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Theoretical estimates of lung diffusing capacity
Author(s) -
Roy Tuhin K,
Secomb Timothy W
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.723.3
Subject(s) - diffusing capacity , hematocrit , oxygen transport , chemistry , pulmonary diffusing capacity , oxygen , capillary action , diffusion , membrane , lung , biophysics , analytical chemistry (journal) , chromatography , thermodynamics , medicine , biochemistry , biology , physics , endocrinology , lung function , organic chemistry
The process of pulmonary oxygen uptake is analyzed to obtain quantitative estimates of pulmonary diffusing capacity. An axisymmetric model is used to represent radial diffusion of oxygen from alveoli through the alveolar‐capillary membrane, through the plasma, and into the erythrocytes. Analysis of unsteady diffusion due to the passage of the discrete erythrocytes shows that the transport of oxygen through the alveolar‐capillary membrane occurs mainly in the regions adjacent to erythrocytes, and that oxygen transport through regions adjacent to plasma gaps can be neglected. Calculations are performed for a range of discharge hematocrit and capillary diameter values. A value of approximately 75 mlO 2 mmHg −1 min −1 is obtained for normal hematocrit, assuming a capillary diameter of 6.75 μm. This value is much lower than the estimates obtained previously by the morphometric method, which considers the total membrane area and the specific uptake rate of erythrocytes. Simulations of pulmonary oxygen uptake based on the new estimates of lung diffusing capacity are consistent with experimental data on oxygen uptake in exercise and hypoxia. Supported by NIH grant HL070657.