Originally described by Northway in 1967 using clinical , radiographic & histologic criteria .
Bancalari refined definition using ventilation criteria , O2 requirement @ 28days to keep PaO2>50mmhg & abnormalities in chest x –ray .
Antenatal steroids , early surfactant Rx & gentle modes of ventilation minimize severity of lung injury .
It is Multifactorial
Major organ systems involved are lungs & heart
Alveolar stage of lung development - 36wks GA to 18 months post conception
Mechanical ventilation & O2 interferes with alveolar & pulmonary vascular development in preterm mammals .
Severe BPD leads to Pulmonary HT & abnormal pulmonary vascular development .
Stages of Bronchopulmonary Dysplasia
Stage 1 - similar to uncomplicated RDS
Stage 2 - pulmonary parenchymal opacities with bubbly appearance of lungs
Stage 3 & 4 – areas of atelectasis , hyperinflation & fibrous sheaths
Recently CT & MRI of chest – reveals more details of lung injury
Infants with severe BPD have Increased risk of pulmonary morbidity & mortality within the first 2 years of life.
Pulmonary Complications of BPD
Increased resistance & airway reactivity evident in early stages of BPD along with increased FRC .
Severe BPD results in Significant airway obstruction with expiratory flow limitations & further increased FRC secondary to air trapping & hyperinflation