Acute respiratory distress syndrome (ARDS) is a life-threatening lung condition that prevents enough oxygen from getting to the lungs and into the blood. Infants can also have respiratory distress syndrome.

ARDS can be caused by any major direct or indirect injury to the lung. Common causes include:

  • Breathing vomit into the lungs (aspiration)

  • Inhaling chemicals

  • Lung transplant

  • Pneumonia

  • Septic shock (infection throughout the body)

  • Trauma

ARDS leads to a buildup of fluid in the air sacs (alveoli). This fluid prevents enough oxygen from passing into the bloodstream.

The fluid buildup also makes the lungs heavy and stiff, which decreases the lungs' ability to expand. The level of oxygen in the blood can stay dangerously low, even if the person receives oxygen from a breathing machine (ventilator) through a breathing tube (endotracheal tube).

ARDS often occurs along with the failure of other organ systems, such as the liver or kidneys. Cigarette smoking and heavy alcohol use may be risk factors.

Symptoms of Acute Respiratory Distress Syndrome

Symptoms usually develop within 24 to 48 hours of the injury or illness. Often, people with ARDS are so sick they cannot complain of symptoms. Symptoms can include any of the following:

  • Difficulty breathing

  • Low blood pressure and organ failure

  • Rapid breathing

  • Shortness of breath

Diagnosing Acute Respiratory Distress Syndrome

Listening to the chest with a stethoscope (auscultation) reveals abnormal breath sounds, such as crackles, which may be signs of fluid in the lungs. Often, blood pressure is low. Cyanosis (blue skin, lips, and nails caused by lack of oxygen to the tissues) is often seen.

Tests used to diagnose ARDS include:

  • Arterial blood gas

  • Blood tests, including CBC and blood chemistries

  • Blood and urine cultures

  • Bronchoscopy in some people

  • Chest x-ray

  • Sputum cultures and analysis

  • Tests for possible infections

An echocardiogram may be needed to rule out heart failure, which can look similar to ARDS on a chest x-ray.

Acute Respiratory Distress Syndrome Treatment

ARDS often needs to be treated in an intensive care unit (ICU).

The goal of treatment is to provide breathing support and treat the cause of ARDS. This may involve medicines to treat infections, reduce inflammation, and remove fluid from the lungs.

A ventilator is used to deliver high doses of oxygen and positive pressure to the damaged lungs. People often need to be deeply sedated with medicines. During treatment, health care providers make every effort to protect the lungs from further damage. Treatment is mainly supportive until the lungs recover.