[Ventilation mechanics in the newborn. II. Dynamical measurements of the isolated lungs (author's transl)].

On 31 pairs of lungs from still borns and newborns and new borns of differing stages of maturation and age (23rd week of gestation up to the 24th week after birth), dynamical measurements within an artificial thorax were performed including systematical changes of ventilation types, particularly breathing frequency. In 12 pairs of lungs, surfactant activity was diminished. In these cases, a marked heterogeneity of ventilation and partly excessive increases of work of breathing correlated with the life span following birth could be shown, and some pathogenetical ways of cardiorespiratory failure as well as mechanisms of damaging late effects of the lungs following respiratory distress syndrome could be demonstrated. Moreover, by measurements of airway resistance it could be shown that in diseased and normal lungs of unmature infants the range of laminar flow is low due to the lability of the bronchial walls. A new method of valuation of the experimental data using the laws of alternating current (Heusinger) has been proven to be useful in the analysis of pulmonary mechanics.