18th February 2025

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an important cause of non-cardiogenic pulmonary oedema. It can result from sepsis, pneumonia, massive trauma with shock, DIC, acute pancreatitis, and inhalation of vomit, smoke or toxic chemicals.

Diagnostic (Berlin) criteria are as follows:

• Timing: onset of lung injury within 1 week of insult or new/worsening respiratory symptoms over a week
• Imaging: bilateral opacities on CXR not fully explained by effusions, collapse or nodules
• Origin of oedema: respiratory failure not fully explained by cardiac failure or fluid overload
• Oxygenation: hypoxaemia (PaO2/FiO2 ratio ≤ 300 requiring a minimum PEEP/CPAP of 5 cmH2O to maintain target sats)

Management is with respiratory support (often in ITU) and treatment of underlying causes. CPAP may be adequate in the first instance but a majority of patients will need intubation and ventilation.