Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1997-1-6
|
| pubmed:abstractText |
A one-dimensional unsteady state diffusion model was used as a basis for simulating the absorption (lambda), breakthrough (V(B)), and dispersion (sigma2) of inhaled ozone boluses as a function of penetration (V(P)) into intact human lungs. The model idealized the respiratory system as a single equivalent tube with cross-sectional and surface areas that varied as a function of longitudinal position. Longitudinal gas transport in the lumen of the equivalent tube occurred by the joint action of bulk flow and a dispersion coefficient, D. Lateral absorption between respired gas and the tube wall was characterized by an overall mass transfer coefficient, K. By inputting published values of anatomic dimensions scaled to a 160-ml conducting airway volume, D values previously reported for inert insoluble gases, and K values equal to gas-phase transfer coefficients determined in physical lung models, a reasonable simulation of the lambda-V(P) distribution measured at a 250 ml/sec respiratory flow was obtained. Simulations of the corresponding V(B)-V(P) and sigma2-V(P) distributions both exhibited the correct shapes but underestimated the actual values. Although the addition of an estimated tissue resistance to K resulted in a poorer simulation of the data, an increase in conducting airway volume from a value of 160 ml estimated by the subjects' CO2 dead space to a value of 200 ml substantially improved the V(B)-V(P) and sigma2-V(P) simulations without sacrificing the quality of the lambda-V(P) simulation. We conclude that the inclusion of a tissue diffusion resistance is not necessary to properly simulate bolus inhalation data during quiet breathing, but a reliable measurement of conducting airway volume is crucial.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Oct
|
| pubmed:issn |
0041-008X
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
140
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
219-26
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading | |
| pubmed:year |
1996
|
| pubmed:articleTitle |
Longitudinal distribution of ozone absorption in the lung: simulation with a single-path model.
|
| pubmed:affiliation |
Department of Chemical Engineering, Pennsylvania State University, University Park 16802, USA.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
|