Abstract
The pulmonary diffusing capacity is related to the quantitative design characteristics of the pulmonary gas exchanger. The current model for estimating D l O 2 from morphometric data breaks the diffusion path for O 2 into four steps, three of which represent the membrane part of D l O 2. A critique of this model on the basis of newer evidence leads to a modification of the model where the path from the alveolar surface to the erythrocyte membrane is considered as a single step. The structural determinant of this model for D m O 2 is the ratio of effective diffusion surface to effective total barrier thickness. The effective surface is formulated as a fraction of the alveolar surface area, the most robust measure of lung design, whereas the effective barrier thickness is the harmonic mean distance - or mean proximity - between alveolar surface and erythrocyte surface. The methods for obtaining the morphometric measurements are discussed. The results show that the new morphometric estimates of D m O 2 are 33% lower than those obtained with the old model, resulting in a reduction of the estimates of D l O 2 by 10–20%.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.