Background. Extreme prematurity and bronchopulmonary dysplasia (BPD) are associated with the development of progressive airway obstruction and decline of lung function in children into adulthood. We aimed to describe the early assessment of lung function and respiratory morbidity in children born extremely preterm with or without BPD.  

Methods. Prospective study including all the children born at ?28 weeks of gestation who received treatment in the NICU of the Centre Intercommunal de Créteil in France, between January 2006 and March 2012. Lung function was assessed at 4 years of age by using the Impulse Oscillometry System and respiratory morbidity were evaluated. We compared the lung function and clinical course of children with and without BPD at 36 weeks of gestation.

Results. We included 136 extremely premature children; 26 (19%) had BPD. Resistance measurements at 5 Hz and 20 Hz and reactance (X5) measurements at age 4 years were similar between the 2 groups. The mean z-score for resistance at 5 Hz for all premature newborns was at the upper limit of normal, whereas the mean resistance at 20 Hz was normal (z-score: 1.1). After treatment with bronchodilators, all preterm children showed no change in resistance. The prevalence of asthma symptoms was common and estimated at 30% regardless of BPD status.

Conclusion. Assessment of lung function at 4 years old in preterm children born at ?28 weeks of gestation may support the development of fixed small-bronchial obstructions in all extremely preterm children, regardless of BPD status.