AJP - Heart and Circulatory Physiology, Vol 269, Issue 5 1811-H1819, Copyright © 1995 by American Physiological Society
Pulmonary vascular extraction and distribution of antipyrine with alveolar flooding
W. O. Cua, V. Bower, C. Tice and F. P. Chinard
Department of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103, USA.
Transport characteristics of antipyrine (AP), 22Na+, and tritiated water
(THO) were assessed in dog lungs by multiple indicator-dilution experiments
in vivo with anesthesia and in isolated perfused preparations before and
after alveolar flooding. In controls, outflow patterns of AP and THO were
nearly identical. In flooding, AP and THO patterns separated. THO upslopes
decreased and mean (t) and modal (tmax) transit times increased as flooding
increased; AP initial upslopes remained relatively unchanged but t
increased, whereas tmax decreased. Patterns of 22Na+ were unchanged. The
results indicate 22Na+ limitation at the endothelium, AP limitation only at
the epithelium, and no THO limitation. A mathematical model is based on
axial and orthogonal distribution of AP and THO. With alveolar flooding,
diffusional distance may be a limiting factor in this distribution.
