Definition and epidemiology
Pediatric acute respiratory distress syndrome (PARDS) is acute, diffuse inflammatory lung injury producing hypoxaemia and bilateral parenchymal disease that is not fully explained by cardiac failure or fluid overload. The 2023 Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2) is the current standard and deliberately departs from the adult Berlin Definition: it excludes perinatal-related lung disease, uses oxygenation indices rather than the PaO2/FiO2 ratio as the primary severity metric, and accommodates children supported with non-invasive respiratory support. PARDS complicates roughly 2–3% of PICU admissions and a higher fraction of mechanically ventilated children, with mortality rising in step with oxygenation severity and the presence of non-pulmonary organ dysfunction.
Clinical features
PARDS follows a precipitating insult — most commonly pneumonia (viral or bacterial), sepsis, aspiration, near-drowning, or trauma. Children present with escalating work of breathing, tachypnoea, hypoxaemia refractory to supplemental oxygen, and diffuse crackles. New bilateral opacities appear on chest imaging. The course is one of decreasing compliance, increasing FiO2 and mean airway pressure requirements, and — in severe disease — progression to refractory hypoxaemia.
Diagnosis
PALICC-2 requires: onset within 7 days of a known clinical insult; chest imaging showing new infiltrate(s) consistent with acute parenchymal disease; oedema not fully explained by cardiac failure or fluid overload; and a defined oxygenation deficit. For invasively ventilated children, severity is graded by oxygenation index (OI = FiO2 × mean airway pressure × 100 / PaO2) or, when no arterial line is available, the oxygen saturation index (OSI), with SpO2 titrated to 88–97% before calculating indices. On non-invasive support, an SpO2/FiO2 ratio ≤250 (revised down from 264) or PaO2/FiO2 ≤300 defines PARDS only when delivered by full-face CPAP/BiPAP at ≥5 cmH₂O; the same oxygenation deficit on HFNC or lower support qualifies as possible PARDS, not PARDS. PALICC-2 introduced “possible PARDS” and “at risk for PARDS” categories to drive earlier recognition, and recommends restratifying severity at least 4 hours after initial diagnosis.
See the full criteria: PARDS
Red flags
- Rising OI/OSI despite escalating support — marks transition to moderate/severe PARDS
- Refractory hypoxaemia or hypercapnia unresponsive to ventilator optimisation
- Concurrent non-pulmonary organ dysfunction or shock (multiplies mortality)
- Air leak (pneumothorax, pneumomediastinum) on a tiring child
- Failure of non-invasive support — do not delay intubation in a deteriorating child
Management overview
Care is supportive and centred on lung-protective ventilation: limited tidal volumes, plateau/inspiratory pressure limitation, PEEP titrated to oxygenation and haemodynamics, and permissive hypercapnia and conservative oxygenation targets to minimise ventilator-induced lung injury. Treat the underlying cause (e.g. antimicrobials for pneumonia/sepsis) and use conservative fluid strategies once resuscitated. For moderate-to-severe disease, prone positioning, neuromuscular blockade, and recruitment manoeuvres are options; high-frequency oscillatory ventilation and ECMO are reserved for refractory hypoxaemia at experienced centres. Routine corticosteroids and inhaled nitric oxide are not recommended as standard therapy. Bundle in sedation minimisation, nutrition, and prevention of secondary infection.
References
- Emeriaud G, et al. Executive Summary of the Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2). Pediatr Crit Care Med. 2023.
- PALICC Group. Pediatric ARDS: Consensus Recommendations. Pediatr Crit Care Med. 2015.
- ARDS Definition Task Force. The Berlin Definition. JAMA. 2012.
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.