No abstract

Mild abnormalities of peripheral lung function can be detected by simple methods, but it remains difficult to determine when these changes are the result of emphysema rather than disease of the airways. We delay washout of a gas of large mass (SF6) relatively more than that of a gas of low mass (He) so the cumulative expired volume at which endtidal He becomes less than end-tidal SF6 ("crossover volume"), which is small in normal subjects, becomes larger if there is serial inhomogeneity.

No abstract

No abstract

No abstract