Static Recoil of the Lungs and Static Compliance in Healthy Children

Abstract

The static lung compliance was studied in 57 healthy children, 6 to 14 years old. A new method called ‘end-expiratory-compliance’ (C_1EE) has been developed and the results were compared to the data obtained from Zapletal et al. with the ‘static pressure-volume’ curves technique. The advantages of the method are discussed. The static lung compliance of children increases with height. Static lung compliance value is greater than dynamic lung compliance. This difference is discussed. Static recoil pressure of the lung was measured by the oesophageal balloon technique at so-called ‘zero-volume’ of air in the balloon. At functional residual capacity (FRC), i.e. 41-44 % total lung capacity (TLC), static recoil pressure is negative in all children, according to this technique. The taller the child, the more negative is the intrathoracic pressure at the same lung volume in percent of TLC, the slopes of the P/V curve being significantly different in younger and in older children. These data are compared to those observed in adults. The elastic properties of the lungs in younger children seem to be similar to those in older adults as a result of lung growth and aging, which successively influence the elastic behaviour of the lung tissue. The influence of the experimental conditions (intra-oesophageal balloon) on the data collected in children is emphasized.