Journal of Applied Physiology, Vol 51, Issue 4 955-962, Copyright © 1981 by American Physiological Society
Assessment of alveolar-capillary membrane permeability of dogs by aerosolization
G. J. Huchon, J. W. Little and J. F. Murray
We developed a method for measuring an index of alveolar-capillary membrane
permeability (PI) by aerosolizing a mixture of
99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) and 125I-antipyrine
(I-AP) and injecting 111In-DTPA (In-DTPA). The I-AP was used to compute the
quantity of Tc-DTPA delivered and the In-DTPA the quantity of Tc-DTPA in
the body. The PI was the ratio of the uptake of Tc-DTPA per minute to the
amount deposited at the end of aerosolization. In 14 anesthetized dogs we
measured the volume of distribution of I-AP (0.54 +/- 0.034 l/kg body wt)
and/or showed that the volumes of distribution of Tc-DTPA and In-DTPA were
similar. We measured PI in four groups of dogs: control (n = 5), oleic acid
(n = 5), hydrochloric acid (n = 6), and high left atrial pressure (n = 5).
The PI increased significantly in both groups with acid-induced increased
permeability compared with the control and high left atrial pressure
groups, which did not differ from each other. We conclude that the
aerosolization method is suitable for differentiating increased from normal
permeability.
