Longitudinal Measures of Lung Function in Healthy Infants

Abstract

Effective treatment of paediatric pulmonary disease relies on early diagnostics, and thus requires pulmonary function testing. Before infant pulmonary function testing can be applied to detect disease, it must first be understood in health, especially in the context of the developing lung. Adult studies have suggested that the rapid expansion of alveoli leads to faster growth in the lung parenchyma with respect to the conducting airways. By longitudinally evaluating lung function parameters that approximate the size of the parenchyma and the airways in infants, it can be determined whether dysanapsis is present in this young age group. However, while we were unable to find functional dysanapsis in tidal breathing measures, it was found when comparing forced flow and volumetric measures. This indicates that while the airways are proportionally larger in youngest infants, rapid parenchymal expansion leads a decrease in the relative size of these airways compared to overall lung volume.