Girl blowing dandelion

ARDS - Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome (ARDS) is a life threatening disease that causes severe fluid build up in the lungs.  This fluid build up, along with associated collapsed air sacs, leads to increased difficulty in breathing and lower oxygen levels in the blood.  About 1 out of every 3 people that develope ARDS will die.

History of ARDS

ARDS was first described in 1967.  It was originally called Adult Respiratory Distress Syndrome.  However, the name has since been changed to Acute Respiratory Distress Syndrome because the condition can also occur in children.

Causes of ARDS

There are several conditions that can lead to a person getting ARDS.  Risk factors are broken down into two main catagories - direct lung injury and indirect injury.

  • Direct Lung Injury
    • Inhalation of toxic fumes or smoke
    • Severe pneumonia
    • Aspiration (breathing in vomited stomach contents)
    • physical injury or bruising of the lungs
  • Indirect Injury
    • Sepsis (a severe infection throughout the body)
    • Severe bleeding requiring blood transfusions
    • Drug overdose
    • Inflamed Pancreas

Stages of ARDS

Acute Respiratory Distress Syndrome occurs in 3 phases.
Phase 1 - During the first phase, a break down begins at the point where the blood vessels meet the air sacs of the lungs.  This break down allows fluid to leak from the blood vessels into the air sacs of the lung.  While some air sacs become full of fluid, other air sacs will collapse.  During this stage, it becomes more difficult to breathe and oxygen levels begin to fall.  Many ARDS victims will need to be placed on a mechanical ventilator if breathing becomes too difficult or if safe oxygen levels can't be maintained.
Phase 2 - During this phase, the lungs continue to fill with fluid and scar tissue begins to form.  This phase can begin as early as 5-7 days after the initial onset.  This is a particularly damaging phase of the syndrome and has an increased risk of death.
Phase 3 - This is the recovery phase.  The fluid begins to drain and the lungs begin to heal.  Many ARDS survivors will return to normal lung funtion within 6-12 months.  However, some survivors will have lasting effects due to scar tissue and other damage.

Mortality (Death Rate)

The National Institute of Health estimates the death rate for ARDS to be about 30%.  This is much better than past estimates of 40-60% mortality.  Factors that decrease the chance of surviving ARDS include: chronic liver disease, other organ failure, sepsis, and advanced age.  Failure of lung function to improve during the first week of treatment has not been shown to be a negative factor in predicting chance of survival.