title: A consideration of density dependence of maximum expiratory flow.
abstract: Density dependence of maximum expiratory flow was considered in terms of equal pressure point and wave speed theories of flow limitation. It appears likely that the sites of flow-limitation, patterns of flow, and airway geometry differ with the density of the gas being expired. Because the conditions which determine maximum expiratory flow for helium-oxygen and for air differ, measurement of density dependence is of questionable value as a test for peripheral airways dysfunction.
mesh_terms: D005740:Gases; D006801:Humans; D008433:Mathematics; D008448:Maximal Expiratory Flow Rate; D011312:Pressure; D012123:Pulmonary Ventilation
chemical_list: D005740:Gases