Exchanges of oxygen and carbon dioxide alter inert gas pattern in single-breath tests

1981 ◽  
Vol 50 (1) ◽  
pp. 228-228
Author(s):  
H. D. Van Liew ◽  
R. Arieli
Keyword(s):  
Carbon Dioxide ◽  
Inert Gas ◽  
Breath Tests ◽  
Single Breath

Exchanges of oxygen and carbon dioxide alter inert gas pattern in single-breath tests

1981 ◽  
Vol 50 (3) ◽  
pp. 487-492 ◽  
Author(s):  
H. D. Van Liew ◽  
R. Arieli
Keyword(s):  
Inert Gas ◽  
Phase Iii ◽  
Closing Volume ◽  
Absolute Concentration ◽  
Breath Tests ◽  
Gas Concentration ◽  
Single Breath ◽  
Conventional Manner ◽  
Gas Effect ◽  
The Ideal

Concentration of inert gas in the lung is lowered when CO2 entrance exceeds O2 exit and is raised when O2 exit predominates. In air-breathing subjects who expire to residual volume, this "metabolic gas effect" often causes a rising N2 concentration when in fact there should be a terminal fall because of low N2 in apical regions. In single-breath tests, we compared the dilution of resident N2 with dilution of an inspired gas, Ne, to find the "ideal" inert gas concentration (due only to mixing of resident gas with inspired gas). The displacement from the ideal concentration vs. volume pattern depends on the timing of the breath, because early CO2 entrance gives way later to O2 exit. Sometimes observed patterns are above or below but parallel to the ideal, and sometimes the observed slope of phase III is steeper than ideal for N2 and flatter than ideal for Ne. In addition to phase III distortions, the metabolic gas effect sometimes also distorts phase IV height and the intersection between phases III and IV. The distortions depend strongly on absolute concentration of the indicator gas in the lung, so they are very small when "closing volume" maneuvers are done in the conventional manner. However, distortions can be large and misleading when single-breath maneuvers are done in unconventional ways.

scholarly journals Consensus statement for inert gas washout measurement using multiple- and single- breath tests

2013 ◽  
Vol 41 (3) ◽  
pp. 507-522 ◽  
Author(s):  
Paul D. Robinson ◽  
Philipp Latzin ◽  
Sylvia Verbanck ◽  
Graham L. Hall ◽  
Alexander Horsley ◽  
...  
Keyword(s):  
Consensus Statement ◽  
Inert Gas ◽  
Breath Tests ◽  
Single Breath

Labeled carbon dioxide (C18O2): an indicator gas for phase II in expirograms

2004 ◽  
Vol 97 (5) ◽  
pp. 1755-1762 ◽  
Author(s):  
Holger Schulz ◽  
Anne Schulz ◽  
Gunter Eder ◽  
Joachim Heyder
Keyword(s):  
Carbon Dioxide ◽  
Phase Ii ◽  
Dead Space ◽  
Moment Analysis ◽  
Cumulative Distribution ◽  
Breath Holding ◽  
Power Moment ◽  
Single Breath ◽  
Dead Space Volume ◽  
Space Volume

Carbon dioxide labeled with 18O (C18O2) was used as a tracer gas for single-breath measurements in six anesthetized, mechanically ventilated beagle dogs. C18O2 is taken up quasi-instantaneously in the gas-exchanging region of the lungs but much less so in the conducting airways. Its use allows a clear separation of phase II in an expirogram even from diseased individuals and excludes the influence of alveolar concentration differences. Phase II of a C18O2 expirogram mathematically corresponds to the cumulative distribution of bronchial pathways to be traversed completely in the course of exhalation. The derivative of this cumulative distribution with respect to respired volume was submitted to a power moment analysis to characterize volumetric mean (position), standard deviation (broadness), and skewness (asymmetry) of phase II. Position is an estimate of dead space volume, whereas broadness and skewness are measures of the range and asymmetry of functional airway pathway lengths. The effects of changing ventilatory patterns and of changes in airway size (via carbachol-induced bronchoconstriction) were studied. Increasing inspiratory or expiratory flow rates or tidal volume had only minor influence on position and shape of phase II. With the introduction of a postinspiratory breath hold, phase II was continually shifted toward the airway opening (maximum 45% at 16 s) and became steeper by up to 16%, whereas skewness showed a biphasic response with a moderate decrease at short breath holding and a significant increase at longer breath holds. Stepwise bronchoconstriction decreased position up to 45 ± 2% and broadness of phase II up to 43 ± 4%, whereas skewness was increased up to twofold at high-carbachol concentrations. Under all circumstances, position of phase II by power moment analysis and dead space volume by the Fowler technique agreed closely in our healthy dogs. Overall, power moment analysis provides a more comprehensive view on phase II of single-breath expirograms than conventional dead space volume determinations and may be useful for respiratory physiology studies as well as for the study of diseased lungs.

