[Closing volume and ventilatory distribution disturbances (author's transl)].

Ventilatory disturbances are induced by airway closure associated with an increase of the venous admixture from alveoli with a low ventilation-perfusion-ratio. Closing volume was measured by single breath nitrogen washout curves and correlated with ventilatory disturbances derived from multiple breath nitrogen washout curves and an inspiratory gas distribution index (IDI). There was present a close correlation between the closing volume in relation to the functional residual capacity and the IDI. With rising closing volume in relation to functional residual capacity a deterioration of the inspiratory gas distribution with increasing venous admixture was observed.