Maturation of Interdependence Between Extra‐alveolar Arteries and Lung Parenchyma in Piglets
作者:
Anthony Mansell,
Allison McAteer,
Allen Pipkin,
期刊:
Circulation Research
(OVID Available online 1992)
卷期:
Volume 71,
issue 3
页码: 701-710
ISSN:0009-7330
年代: 1992
出版商: OVID
关键词: blood vessel-parenchyma interdependence;lung growth;lung micromechanics;pulmonary circulation
数据来源: OVID
摘要:
Mechanical interdependence between intrapulmonary structures and parenchyma has not been studied previously in immature postnatal lungs. To study these interactions, lung elastic moduli were measured by pressure-volume and punch indentation studies in lobes excised from 3-day-old (n=6), 1-month-old (n=6), and 3-month-old (n=7) piglets. After extra-alveolar arteries were filled with a radiopaque fluid silicone compound, transpulmonary pressure and arterial pressure were varied independently as the lobar vein was occluded. Arterial diameters and lengths were measured from radiographs. Behavior of 3-month-old lungs was consistent with previous studies of adult lungs, but results were unique in 3-day-old lungs. That is, during stepwise deflation of the immature lungs 1) intravascular pressures fell when arteries were occluded experimentally, 2) arteries increased their diameters when kept at a constant intravascular pressure, and 3) arterial lengths decreased by <3%. Behavior of 1-month-old lungs was intermediate. A previous continuum mechanics analysis of pressure-diameter behavior was modified to account for compression by alveolar pressure as vascular diameters increase. It was concluded that 1) radial and axial dimensions of extra-alveolar arteries are virtually independent of parenchymal expansion in newborn piglet lungs and 2) periarterial interstitial pressures increase as these lungs are inflated. Our interpretation of these findings is that a mechanical association of the arteries to the parenchyma occurs gradually with postnatal maturation.
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