Measurement of Single Breath Diffusion Capacity for CO Using Inert Gases of Different Diffusiveness1

2015 ◽  
pp. 297-304 ◽  
Author(s):  
H. Magnussen ◽  
J. P. Holle ◽  
V. Hartmann ◽  
M. Berres
Keyword(s):  
Inert Gases ◽  
Diffusion Capacity ◽  
Single Breath

scholarly journals Relationship between diffusion capacity and small airway abnormality in COPDGene

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Rachel N. Criner ◽  
Charles R. Hatt ◽  
Craig J. Galbán ◽  
Ella A. Kazerooni ◽  
David A. Lynch ◽  
...  
Keyword(s):  
Severe Disease ◽  
Small Airways ◽  
Precursor Lesion ◽  
Diffusing Capacity ◽  
Diffusion Capacity ◽  
Response Mapping ◽  
Single Breath ◽  
Using Data ◽  
The Relationship ◽  
Parametric Response

Abstract Impaired single breath carbon monoxide diffusing capacity (DLCO) is associated with emphysema. Small airways disease (SAD) may be a precursor lesion to emphysema, but the relationship between SAD and DLCO is undescribed. We hypothesized that in mild COPD, functional SAD (fSAD) defined by computed tomography (CT) and Parametric Response Mapping methodology would correlate with impaired DLCO. Using data from ever-smokers in the COPDGene cohort, we established that fSAD correlated significantly with lower DLCO among both non-obstructed and GOLD 1–2 subjects. The relationship between DLCO with CT-defined emphysema was present in all GOLD stages, but most prominent in severe disease. Trial registration NCT00608764. Registry: COPDGene. Registered 06 February 2008, retrospectively registered.

Cardiogenic oscillations in He and SF6 expirograms during airway and venous loading

1990 ◽  
Vol 69 (3) ◽  
pp. 945-955 ◽  
Author(s):  
M. Meyer ◽  
S. M. Lewis ◽  
M. Mohr ◽  
H. Schulz ◽  
K. D. Schuster ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Oscillation Amplitude ◽  
Alveolar Ventilation ◽  
Inert Gases ◽  
Breath Holding ◽  
Alveolar Volume ◽  
Test Gas ◽  
Single Breath ◽  
Pressure Profiles ◽  
Cardiogenic Oscillations

Cardiogenic oscillations in the expired partial pressure profiles of two inert gases (He and SF6) were monitored in seven anesthetized paralyzed mechanically ventilated dogs. He and SF6 were administered either intravenously by a membrane oxygenator and partial arteriovenous bypass [venous loading (VL)] or by washin into lung gas [airway loading (AL)]. The single-breath expirograms obtained during constant-flow expiration after inspiration of test gas-free air displayed distinct and regular cardiogenic oscillations. The relative oscillation amplitude (ROA), calculated as oscillation amplitude divided by mixed expired-inspired partial pressure difference, was in the range of 1-8%. The ROA for both He and SF6 was approximately 4.2 times higher in VL than in AL, which indicated that among lung units that emptied sequentially in the cardiac cycle, the effects of alveolar ventilation-perfusion (VA/Q) inequality were more pronounced than those of alveolar ventilation-alveolar volume (VA/VA) inequality. In AL, He and SF6 oscillations were 180 degrees out of phase compared with CO2 and O2 oscillations and with He and SF6 oscillations in VL, which suggests that regions with low VA/VA had high VA/Q and very low Q/VA. The ROA was practically unaffected by breath holding in both AL and VL, which indicates that there was little diffusive or convective (cardiogenic) mixing between the lung units that were responsible for cardiogenic oscillations. The ROA was consistently higher for He than for SF6, and the He-to-SF6 ratio was independent of route of test gas loading, averaging 1.6 in both AL and VL. This result may be explained by laminar Taylor dispersion, whereby oscillations generated in peripheral lung regions are dissipated in inverse proportion to diffusion coefficient during transit through the proximal (larger) airways.

scholarly journals New standards for measuring the diffusion capacity of the lungs by carbon monoxide by single breath method

2020 ◽  
pp. 15-23
Author(s):  
G. V. Nekludova ◽  
A. V. Chernyak
Keyword(s):  
Carbon Monoxide ◽  
Working Group ◽  
American Thoracic Society ◽  
Diagnostic Systems ◽  
European Respiratory Society ◽  
Diffusion Capacity ◽  
Single Breath ◽  
Joint Working Group ◽  
Single Breath Method

The article provides an overview of the technical capabilities and updated standards for the study of diffusion capacity of the lungs using diagnostic systems using rapidly responding gas analyzers (RGA analyzers — rapidly responding gas analyzers) of carbon monoxide and indicator gas, presented by a joint working group of the European Respiratory Society (ERC) and the American Thoracic Society (ATS).

