| Objective To test the value of EC50 and its 95% reliable interval of propofol inhibiting endotracheal intubation response when compositing etomidate in diffe rent target concentration; By observing the hemodynamic indexes and the adver se reactions occurred, to find out the suitable ratio of concentration for etomid ate and propofol target controlled induction.Methods Select 120 patients who will undergo endotracheal intubation of gene ral anesthesia surgery, ASA class I- II, age between 18 and 60 years old, di vided into four groups randomly, 30 patients in each group. Group A is contr ol group, which is plasma target controlled infusion of propofol alone. Group B1-B3 are observation groups, at the same time of plasma target controlled inf using propofol, using the concentration of 0.30?g/ml(Group B1)?0.33?g/ml(Group B2)?0.36?g/ml(Group B3)to target controlled infusing etomidate, a nd the initial target plasma concentrations of propofol in each group are all 2.5?g/ml.After patients into the operating room, establish the venous channel, sel ect themedian cubital vein in one side for venipuncture, local anesthesia to do wnlink radial artery, then puncture and cathetering. Connect the multi-function ECG monitoring instrument, to do the routine ECG ?MAP?Sp O2?BIS monit oring, When the alert/sedation scores(OAA/S) ?1, intravenous inject 0.3?g/kg sufentanil and 0.15 mg/kg cisatracurium in succession. When the BIS value is less th-an 60, the effect compartment concentration of propofol reaches the pre set tar-get plasma concentration, make breath tube intubation and connect the a nesthesia machine immediately, give control of mechanical ventilation capacity,tidal volume at 8 ml/kg, respiratory frequency at 12 times/min, absorption rati o(I: E) at 2:3, maintain the CO2 partial pressure at the end of the breath bet ween 35 and 45 mm Hg.Determine the target controlled concentration of propof ol in next case based on the response of intubation, that if it's positive reactio n, the plasma target concentration of propofol in next case need to increase by one grade; if it's negative reaction, the plasma target concentration of propofol in next case need to decrease by one grade, and the target plasma concentration ratio for adjacent propofol is 1.2, the case before the intubation positive re action occurs will be the first study of this experiment. During the study, whe n there are seven consecutive intubation response positive cases or seven conse cutive negative inflection points,stop the experiment, record the value of MAP?HR?BIS when entering the room(T0), the moment of just before the intuba tion(T1), as well as 1min(T2)?3min(T3)?5min(T4)after the intubati on, also record the adverse reactions such as intravenous injection pain, myocl onia.Results(1)There's no statistically significant difference for the average age?height?body mass between the 4 groups of patients(P > 0.05, table 2).(2)On hemodynamics area,There are no significant difference in baseline of MAP and HR of four groups at T0 period(P>0.05).Compared with T0 period,the value of MAP?HR of four groups has declined at T1 and T2 period.Thevalue of MAP and HRfor the patients in Group A decline obviously at T1 and T2 period(P<0.05),while the?MAP and HR value are not obvious changed in Group B1-B3(P>0.05).(3)The concentration of propofol EC50(EC50 95% CI) with the function of inhibiting the sympathetic response of intubation in the 4 groups are, Group A is 1.95(1.760-2.22)?g/ml;Group B1 is 1.60(1.38-1.82)?g/ml;Group B2 is 1.46(1.29-1.64)?g/ml;Group B3 is 1.44(1.16-1.61)?g/ml.Compared with Group A, the value of EC50 with the function of inhibiting the sympathetic response of intubation in the observation groups(B1- B3)decreased significantly(P < 0.05), and from B1 to B3, the value of propofol EC50 with the function of inhibiting the sympathetic response of intubation reduced gradually when the target concentration of etomidate increase. The value of EC50 in Group B2?B3 are lower than which of Group B1 obviously(P<0.05),while the value of p-ropofol EC50 in Group B2 and B3 has no statistically significant difference(P > 0.05).(4) The incidence rate of intravenous injection pain in Group A is significantly higher than the 3 observation groups(P < 0.05), the incidence rate of propofol injection pain in Group B1 is higher than which in Group B2 and B3(P<0.05), the propofol injection pain incidence between B2 and B3 has no significant difference(P > 0.05),themyoclonus incidence rate increased with the increasing of the target concentration for etomidate; the incidence of myoclonus in Group B3 is obviously higher than which of otherthree groups(P < 0.05).Conclusion It's hemodynamic stability that using etomidate combining propofol target controlled induction, the median effective concentration of propofol to in hibit the sympathetic response of intubation in general anesthesia status is redu ced gradually in a certain range with the target concentration of etomidate incr eased; Using 0.33?g/ml etomidate and 1.46?g /ml propofol combine target cont rolled infusion can make the loop stability during endotracheal intubation for h alf of the patients, and the incidence rate of propofol injection pain and etomi date myoclonus are also the lowest, which is suitable for clinical choice. |
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