title: The output of two sevoflurane vaporizers in the presence of helium.
abstract: BACKGROUND
  Modern vaporizers are designed to deliver accurate and stable concentrations of volatile anaesthetic agents. Carrier gas composition may adversely affect the output from vaporizers. No previous study has tested helium in combination with sevoflurane vaporizers, a clinically useful combination especially in anaesthesia for upper airway obstruction.
  
  
  METHODS
  This study evaluated the effect of increasing helium concentrations, carrier gas flow rates and varying the vaporizer dial setting on the output from Blease Datum and Drager Vapor 19.3 sevoflurane vaporizers.
  
  
  RESULTS
  The presence of helium in the carrier gas had negligible effects on the output from both of the sevoflurane vaporizers tested. Carrier gas flow rates had the greatest effect on output but changes were within +/- 10% of baseline.
  
  
  CONCLUSIONS
  Helium/oxygen mixtures can be used with these vaporizers without adversely affecting their performance.
authors.affiliation: Department of Anaesthesia, Royal Devon and Exeter Healthcare NHS Trust, Exeter, UK.
authors.forename: B
authors.initials: B
authors.lastname: Carvalho
authors.forename: D
authors.initials: D
authors.lastname: Sanders
mesh_terms: D000769:Anesthesia, Inhalation / Q000295:instrumentation; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers / Q000494:pharmacology; D006371:Helium / Q000494:pharmacology*; D006801:Humans; D008738:Methyl Ethers / Q000008:administration & dosage*; D009330:Nebulizers and Vaporizers; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D004337:Drug Carriers; D008738:Methyl Ethers; D006371:Helium; D000077149:Sevoflurane