Journal of Applied Physiology, Vol 52, Issue 6 1519-1523, Copyright © 1982 by American Physiological Society
Effect of oleic acid injury on lung-heart interaction during ventricular filling
T. C. Lloyd Jr
Part of ventricular filling pressure is expended in deforming the lungs and
oleic acid lung injury, which reduces lung compliance, might be expected to
change the magnitude of this effect. Left ventricular pressure-volume
curves from 13 treated and 13 uninjured dogs were compared. Curves were
obtained by inflating a balloon in the flaccid left ventricle of the
freshly dead dog. The extracardiac compliance component was determined by
subtracting ventricular pressures observed when lungs were collapsed from
those observed during inflation to levels duplicating both airway pressure
and lung volume of uninjured dogs. We found that the respiratory system
compliance opposing ventricular filling is much less than is predicted from
the compliance opposing tidal ventilation. This suggests that cardiac
filling imposes a local shape change rather than a general lung volume
change. Injury only slightly decreased cardiac filling compliance although
it markedly reduced lung inflating compliance. These results are consistent
with citations showing that edema increases lung compliance by altering
surface properties and airway closure with little change in tissue
deformability. Thus, while edema may alter cardiac performance by changing
pleural pressure, it has little influence on the pulmonary component of
diastolic compliance.
