Alveolar surface area to lung volume ratio in oleic acid induced
pulmonary edema.
Suzuki, Shunsuke, Tadashi Akahori, Naoki Miyazawa, Mari Numata, Takao
Okubo, and James P. Butler.
The First Department of Internal Medicine, Yokohama City University
School of Medicine, Yokohama 236, JAPAN, and Respiratory Biology
Program, Harvard School of Public Health, Boston, MA 02115
APStracts 2:0449A, 1995.
It is unknown how the in vivo alveolar surface-to-volume (S/V) ratio
changes in low pressure pulmonary edema. Here S/V is the area of the
air-tissue interface per unit total volume (air plus tissue). We
hypothesized that in oleic acid (OA)-induced edema, inactivation of
the pulmonary surfactant may increase surface tension and decrease
the S/V ratio at any given lung volume. OA of 0.04mg/kg was
intravenously injected to dogs. We measured the in vivo S/V ratio
(equivalent to inverse of optical mean free path, _) by light
-scattering stereology and the pressure-volume (P-V) curve 60-90 min
after OA administration. OA administration decreased the lung volume
at each transpulmonary pressure (Ptp) and increased the wet-to-dry
weight ratio. The S/V ratio decreased after OA administration (_
increased). The air-filled P-V curves shifted downward after OA, but
the saline-filled P-V curves after OA administration did not differ
significantly from control saline-filled curves. The difference in
transpulmonary pressure between air- and saline-filled P-V curves (an
index of the magnitude of surface tension) was increased in OA
-induced pulmonary edema. This study suggests that in OA-induced
pulmonary edema, the alveolar surface tension increases and the S/V
decreases, presumably due to inactivation of surfactant by serum
leakage to alveoli.
Received 28 December 1994; accepted in final form 4 October 1995.
APS Manuscript Number A1353-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95