Static volume-pressure relations of excised lungs of infants with hyaline membrane disease, newborn and stillborn infants.

The clinical features of hyaline membrane disease have been reviewed recently (1, 2). When the disease is fatal the lungs at autopsy are usually grossly atelectatic, suggesting the appearance of liver. Microscopically, this atelectasis is seen to be patchy and widespread; scattered through the lungs are dilated terminal bronchioles and alveolar ducts that are lined with an eosinophilic membrane. The significance of the membrane during life is uncertain. Behrle, Gibson and Miller (3) demonstrated at autopsy that the expansion of lungs of infants was impeded by the membrane. More recently, Craig, Fenton and Gitlin (4) showed from latex casts of the airways that the membrane may cause obstruction. But Gruenwald (5) has taken the view that the membrane may be only "a secondary phenomenon that appears in a previously diseased lung." He has stressed instead the greater importance of the atelectasis to which these lungs appear vulnerable. Our object was to study the static elastic behavior of lungs containing hyaline membranes. For this purpose static volume-pressure relations of lungs from three sources were compared: newborn infants with a histologic diagnosis of hyaline membrane disease, newborn infants dying of other causes, and stillborn infants. On the basis of these measurements, estimates were made of the differences in functional residual capacity (FRC) and pulmonary compliance that might have pre-