Computerized single-breath nitrogen washout: Predicted values in a rural French community

Lung ◽  
2004 ◽  
Vol 174 (1) ◽  
Author(s):  
D.B. Teculescu ◽  
M.-C. Daniel ◽  
E. Costantino ◽  
O. Buhler ◽  
A.B. Bohadana ◽  
...  
Keyword(s):  
Nitrogen Washout ◽  
Single Breath ◽  
Predicted Values

Inflection point on transpulmonary pressure-volume curves and closing volume

1975 ◽  
Vol 38 (2) ◽  
pp. 228-235 ◽  
Author(s):  
M. Demedts ◽  
J. Clement ◽  
D. C. Stanescu ◽  
K. P. van de Woestijne
Keyword(s):  
Inflection Point ◽  
Vital Capacity ◽  
Transpulmonary Pressure ◽  
Bronchial Obstruction ◽  
Closing Volume ◽  
Lung Volumes ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Space Effect ◽  
Washout Curves

In 20 healthy subjects and 18 patients with bronchial obstruction, closing volume (CV) on single-breath nitrogen washout curves and inflection point (IP) on transpulmonary pressure-volume curves were recorded simultaneously during slow expiratory vital capacity maneuvers. IP and CV did not occur at identical lung volumes, IP being systematically larger than CV for small CV values. This discrepancy could not be attributed to an esophageal or mediastinal artifact. It is suggested that, though CV and IP both express “airway closure,” their sensitivity to closure may differ: CV underestimates closure because of a dead space effect; the latter may vary individually. On the other hand, IP may not reflect the true beginning of closure, particularly when it occurs at higher lung volumes.

Mode shift of an inhaled aerosol bolus is correlated with flow sequencing in the human lung

2002 ◽  
Vol 92 (3) ◽  
pp. 1232-1238 ◽  
Author(s):  
Christopher N. Mills ◽  
Chantal Darquenne ◽  
G. Kim Prisk
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Mode Shift ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Posture Change ◽  
Supine Posture ◽  
Residual Capacity ◽  
Phase Iii Slope

We studied the effects on aerosol bolus inhalations of small changes in convective inhomogeneity induced by posture change from upright to supine in nine normal subjects. Vital capacity single-breath nitrogen washout tests were used to determine ventilatory inhomogeneity change between postures. Relative to upright, supine phase III slope was increased 33 ± 11% (mean ± SE, P < 0.05) and phase IV height increased 25 ± 11% ( P < 0.05), consistent with an increase in convective inhomogeneity likely due to increases in flow sequencing. Subjects also performed 0.5-μm-particle bolus inhalations to penetration volumes (Vp) between 150 and 1,200 ml during a standardized inhalation from residual volume to 1 liter above upright functional residual capacity. Mode shift (MS) in supine posture was more mouthward than upright at all Vp, changing by 11.6 ml at Vp = 150 ml ( P < 0.05) and 38.4 ml at Vp = 1,200 ml ( P < 0.05). MS and phase III slope changes correlated positively at deeper Vp. Deposition did not change at any Vp, suggesting that deposition did not cause the MS change. We propose that the MS change results from increased sequencing in supine vs. upright posture.

Can Single Breath Nitrogen Washout Test Reflect the Severity of Emphysema?

CHEST Journal ◽  
2017 ◽  
Vol 152 (4) ◽  
pp. A803
Author(s):  
Michael Hanna ◽  
Zeron Ghazarian ◽  
Raminderjit Sekhon ◽  
Tapan Pandya ◽  
Zainab Syed ◽  
...  
Keyword(s):  
Nitrogen Washout ◽  
Single Breath

Single-Breath Nitrogen Washout

CHEST Journal ◽  
1979 ◽  
Vol 76 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Faiq J. Al-Bazzaz
Keyword(s):  
Nitrogen Washout ◽  
Single Breath

Pulmonary Function Abnormalities in Thalassemia Patients on a Hypertransfusion Program

PEDIATRICS ◽  
1980 ◽  
Vol 65 (5) ◽  
pp. 1013-1017
Author(s):  
Thomas G. Keens ◽  
Margaret H. O'Neal ◽  
Jorge A. Ortega ◽  
Carol B. Hyman ◽  
Arnold C.G. Platzker
Keyword(s):  
Carbon Monoxide ◽  
Pulmonary Function ◽  
Total Lung Capacity ◽  
Small Airway ◽  
Phase Iii ◽  
Diffusing Capacity ◽  
Lung Capacity ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Expiratory Flow

