Clinical Features, Treatments, and Outcomes in Acute Respiratory Distress Syndrome (ARDS-CTO)

Inclusion Criteria

• •Age ≥ 18 years.
• •Receiving respiratory support with one of the following:
• •High-flow nasal oxygen (HFNO) at a flow rate ≥ 30 L/min,
• •Noninvasive ventilation (NIV) with positive end-expiratory pressure (PEEP) of ≥ 5 cm H₂O, or
• •Invasive mechanical ventilation with PEEP of ≥ 5 cm H₂O.
• •Within 48 hours before or after eligibility screening, the following criteria must be met:
• •PaO₂/FiO₂ ≤ 300 mmHg under the above respiratory support.
• •Bilateral opacities on chest radiograph or computed tomography, not fully explained by effusions, lobar/lung collapse (atelectasis), or pulmonary nodules/masses.
• •Respiratory failure not fully explained by cardiac failure or fluid overload; when no clear ARDS risk factor is identified, an objective assessment (e.g., echocardiography) is required to exclude hydrostatic edema.