| Diffusion-dependence of pulmonary gas mixing at 5.5 and 9.5 ATA. | |
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MedLine Citation:
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PMID: 524527 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Gas-phase diffusivity is inversely proportional to pressure, so mixing of inspired gas in the lung can be expected to be poor in hyperbaric environments. Subjects performed multiple-breath wash-in of a mixture (4% each of SF6, Ar, Ne, and He; 21% O2, 63% N2) at 1.5, 5.5, and 9.5 ATA. At the higher pressures there were marked differences of concentrations between the indicator gases, measured by mass spectrometer at the mouth during a single expiration. Compared to heavier gases, light gases fell from dead space concentration to the "alveolar" level sooner, had a flatter plateau, and had a lower average expired concentration, indicating that more of the light gases were retained in the Functional Residual Capacity (FRC) after the breath. However, wash-in rates for the indicators were about the same; a rapid initial rate for He diminished so that it was about the same as the SF6 rate, because in later breaths a back pressure developed for He. The findings illustrate the basic principle that the amount of gas that diffuses from one location to another in a container depends not only on diffusivity, but also in an interdependent manner on concentration gradient, time for diffusion, and configuration of the container. |
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Authors:
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H D van Liew; E D Thalmann; D K Sponholtz |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Undersea biomedical research Volume: 6 ISSN: 0093-5387 ISO Abbreviation: Undersea Biomed Res Publication Date: 1979 Sep |
Date Detail:
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Created Date: 1980-03-27 Completed Date: 1980-03-27 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0421514 Medline TA: Undersea Biomed Res Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 251-8 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Argon
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diagnostic use Diffusion Helium / diagnostic use Humans Male Mathematics Neon / diagnostic use Pressure / adverse effects Pulmonary Diffusing Capacity* Sulfur Hexafluoride / diagnostic use Time Factors |
| Chemical | |
Reg. No./Substance:
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2551-62-4/Sulfur Hexafluoride; 7440-01-9/Neon; 7440-37-1/Argon; 7440-59-7/Helium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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