title: The end-tidal desflurane concentration for smooth removal of the laryngeal mask airway in anaesthetised adults.
abstract: OBJECTIVE
  The end-tidal desflurane concentration required for smooth removal of the laryngeal mask airway (LMA) has not been established. Therefore, we aimed to find the end-tidal desflurane concentration for safe, smooth, and uncomplicated LMA removal.
  
  
  METHODS
  The study was approved by the Ethical Committee of the Ministry of Health, Diskapi Yildirim Beyazit Research and the Training Hospital, Ankara, Turkey. All patients provided written consent. A total of 23 adults, 18-60 years of age and American Society of Anesthesiologists physical status class I, who had been scheduled for urological surgery were included in the study. The intravenous induction of anaesthesia was performed with propofol 2.5 mg kg⁻¹ and remifentanil 10 μg within 30 s. The LMA was inserted. Maintenance of anaesthesia was provided by desflurane, with nitrous oxide and oxygen. The LMA was removed at predetermined end-tidal desflurane concentrations at the end of surgery. The concentration at which LMA removal was attempted was determined by Dixon's up-down method with 0.5% as the step size. When LMA removal was accomplished without coughing, teeth clenching, gross purposeful movements, breath holding, laryngospasm, and desaturation to SpO(2) less than 90%, it was considered a smooth (successful) removal.
  
  
  RESULTS
  For smooth removal of the LMA, end-tidal desflurane EC50 was 2.1% [95% confidence interval (CI) 1.1-2.9%], and the EC95 value was 3.9% (95% CI 3.1-7.9%).
  
  
  CONCLUSIONS
  The EC95 of end-tidal desflurane for the smooth removal of the LMA is 3.9%. LMA removal in adults receiving desflurane may be possible at approximately 0.7 minimum alveolar concentration.
authors.affiliation: Department of Anesthesiology, Ministry of Health Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey.
authors.forename: Yeliz
authors.initials: Y
authors.lastname: Sahiner
authors.forename: Derya
authors.initials: D
authors.lastname: Özkan
authors.forename: Taylan
authors.initials: T
authors.lastname: Akkaya
authors.forename: Nilgün
authors.initials: N
authors.lastname: Göral
authors.forename: Alp
authors.initials: A
authors.lastname: Alptekin
authors.forename: Haluk
authors.initials: H
authors.lastname: Gümüs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000077335:Desflurane; D020878:Device Removal; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage; D015742:Propofol / Q000008:administration & dosage; D000077208:Remifentanil; D013520:Urologic Surgical Procedures / Q000379:methods; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077335:Desflurane; D007530:Isoflurane; D000077208:Remifentanil; D015742:Propofol