Acute respiratory distress syndrome (ARDS)

New Global Definition of ARDS[1]Matthay MA, Arabi Y, Arroliga AC, et al. A new global definition of acute respiratory distress syndrome. Am J Respir Crit Care Med. 2024 Jan 1;209(1):37-47. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10870872 http://www.ncbi.nlm.nih.gov/pubmed/37487152?tool=bestpractice.com ​​

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 fulfills 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

• Nonintubated 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 noninvasive 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%).