[Two new characteristic quantities for characterization of the bronchial state in vivo and of pharmacological effects. The discordant behaviour of the bronchial system (author's transl)].

The classical quantity to characterize the state of the human bronchial system is the airway resistance (Raw). We have developed a new method for measuring the anatomical dead space (VD) and we have shown that the bronchial system may be characterized by the anatomical VD as well. Both Raw and VD are taken as mean values. In systematic investigations with our new VD method we found two facts: (1) under certain conditions VD depends unequivocally on the tidal volume (VT), the socalled VT gradient, and (2) VD varies periodically (bronchial peristalsis). The same is valid for Raw. From these observations one can derive two new characteristic quantities for the human bronchial system: (1) the standard deviation of the oscillations (sigma) as a measure of the bronchial motility and (2) the VT gradient as a measure of the bronchial compliance. With the aid of the two new characteristic quantities two types of bronchial reactions are defined: the concordant and the discordant reaction. Concordant means: VD increases (Raw decreases, respectively), sigma decreases, and the absolute value of the VT gradient increases or all effects are inverted. Discordant means: deviations from the concordant behaviour. All given examples but one show a discordant reaction. The new characteristic quantities improve the possibility to discriminate bronchial reactions, e.g., on drugs. The discordant behaviour is an expression for the complexity of the bronchial system.