Pulmonary gas transfer in children and adolescents born extremely preterm.

In extremely preterm-born infants, gas exchange takes place in developmentally fetal lungs, disturbing normal acinar growth and differentiation, potentially with long term negative consequences for lung function. The aim was to compare alveolar function in children and adolescents born extremely preterm and at term by measuring diffusing capacity of the lung for carbon monoxide (DLCO). Since this procedure may be challenging for subjects with shortcomings often seen after extremely preterm birth, we also assessed the reproducibility of the method. DLCO and DLCO adjusted for lung volume (KCO) were measured twice within 2 weeks in two population-based cohorts born at gestational age ≤28 weeks or with birth weight ≤1000 g, aged 10.6 years (n = 35) and 17.7 years (n = 46), and in 81 term-born controls individually matched for sex, age and place of birth. Reproducibility of DLCO measurements was in the same range for preterm and term-born children and young adults, and coefficients of variation were below 10% for all subgroups. KCO was significantly reduced with 7.9% and 7.2% for the oldest and youngest preterm birth cohorts, respectively. Reproducibility of DLCO in children and young adults born extremely preterm was adequate. DLCO and KCO were modestly reduced, supporting recent reports suggesting continuing alveolar growth throughout childhood.