Acute Respiratory Distress Syndrome

DEFINITION

Acute respiratory distress syndrome (ARDS) occurs when fluid builds up in the small, elastic air sacs (alveoli) in the lungs. The more fluid in the lungs, the less oxygen can get into the blood. This deprives the body of the oxygen it needs to function.

ARDS usually occurs in people who are already seriously ill or seriously injured. Severe shortness of breath, the main symptom of ARDS, usually occurs within hours or days of the initial illness or injury. Many people who develop ARDS do not survive.

The risk of death increases with age and with the severity of the disease. Some of those who survive ARDS have made a full recovery, while others have permanent lung damage.

SYMPTOMS

The signs and symptoms of ARDS can vary in intensity depending on the cause and severity of the disease, and whether there is an underlying heart or lung disease.

These include

• Severe Shortness Of Breath
• Shortness Of Breath
• Abnormally Fast Breathing
• Low Blood Pressure
• Confusion
• Extreme Fatigue

CAUSES

The mechanical causes of ARDS are leakage of fluid from the smallest blood vessels in the lungs into the tiny air sacs where the blood is supplied with oxygen. Shields usually store this liquid in a container. However, serious illness or injury can cause inflammation that destroys the integrity of the membrane, leading to fluid leakage in ARDS.

The most common causes of ARDS are:

• blood poisoning. The most common cause of ARDS is sepsis, a serious and widespread infection of the bloodstream. Inhale pollutants.
• Inhalation of fumes or inhalation of high concentrations of chemical fumes can cause ARDS and inhalation (aspiration) of vomit. 
• severe pneumonia. Severe pneumonia usually affects all five lobes of the lungs. 
• Head, chest or other serious injury. Accidents such as falls or car accidents can directly damage the lungs or the part of the brain that controls breathing.

RISK FACTORS

Most people who develop ARDS have already been hospitalized for other conditions, and many are seriously ill. It is especially dangerous if there is a widespread infection in the blood (sepsis).

People with a history of chronic alcoholism are at a higher risk of developing ARDS. They are also more likely to die from ARDS.

COMPLICATIONS

Complications are very serious, but with better treatment, more people suffer from them. However, many survivors experience potentially serious and sometimes irreversible complications, including:

• Scarring of the lungs (pulmonary fibrosis). A thickening of the tissue between the scar tissue and the air sacs may appear several weeks after the onset of ARDS. This hardens in the lungs, making it difficult for oxygen to get from the air sacs to the bloodstream.
• Collapse of the lungs (pneumothorax). In most cases of ARDS, a breathing machine called a ventilator is used to increase oxygen in the body and push fluid out of the lungs. However, the pressure and volume of air exiting the ventilator can cause gas to pass through tiny pores on the outside of the lungs, causing the lungs to collapse.
• blood clotting. Being in the hospital on a ventilator can increase the risk of blood clots, especially in the deep veins of the legs. When a blood clot forms in the leg, it can break off and travel to one or both lungs (pulmonary embolism), blocking blood flow. 
• Epidemic. Since the ventilator is attached directly to the tube in the bronchi, bacteria can infect and more easily damage the lungs. Limited lung function.
• Abnormal lung function. Many people with ARDS regain most of their lung function within a few months to two years, but others may have breathing problems for the rest of their lives. Even normal people are usually short of breath and tired and may need supplemental oxygen at home for several months.
• Memory problems, cognitive and emotional problems. Sedation and low blood oxygen can cause memory loss and cognitive problems after ARDS. In some cases, the effect may disappear with time, while in other cases the damage may be irreversible. Most ARDS survivors also report that they are going through a treatable stage of depression.

TESTS AND DIAGNOSIS

There is no specific test to identify ARDS. Diagnosis is based on a physical examination, chest x-ray, and oxygen levels and rules out other diseases and conditions, such as certain heart problems, that can cause similar symptoms.

Chest Radiograph.

• A chest x-ray can show parts of the lungs, the amount of fluid in the lungs, and whether the heart is enlarged.
• Computed tomography (CT). Computed tomography combines x-rays taken from different directions into a cross section of an internal organ. A CT scan can provide detailed information about the structure of the heart and lungs.

Lab Tests

Blood tests taken from the arteries of the wrist can measure oxygen levels. Other types of blood tests may show signs of infection or anemia. If doctors suspect a lung infection, they may examine secretions from the respiratory tract to determine the cause of the infection.

Heart Tests

Because the signs and symptoms of ARDS are similar to those of some heart problems, your doctor may recommend a heart test, such as:

• Electrocardiogram. This painless test tracks the electrical activity of the heart. Several wired sensors are attached to the case.
• Echocardiography. This test can reveal problems with the structure and function of the heart.

TREATMENTS AND MEDICATIONS

The first goal of treating ARDS is to increase the level of oxygen in the blood. Without oxygen, the organs cannot function normally.

Oxygenation

To oxygenate the blood, the doctor will use:

• Supplemental Oxygen. For mild symptoms or as a temporary measure, oxygen can be given through a mask that covers the nose and mouth. 
• Mechanical Ventilation. Most people with ARDS need a breathing machine. A mechanical ventilator forces air into the lungs and pushes some of the body fluid out of the air sacs.

Fluids

It is important to handle intravenous fluids with care. Too much fluid can increase fluid buildup in the lungs. Too little fluid can put pressure on the heart and other organs, causing shock.

Medications

People with ARDS are usually prescribed medications to:

• Prevent and treat infection
• Ease pain and discomfort
• Prevent blood clots in the legs and lungs 
• Prevent stomach reflux
• Minimize sedation

Lifestyle And Home Care

If you are recovering from ARDS, the following tips may help protect your lungs. 

• Quit Smoking. If you smoke, seek help to quit smoking and avoid secondhand smoke whenever possible.
• Avoid Alcohol. Alcohol can relax the part of the upper airway that prevents foreign bodies from entering the lungs (aspiration). 
• Vaccination. Annual flu vaccination and pneumonia vaccine every 5 years can reduce the risk of lung infections.

CONTRIBUTIONS AND SUPPORT

Recovery from ARDS can be long and require significant support. Everyone's recovery is different, but it can be helpful to recognize common physical and mental issues that other people with disabilities face. Remember these tips:

• Ask For Help. Get help with daily tasks, especially after leaving the hospital, until you know what you can do on your own.
• Participation in Pulmonary Rehabilitation. Many medical centers now offer lung rehabilitation programs that include exercise, education, and counseling to help you return to your normal activities and learn how to reach your ideal weight.
• Join A Support Group. There are support groups for people with chronic lung disease. Find out what's available in the community or online and consider joining others who have had a similar experience.
• Get Expert Help. If you have any of the following symptoms of depression: If you feel hopeless and lose interest in your daily activities, tell your doctor or see a psychiatrist. Depression is common in people with ARDS, and medications can help.