[Dependence of the anatomical dead space on the tidal volume and on the endexpiratory lung volume: dynamic behaviour and stabilization of the bronchiolar tone (author's transl)].

The anatomical dead space was measured in dependence on the tidal volume and on the endexpiratory lung volume (respiratory level). A new method, the method of dead air plateau, was employed. The dead space increases with tidal volume (4 ml/100 ml). It is not dependent on the respiratory level. This was also directly shown in breathing manoeuvres changing the respiratory level rectangularly. In such manoeuvres a stabilization process can be seen. The same results give resistance measurements (oscillatory method). Values are taken in the endinspiratory state. This corresponds to the dead space volume. The 70% time of the stabilization reaction can be estimated, it is 20 sec. Taking this time into account, it is well understood that dead space volume is dependent on the tidal volume, but not dependent on the respiratory level. This time also makes evident that the often mentioned history of lung parameters lasts approximately 20 sec. The biological significance of the stabilization is discussed.