ARDS stands for acute respiratory distress syndrome which occurs when fluid builds up in the tiny, elastic air alveoli in the lungs. More fluid in the lungs means less oxygen can reach the bloodstream. This deprives the organs of the oxygen they need to function.

ARDS typically occurs in people who are already critically ill or who have significant injuries. Severe shortness of breath, the main symptom of ARDS, usually develops within a few hours to a few days after the original disease or trauma.

For many people who develop ARDS it is fatal. The risk of death increases with age and severity of illness. Of the people who do survive ARDS, some recover completely while others experience lasting damage to their lungs.


The symptoms of ARDS can vary in intensity, depending on its cause and severity, as well as the presence of underlying heart or lung disease. They include:

  • Low blood pressure
  • Severe shortness of breath
  • Labored and unusually rapid breathing
  • Confusion and extreme tiredness


The cause of ARDS is the fluid which has leaked from the smallest blood vessels in the lungs into the tiny air sacs where blood is oxygenated. There is normally a protective membrane which keeps this fluid in the vessels. Severe illness or injury, however, can cause inflammation that destroys the membrane's integrity, leading to leakage of the fluid.

The most common underlying causes of ARDS include:

  • Sepsis,
  • Inhalation of harmful substances,
  • Severe pneumonia,
  • Head, chest or other major injury.

Risk factors

Most people who develop ARDS are already hospitalized for another condition, and many are critically ill. There is additional risk in cases of a widespread infection in the bloodstream (sepsis).

People who have a history of chronic alcoholism are at higher risk of developing ARDS. They're also more likely to die of ARDS.


Improved treatments of ARDS, which is an extremely serious ill ness,  provide for more people to survive it. However, many survivors end up with potentially serious and sometimes lasting complications, including:

  • Scarring in the lungs (pulmonary fibrosis),
  • Collapsed lung (pneumothorax),
  • Blood clots,
  • Infections,
  • Abnormal lung function,
  • Memory, cognitive and emotional problems.


The first obstacle to preventing ARDS is identifying patients at risk of developing ARDS. Implementing preventive measures requires an algorithm for early detection. The combination of early clinical recognition and predictive scores could help in the detection of patients at risk and in the early treatment or implementation of preventive strategies.