title: Concentrations of oxygen delivered by air entrainment oxygen masks.
abstract: The air entrainment devices from oxygen masks of four manufacturers (Henleys Medical Supplies Ltd, Vickers Medical, Intersurgical Ltd, C R Bard International Ltd) were studied. All were found to deliver concentrations of oxygen close to those specified. The literature is reviewed and it is suggested that provision of a total flow in excess of 60 litres/minute is most likely to provide a constant inspired oxygen concentration, whichever nominal concentration or design of mask is selected and provided distal obstruction is avoided.
mesh_terms: D006801:Humans; D010100:Oxygen / Q000008:administration & dosage*; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*
chemical_list: D010100:Oxygen