scholarly journals Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

1997 ◽  
Vol 83 (3) ◽  
pp. 810-816 ◽  
Author(s):  
Sylvia Verbanck ◽  
Hans Larsson ◽  
Dag Linnarsson ◽  
G. Kim Prisk ◽  
John B. West ◽  
...  
Keyword(s):  
Capillary Blood ◽  
Diffusing Capacity ◽  
Pulmonary Tissue ◽  
Tissue Volume ◽  
Pulmonary Capillary ◽  
Interstitial Pulmonary Edema ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Tissue Volume ◽  
Pulmonary Capillary Blood Volume

Verbanck, Sylvia, Hans Larsson, Dag Linnarsson, G. Kim Prisk, John B. West, and Manuel Paiva. Pulmonary tissue volume, cardiac output and diffusing capacity in sustained microgravity. J. Appl. Physiol. 83(3): 810–816, 1997.—In microgravity (μG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to μG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls ( P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P< 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to μG.

Differential changes of lung diffusing capacity and tissue volume in hypergravity

2002 ◽  
Vol 93 (3) ◽  
pp. 931-935 ◽  
Author(s):  
Malin Rohdin ◽  
Dag Linnarsson
Keyword(s):  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Alveolar Volume ◽  
Tissue Volume ◽  
Dependent Part ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Capillary Blood Volume

In normal gravity, lung diffusing capacity (Dl CO) and lung tissue volume (LTV; including pulmonary capillary blood volume) change in concert, for example, during shifts between upright and supine. Accordingly, Dl CO and LTV might be expected to decrease together in sitting subjects in hypergravity due to peripheral pooling of blood and reduced central blood volume. Nine sitting subjects in a human centrifuge were exposed to one, two, and three times increased gravity in the head-to-feet direction (Gz+) and rebreathed a gas containing trace amounts of acetylene and carbon monoxide. Dl CO was 25.2 ± 2.6, 20.0 ± 2.1, and 16.7 ± 1.7 ml · min−1 · mbar−1(means ± SE) at 1, 2, and 3 Gz+, respectively (ANOVA P < 0.001). Corresponding values for LTV increased from 541 ± 34 to 677 ± 43, and 756 ± 71 ml ( P < 0.001) at 2 and 3 Gz+. Results are compatible with sequestration of blood in the dependent part of the pulmonary circulation just as in the systemic counterpart. Dl CO, which under normoxic conditions is mainly determined by its membrane component, decreased despite an increased pulmonary capillary blood volume, most likely as a consequence of a less homogenous distribution of alveolar volume with respect to pulmonary capillary blood volume.

Determination of tissue volume and carbon dioxide dissociation slope of the lungs in man

1964 ◽  
Vol 19 (3) ◽  
pp. 374-380 ◽  
Author(s):  
Marvin A. Sackner ◽  
Khalil A. Feisal ◽  
Arthur B. DuBois
Keyword(s):  
Carbon Dioxide ◽  
Lung Tissue ◽  
Capillary Blood ◽  
Adult Males ◽  
Pulmonary Tissue ◽  
Tissue Volume ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Tissue Volume

The volume of N2O absorbed by the lung can be measured during inspiration before the gas is taken up in significant amounts by the capillary blood flow by a plethysmographic technique. If the alveolar fraction of N2O and its solubility coefficient are known, the combined pulmonary tissue and capillary blood volume (Vt+c) can be calculated. Vt+c averaged 517 ml, sd 61 ml, in nine adult males, values in good agreement with those obtained by other methods. The pulmonary tissue volume alone, Vt, in six of these subjects was 438 ml, sd 58 ml. A modification of the technique, using CO2 as the test gas, permitted calculation of the CO2 dissociation slope of the lung tissue. In five subjects, the CO2 dissociation slope of the lung, without the buffering effect of pulmonary capillary blood, over a range of PaCOCO2 from 31 to 55 mm Hg, averaged 0.30 ml CO2 STPD/100 ml lung tissue per mm Hg, or including physically dissolved CO2, 0.38 ml CO2 STPD/100 ml lung tissue per mm Hg. Because Vt is about four times larger than Vc, the lung tissue is of greater importance than the pulmonary capillary blood in buffering fluctuations in alveolar carbon dioxide during respiration. pulmonary tissue volume; pulmonary tissue space for N2O Submitted on August 26, 1963

