Journal of Applied Physiology, Vol 48, Issue 1 177-185, Copyright © 1980 by American Physiological Society
Vascular and airway pressures, and intersititial edema, affect peribronchial fluid pressure
H. Inoue, C. Inoue and J. Hildebrandt
Peribronchial-perivascular fluid pressure (Px(f) was measured relative to
pleural pressure in six freshly excised dog lobes. Rapidly equilibrating
saline-filled open-end catheters were inserted between lobar bronchus and
artery to depths of 3 cm from the hilum. Px(f) was -4 to -8 cmH2O at
resting lung volume and became more negative as transpulmonary pressure
(Ptp) was increased, and less negative as vascular volume was increased.
For example, at constnat Ptp = 30 cmH2O, mean Px(f) rose, respectively,
from -35 to -31, -24, -16, and -4 cmH2O, as vascular pressure (Ppa/pv) was
increased from -15 to 0, +10, +20, and +30 cmH2O. Lung weight rose steadily
at Ppa/pv above 10, reflecting the development of edema. Px(f) had a
significant hysteresis with respect to Ptp, being more negative in
deflation. As lung edema developed, Px(f) became progressively less
negative or slightly positive (even at high Ptp and low Ppa/pv) and
hysteresis diminished. Modified wick catheters employed in four additional
lobes gave similar results.These data suggest that Px(f) is strongly
influenced by bronchovascular-parenchymal interdependence, and that when
regions with negative Px(f) absorb fluid the negative pressure may be
eliminated.
