Definition of Acute respiratory distress syndrome:

Acute respiratory distress syndrome (ARDS) is a life-threatening lung condition that prevents enough oxygen from getting into the blood.

See also: Infant respiratory distress syndrome

Causes, incidence, and risk factors:

ARDS can be caused by any major swelling (inflammation) or injury to the lung. Some common causes include:

• Breathing vomit into the lungs (aspiration)
• Inhaling chemicals
• Pneumonia
• Septic shock
• Trauma

ARDS leads to a buildup of fluid in the air sacs. This fluid prevents enough oxygen from passing into the bloodstream.

The fluid buildup also makes the lungs heavy and stiff, and decreases the lungs' ability to expand. The level of oxygen in the blood can stay dangerously low, even if the person receives oxygen from a breathing machine (mechanical ventilator) through a breathing tube (endotracheal tube).

ARDS often occurs along with the failure of other organ systems, such as the liver or the kidneys. Cigarette smoking and heavy alcohol use may be risk factors.