Ventilation Rate and End -- Tidal Steady State Pulmonary Diffusing Capacity (DLCOss2) at Rest

1974 ◽  
Vol 33 (4) ◽  
pp. 379-386
Author(s):  
G. Sundström
Keyword(s):  
Steady State ◽  
Ventilation Rate ◽  
Diffusing Capacity ◽  
Pulmonary Diffusing Capacity ◽  
End Tidal

Relationship of increased breath-holding diffusing capacity to ventilation in exercise

1963 ◽  
Vol 18 (4) ◽  
pp. 794-797 ◽  
Author(s):  
Joseph C. Ross ◽  
Ronald W. Reinhart ◽  
John F. Boxell ◽  
Leroy H. King
Keyword(s):  
Steady State ◽  
Ventilation Rate ◽  
The Other ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Voluntary Hyperventilation ◽  
Pulmonary Diffusing Capacity ◽  
Pulmonary Capillaries ◽  
The Mean ◽  
Relationship Of

Pulmonary diffusing capacity (Dl), as measured by all techniques, increases with exercise possibly due to an increase in the volume of blood in pulmonary capillaries (Vc), but the mechanism for the latter is not known. Previous studies have indicated that the steady-state Dl can be increased by hyperventilation alone, enough possibly to account for the increase in Dl as measured by this method with exercise. On the other hand, breath-holding Dl is not increased by voluntary hyperventilation preceding the measurement. The present study was carried out to determine whether or not the increase in ventilation rate is a necessary part of a combination of factors which account for the rise in Dl during exercise. In this study breath-holding Dl was measured in five subjects. All of the five subjects studied had an increase in Dl during exercise when ventilation was voluntarily restrained to the resting level, and the mean increase was as great as the mean increase during the same amount of exercise with normal unrestricted breathing. The increase in Dl when breathing was restricted during exercise could not be accounted for by differences in alveolar volumes or by differences in alveolar O2 and CO2 tensions in the two situations. This study demonstrates that increase in ventilation preceding the measurement is not a determinant of the increase in breath-holding Dl with exercise Submitted on January 7, 1963

Effect of exercise on pulmonary diffusing capacity

1963 ◽  
Vol 18 (3) ◽  
pp. 447-456 ◽  
Author(s):  
G. M. Turino ◽  
E. H. Bergofsky ◽  
R. M. Goldring ◽  
A. P. Fishman
Keyword(s):  
Carbon Monoxide ◽  
Young Adults ◽  
Steady State ◽  
Body Position ◽  
Diffusing Capacity ◽  
Pulmonary Diffusing Capacity ◽  
Graded Exercise ◽  
Normal Man ◽  
The Difference

The effect of graded exercise on the pulmonary diffusing capacity for both oxygen and carbon monoxide measured simultaneously was studied in healthy young adults by steady-state methods. Pulmonary diffusing capacity for oxygen increases progressively with increasing severity of exercise; it exceeds the DlCO at high levels of exercise by amounts greater than can be accounted for by the difference in diffusivity of the test gases. Diffusing capacity for carbon monoxide increases less than DlOO2 for comparable grades of exercise but no definite plateau value could be established. The supine or upright body position does not influence the values of either DlOO2 or DlCO during exercise. Diffusing capacity of the lung for oxygen does not limit the maximum levels of exercise which may be achieved by normal man. Submitted on August 6, 1962

Comparison of steady state pulmonary diffusing capacity estimates for O2 and CO in dogs

1980 ◽  
Vol 42 (1) ◽  
pp. 43-59 ◽  
Author(s):  
J. Savoy ◽  
M.-C. Michoud ◽  
M. Robert ◽  
J. Geiser ◽  
P. Haab ◽  
...  
Keyword(s):  
Steady State ◽  
Diffusing Capacity ◽  
Pulmonary Diffusing Capacity ◽  
Capacity Estimates

Noninvasive diffusing capacity and cardiac output in exercising dogs

1988 ◽  
Vol 65 (2) ◽  
pp. 669-674 ◽  
Author(s):  
J. I. Carlin ◽  
S. S. Cassidy ◽  
U. Rajagopal ◽  
P. S. Clifford ◽  
R. L. Johnson
Keyword(s):  
Blood Flow ◽  
Body Weight ◽  
Cardiac Output ◽  
Steady State ◽  
Pulmonary Blood Flow ◽  
Maximal Exercise ◽  
O2 Consumption ◽  
Diffusing Capacity ◽  
Metabolic Capacity ◽  
End Tidal

