Estimation of the plasma-effect site equilibration rate content(Ke0)in patients before operation / 中华麻醉学杂志

ABSTRACT

Objective To estimate the value for the plasma-effect site equilibration rate constant(Ke0)of propofol using the time to peak effect(Tpeak)method and two pharmacokinetic models for propofol.Methods The Tpeak after a submaximal bolus dose 1.5 mg?kg~(-1) of propofol was measured with AAI A-line auditory evoked potential monitor in 36 patients scheduled for elective surgery under general anesthesia.Using Tpeak and two sets of pharmacokinetic parameters for propofol reported by Marsh and Shafer,the Ke0 was estimated according to the method described by Minto.Results The mean Tpeak was(142?62)s in 30 patients.The Ke0 was 0.626 min~(-1) with the model by Marsh and 0.914 min~(-1) with the model by Shafer.The corresponding t_(1/2) Ke0 values were 1.107 min and 0.759 min respectively(P＜0.01).Conclusion The Ke0 value of propofol estimated depends on the pharmacokinetic models used.The values we estimated in Chinese patients are significantly different from the values reported by foreign authors