title: Closed-loop coadministration of propofol and remifentanil guided by bispectral index: a randomized multicenter study.
abstract: BACKGROUND
  We have developed a proportional-integral-derivative controller allowing the closed-loop coadministration of propofol and remifentanil, guided by a Bispectral Index (BIS) monitor, during induction and maintenance of general anesthesia. The controller was compared with manual target-controlled infusion.
  
  
  METHODS
  In a multicenter study, 196 surgical patients were randomly assigned to dual closed-loop or manual administration of propofol and remifentanil. Comparison between groups was evaluated by calculating a global score that characterized the overall performance of the controller including the percentage of adequate anesthesia, defined as BIS between 40 and 60, the median absolute performance error, and wobble. Secondary outcomes included occurrence of burst suppression ratio, time to tracheal extubation, and drug consumption.
  
  
  RESULTS
  Eighty-three patients assigned to dual-loop control and 84 patients assigned to manual control completed the study. The global score and the percentage of time with BIS between 40 and 60 were better in the dual-loop group (26 ± 11 vs 43 ± 40, P < 0.0001; 82% ± 12% vs 71% ± 19%, P < 0.0001). Overshoot (BIS <40), undershoot (BIS >60), and burst suppression ratio were all significantly less common in the dual-loop group. Modifications to the propofol and remifentanil infusions were more frequent, and adjustments smaller in the dual-loop group. Remifentanil consumption was greater (0.22 ± 0.07 vs 0.16 ± 0.07 μg · kg(-1) · min(-1); P < 0.0001) and the speed to tracheal extubation was shorter (10 ± 4 vs 11 ± 5 minutes; P = 0.02) in the dual-loop group.
  
  
  CONCLUSIONS
  The controller allows the automated delivery of propofol and remifentanil and maintains BIS values in predetermined boundaries during general anesthesia better than manual administration.
authors.affiliation: Service d'Anesthésie, Hôpital Foch, 40 rue Worth, 92150 Suresnes, France.
authors.forename: Ngai
authors.initials: N
authors.lastname: Liu
authors.forename: Thierry
authors.initials: T
authors.lastname: Chazot
authors.forename: Sophie
authors.initials: S
authors.lastname: Hamada
authors.forename: Alain
authors.initials: A
authors.lastname: Landais
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boichut
authors.forename: Corinne
authors.initials: C
authors.lastname: Dussaussoy
authors.forename: Bernard
authors.initials: B
authors.lastname: Trillat
authors.forename: Laurent
authors.initials: L
authors.lastname: Beydon
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Samain
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Marc
authors.initials: M
authors.lastname: Fischler
mesh_terms: D000368:Aged; D000764:Anesthesia, Closed-Circuit / Q000379:methods*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D010880:Piperidines / Q000008:administration & dosage*; D015742:Propofol / Q000008:administration & dosage*; D000077208:Remifentanil
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol