Acute respiratory distress syndrome

Most common symptoms and signs are dyspnea and hypoxemia, which progress to acute respiratory failure.

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

Mortality is between 40% and 50%.

Low tidal volume, plateau-pressure-limited mechanical ventilation is the primary treatment that has been shown to reduce mortality. In severe acute respiratory distress syndrome (ARDS), neuromuscular blockade and prone positioning 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 noncardiogenic pulmonary edema and diffuse lung inflammation syndrome that often complicates critical illness. The diagnosis of ARDS is based on fulfilling three criteria:

• Acute onset (within 1 week)

• Bilateral opacities on chest x-ray

• PaO₂/FiO₂ (arterial to inspired oxygen) ratio of ≤300 on positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) ≥5 cm H₂O. [1]Ranieri VM, Rubenfeld GD, Thompson BT, et al; ARDS Definition Task Force. Acute respiratory distress syndrome: the Berlin definition. JAMA. 2012 Jun 20;307(23):2526-33. http://www.ncbi.nlm.nih.gov/pubmed/22797452?tool=bestpractice.com

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