Membrane and Capillary Components of Lung Diffusion in Infants with Bronchopulmonary Dysplasia

Rationale: Autopsied lungs of infants with bronchopulmonary dysplasia (BPD) demonstrate impaired alveolar development with larger and fewer alveoli, which is consistent with our previous physiologic findings of lower pulmonary diffusing capacity of the lung for carbon monoxide (DlCO) in infants and toddlers with BPD compared with healthy controls born at full term (FT). However, it is not known whether the decreased DlCO in infants with BPD results from a reduction in both components of DlCO: pulmonary membrane diffusing capacity (Dm) and Vc.Objectives: We hypothesized that impairment of alveolar development in BPD results in a decrease in both Dm and Vc components of DlCO but that the Dm/Vc ratio would not differ between the BPD and FT groups.Methods: DlCO was measured under conditions of room air and high inspired oxygen (90%), which enabled Dm and Vc to be calculated.Measurements and Main Results: Dm and Vc increased with increasing body length; however, infants with BPD had significantly lower Dm and ...