Criteria

New Global Definition of ARDS[1]​​

In 2024, modifications to the Berlin definition of ARDS (termed the 'Global Definition') were made. A diagnosis of ARDS can be made if the patient fulfils all of the following criteria:

  • Acute onset (within 1 week of known clinical insult)

  • Bilateral opacities on chest radiography or computed tomography (CT), or bilateral B lines and/or consolidations on ultrasound not fully explained by effusions, atelectasis, or nodules/masses

  • PaO₂/FiO₂ (arterial to inspired oxygen) ratio of ≤300 or SpO₂/FiO₂ (pulse oximetric saturation to inspired oxygen) ratio of ≤315

  • Respiratory failure not fully explained by heart failure or fluid overload (objective assessment such as echocardiogram recommended if no risk factor).

Categories of ARDS

  • Non-intubated ARDS. PaO₂:FiO₂ ≤300 mmHg or SpO₂:FiO₂ ≤315 (if SpO₂ ≤97%) on high flow nasal oxygen (HFNO) with flow of ≥30 L/min or non-invasive ventilation (NIV)/continuous positive airway pressure (CPAP) with at least 5 cm H₂O end-expiratory pressure

  • Intubated ARDS. PaO₂:FiO₂ ≤300 mmHg or SpO₂:FiO₂ ≤315 (if SpO₂ ≤97%) on invasive mechanical ventilation

  • ARDS in resource-limited settings. SpO₂:FiO₂ ≤315 (if SpO₂ ≤97%). Neither positive end-expiratory pressure nor a minimum flow rate of oxygen is required for diagnosis in resource-limited settings.

Severity of Intubated ARDS

  • Mild: 200 <PaO₂:FiO₂ ≤300 mmHg or 235 <SpO₂:FiO₂ ≤315 (if SpO₂ ≤97%)

  • Moderate: 100 <PaO₂:FiO₂ ≤200 mmHg or 148 <SpO₂:FiO₂ ≤235 (if SpO₂ ≤97%)

  • Severe: PaO₂:FiO₂ ≤100 mmHg or SpO₂:FiO₂ ≤148 (if SpO₂ ≤97%).

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