Bronchial venular leakage during endotoxin shock.

The pulmonary effects of endotoxin shock were investigated in dogs by a combination of anatomic and physiologic technics. Shock was produced in 14 dogs by injecting Escherichia coli lipopolysaccharide intravenously. Three dogs in hypovolemic shock and 6 untreated dogs served as controls. Colloidal carbon was injected intravenously to detect sites of pathologic increase in vascular permeability. During the first hour of endotoxin shock, bronchial venules allowed carbon and blood elements to traverse their walls, whereas no leakage of these large particles or ultrastructural changes could be detected in the alveolar walls. Only after the first hour was bronchial venular leakage accompanied by focal degenerative changes in the alveolar endothelium, focal interstitial edema in the alveolar septum and sequestration of damaged leukocytes in the alveolar capillaries. In contrast to these observations in endotoxin shock, control dogs in hypovolemic shock did not show bronchial venous leakage. Our findings suggest that the leakage of bronchial venules may be involved in the pathogenesis of pulmonary interstitial edema caused by endotoxin shock.