Static mechanical lung properties in healthy children.

The elastic properties of the lung (elastic recoil and static compliance) have been studied in 27 children from 7 to 15 years of age by a quasi-static method. There is a significant relationship between the static expiratory compliance and the quasistatic pressures at different percentages of total lung capacity on the one hand, and height and age on the other. The specific compliance is independent of both height and age. The authors also use a sigmoid mathematical model based on the relationship between specific compliance and maximum pulmonary volume. This model fits well with the experimental data. Comparison is made with the currently used exponential model of Salazar & Knowles. The results favour the hypothesis of an increase in the number of alveoli all through childhood.