| Breath-by-breath assessment of alveolar gas stores and exchange. | |
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MedLine Citation:
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PMID: 14657046 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The volume of O(2) exchanged at the mouth during a breath (Vo(2,m)) is equal to that taken up by pulmonary capillaries (Vo(2,A)) only if lung O(2) stores are constant. The latter change if either end-expiratory lung volume (EELV), or alveolar O(2) fraction (Fa(O(2))) change. Measuring this requires breath-by-breath (BbB) measurement of absolute EELV, for which we used optoelectronic plethysmography combined with measurement of O(2) fraction at the mouth to measure Vo(2,A) = Vo(2,m) - (DeltaEELV x Fa(O(2)) + EELV x DeltaFa(O(2))), and divided by respiratory cycle time to obtain BbB O(2) consumption (Vo(2)) in seven healthy men during incremental exercise and recovery. To synchronize O(2) and volume signals, we measured gas transit time from mouthpiece to O(2) meter and compared Vo(2) measured during steady-state exercise by using expired gas collection with the mean BbB measurement over the same time period. In one subject, we adjusted the instrumental response time by 20-ms increments to maximize the agreement between the two Vo(2) measurements. We then applied the same total time delay (transit time plus instrumental delay = 660 ms) to all other subjects. The comparison of pooled data from all subjects revealed r(2) = 0.990, percent error = 0.039 +/- 1.61 SE, and slope = 1.02 +/- 0.015 (SE). During recovery, increases in EELV introduced systematic errors in Vo(2) if measured without taking DeltaEELV x Ca(O(2))+EELV x DeltaFa(O(2)) into account. We conclude that optoelectronic plethysmography can be used to measure BbB Vo(2) accurately when studying BbB gas exchange in conditions when EELV changes, as during on- and off-transients. |
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Authors:
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A Aliverti; B Kayser; P T Macklem |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2003-12-02 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 96 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2004 Apr |
Date Detail:
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Created Date: 2004-03-12 Completed Date: 2004-10-13 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1464-9 Citation Subset: IM |
Affiliation:
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Dipartimento di Bioingegneria, Politecnico di Milano, 20133 Milano, Italy. andrea.aliverti@polimi.it |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Bicycling Exercise / physiology Exhalation Gases / metabolism* Humans Lung Volume Measurements Male Models, Biological Monitoring, Physiologic* / methods Oxygen Consumption Plethysmography Pulmonary Alveoli / metabolism* Pulmonary Gas Exchange* |
| Chemical | |
Reg. No./Substance:
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0/Gases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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