SINGLE-BREATH DIFFUSING CAPACITY AS AID IN EVALUATION + PROGNOSIS OF CARDIOPULMONARY DISEASE

Abstract

Reduced values for the pulmonary diffusing capacity determined by the breath-holding technique were found in 11 of 43 patients with mitral stenosis, in 10 of 11 patients with diffuse pulmonary disease, and in 17 of 34 patients with chronic obstructive disease of the airways. In 22 cases of mitral stenosis studied after mitral valvuloplasty there was no consistent change. The survival status of 28 patients with mitral stenosis followed after mitral valvuloplasty, and of all patients in the other 2 groups during 1963, demonstrated a correlation between survival and diffusing capacity. The computed 7-year life-table ratio for those with a reduced diffusing capacity was 58% [plus or minus] 17%, whereas the same value for those with a normal diffusing capacity was 94% [plus or minus] 8%. It was also determined that the vital capacity test had equal prognostic value in mitral stenosis and diffuse pulmonary disease, while the maximal ventilatory capacity test was equally or more accurate in predicting survival or non-survival in chronic obstructive disease. The sensitivity of the diffusing capacity test to the presence of diffuse pulmonary disease and the serious implications of reduced values suggest that it should be useful in making decisions in this group regarding lung biopsy and therapy, particularly in instances in which the vital capacity is normal.