ARDS
DEFINITION
Acute respiratory distress syndrome (ARDS) occurs when fluid builds up in the tiny, elastic air sacs (alveoli) in your lungs. More fluid in your lungs means less oxygen can reach your bloodstream. This deprives your 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.
Many people who develop ARDS don’t survive. 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.
CAUSES
The mechanical cause of ARDS is fluid leaked from the smallest blood vessels in the lungs into the tiny air sacs where blood is oxygenated. Normally, a protective membrane keeps this fluid in the vessels. Severe illness or injury, however, can cause inflammation that undermines the membrane’s integrity, leading to the fluid leakage of ARDS.
The most common underlying causes of ARDS include:
- Sepsis. The most common cause of ARDS is sepsis, a serious and widespread infection of the bloodstream.
- Inhalation of harmful substances. Breathing high concentrations of smoke or chemical fumes can result in ARDS, as can inhaling (aspirating) vomit.
- Severe pneumonia. Severe cases of pneumonia usually affect all five lobes of the lungs.
- Head, chest or other major injury. Accidents, such as falls or car crashes, can directly damage the lungs or the portion of the brain that controls breathing.
SYMPTOMS
The signs and 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:
- Severe shortness of breath
- Labored and unusually rapid breathing
- Low blood pressure
- Confusion and extreme tiredness
When to see a doctor
ARDS usually follows a major illness or injury, and most people who are affected are already hospitalized.
