The Pulmonary Lymphatics in Neonatal Hyaline Membrane Disease

Histometrical measurements have revealed that the mean diameter of the pulmonary lymphatics is consistently greater in the idiopathic respiratory distress syndrome, when compared to a control group of other newborns. This lymphangiectasis and congestion is most marked in the perivenous lymphatics, less in the peribronchial and periarterial, and least in the pleural lymphatics. This hitherto unreported morphologic feature of hyaline membrane disease seems to be most closely related to the known disturbance of alveolocapillary barrier permeability; it remains, however, a challenge to the investigator as some anatomical and histophysiological characteristics of the lymphatics of the lung, together with other aspects of the disease (i.e., surfactant deficiency, even neonatal pulmonary arterial hypoperfusion and venous congestion) could play important roles as well.