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The Sevoflurane Washout Profile of Seven Recent Anesthesia Workstations for Malignant Hyperthermia-Susceptible Adults and Infants: A Bench Test Study

Cottron, Nicolas MD; Larcher, Claire MD; Sommet, Agnès MD, PhD; Fesseau, Rose MD; Alacoque, Xavier MD; Minville, Vincent MD, PhD; Fourcade, Olivier MD, PhD; Kern, Delphine MD, PhD

doi: 10.1213/ANE.0000000000000208
Technology, Computing, and Simulation: Research Report

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.

Published ahead of print May 7, 2014

From the Department of Anesthesiology and Intensive Care, University Hospital of Toulouse, Toulouse, IFR, France.

Accepted for publication December 19, 2013.

Published ahead of print May 7, 2014

Funding: Not funded.

Conflicts of Interest: See Disclosures at the end of the article.

This report was previously presented, in part, at the SFAR annual congress (Société Française d'Anesthésie Réanimation), 2011.

Reprints will not be available from the authors.

Address correspondence to Delphine Kern, MD, PhD, Department of Anesthesiology and Intensive Care, University Hospital of Toulouse, EA 4564 MATN, IFR 150, CHRU Toulouse Purpan, place du Dr Baylac, TSA 40031, 31059 Toulouse cedex 9, France. Address e-mail to

© 2014 International Anesthesia Research Society