Over the past three decades, advances in prenatal and neonatal intensive care have
contributed to marked improvements in survival rates for extremely immature infants born
during the canalicular phase of lung development at 24 to 26 weeks, a time when alveolar
and distal vascular development is rapidly occurring. The histopathological lesions of severe
airway injury and alternating sites of overinflation and fibrosis in “old” BPD have been
replaced in “new” BPD with the pathologic changes of large, simplified alveolar structures, a …