Alveolar slope and dead space of He and SF6 in dogs: comparison of airway and venous loading

1990 ◽  
Vol 69 (3) ◽  
pp. 937-944 ◽  
Author(s):  
M. Meyer ◽  
K. D. Schuster ◽  
H. Schulz ◽  
M. Mohr ◽  
J. Piiper
Keyword(s):  
Partial Pressure ◽  
Dead Space ◽  
Venous Blood ◽  
Inert Gases ◽  
Volume Distribution ◽  
Mechanically Ventilated ◽  
Alveolar Plateau ◽  
Single Breath ◽  
Sequential Emptying

Series (Fowler) dead space (VD) and slope of the alveolar plateau of two inert gases (He and SF6) with similar blood-gas partition coefficients (approximately 0.01) but different diffusivities were analyzed in 10 anesthetized paralyzed mechanically ventilated dogs (mean body wt 20 kg). Single-breath constant-flow expirograms were simultaneously recorded in two conditions: 1) after equilibration of lung gas with the inert gases at tracer concentrations [airway loading (AL)] and 2) during steady-state elimination of the inert gases continuously introduced into venous blood by a membrane oxygenator and partial arteriovenous bypass [venous loading (VL)]. VD was consistently larger for SF6 than for He, but there was no difference between AL and VL. The relative alveolar slope, defined as increment of partial pressure per increment of expired volume and normalized to mixed expired-inspired partial pressure difference, was larger by a factor of two in VL than in AL for both He and SF6. The He-to-SF6 ratio of relative alveolar slope was generally smaller than unity in both VL and AL. Whereas unequal ventilation-volume distribution combined with sequential emptying of parallel lung regions appears to be responsible for the sloping alveolar plateau during AL, the steeper slope during VL is attributed to the combined effects of continuing gas exchange and ventilation-perfusion inequality coupled with sequential emptying. The differences between He and SF6 point at the contributing role of diffusion-dependent mechanisms in intrapulmonary gas mixing.

scholarly journals Pulmonary edema and hemoptysis after breath-hold diving at residual volume

2008 ◽  
Vol 104 (4) ◽  
pp. 912-917 ◽  
Author(s):  
Peter Lindholm ◽  
Andreas Ekborn ◽  
Daniel Öberg ◽  
Mikael Gennser
Keyword(s):  
Pulmonary Edema ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Pressure Effects ◽  
Breath Hold ◽  
Residual Volume ◽  
Fresh Blood ◽  
Diffusion Capacity ◽  
Safe Environment ◽  
Single Breath

To simulate pressure effects and experience thoracic compression while breath-hold diving in a relatively safe environment, competitive breath-hold divers exhale to residual volume before diving in a swimming pool, thus compressing the chest even at depth of only 3–6 m. The study was undertaken to investigate whether such diving could cause pulmonary edema and hemoptysis. Eleven volunteer breath-hold divers who regularly dive on full exhalation performed repeated dives to 6 m during a 20-min period. The subjects were studied with dynamic spirometry, video-fibernasolaryngoscopy, and single-breath diffusion capacity of carbon monoxide (DlCO). The duration of dives with empty lungs ranged from 30 to 120 s. Postdiving forced vital capacity (FVC) was reduced from mean (SD) 6.57 ± 0.88 to 6.23 ± 1.02 liters ( P < 0.05), and forced expiratory volume during the first second (FEV1.0) was reduced from 5.09 ± 0.64 to 4.59 ± 0.72 liters ( P < 0.001) ( n = 11). FEV1.0/FVC was 0.78 ± 0.05 prediving and 0.74 ± 0.05 postdiving ( P < 0.001) ( n = 11). All subjects reported a (reversible) change in their voice after diving, irritation, and slight congestion in the larynx. Fresh blood that originated from somewhere below the vocal cords was found by laryngoscopy in two subjects. DlCO/alveolar ventilation (V̇a) was 1.56 ± 0.17 mmol·kPa−1·min−1·l−1 before diving. After diving, the DlCO/V̇a increased to 1.72 ± 0.24 ( P = 0.001), but 20 min later it was indistinguishable from the predive value: 1.57 ± 0.20 ( n = 11). Breath-hold diving with empty lungs to shallow depths can induce hemoptysis in healthy subjects. Edema was possibly present in the lower airways, as suggested by reduced dynamic spirometry.

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