Pharmacokinetics of intravenously infused domestic alfentanil in patients undergoing general anesthesia / 中华麻醉学杂志

ABSTRACT

Objective To investigate the pharmacokinetics of intravenously infused domestic alfentanil in the patients undergoing general anesthesia.Methods Twelve American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes,aged 18-47 yr,weighing 49-86 kg,scheduled for elective subtotal thyroidectomy under general anesthesia,were enrolled in the study.Anesthesia was induced with iv midazolam 0.02 mg/kg,alfentanil 25 μg/kg,propofol 1.5 mg/kg and rocuronium 0.8 mg/kg.The patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with inhalation of 0.8％-2.0％ sevoflurane,iv infusion of alfentanil 1 μg · kg-1 · min-1,and intermittent iv boluses of rocuronium 10-20 mg,bispectral index value was maintained at 40-60,and infusion was stopped at 10 min before the end of surgery.Before induction of anesthesia,at 1,3,5,8,10,14,20,35,65,95 and 125 min ofalfentanil infusion,and at 5,15,30,60,120,180,240,300 and 360 min after termination of alfentanil infusion,venous blood samples were collected for determination of the plasma concentration of alfentanil (by high performance liquid chromatography-mass spectrometry/mass spectrometry).DAS 3.0 software was used to analyze the pharmacokinetic parameters of alfentanil.Results The pharmacokinetics of domestic alfentanil was best described by a two-compartment pharmacokinetic model.The distribution half-life was (1.8 ± 0.8) min,and the elimination half-life was (91±22) min.The volume of distribution at steady state was (0.38±0.12) L/kg,and the clearance was (4.3± 1.6) ml · kg-1 · min-1.The elimination of domestic alfentanil followed the first-order kinetics.Conclusion The distribution of intravenously infused domestic alfentanil is fitted to a two-compartment pharmacokinetic model with elimination following the first-order kinetics in the patients undergoing general anesthesia.