Changes in definition and pathogenesis of bronchopulmonary dysplasia in preterm infants: A review

Abstract

Bronchopulmonary dysplasia (BPD) is a common complication in preterm neonates, especially extremely preterm. However, effective prevention strategies and treatment methods are still being explored. Although the concept of BPD emerged a few decades ago, a consensus definition has not been established globally yet. The syndrome of BPD was introduced by Northway in 1967. With constant changes and improvements in newborn care and understanding about its pathogenesis, the definition of BPD has been changing and updated accordingly. NICHD (National Institute of Child Health and Human Development) first published the classification of BDP severity based on the level of required oxygen in 2001. Seventeen years later, in 2018, a new grading system was proposed to include new ventilation support methods. Unified diagnosis criteria and severity classification are important to facilitate consistent diagnosis between centers. Besides, understanding of BPD pathogenesis suggests antenatal risk factors such as genetic factors, intrauterine growth restriction, pre-eclampsia, inflammation, smoking during pregnancy; as well as postnatal risk factors such as oxygen toxicity, inflammation, moderate to large patent ductus arteriosus. Identification of these risk factors provides evidence for more effective treatment methods. This review describes the evolution of definitions, influence of lung development on BPD, and pathogenesis factors associated with BPD.