Differential changes of lung diffusing capacity and tissue volume in hypergravity
| Autor: | Malin Rohdin, D. Linnarsson |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Adult
Male Cardiac output Pulmonary Circulation Supine position Physiology Centrifugation Hypergravity Physiology (medical) Diffusing capacity medicine Humans Lung volumes Respiratory system Lung Blood Volume business.industry Pulmonary capillary blood volume Anatomy medicine.anatomical_structure Pulmonary Diffusing Capacity Female business Lung Volume Measurements Biomedical engineering |
| Zdroj: | Journal of applied physiology (Bethesda, Md. : 1985). 93(3) |
| ISSN: | 8750-7587 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|