Disseminated intravascular coagulation in the pathogenesis of adult respiratory distress syndrome: 2. Experimental study.

The role of disseminated intravascular coagulation (DIC) in the pathogenesis of adult respiratory distress syndrome (ARDS) was studied in the experimental animals. ARDS was simulated in dogs by the administration of various doses of Escherichia coli endotoxin (Difco). The alveolar surface activity in the group which received lethal dose of endotoxin (3 mg/kg) exhibited no significant alterations with mild pulmonary insufficiency and little pathologic change five hours after the induction of shock. On the other hand, a significant decrease in alveolar surface activity was found to develop in the group which received sublethal dose of endotoxin (1 mg/kg) accompanying enlarged alveolar-arterial oxygen tension differences (A-aDO2) and elevated pulmonary vascular resistance after 24 hours. These changes occurred concomitantly with pathologic findings of DIC, interstitial edema and atelectasis. The disturbance in ventilatory function observed in prolonged shock appeared to be related to the impairment of pulmonary microcirculation caused by DIC and subsequent hypoxia of lung tissue which led to a loss of alveolar surfactant.