Table 1 Diagnostic criteria for bronchopulmonary dysplasia (BPD)

	GA weeks
	<32	>32
Treatment with oxygen	>21% for ≥28 days	>21% for ≥28 days
Time-point of assessment	36 weeks post-menstrual age or discharge	>28 but <56 days or discharge
BPD
Mild	Breathing room air at 36 weeks post-menstrual age or discharge	Breathing room air at 56 days post-natal age or discharge
Moderate	Need for <30% oxygen at 36 weeks post-menstrual age or discharge	Need for <30% oxygen at 56 days post-natal age or discharge
Severe	Need for >30% oxygen, with or without PPV or continuous positive pressure at 36 weeks post-menstrual age or discharge	Need for >30% oxygen, with or without PPV or continuous positive pressure at 56 days post-natal age or discharge

GA: gestational age; PPV: positive pressure ventilation. Modified from [16] with permission from the publisher.