Cardiogenic oscillation phase relationships during single-breath tests performed in microgravity

1998 ◽  
Vol 84 (2) ◽  
pp. 661-668 ◽  
Author(s):  
Anne-Marie Lauzon ◽  
Ann R. Elliott ◽  
Manuel Paiva ◽  
John B. West ◽  
G. Kim Prisk
Keyword(s):  
Reversed Phase ◽  
Phase Iii ◽  
Residual Volume ◽  
Airway Closure ◽  
Oscillation Phase ◽  
Breath Tests ◽  
Single Breath ◽  
Cardiogenic Oscillations ◽  
Cardiogenic Oscillation ◽  
Phase Relationships

Lauzon, Anne-Marie, Ann R. Elliott, Manuel Paiva, John B. West, and G. Kim Prisk. Cardiogenic oscillation phase relationships during single-breath tests performed in microgravity. J. Appl. Physiol. 84(2): 661–668, 1998.—We studied the phase relationships of the cardiogenic oscillations in the phase III portion of single-breath washouts (SBW) in normal gravity (1 G) and in sustained microgravity (μG). The SBW consisted of a vital capacity inspiration of 5% He-1.25% sulfurhexafluoride-balance O2, preceded at residual volume by a 150-ml Ar bolus. Pairs of gas signals, all of which still showed cardiogenic oscillations, were cross-correlated, and their phase difference was expressed as an angle. Phase relationships between inspired gases (e.g., He) and resident gas (N2) showed no change from 1 G (211 ± 9°) to μG (163 ± 7°). Ar bolus and He were unaltered between 1 G (173 ± 15°) and μG (211 ± 25°), showing that airway closure in μG remains in regions of high specific ventilation and suggesting that airway closure results from lung regions reaching low regional volume near residual volume. In contrast, CO2 reversed phase with He between 1 G (332 ± 6°) and μG (263 ± 27°), strongly suggesting that, in μG, areas of high ventilation are associated with high ventilation-perfusion ratio (V˙a/Q˙). This widening of the range ofV˙a/Q˙in μG may explain previous measurements (G. K. Prisk, A. R. Elliott, H. J. B. Guy, J. M. Kosonen, and J. B. West. J. Appl. Physiol. 79: 1290–1298, 1995) of an overall unaltered range ofV˙a/Q˙in μG, despite more homogeneous distributions of both ventilation and perfusion.

scholarly journals Effect of N2 on Biological Methanation in a Continuous Stirred-Tank Reactor with Methanothermobacter marburgensis

Fermentation ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 56 ◽  
Author(s):  
Marc Philippe Hoffarth ◽  
Timo Broeker ◽  
Jan Schneider
Keyword(s):  
Carbon Dioxide ◽  
Conversion Rate ◽  
Inert Gas ◽  
Stirred Tank ◽  
Stoichiometric Ratio ◽  
Continuous Stirred Tank Reactor ◽  
Steel Mill ◽  
Tank Reactor ◽  
Continuous Stirred Tank ◽  
Methanothermobacter Marburgensis

In this contribution, the effect of the presence of a presumed inert gas like N2 in the feed gas on the biological methanation of hydrogen and carbon dioxide with Methanothermobacter marburgensis was investigated. N2 can be found as a component besides CO2 in possible feed gases like mine gas, weak gas, or steel mill gas. To determine whether there is an effect on the biological methanation of CO2 and H2 from renewable sources or not, the process was investigated using feed gases containing CO2, H2, and N2 in different ratios, depending on the CO2 content. A possible effect can be a lowered conversion rate of CO2 and H2 to CH4. Feed gases containing up to 47N2 were investigated. The conversion of hydrogen and carbon dioxide was possible with a conversion rate of up to 91 but was limited by the amount of H2 when feeding a stoichiometric ratio of 4:1 and not by adding N2 to the feed gas.

Inert gas single-breath washout after heart-lung transplantation.

1995 ◽  
Vol 152 (3) ◽  
pp. 947-952 ◽  
Author(s):  
A Van Muylem ◽  
M Antoine ◽  
J C Yernault ◽  
M Paiva ◽  
M Estenne
Keyword(s):  
Lung Transplantation ◽  
Inert Gas ◽  
Single Breath
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