Volume displaced by diaphragm motion in emphysema

Citation
B. Singh et al., Volume displaced by diaphragm motion in emphysema, J APP PHYSL, 91(5), 2001, pp. 1913-1923
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physiology
Journal title
JOURNAL OF APPLIED PHYSIOLOGY
ISSN journal
8750-7587 → ACNP
Volume
91
Issue
5
Year of publication
2001
Pages
1913 - 1923
Database
ISI
SICI code
8750-7587(2001)91:5<1913:VDBDMI>2.0.ZU;2-E
Abstract
To examine the effect of hyperinflation on the volume displaced by diaphrag m motion (Delta Vdi), we compared nine subjects with emphysema and severe h yperinflation [residual volume (RV)/ total lung capacity (TLC) 0.65 +/- 0.0 8; mean +/- SD] with 10 healthy controls. Posteroanterior and lateral chest X rays at RV, functional residual capacity, one-half inspiratory capacity, and TLC were used to measure the length of diaphragm apposed to ribcage (L ap), cross-sectional area of the pulmonary ribcage, DVdi, and volume beneat h the lung-apposed dome of the diaphragm. Emphysema subjects, relative to c ontrols, had increased Lap at comparable lung volumes (4.3 vs. 1.0 cm near predicted TLC, 95% confidence interval 3.4-5.2 vs. 0-2.1), pulmonary rib ca ge cross-sectional area (emphysema/controls 1.22 +/- 0.03, P< 0.001 at func tional residual capacity), and <Delta>Vdi/Delta Lap (0.25 vs. 0.14 liters/c m, P< 0.05). During a vital capacity inspiration, relative to controls, <De lta>Vdi was normal in five (1.94 +/- 0.51 liters) and decreased in four (0. 51 +/- 0.40 liters) emphysema subjects, and volume beneath the dome did not increase in emphysema (0 +/- 0.36 vs. 0.82 +/- 0.80 liters, P< 0.05). We c onclude that DVdi can be normal in emphysema because 1) hyperinflation is s hared between ribcage and diaphragm, preserving Lap, and 2) the diaphragm r emains flat during inspiration.