title: Contractures in skeletal muscle of malignant hyperthermia susceptible patients after in vitro exposure to sevoflurane.
abstract: BACKGROUND
  Sevoflurane, a potent inhalational anaesthetic agent that is structurally similar to halothane, has some favourable characteristics, but may also be able to trigger malignant hyperthermia (MH) in susceptible patients. The diagnosis of malignant hyperthermia susceptibility relies on the in vitro contracture test on skeletal muscle. The present study was undertaken to investigate whether exposure to sevoflurane of muscles of malignant hyperthermia susceptible (MHS) patients would also cause an abnormal contracture.
  
  
  METHODS
  Muscle fascicles obtained from three MHS patients, one malignant hyperthermia non-susceptible (MHN) patient, two control patients and one malignant hyperthermia equivocal (MHE) patient were exposed to sevoflurane instead of halothane in the in vitro contracture test, carried out according to the protocol of the European Malignant Hyperthermia Group. The muscle fascicles were surplus to diagnostic requirements. Sevoflurane concentrations in the testbath were measured using a headspace gas chromatographic technique.
  
  
  RESULTS
  The kinetics of sevoflurane concentration in the testbath were similar to those of halothane. An in vitro contracture response of 2 mN or more was seen in all four MHS/MHE patients with sevoflurane but not in the three control/MHN patients. The magnitude of muscle contracture in the sevoflurane test was less than in the conventional halothane test at comparable testbath concentrations.
  
  
  CONCLUSIONS
  Sevoflurane can trigger an abnormal contracture in human muscle in vitro. This is indicative of malignant hyperthermia susceptibility. Exposure to sevoflurane should be avoided in patients thought to be susceptible to malignant hyperthermia.
authors.affiliation: Department of Anaesthesiology, University Hospital Nijmegen, The Netherlands. Anesthesie@cwz.nl
authors.forename: M M
authors.initials: MM
authors.lastname: Snoeck
authors.forename: M J
authors.initials: MJ
authors.lastname: Gielen
authors.forename: A
authors.initials: A
authors.lastname: Tangerman
authors.forename: J
authors.initials: J
authors.lastname: van Egmond
authors.forename: R
authors.initials: R
authors.lastname: Dirksen
mesh_terms: D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D002110:Caffeine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008305:Malignant Hyperthermia / Q000209:etiology*; D008738:Methyl Ethers / Q000009:adverse effects*; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D002110:Caffeine