Impact of chest radiography‐based definition of bronchopulmonary dysplasia.

Background: Bubbly/cystic appearance on chest radiograph is an important factor in severe‐type bronchopulmonary dysplasia (BPD) in Japan. The aim of this study was to determine the perinatal characteristics and neonatal complications of the bubbly/cystic(+) group in extremely preterm infants with BPD, that is, oxygen dependency at day 28 after birth (BPD28). Methods: This was a multicenter retrospective cohort study of population data from infants (birthweight, <1,500 g) enrolled in the Neonatal Research Network of Japan. Of the 15 480 infants born at <28 weeks' gestational age (GA) between 2003 and 2012, 8,979 met the BPD28 criteria. The BPD28 infants were classified according to bubbly/cystic appearance on radiograph (±) at >28 postnatal days. Results: The bubbly/cystic(+) group had lower GA and birthweight and required longer mechanical ventilation and oxygen dependency than the bubbly/cystic(−) group. After adjustment for confounding factors, bubbly/cystic appearance was an independent risk factor for home oxygen therapy at discharge. Conclusion: Bubbly/cystic appearance on chest radiograph was a predictor of short‐term respiratory outcomes in infants with BPD28, which is diagnosed much earlier (≥28 postnatal days), and has a potentially different etiology to BPD36 (oxygen and/or positive pressure respiratory support dependency at 36 weeks' postmenstrual age). [ABSTRACT FROM AUTHOR]