title: Pilot study of closed-loop anaesthesia for liver transplantation.
abstract: BACKGROUND
  Automated titration of propofol and remifentanil guided by the bispectral index (BIS) has been used for numerous surgical procedures. Orthotopic liver transplantation (OLT) uniquely combines major changes in circulating volume, an anhepatic phase, and ischaemia-reperfusion syndrome. We assessed the behaviour of this automated controller during OLT.
  
  
  METHODS
  Adult patients undergoing OLT were included in this pilot study. Consumption of propofol and remifentanil was calculated for each surgery period (dissection, anhepatic, and liver reperfusion phases). Arterial blood samples were collected at several time points to allow comparison of actual with calculated propofol and remifentanil concentrations. Data are presented as median [25th and 75th percentiles] or percentage (95% confidence interval).
  
  
  RESULTS
  Thirteen patients were studied. System performance, defined as the percentage of time with BIS in the range 40-60, was 88% (86-94) of the total duration of anaesthesia. Propofol requirement was decreased during the anhepatic phase compared with the dissection phase (2.9 [1.9-5.0] mg kg(-1) h(-1) and 4.6 [3.5-8.1] mg kg(-1) h(-1); P<0.03) while remifentanil consumption was unchanged (0.11 [0.09-0.19] µg kg- (1) min(-1)). Bland-Altman analysis showed a weak concordance for propofol (bias of 0.7 µg ml(-1) and limits of agreement of -2.2 to +3.7 µg ml(-1)) and remifentanil (bias of 1.3 ng ml(-1) and limits of agreement -4.3 to +6.8 ng ml(-1)). No adverse events were reported during anaesthesia.
  
  
  CONCLUSIONS
  This pilot study indicates that automated titration of propofol and remifentanil guided by the BIS is feasible during OLT.
authors.affiliation: Department of Anaesthesia and Critical Care, Hôpital Beaujon, Clichy, France Université Paris VII Denis Diderot, France aymeric.restoux@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Restoux
authors.affiliation: Department of Pharmacology Mass Spectrometry Facility, UFR Sciences de la Santé Simone Veil, Université Versailles Saint-Quentin en Yvelines, France.
authors.forename: S
authors.initials: S
authors.lastname: Grassin-Delyle
authors.affiliation: Department of Anaesthesia, Hôpital Foch, Suresnes, France Université Versailles Saint-Quentin en Yvelines, France.
authors.forename: N
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Anaesthesia and Critical Care, Hôpital Beaujon, Clichy, France Université Paris VII Denis Diderot, France.
authors.forename: C
authors.initials: C
authors.lastname: Paugam-Burtz
authors.affiliation: Department of Anaesthesia and Critical Care, Hôpital Européen Georges Pompidou, Paris, France Université Paris Descartes, France.
authors.forename: J
authors.initials: J
authors.lastname: Mantz
authors.affiliation: Department of Anaesthesia, Hôpital Foch, Suresnes, France Université Versailles Saint-Quentin en Yvelines, France.
authors.forename: M
authors.initials: M
authors.lastname: Le Guen
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia / Q000379:methods*; D056805:Consciousness Monitors; D005260:Female; D006801:Humans; D016031:Liver Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010880:Piperidines / Q000008:administration & dosage; D015742:Propofol / Q000008:administration & dosage; D000077208:Remifentanil
chemical_list: D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol
keywords: clinical pharmacology; consciousness monitor; transplantation, liver