Pulmonary function tests were performed in 12 thalassemia patients on a hypertransfusion program (age 18.4 ± 2.6 SEM years) to determine the presence of any abnormalities of lung function. These included spirometry, expiratory flow rates, body plethysmography, single-breath nitrogen washout, single breath carbon monoxide diffusing capacity, and arterial blood gases. Only one patient had normal pulmonary function. Arterial hypoxemia was present in ten of 12 patients at rest. The total lung capacity (TLC) was normal. The residual volume was abnormally increased in five of 12 patients. The slope of phase III of single breath nitrogen washout curve was abnormal in five of 12 patients, but the closing volume was normal. The maximal expiratory flow rate at 60% total lung capacity was decreased in four of 12 patients, suggesting the presence of small airway disease. The single breath carbon monoxide diffusing capacity was normal in all patients. These pulmonary function abnormalities did not correlate with age or the cumulative amount of iron via blood transfused. The small airway obstruction, hyperinflation; and hypoxemia observed in thalassemia patients on a hypertransfusion program may result from the basic disease, iron deposition in the lungs, or other factors.

Factors affecting a single-breath N2 washout phase IV

1976 ◽  
Vol 40 (5) ◽  
pp. 715-719 ◽  
Author(s):  
K. Kaneko
Keyword(s):  
Age Groups ◽  
Lung Model ◽  
Factors Affecting ◽  
Lung Capacity ◽  
Single Breath ◽  
Washout Phase ◽  
Younger Age ◽  
Predicted Values ◽  
Closing Pressure ◽  
Phase Iv

A lung model was constructed to examine the effects of the following factors on the phase IV of a single-breath N2 washout: the lung's elasticity change with age, closing pressure (CP), regional volume (Volr) distribution, pleural pressure, and gradient (Grad). The analysis revealed 1) when the CP was assumed to be + 1.0 cmH2O, predicted changes in closing capacity (CC) due to alterations in elasticity agreed with previous experimental results for individuals above 40 yr; for younger age groups, the predicted values were apparently larger, suggesting the CP may be near zero; 2) difference in Volr distribution alone caused alterations in CC and the slope of phase IV; 3) for 1 cmH2O elevation of CP, closing capacity /total lung capacity (CC/TLC) was predicted to increase about 8%; 4) for 0.1 cmHiO/cm Grad increase, CC/TLC was predicted to rise approximately 7%. In conclusion, multiple factors affect phase IV.

Volume of isoflow: effect of distribution of ventilation

1977 ◽  
Vol 43 (5) ◽  
pp. 807-811
Author(s):  
R. D. Fairshter ◽  
A. F. Wilson
Keyword(s):  
Uniform Distribution ◽  
Oxygen Mixture ◽  
Small Airways ◽  
Helium Concentration ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Enhanced Sensitivity ◽  
Airways Obstruction ◽  
End Tidal

Volume of isoflow was determined in smokers and nonsmokers following one (VisoV1) and three (VisoV3) inhalations 80% helium 20% oxygen. In addition, distribution of ventilation was measured by single breath nitrogen washout and end-tidal helium concentration was determined following 1–3 breaths of a helium-oxygen mixture. In all subjects (smokers and non smokers), VisoV1 was significantly higher than VisoV3. Furthermore, VisoV1 was abnormal in 55.6% of smokers, whereas VisoV3 was abnormal in only 38.9%. Differences between VisoV1 and VisoV3 (VisoV1 - VisoV3 = deltaVisoV) were significantly larger in smokers. Non-uniform distribution of ventilation was associated with larger values of delta VisoV and lower end-tidal helium concentrations. VisoV1 is a more effective method than VisoV3 in distinguishing smokers with small airways obstruction from nonsmokers. This enhanced sensitivity can be explained by the observation that the effects of maldistribution of ventilation upon helium concentration in the late expirate are minimized after three breaths of a helium-oxygen mixture.

Sign in / Sign up

Export Citation Format

Share Document