We have developed a rebreathing procedure to determine diffusing capacity (DLCO) and pulmonary blood flow (Qc) in the awake, exercising dog. A low dead space, leak-free respiratory mask with an incorporated mouthpiece was utilized to achieve mixing between the rebreathing bag and the dog's lung. The rebreathing bag was initially filled with approximately 1.0 liter of gas containing 0.6% C2H2, 0.3% C18O, 9% He, and 35-40% O2. End-tidal gas concentrations were measured with a respiratory mass spectrometer. The disappearance of C2H2 and C18O was measured with respect to He to calculate Qc and DLCO. Values for DLCO in dogs, expressed per kilogram of body weight, were much larger than those reported in humans. However, at a given level of absolute O2 consumption, measurements of absolute DLCO in dogs were comparable to those reported in humans by both rebreathing and steady-state methods at rest and near-maximal exercise. These results suggest that DLCO is more closely matched to the metabolic capacity (i.e., maximal O2 consumption) than to body size between these two species.

Single-breath diffusing capacity of NO independent of inspiratory NO concentration in rabbits

1997 ◽  
Vol 273 (6) ◽  
pp. R2055-R2058
Author(s):  
Hartmut Heller ◽  
Klaus-Dieter Schuster
Keyword(s):  
Gas Phase ◽  
Time Course ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Pulmonary Tissue ◽  
Pulmonary Diffusing Capacity ◽  
Single Breath ◽  
Endogenous Release ◽  
End Tidal ◽  
Alveolar Capillary

Pulmonary diffusing capacity of NO (Dl NO) was determined by performing single-breath experiments on six anesthetized paralyzed supine rabbits, applying inspiratory concentrations of NO (Fi NO) within a range of 10 parts per million (ppm) ≤ Fi NO ≤ 800 ppm. Starting from residual volume, the rabbit lungs were inflated by 50 ml of a NO-nitrogen-containing indicator gas mixture. Breath-holding time was set at 0.1, 1, 3, 5, and 7 s. Alveolar partial pressure of NO was determined by analyzing the end-tidal portion from expirates, with the use of respiratory mass spectrometry. In the six animals, pulmonary diffusing capacity of NO averaged Dl NO = 1.92 ± 0.21 ml ⋅ mmHg−1 ⋅ min−1(mean ± SD value). Despite extreme variations in Fi NO, we found very similar Dl NOvalues, and in three rabbits we found identical values even at such different Fi NO levels of 80 ppm or 500, 20, or 200 ppm as well as 10 or 800 ppm. There was also no dependence of Dl NO on the respective duration of the single-breath maneuvers. In addition, the time course of NO removal from alveolar space was independent of applied Fi NOlevels. These results suggest that Dl NOdeterminations are neither affected by chemical reactions of NO in alveolar gas phase as well as in lung tissue nor biased by endogenous release of NO from pulmonary tissue. It is our conclusion that the single-breath diffusing capacity of NO is able to provide a measure of alveolar-capillary gas conductance that is not influenced by the biochemical reactions of NO.

Influence of age on pulmonary diffusing capacity

1959 ◽  
Vol 14 (4) ◽  
pp. 483-492 ◽  
Author(s):  
R. E. Donevan ◽  
W. H. Palmer ◽  
C. J. Varvis ◽  
D. V. Bates
Keyword(s):  
Carbon Monoxide ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Pulmonary Function ◽  
Normal Subjects ◽  
Diffusing Capacity ◽  
O2 Uptake ◽  
Pulmonary Diffusing Capacity ◽  
Simultaneous Measurements ◽  
End Tidal

The pulmonary function of 24 normal subjects ranging in age from 20 to 50 years has been studied at rest and during exercise. At rest there is a significant decrease with age in the pulmonary diffusing capacity and the level of diffusing capacity attained on exercise at any particular oxygen uptake decreases with increasing age. Simultaneous measurements of O2 uptake, ventilation, end tidal O2 and CO2 concentration and calculated alveolar CO2 concentration, using the Bohr equation, show no evidence that any of these measurements are significantly influenced by age. The predicted maximal O2 diffusing capacity ( J. Appl. Physiol. 6: 588, 1954) predicts with fair accuracy the diffusing capacity for carbon monoxide that will be found in any given individual at an O2 uptake of about 2.8 l/min. It correctly predicts the change in CO diffusing capacity with increasing age. Reasons are given for suggesting that the decrease in pulmonary diffusing capacity observed may be explained by a diminution in cardiac output with increasing age. Submitted on November 21, 1958

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