[Ventilation mechanics in the premature and the newborn. I. Statistical measurements of the isolated lungs].

On 31 pairs of lungs from still borns and newborns of differing stages of maturation and age (23rd week of gestation up to the 24th week after birth) statical measurements including liquid fillings were performed. On account of the histo-mechanical tests as well as morphological and clinical data, the group could be divided into normal lungs and lungs with decreased surfactant activity. Between the 35th week of gestation and the 5th week after birth a marked increase in pulmonary maturation with unproportional changes of the histomechanical values could be demonstrated. In lungs with decreased surfactant activity the influence of life span upon the mechanical properties of pulmonary tissue could be shown. The high surface tension decreases, presumably on account of surfactant synthesis, while the values of tissue elasticity decrease as a result of overstretching.