title: The sevoflurane washout profile of seven recent anesthesia workstations for malignant hyperthermia-susceptible adults and infants: a bench test study.
abstract: BACKGROUND
  Preoperative flushing of an anesthesia workstation is an alternative for preparation of the anesthesia workstation before use in malignant hyperthermia-susceptible patients (MHS). We studied in vitro, using a test lung, the washout profile of sevoflurane in 7 recent workstations during adult and, for the first time, pediatric ventilation patterns.
  
  
  METHODS
  Anesthesia workstations were first primed with 3% sevoflurane for 2 hours and then prepared according to the recommendations of the Malignant Hyperthermia Association of the United States. The flush was done with maximal fresh gas flow (FGF) with a minute ventilation equal to 600 mL × 15, to reach a sevoflurane concentration of <5 parts per million. After flush, 2 clinical situations were simulated in vitro to test the efficiency of preparation: decrease of FGF from max to 10 L/min, or decrease of minute ventilation to 50 mL × 30, to simulate the ventilation of an MHS infant.
  
  
  RESULTS
  We report washout delays for MHS patients for previously studied workstations (Primus®, Avance®, and Zeus®) and more interestingly, for machines not previously tested (Felix®, Flow-I®, Perseus®, and Leon®). An increase of sevoflurane concentration was observed when decreasing FGF (except for flow-I® and Leon®) and during simulation of MHS infant ventilation (except for Felix®).
  
  
  CONCLUSIONS
  This descriptive study strongly suggests that washout profiles may differ for each anesthesia workstation. We advise the use of maximal FGF during preparation and anesthesia. Required flushing times are longer when preparing an anesthesia workstation before providing anesthesia for MHS infants.
authors.affiliation: From the Department of Anesthesiology and Intensive Care, University Hospital of Toulouse, Toulouse, IFR, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cottron
authors.forename: Claire
authors.initials: C
authors.lastname: Larcher
authors.forename: Agnès
authors.initials: A
authors.lastname: Sommet
authors.forename: Rose
authors.initials: R
authors.lastname: Fesseau
authors.forename: Xavier
authors.initials: X
authors.lastname: Alacoque
authors.forename: Vincent
authors.initials: V
authors.lastname: Minville
authors.forename: Olivier
authors.initials: O
authors.lastname: Fourcade
authors.forename: Delphine
authors.initials: D
authors.lastname: Kern
mesh_terms: D000328:Adult; D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D006801:Humans; D007223:Infant; D008305:Malignant Hyperthermia / Q000517:prevention & control*; D008738:Methyl Ethers / Q000008:administration & dosage*; D011446:Prospective Studies; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane