title: Population pharmacokinetics of remifentanil in patients undergoing orthotopic liver transplantation.
abstract: BACKGROUND
  Little is known about the influence of liver transplantation on the pharmacokinetics of most anesthetic drugs. The goal of this study was to study the population pharmacokinetics of remifentanil in the different phases of orthotopic liver transplantation (OLT) and the influence of relevant factors.
  
  
  METHODS
  Thirteen adult patients undergoing OLT were enrolled. A single bolus infusion of remifentanil 5 microg/kg was administered during the preanhepatic, anhepatic and neohepatic phases of OLT. Arterial blood samples of 1.5 ml were collected at 0 (baseline), 1, 2, 3, 5, 7, 10, 15, 20, 25, 30, 45, 60 and 90 minutes after drug administration. Remifentanil concentration was assayed by high-performance liquid chromatography/mass spectrometry/mass spectrometry (HPLC/MS/MS). Population pharmacokinetic modeling was performed using nonlinear mixed-effects modeling (NONMEM).
  
  
  RESULTS
  The pharmacokinetics of remifentanil in patients undergoing OLT was best described by a two-compartment open model. The pharmacokinetic parameters were not influenced by age, gender, operative phase, blood temperature, rehydration volume, or blood loss volume during sampling. The volume of distribution in the central compartment (V(1)) and the volume of distribution in the peripheral compartment (V(2)) were influenced by body weight.
  
  
  CONCLUSIONS
  The population pharmacokinetics of remifentanil in patients undergoing OLT can be well described by a two-compartment open model. The functional status of the liver does not significantly affect the pharmacokinetics of remifentanil, but the body weight is an influential factor of V(1) and V(2).
authors.affiliation: Department of Anesthesiology, Peking University Third Hospital, Beijing, China.
authors.forename: Li-ping
authors.initials: LP
authors.lastname: Zhang
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Bi
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Xian-hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Suo-di
authors.initials: SD
authors.lastname: Zhai
authors.forename: Li-ping
authors.initials: LP
authors.lastname: Duan
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000077208:Remifentanil; D053719:Tandem Mass Spectrometry
chemical_list: D010880:Piperidines; D000077208:Remifentanil