title: Factitious halothane detection during trigger-free anesthesia in a malignant hyperthermia susceptible patient.
abstract: OBJECTIVE
  To discuss the problems encountered when halothane was detected in a presumed 'clean' patient circuit during the 'trigger-free' anesthetic management of a known Malignant Hyperthermia Susceptible (MHS) patient for routine orthopedic surgery.
  
  
  METHODS
  A 29-yr-old MHS woman had a wrist arthroscopy/exploration/fusion under general anesthesia. During the course of the 'trigger-free' anesthetic the respiratory gas analyser detected end-tidal halothane in the patient circuit. The patient was disconnected from the circuit as attempts to identify the source of the readings were undertaken. After ruling out the presence of halothane by various clinical manoeuvre the patient was reconnected to the circuit without sequelae.
  
  
  CONCLUSIONS
  By exclusion the problem was presumed to be a factitious reading resulting from the respiratory gas analyser incorrectly identifying patient-expired methane as halothane.
authors.affiliation: Department of Anesthesiology, Queen's University, Kingston General Hospital, Ontario. chawk@nb.sympatico.ca
authors.forename: C A
authors.initials: CA
authors.lastname: Hawkes
mesh_terms: D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D001174:Arthrodesis; D001182:Arthroscopy; D004198:Disease Susceptibility; D004724:Endoscopy; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006221:Halothane / Q000032:analysis*; D006801:Humans; D017214:Laryngeal Masks; D008012:Lidocaine / Q000008:administration & dosage; D008305:Malignant Hyperthermia / Q000503:physiopathology*; D008697:Methane / Q000032:analysis; D015742:Propofol / Q000008:administration & dosage; D013147:Spirometry / Q000295:instrumentation*; D013990:Tidal Volume; D012122:Ventilators, Mechanical; D014955:Wrist Joint / Q000601:surgery
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D008697:Methane; D005283:Fentanyl; D006221:Halothane; D015742:Propofol