Alveolo-capillary permeability and alveolar fluid accumulation in experimental models of surfactant dysfunction and lung injury

We studied alveolar fluid accumulation to and alveolo-capillary transfer of inhaled Tc-99m-DTPA in experimental models of surfactant dysfunction and l ung injury. Surfactant dysfunction was induced in rabbits by aerosol administration of a detergent and lung injury by intravenous oleic acid. Tc-99m-DTPA was give n in aerosol and clearance was measured. Alveolar fluid accumulation was me asured as alveolar recovery of intravenously infused Cr-51-EDTA. The half-life of Tc-99m-DTPA in the lungs was 7.1 +/- 3.5 min in surfactant dysfunction, 22 +/- 14 in lung injury and 115 +/- 63 in the controls. Reco very of Cr-51-EDTA in lavage fluid was 0.3 +/- 0.3 ml, 1.4 +/- 1.0 ml and 8 .6 +/- 1.9 ml, respectively. All between groups differences were statistically significant. Impaired sur factant function may greatly increase the rate of solute absorption across the alveole-capillary barrier, while there is only moderate alveolar accumu lation of alveolar fluid. Lung injury induced by oleic acid, increases alve ole-capillary transfer of Tc-99m-DTPA along with accumulation of large amou nts of alveolar fluid.