The ventilation distribution of helium–oxygen mixtures and the role of inertial losses in the presence of heterogeneous airway obstructions

• Published in: Journal of biomechanics Vol. 44; no. 6; pp. 1137 - 1143
• Main Authors: Katz, Ira M, Martin, Andrew R, Muller, Pierre-Antoine, Terzibachi, Karine, Feng, Chia-Hsiang, Caillibotte, Georges, Sandeau, Julien, Texereau, Joëlle
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 07-04-2011; Elsevier; Elsevier Limited
• Subjects: Adult; Airway Obstruction - physiopathology; Airways; Biological and medical sciences; Chronic obstructive pulmonary disease, asthma; Compartments; Density; Flow resistance; Gynecology. Andrology. Obstetrics; Helium; Helium-Oxygen; Heterogeneous obstruction; Humans; In vitro testing; Inertial; Lung - physiopathology; Lungs; Male genital diseases; Mathematical model; Medical sciences; Models, Biological; Obstructions; Oxygen; Physical Medicine and Rehabilitation; Pneumology; Pulmonary Ventilation; Respiratory mechanics; Tumors; Turbulence; Two-compartment test lung; Respiratory mechanics; Turbulence; Helium–oxygen; Mathematical model; Two-compartment test lung; Heterogeneous obstruction; Oxygen; Respiratory disease; Lung; Modeling; Biomechanics; Distribution; Mechanic of breathing; Airways obstruction; Pulmonary ventilation; Respiration; Helium-oxygen; Biomedical engineering
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2011.01.022

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.