title: The ventilation distribution of helium-oxygen mixtures and the role of inertial losses in the presence of heterogeneous airway obstructions.
abstract: The regional distribution of inhaled gas within the lung is affected in part by normal variations in airway geometry or by obstructions resulting from disease. In the present work, the effects of heterogeneous airway obstructions on the distribution of air and helium-oxygen were examined using an in vitro model, the two compartments of a dual adult test lung. Breathing helium-oxygen resulted in a consistently more uniform distribution, with the gas volume delivered to a severely obstructed compartment increased by almost 80%. An engineering approach to pipe flow was used to analyze the test lung and was extrapolated to a human lung model to show that the in vitro experimental parameters are relevant to the observed in vivo conditions. The engineering analysis also showed that helium-oxygen can decrease the relative weight of the flow resistance due to obstructions if they are inertial in nature (i.e., density dependent) due to either turbulence or laminar convective losses.
authors.affiliation: Medical Gases Group, Air Liquide Santé International, Centre de Recherche Claude Delorme, 1 Chemin de la Porte des Loges, B.P. 126, Les Loges-en-Josas 78354, France. ira.katz@airliquide.com
authors.forename: Ira M
authors.initials: IM
authors.lastname: Katz
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Martin
authors.forename: Pierre-Antoine
authors.initials: PA
authors.lastname: Muller
authors.forename: Karine
authors.initials: K
authors.lastname: Terzibachi
authors.forename: Chia-Hsiang
authors.initials: CH
authors.lastname: Feng
authors.forename: Georges
authors.initials: G
authors.lastname: Caillibotte
authors.forename: Julien
authors.initials: J
authors.lastname: Sandeau
authors.forename: Joëlle
authors.initials: J
authors.lastname: Texereau
mesh_terms: D000328:Adult; D000402:Airway Obstruction / Q000503:physiopathology*; D006371:Helium; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008954:Models, Biological; D010100:Oxygen; D012123:Pulmonary Ventilation
chemical_list: D006371:Helium; D010100:Oxygen