Bubbly and cystic appearance on chest radiograph of extremely preterm infants with bronchopulmonary dysplasia is associated with wheezing disorder.

AIM: Bubbly/cystic appearance on chest X-ray (CXR) is an important factor in cases of severe bronchopulmonary dysplasia (BPD). We aimed to determine whether CXR -based BPD classifications obtained in extremely preterm infants with oxygen dependency at 28 days after birth (BPD28) is associated with wheezing disorders. METHODS: This was a multicentre retrospective cohort study of population data from infants (body weight, <1500 g) enrolled in the Neonatal Research Network of Japan. Of the 15 480 infants born at <28 weeks of gestation between 2003 and 2012, 8979 met the BPD28 criteria, and 4007 were classified as the no BPD28 group. BPD28 infants were classified according to the bubbly/cystic or no bubbly/cystic appearance on CXR at postnatal ≧28 days. The effects on wheezing disorder at 3 years of age were analysed. RESULTS: Bubbly/cystic BPD28 infants showed higher rates of wheezing disorders compared with no BPD28 infants. Bubbly/cystic BPD28 (odds ratio 1.7; 95% confidence interval, 1.3-2.2) was a significant independent factor for wheezing disorders. CONCLUSION: A bubbly/cystic appearance on CXR with BPD28 was a potential risk factor of wheezing disorders at 3 years of age. This may be a useful early diagnostic tool at ≧28 postnatal days in extremely preterm infants.

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).