Acute respiratory distress syndrome (ARDS)

Acute respiratory distress syndrome (ARDS) typically presents with dyspnoea and hypoxaemia, which progress to acute respiratory failure.

Common causes are pneumonia, sepsis, aspiration, and severe trauma.

Mortality is between 30% and 50%.

Low tidal volume, plateau-pressure-limited mechanical ventilation is the primary treatment that has been shown to reduce mortality. In severe ARDS, neuromuscular blockade, prone positioning, and extracorporeal membrane oxygenation (ECMO) may improve clinical outcomes.

Complications include pneumothorax, ventilator-associated pneumonia, multiple organ failure, and pulmonary fibrosis with prolonged respiratory failure.

This topic covers ARDS in patients over the age of 12 years.

Acute respiratory distress syndrome (ARDS) is a non-cardiogenic pulmonary oedema and diffuse lung inflammation syndrome that often complicates critical illness. The clinical definition of ARDS was updated in 2024 to include both intubated and non-intubated patients and to allow diagnosis of ARDS in resource-limited settings.[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 Diagnosis of ARDS is based on fulfilling three criteria: 

• Acute onset (within 1 week)

• 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.[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 ​​

If no risk factors for ARDS are present, then acute pulmonary oedema as a result of heart failure should be ruled out.