Thrombin-induced disseminated intravascular coagulation in the dog. II. Cardiorespiratory changes during spontaneous and controlled ventilation.

Disseminated intravascular coagulation (DIC) was induced in anaesthetized dogs by the infusion of a fibrinolytic inhibitor followed by thrombin. The occurrence of DIC was confirmed by haematological and histological examinations. After the thrombin infusion there was a progressive reduction in cardiac index and systemic arterial pressure, only four of the 14 dogs surviving for 4 hr. Pulmonary artery pressure increased after the thrombin infusion, but decreased subsequently in seven animals allowed to breathe spontaneously. In these animals, there was an increase in respiratory rate, minute volume and deadspace/tidal volume ratio, but there were no changes in the arterial-to-alveolar PCO2 difference. Arterial PCO2 and PO2 decreased, but there were no significant changes in total venous admixture. In seven dogs submitted to controlled ventilation, arterial PO2 decreased to the same extent, but there were no significant changes in arterial PCO2, deadspace/tidal volume ratio or venous admixture.