Pathophysiology and morphometry of the early pulmonary fibrosis in dogs

A physiological (hemodynamics, gas exchange and respiratory mechanics) and morphometric evaluation has been undertaken on six normal dogs (N) and seven dogs (F) whose lungs showed variable degrees of fibrosis produced by successive injections of oleic acid. The correlation between the degree of fibrosis and the ratio of measured to predicted alveolar surface was --0.97 (alpha < 0.01). Moderate pulmonary hypertension was present in group F. The greater the fibrosis, the more the volume/pressure curve was displaced downward and to the right. There was a good (positive or negative) correlation between the degree of fibrosis and the following data: expired quasi-static compliance, DLCO, PAO2, (A--a)Do2 and the intrapulmonary shunt. Except for the increase in shunt, the VA/Q distribution was not disturbed.