title: Evaluation of the effect of intravenous lidocaine on propofol requirements during total intravenous anaesthesia as measured by bispectral index.
abstract: BACKGROUND
  I.V. lidocaine is increasingly used as an adjuvant during general anaesthesia. The aim of this study was to evaluate the effect of i.v. lidocaine in reducing propofol anaesthetic requirements during total i.v. anaesthesia (TIVA) maintenance and to evaluate its effect on early recovery from anaesthesia.
  
  
  METHODS
  Forty adult patients undergoing elective laparoscopic cholecystectomy under TIVA were randomly allocated into the lidocaine group (administered 1.5 mg kg(-1) i.v. lidocaine over 5 min followed by 2 mg kg(-1) h(-1)) and the control group (administered an equal volume of saline). Propofol was administered using a target-controlled infusion to maintain the bispectral index values between 40 and 60. After surgery, all infusions were discontinued and the time to extubation was recorded. Serial arterial blood samples were drawn to assess drug plasma levels.
  
  
  RESULTS
  The maintenance dose of propofol was significantly lower in the lidocaine group [6.00 (0.97) mg kg(-1) h(-1)] vs the control group [7.25 (1.13) mg kg(-1) h(-1); P=0.01]. Propofol plasma levels measured at the end of the infusion were 3.71 (0.89) μg ml(-1) in the lidocaine group and 3.67 (1.28) μg ml(-1) in the control group (P=0.91). The median time to extubation was longer (11.0 min; range: 10.0-21.0) in the lidocaine group vs the control group (8.3 min; range: 5.5-12.5; P=0.02).
  
  
  CONCLUSIONS
  I.V. lidocaine reduces propofol requirements during the maintenance phase of TIVA, particularly during surgical stimulation. This sparing effect is associated with an increased time to extubation. Owing to its effect on early recovery from anaesthesia, i.v. lidocaine should be taken into account when used as a component of i.v. anaesthesia.
authors.affiliation: Departamentos de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 367, 8330024 Santiago, Chile. fernando.altermatt@gmail.com
authors.forename: F R
authors.initials: FR
authors.lastname: Altermatt
authors.forename: D A
authors.initials: DA
authors.lastname: Bugedo
authors.forename: A E
authors.initials: AE
authors.lastname: Delfino
authors.forename: S
authors.initials: S
authors.lastname: Solari
authors.forename: I
authors.initials: I
authors.lastname: Guerra
authors.forename: H R
authors.initials: HR
authors.lastname: Muñoz
authors.forename: L I
authors.initials: LI
authors.lastname: Cortínez
mesh_terms: D000328:Adult; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000494:pharmacology*; D017081:Cholecystectomy, Laparoscopic; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000008:administration & dosage* / Q000097:blood
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D015742:Propofol