Acute respiratory distress syndrome is widespread lung inflammation that floods the air sacs with fluid, causing severe low oxygen within a week of a trigger such as sepsis, pneumonia or trauma. It is not caused by heart failure and usually needs intensive care and mechanical ventilation.
Key symptoms
- Severe and worsening shortness of breath
- Rapid breathing
- Low oxygen that does not improve much with oxygen
- Confusion or agitation
What you find on exam
- Tachypnea and use of accessory muscles
- Crackles in both lungs
- Low oxygen saturation despite high-flow oxygen
- Signs of the underlying cause such as fever or shock
Tests
- Arterial blood gas: PaO2/FiO2 ratio of 300 or less
- Chest X-ray: patchy opacities in both lungs
- Echocardiogram or BNP to rule out heart failure
- Cultures and lactate to look for sepsis
Treatment basics
- Low tidal volume ventilation at 6 mL/kg of ideal body weight
- PEEP and oxygen to keep saturation about 88 to 95 percent
- Prone positioning for severe cases
- Conservative fluids once shock is controlled
- Treat the cause and prevent complications such as pressure injuries and blood clots
Red flags
- Saturation falling despite maximum oxygen
- Rising airway pressures on the ventilator
- Low blood pressure or new arrhythmia
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Related guides
Sources: Open RN, Nursing Fundamentals 2e; NCSBN 2026 NCLEX-RN Test Plan; NCCPA PANCE Content Blueprint. Written by Making Synapses. Making Synapses is not affiliated with these organizations.