When can one diagnose acute respiratory distress in a child?

Diagnostic criteria of ARDS in children: BERLIN DEFINITION CRITERIA Timing Within 1 wk of a known clinical insult or new or worsening respiratory symptoms Chest X-rays or tomography scan Bilateral opacities not fully explained by effusions, lobar/lung collapse, or nodules Origin of edema Respiratory failure not fully explained by cardiac failure or fluid overload Oxygenation Mild: PaO2/FiO2 - 200-300 mm Hg Moderate: PaO2/FiO2 - 100-200 mm Hg Severe: PaO2/FiO2 <100 mm Hg