Acute Respiratory Distress Syndrome

Also known as: Adult Respiratory Distress Syndrome (ARDS)
What is it?
It is a type of lung failure that can occur when large amounts of fluid accumulate in the lungs. ARDS should be treated as a medical emergency.
Who gets it?
About 14 in 100,000 people, both adults and children, develop ARDS each year. People at risk include those with infections that commonly cause fluid to accumulate in the lungs.
What causes it?
Tiny air sacs called alveoli are located at the tips of the body’s smallest breathing tubes, called the bronchi. The alveoli are responsible for passing oxygen into the blood. When the lungs are injured by infection or disease, blood and fluid begin to leak into the alveoli. When this happens, oxygen can’t enter the alveoli, which means oxygen is no longer getting into the blood. Because the lungs are inflamed and filled with fluid, the patient finds it increasingly difficult to breathe. The inflammation in the lungs leads to scarring, which is called fibrosis. The lungs eventually become stiff with scar tissue and breathing becomes very difficult. There are many possible causes of the type of lung injury that leads to ARDS. These include inhaling high concentrations of smoke, toxins, or oxygen; severe burns; blood infection (sepsis); pneumonia; pancreatitis; trauma to other parts of the body; or drug overdose. Fluids can also get into the lungs and cause injury when they are breathed in (aspirated), such as in a near drowning or when a person who is unconscious vomits.
What are the symptoms?
A patient will usually develop ARDS within 24 to 48 hours of the original illness or injury. Symptoms include difficult, shallow, rapid breathing; feelings of anxiety; and low blood pressure. Patients with fluid in the lungs will usually have a “crackling” and wheezing sound in the lungs that can be heard with a stethoscope. Because the blood oxygen is so low, the patient’s skin may look mottled or blue. In severe cases, low blood oxygen causes other organ systems, such as the liver, kidneys, heart, and brain, to fail.
How is it diagnosed?
Your doctor will check the level of oxygen in your blood either through a blood test called an arterial blood gas, or by using a device called an oximeter, which is clipped to your earlobe. A chest x-ray will show if there is any fluid in the lungs. To make a definite diagnosis, it is important to determine whether the symptoms are caused by ARDS or by heart failure. To do this, your doctor will test the pressure in the capillaries of the lungs by placing a catheter into a vein and moving it to the main artery of the lung. If the condition is caused by heart failure, the pressure will be high. If the pressure is normal, the symptoms are caused by ARDS.
What is the treatment?
Patients with ARDS are treated in a hospital’s Intensive Care Unit (ICU). They are given oxygen through either a nasal tube or face mask. Severe cases require a ventilator, a mechanical device that forces air in and out of the lungs through a tube passed through the nose or mouth and into the trachea. Medications, such as antibiotics and steroids, may also be used to treat infections and reduce inflammation. The amount of oxygen needed decreases as the lungs heal. During treatment, intravenous fluids are given to prevent dehydration and provide nutrition. The outlook for recovery is good when ARDS is treated quickly and the patient responds promptly. However, patients who spend long periods of time on a ventilator usually develop scarring on the lungs. This scarring may take months to heal and will cause mild to severe breathing difficulties depending upon the amount of permanent damage.
Self-care tips

While there is no way to prevent ARDS, patients with any type of lung infection should receive prompt treatment to avoid ARDS. Without immediate treatment, patients with ARDS will die. Patients on oxygen therapy should receive the lowest level necessary because high concentrations of oxygen can result in lung damage.