Henry F. Smyth

Morphologic criteria of pulmonary edema.

The usual morphologic criterion of alveolar edema is the presence of homogeneous acidophilic material in the air spaces. When interstitial pulmonary edema is present, it is often assumed that alveolar edema is associated even though there may not be any demonstrable proteinaceous material in the air spaces. Findings in rat lungs are described that serve as additional criteria of alveolar edema. These are separations of surface epithelium from the alveolar septum to form blebs and larger clear spaces on the alveolar wall, finally resulting in cast-off membranes completely free in the air spaces.