Journal of Applied Physiology, Vol 53, Issue 1 70-74, Copyright © 1982 by American Physiological Society
Changes in collateral ventilation with increased vascular pressure and edema formation
D. L. Emery, B. Shown, G. Batra and M. H. Gee
To test the hypothesis that development of hemodynamic edema results in
decreased collateral ventilation, we rapidly volume-expanded anesthetized
dogs with volumes equivalent to 10 (n = 5) and 15% (n = 5) of body weight.
We measured collateral resistance (Rcoll), pulmonary arterial pressure, and
left ventricular end-diastolic pressure before, during, and for 1-2 h after
the infusion. Lungs were subsequently processed for microscopic examination
and measurement of extravascular lung water content. During the infusion,
Rcoll increased modestly independent of the fluid-infusion rate or the rate
of increase in vascular pressures. After the infusion, Rcoll continued to
increase to maximum levels 2-33 times base line even though pressures
decreased dramatically. At the end of the experiment, Rcoll returned to
base line in one dog and was 3-15 times base line in the other dogs. These
changes bore no relationship to the severity of edema formation. Until
alveolar flooding occurs, accumulation of lung interstitial fluid and
changes in collateral ventilation appear to be coincident events rather
than causally related variables.
