Acute respiratory distress syndrome (ARDS) is the rapid onset of respiratory failure (ability to adequately oxygenate the blood) that can occur in critically ill persons of any age over 1 year. The condition can be life threatening and occurs when the lungs cannot perform normal gas exchange due to severe fluid buildup in both lungs.
- ARDS is mainly caused by extensive lung inflammation and small blood vessel injury due to sepsis (generalized infection), trauma and/or severe pulmonary infection such as pneumonia. However, ARDS can be associated with multiple transfusions, inhalation of salt water, smoke inhalation, tricyclic antidepressants overdoses and shock from any cause.
- Onset usually occurs within 24 hours to 3 days of the original illness or injury. At 72 hours, 85 percent of patients have clinically apparent ARDS.
- The incidence of ARDS has been difficult to determine but various published estimates have ranged from 1.5 to 75 cases per 100,000 populations. NHLBI suggest that ARDS affects about 150,000 people each year in the United States.
- ARDS morality rates have been continuously higher for African Americans than Whites. In 2003, however, 0.5 per 100,000 African Americans died from ARDS compared to 0.7 per 100,000 Whites.
- Among deaths of persons under 35 years of age, 27 percent were African American.
- ARDS has a fatality rate of approximately 30 to 40 percent. Deaths usually result from multisystem organ failure rather than lung failure alone.
- The majority of ARDS patients who survive will make a full recovery, however, some will have lasting damage to their lungs. A study found that survivors of ARDS may have persistent functional disability one year after discharge from the intensive care unit, most commonly muscle wasting and weakness.
- ARDS patients are usually treated in the intensive or critical care unit of a hospital. Treatment consists of mechanical ventilation along with careful attention to fluid balance and a supportive breathing technique called positive end expiratory pressure (PEEP). These are combined with continuing treatment of the precipitating illness or injury.
- A recent study found that receiving small, rather than large, breaths of air from a mechanical ventilator reduced the number of deaths by 22 percent and increased the number of days without ventilator use.
There are many experimental therapies that show promise for the treatment of ARDS. These include replacement surfactant (a natural soapy substance that keeps the lung air sacs open) and the use of anti-inflammatory agents.