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 damage to the membrane, leading to the fluid leakage of ARDS.

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 or near-drowning episodes.
• 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.
• Coronavirus disease 2019 (COVID-19). People who have severe COVID-19 may develop ARDS.
• Others. Pancreatitis (inflammation of the pancreas), massive blood transfusions and burns.