Gas Transfer for Carbon Monoxide in Polycythaemia Secondary to Hypoxic Lung Disease

1985 ◽  
Vol 68 (1) ◽  
pp. 57-62 ◽  
Author(s):  
J. A. Wedzicha ◽  
F. E. Cotter ◽  
P. J. W. Wallis ◽  
A. C. Newland ◽  
D. W. Empey
Keyword(s):  
Carbon Monoxide ◽  
Lung Disease ◽  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Capillary Blood Volume ◽  
The Mean

1. The transfer factor for carbon monoxide and its subdivisions, the membrane diffusing capacity (Dm) and the pulmonary capillary blood volume (Vc), were measured in 16 patients with polycythaemia secondary to chronic hypoxic lung disease and in ten hypoxic non-polycythaemic control subjects. 2. The mean pulmonary capillary blood volume was significantly lower in the polycythaemic patients (31.6 ml, sd 11.2) compared with the control group (65.2 ml, sd 22.5) (P<0.001). 3. Erythrapheresis, as a method of isovolaemic haemodilution, was performed in 15 of the polycythaemic patients. The mean packed cell volume fell from 58 (sd 5)% to 47 (sd 5)% after treatment, with significant reductions in blood viscosity at both high and lower shear rates (P<0.001). 4. The mean pulmonary capillary blood volume increased from 32.3 ml (sd 11.3) before treatment to 48.7 ml (sd 18.7) after erythrapheresis (P<0.01), with no significant change in membrane diffusing capacity. 5. The rise in pulmonary capillary blood volume is another potential physiological advantage of the reduction of packed cell volume in patients with polycythaemia secondary to hypoxic lung disease.

Pulmonary diffusing capacity and pulmonary capillary blood volume during parabolic flights

1997 ◽  
Vol 82 (4) ◽  
pp. 1091-1097 ◽  
Author(s):  
Pierre Vaïda ◽  
Christian Kays ◽  
Daniel Rivière ◽  
Pierre Téchoueyres ◽  
Jean-Luc Lachaud
Keyword(s):  
Nitric Oxide ◽  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Parabolic Flights ◽  
Pulmonary Diffusing Capacity ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Capillary Blood Volume

Vaı̈da, Pierre, Christian Kays, Daniel Rivière, Pierre Téchoueyres, and Jean-Luc Lachaud.Pulmonary diffusing capacity and pulmonary capillary blood volume during parabolic flights. J. Appl. Physiol. 82(4): 1091–1097, 1997.—Data from the Spacelab Life Sciences-1 (SLS-1) mission have shown sustained but moderate increase in pulmonary diffusing capacity (Dl). Because of the occupational constraints of the mission, data were only obtained after 24 h of exposure to microgravity. Parabolic flights are often used to study some effects of microgravity, and we measured changes in Dl occurring at the very onset of weightlessness. Measurements of Dl, membrane diffusing capacity, and pulmonary capillary blood volume were made in 10 male subjects during the 20-s 0-G phases of parabolic flights performed by the “zero-G” Caravelle aircraft. Using the standardized single-breath technique, we measured Dl for CO and nitric oxide simultaneously. We found significant increases indl for CO (62%), in membrane diffusing capacity for CO (47%), in Dl for nitric oxide (47%), and in pulmonary capillary blood volume (71%). We conclude that major changes in the alveolar membrane gas transfers and in the pulmonary capillary bed occur at the very onset of microgravity. Because these changes are much greater than those reported during sustained microgravity, the effects of rapid transition from hypergravity to microgravity during parabolic flights remain questionable.

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