Malignant Hyperthermia Studies

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Preparation of the Datex-Ohmeda Aestiva Anesthetic Machine for Malignant Hyperthermia Cases

October 18, 2008
2:00 PM - 4:00 PM
Room Hall E2-Area N

Kelly S. Shinkaruk, M.D., Kevin Nolan, M.D., F.R.C.P.C., Marylou Crossan, B.S.
Anesthesiology, University of Ottawa, Ottawa, ON, Canada

Current guidelines for preparing anesthetic machines for malignant hyperthermia susceptible patients were outlined based on studies looking at older models. The newer generation Datex-Ohmeda Aestiva anesthetic machine was studied in order to determine the washout profile of sevoflurane and to establish new guidelines for its preparation.

Technical Features:
Initially, sevoflurane was run at 2% (MAC) for two hours. After priming, the anesthetic machine was prepared as per institutional guidelines for a malignant hyperthermia susceptible patient. Fresh gas flows were increased to 10L/min and circuit and gas analysis tubing was replaced with new tubing; a MIRan infrared gas analyzer was utilized to determine sevoflurane concentration in ppm every minute until a concentration below 5ppm was attained. Following this procedure, it was determined that sevoflurane washout time in an Aestiva anesthetic machine was 52 to 59 minutes with a 95% confidence interval.

Given these results, it is concluded that the Aestiva machine must be flushed with a fresh gas flow of 10L/min for at least 55min in order to achieve a sevoflurane concentration of less than 5ppm.

Anesthesiology 2008; 109 A279