intraoperative respiratory depression,hypotension,and bradycardia and postoperative dizziness,drowsiness,nausea,and vomiting.Results:The EC50and 95%CI of propofol in Group A was 4.571(3.828～6.414)μg/ml,group B was 3.798(3.508～4.153)μg/ml,group C was 3.459(3.023～4.637)μg/ml,and group D was 3.013(2.724～3.313)μg/ml.The EC50 in group D were significantly lower than that in group A and group B(P<0.05)and the dose of propofol in group D was lower than that in group A(P<0.05).The awakingtime of group B and C was significantly shorter than that of group A(P<0.05);The awaking time in group D was more significantly increased compared with group B(P<0.05).Intraoperative blood pressure and heart rate were significantly decreased in each groups compared with T0,and the incidence of hypotension in group D was significantly lower than that of group A(P<0.05).Intraoperative respiratory rate in groups C and D was significantly lower than group A(P<0.05)and the incidence of respiratory depressionwas significantly increased in group D than in group A(P<0.05).RR were decreased at T1 among the four groups compared with T0 and the duration of reduced RR were prolonged with the dose of butorphanol increased.OAA/S score of group D was significantly lower than that in group A and group B at t2(P<0.05),and VAS score of group B,C,Dwere lower than that of group A at t3(P<0.05).The incidence of postoperative dizziness and drowsiness in group C and group D was significantly increased than those in group A(P<0.05).Conclusions:Butorphanol has a dose-dependent effect on reducing the EC50 and dose of propofol,with more stable hemodynamic changesand betterpostoperative recovery.10μg/kg butorphanol is the recommended dose when butorphanol co-administrated with propofol during hysteroscopy.