Acute respiratory distress syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 26, 2016
StartDiseasesAcute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a condition which often affects people who are critically ill from a severe injury, sepsis (severe body infection), shock, trauma or pneumonia. ARDS can affect the amount of oxygen entering and leaving the lungs by causing the alveoli (air sacs) to collapse. The mortality rate for those with ARDS is about 50 percent.

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Definition & Facts

Acute respiratory distress syndrome, also called ARDS, involves fluid building up in the air sacs in the lungs. These air sacs become damaged and can collapse or fail to receive oxygen or expel carbon dioxide. As lungs lose their ability to inhale and exhale, they become filled with inflammatory cells, water, and scar tissue. When this occurs, mechanical ventilation may be required.

This condition commonly occurs in critically ill people or those who have sustained severe injuries. ARDS often develops in a hospital setting where the patient is receiving care for another illness or medical problem. It can develop quickly in a few hours or a few days. Many who develop this condition do not survive, especially those who have a severe illness or are elderly.

ARDS occurs with the same relative frequency among men as among women, and though it can affect people of all ages, it has a higher incidence among the elderly than among youth. This reflects the higher incidence of underlying diseases and health conditions among the elderly that cause ARDS. The most common causes for pediatric cases of ARDS are shock, sepsis, and near-drowning.

Symptoms & Complaints

As the lungs fill up with fluid, the first sign of ARDS is severe shortness of of breath. Also present is low blood pressure, heavy and rapid breathing, extreme tiredness, and confusion.

After around 10 days, pulmonary fibrosis (scar tissue) begins, and severe damage occurs after three weeks. ARDS can develop in a patient within a few hours or days after the original injury or disease. Those who survive the trauma often have lasting damage to their lungs and are on long-term medication.

Severe cognitive impairment, speech problems, and memory loss may occur due to brain damage incurred from the absence of oxygenated blood flowing to the brain during ARDS. Upon recovery, survivors of ARDS symptoms sometimes experience psychiatric disorders like depression, anxiety, and posttraumatic stress disorder.

Causes

ARDS can be caused by direct injury as well as indirect injury to the lungs. Direct injuries include inhalation of smoke, vomit, and toxic fumes; pneumonia; and near-drowning. Indirect causes include drug overdoses, sepsis, pancreatitis, trauma, and shock. Bleeding throughout the body, a systemic inflammatory response (SIRS), and burns may also prompt ARDS to occur. Blood transfusions and organ transplants are additional indirect injurious causes of ARDS. Cigarette smoking and alcoholism are risk factors.

Diagnosis & Tests

The diagnostic process involves a physical examination as well as taking and viewing chest X-rays and CT scan. The chest X-ray will determine if the heart is enlarged and where the fluid is in the lungs. A CT scan is more detailed and provides cross-sectional views of the heart and lungs.

A lab blood test is given to check for infection or anemia and determine the blood oxygen level. With a lung infection, sometimes airway secretions are tested to determine. There are a number of heart tests given because of the similarity between ARDS symptoms and those of heart problems. These tests include an electrocardiogram, which tracks the heart's electrical activity and echocardiogram, which examines the function and structure of the heart.

Treatment & Therapy

Treatment in an intensive care unit with the use of supplemental oxygen and a mechanical ventilator is often used to assist a patient's lungs to heal. Antibiotics may be needed to treat an underlying bacterial infection. The patient will often be put in a prone position. This helps increase lung volume and oxygenation.

The use of pulmonary vasodilators like nitric oxide may help increase blood flow. Treatment will also offer nutritional support to the patient. Because mortality from ARDS often results from complications and organ failure, it is important for treatment to encompass total support to the patient.

Prevention & Prophylaxis

ARDS has become much more preventable and treatable with greater prevention of blood infections due to the use of antibiotics as well as the adoption of a more restrictive approach in hospitals for blood transfusions. Preventing ARDS often involves health care professionals in hospitals recognizing patients who are at-risk for developing ARDS.

It is urgent that professionals in intensive care units (ICU) keep close watch on seriously ill patients for conditions like IV line infections, pulmonary embolisms, deep vein thrombosis, muscle weakness, or any other unusual developments, which can be indicative of ARDS.