Breath-by-breath assessment of alveolar gas stores and exchange.

Details

Serval ID
serval:BIB_1D6516B513CC
Type
Article: article from journal or magazin.
Collection
Publications
Title
Breath-by-breath assessment of alveolar gas stores and exchange.
Journal
Journal of Applied Physiology
Author(s)
Aliverti A., Kayser B., Macklem P.T.
ISSN
8750-7587 (Print)
ISSN-L
0161-7567
Publication state
Published
Issued date
2004
Volume
96
Number
4
Pages
1464-1469
Language
english
Abstract
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.
Keywords
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
Pubmed
Web of science
Create date
19/09/2013 9:45
Last modification date
20/08/2019 12:53
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