Table 1 NICHD diagnostic criteria for severity of BPD

Mild

Supplemental oxygen required ≥ 28 days, termination of supplemental oxygen by 36 weeks cGA or discharge

Moderate

Supplemental oxygen required ≥ 28 days, requirement of < 30% O₂ at 36 weeks cGA or discharge

Severe

Supplemental oxygen required ≥ 28 days, requirement of ≥ 30% O₂ and/or continuous positive airway pressure or mechanical ventilation at 36 weeks cGA or discharge