[State of pulmonary surfactant and ultrastructure of the aerohematic barrier in acute hypoxia].

Experiments on 8 dogs with acute respiratory hypoxia that lasted 1.5-2 hours were made to study ultrastructure of the aerohematic barrier, lung surface activity and the composition of individual phospholipid fractions in bronchoalveolar washings. The studies were performed with the use of histological, electron microscopy, physical and biochemical methods. The dogs with acute hypoxia manifested the impairment of the aerohematic barrier ultrastructure, edema of the interalveolar septa, a 5-fold decrease in the surface lung activity, a significant lowering of the content of phosphatidylcholine (the main component of lung surfactant) in the bronchoalveolar washings, as well as a concurrent 2-fold increase in the content of lysophosphatidylcholine with low surface active properties. Possible causes of alterations in the aerohematic barrier and lung surfactant in acute hypoxia are discussed.