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Acute Respiratory Distress Syndrome (ARDS)

Also known as Adult Respiratory Distress Syndrome is a life threatening lung condition in which fluid accumulates in the lung leading to low levels of oxygen in the blood.

When a healthy person breathes, air will enter the nose and mouth passing through the trachea (windpipe) to reach the alveoli (air sacs) of the lungs. Oxygen will pass from the alveoli to small blood vessels surrounding the alveoli called the capillaries and from the capillaries to the bloodstream where it will be carried to different parts of the body. When the lung is injured from many causes including severe burns fluid and blood will leak from the capillaries into the alveoli, this will prevent air from entering the alveoli leading to decreased oxygen in the bloodstream and in turn decrease the oxygen supply to different organs which will affect their function. The lungs become inflamed, the inflammation will lead to scaring and fibrosis of the lungs causing the lungs to become stiff. This stiffness of the lung with fluid will make breathing very difficult for the patient.

Causes may include:

Symptoms and signs include:

  • Difficulty in breathing.
  • Increased respiratory rate (tachypnea).
  • Increased heart rate.
  • Fever.
  • Anxiety.
  • Wheezing herd with a stethoscope.


Investigations include arterial blood gas measurement, Chest X-ray, monitoring pulmonary capillary pressure by a pulmonary artery catheter introduced through a vein. Depending on the cause other investigations may include Complete blood count, liver function test, renal function test, CT scan and bronchoscopy.

Patients with ARDS are usually hospitalized and treated in the Intensive Care Unit, The goal of treatment is to provide breathing support and treat the cause of ARDS. This may involve:

  • Oxygen supplementation and the use of a mechanical ventilator (See mechanical ventilator part I, II).
  • Medications may be used in the form of antibiotics to treat infection, corticosteroids to reduce inflammation, pain medicine to reduce the pain, muscle relaxents to relax the muscles and decrease muscle spasms, antianxiety medications to decrease anxiety.
  • Intravenous fluid to prevent dehydration and provide nutrition.


Survival rate of patients with ARDS has improved; among factors that affect the outlook are the age of the patient, underlying cause of ARDS and any associated illness. Normal lung function is resumed in some patients after recovery. However others may experience breathing difficulties ranging from mild to severe. Patients who spend a long time on the ventilator and those with severe disease are more liable for persistent lung damage.

Possible complications:

  • Multiorgan system failure.
  • Ventilator associated lung infection (pneumonia).
  • Ventilator induced lung injury such as lung collapse and lung scarring (pulmonary fibrosis).

Support Groups
Many family members of patients with ARDS may suffer from severe stress. This stress can often be relieved by joining support groups where members can share common problems and experiences.

This information is not intended nor implied to be a substitute for professional medical advice; it should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. Call 911 for all medical emergencies.

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