[Relationship of closing volume to other lung function tests]

The closing volume method is suitably to be used in exposed groups of the population, the preliminary diagnostics of them is inconspicuous, in order to establish in time beginning and thus therapeutically influencible alterations of the small respiratory tract. In such a group of test persons only relatively slight connections with the other conventional lung standard methods are the result, by means of which its independence is emphasized. On the other hand less promising seems to be the application of the method in the verification of a "small airways obstruction" in smokers, whose vital capacity, forced expiratory volume and residual volume are within the normal.