Table 1.

Comparison of the PALICC definition of paediatric ARDS with the Berlin definition. ∗For non-invasive mechanical ventilation, there is no severity stratification. The oxygenation criteria with full face-mask bilevel ventilation or CPAP ≥5 cm H₂O is P/F ratio ≤39.9 kPa.^1†Oxygenation index (OI)=(Fio₂ × mean airway pressure × 100)/Pao₂. ^‡Oxygenation saturation index (OSI)=(Fio₂ × mean airway pressure × 100)/Spo₂. ARDS, acute respiratory distress syndrome; CPAP, continuous positive airway pressure; ECHO, Echocardiogram, PALICC, Pediatric Acute Lung Injury Consensus Conference.

	PALICC definition of PARDS1	Berlin definition of ARDS5
Age	Exclude hypoxaemia secondary to perinatal-related lung disease.	–
Timing	Within 7 days of known clinical insult.	Within 1 week of known clinical insult or new/worsening respiratory symptoms.
Chest imaging	New infiltrate(s) consistent with pulmonary parenchymal disease are necessary.	Bilateral opacities not fully explained by effusions, lobar/lung collapse or nodules.
Origin of oedema	Respiratory failure and new chest imaging not explained by acute left ventricular failure or fluid overload.	Respiratory failure not fully explained by cardiac failure of fluid overload. Echocardiogram required to exclude hydrostatic oedema if no risk factor present.
Oxygenation∗	Use of OI† or OSI‡ to stratify severity during invasive mechanical ventilation.	Use of PaO2/FiO2 (P/F ratio) to stratify severity.
Mild	4 ≤ OI < 8 5 ≤ OSI < 7.5	26.6 kPa < P/F ratio ≤ 39.9 kPa with PEEP/CPAP ≥ 5 cm H2O
Moderate	8 ≤ OI <16 7.5 ≤ OSI 12.3	13.3 kPa < P/F ratio ≤ 26.6 kPa with PEEP/CPAP ≥ 5 cm H2O
Severe	OI ≥ 16 OSI ≥ 12.3	P/F ratio ≤ 13.3 kPa with PEEP/CPAP ≥ 5 cm H2O
Special considerations1
Cyanotic heart disease	As per PALICC definition above but ‘deterioration in oxygenation not explained by underlying cardiac disease’.
Chronic lung disease	As per PALICC definition above with ‘chest imaging changes consistent with new infiltrate and ac acute deterioration in oxygenation from baseline’.
Left ventricular dysfunction	As per PALICC definition above with ‘acute deterioration in oxygenation not explained by left ventricular dysfunction’.