Reference values for pulmonary tissue volume, membrane diffusing capacity, and pulmonary capillary blood volume.

Pulmonary tissue volume (Vti), carbon monoxide diffusing capacity, membrane diffusing capacity, pulmonary capillary blood flow and pulmonary capillary blood volume were measured in ninety (54 men and 36 women) healthy lifetime nonsmokers using an inert gas rebreathing technique. Prediction equations were generated using multiple linear regressions with height and age as the independent variables. Normalizing the data by dividing by functional residual capacity eliminated all sex differences. In contrast to the other variables, normalized pulmonary tissue volume did not correlate with any of the independent variables tested. Therefore, an average normalized Vti value can be recommended as a reference value