Journal of Applied Physiology, Vol 49, Issue 5 834-840, Copyright © 1980 by American Physiological Society
Effects of pulmonary edema on regional pulmonary perfusion in the intact dog lung
A. B. Malik, H. van der Zee, P. H. Neumann and N. B. Gertzberg
Regional pulmonary blood flow was determined in dogs during varying degrees
of pulmonary edema induced by infusing 179.2-659.4 ml/kg normal saline over
2-3 h. Pulmonary hemodynamics and regional blood flows were measured during
the base-line period and at 30 min postinfusion. The degree of pulmonary
edema was determined by the final extravascular lung water-to-bloodless dry
lung weight ratio (W/D). In dogs developing gross alveolar edema (W/D of
10.70 +/- 0.88 vs. 3.10 +/- 0.30 in controls), the blood flow was shifted
to either upper or dependent lung regions. The shift to the upper regions
was associated with an increased (P < 0.05) pulmonary arterial pressure
(Ppa), whereas the shift to the dependent lung was not associated with a
significant change in Ppa. Breathing 100% O2 did not prevent these shifts,
suggesting that they were not due to localized hypoxic pulmonary
vasoconstriction. The flow distribution patterns were also not related to
regional differences in edema. In contrast to the changes during fulminant
edema, blood flow distribution did not change after moderate levels of
pulmonary edema (W/D of 6.03 0.69), suggesting that gross alveolar
flooding is required for a redistribution of pulmonary blood flow. Flow
redistribution to the upper lung during airway flooding may be due to
increase in Ppa, whereas the increased flow in the dependent lung during
the same degree of edema may be due to "bulging" of alveolar vessels into
the air spaces, secondary to a decrease in surface activity.
