A numerical index of the stability of lung expansion

Abstract

Determinations of the stability of lung expansion as described here are based on the assumption that any given pair of lungs behaves in a uniform manner from lobule to lobule. The distribution of the values obtained and their good correlation with pathologic data, as well as observation of specimens during deflation, suggest that this is true in all or most of the material studied. The possibility has recently been suggested in conversation, not with reference to infant material that some portions of a lung may differ in stability from the rest owing perhaps to pathologic or experimental changes. This would interfere with the usefulness of the index; it might be suspected when, upon repeated deflation, certain portions are seen to collapse consistently long before the rest. It is therefore suggested to check the progress of deflation by inspection of the specimen.