What Is Acute Respiratory Distress Syndrome (ARDS)?
When a lung injury occurs, the lung may become inflamed. Its small blood vessels (capillaries) may leak too much fluid into the lung's air sacs (alveoli). This keeps the lungs from filling with air, causing the respiratory system to fail. This condition is called acute respiratory distress syndrome (ARDS). It is a severe form of acute lung injury (ALI). It usually occurs within one to three days after an injury. A type of noncardiac pulmonary edema (a buildup of fluid in the lungs), ARDS can lead to low oxygen levels in the blood. In most cases, people develop ARDS while in the hospital for other health problems, such as a severe injury or illness.
ARDS can be life threatening because organs and other tissues require oxygen to work properly. However, because of improved treatment, many more people survive a lung injury and ARDS than in the past. Nearly 190,000 Americans are affected by ARDS each year.
Signs and Symptoms of Lung Injuries
Signs and symptoms may differ depending upon the cause of the lung injury. You may have symptoms like these, either because of the underlying injury or from ARDS and low oxygen levels:
- Rapid breathing; trouble getting enough air
- Abnormal breathing sounds, such as a crackling noise
- Low blood pressure
- Extreme fatigue
- Bluish lip or skin color
- Anxiety or agitation
Diagnosing a Lung Injury
In some cases, the cause of the lung injury is apparent. In other cases, the doctor asks questions and does a physical exam, listening to lungs and heart and checking skin and lip color. To confirm the cause of the symptoms and lung injury, as well as its severity, the doctor may order tests, such as these:
- An arterial blood gas test shows levels of oxygen and carbon dioxide in the blood.
- A chest X-ray takes a picture of the lungs and can reveal extra fluid.
- Blood tests can spot problems such as infection.
- Sputum cultures help pinpoint the cause of an infection.
- A computed tomography (CT) scan creates detailed pictures of the lungs to reveal underlying problems such as an obstruction.
- Bronchoscopy can help evaluate lung infections with the help of a viewing tube or, combined with biopsy, may rule out other problems such as tumors.
- Heart tests such as an echocardiogram may help rule out other potential causes of fluid buildup in the lungs, such as heart failure.
Treating a Lung Injury
Some lung injuries heal on their own. However, a pneumothorax, for example, may require removal of excess air through a syringe, needle, or suction tube. In some cases, a chest tube is inserted. Rest, elevation of the head of the bed, and other steps may help with healing.