title: Plasma propofol concentrations during orthotopic liver transplantation.
abstract: OBJECTIVE
  The aim of this study was to investigate the changes in plasma concentrations of propofol in three phases (the paleohepatic, anhepatic, and neohepatic phases) during orthotopic liver transplantation (OLT) using target-controlled infusion (TCI).
  
  
  METHODS
  Ten patients undergoing OLT without venovenous bypass were studied (age 29-53 years, weight 56-79 kg). After intubation, a non-hypnotic target concentration of propofol 0.5 microg ml(-1) using a Diprifusor pump (Zeneca Pharmaceuticals, Macclesfield, UK) was administered as a supplement anesthesia throughout the procedure. Plasma samples were obtained in each phase for propofol assay, respectively. Performance parameters for the Diprifusor system in each phase, the percentage median performance error (MDPE), the percentage median absolute performance error (MDAPE), and the percentage median absolute constancy error (MDACE) were evaluated.
  
  
  RESULTS
  In all patients, measured plasma propofol concentrations were several times higher than Diprifusor values in each phase during the procedure. In nine patients, propofol concentrations in the anhepatic phase were higher than those in the paleohepatic or neohepatic phase (P < 0.05). There were no significant differences between the paleohepatic and neohepatic phases. Interindividual variation of the plasma propofol concentrations was significant (P < 0.05). Percentage median performance error of Diprifusor in each phase, as well as MDAPE, was large (>300%) and was significantly higher in the anhepatic phase (P < 0.01), whereas MDACE was relatively small and there was no significant difference between phases.
  
  
  CONCLUSIONS
  Models used by Diprifusor are not suitable for liver transplantation patients. A further study should be performed in order to determine all pharmacokinetic parameters of propofol in these patients.
authors.affiliation: Department of Anesthesiology, 1st Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China. wujian888888@163.com
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: S M
authors.initials: SM
authors.lastname: Zhu
authors.forename: H L
authors.initials: HL
authors.lastname: He
authors.forename: X C
authors.initials: XC
authors.lastname: Weng
authors.forename: S Q
authors.initials: SQ
authors.lastname: Huang
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Chen
mesh_terms: D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood*; D001794:Blood Pressure / Q000187:drug effects; D002496:Central Venous Pressure / Q000187:drug effects; D016503:Drug Delivery Systems; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015742:Propofol / Q000008:administration & dosage / Q000097:blood*
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol