Background

Acute Respiratory Distress Syndrome (ARDS)

• Acute respiratory distress syndrome (ARDS) is an acute, diffuse, inflammatory form of lung injury, characterized by poor oxygenation, pulmonary infiltrates, and acuity of onset.
• ARDS is defined as an acute disorder that starts within 7 days of the inciting event and is characterized by:
  • Bilateral lung infiltrates
  • Severe progressive hypoxemia in the absence of any evidence of cardiogenic pulmonary edema
• Once ARDS develops, patients usually have varying degrees of pulmonary artery vasoconstriction and may subsequently develop pulmonary hypertension.
• ARDS carries a high mortality, and few effective therapeutic modalities exist to combat this condition.

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Epidemiology

• Estimates of the incidence of ARDS in the United States range from 64.2 to 78.9 cases/100,000 person-years.
• Twenty-five percent of ARDS cases are initially classified as mild and 75% as moderate or severe.
• However, a third of the mild cases go on to progress to moderate or severe disease.
• The overall pooled mortality rate for all the studies evaluated was 43%.
• The mortality of ARDS is commensurate to the severity of the disease; it is 27%, 32%, and 45% for mild, moderate, and severe disease, respectively.

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Definitions

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Risk Factors

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