ARDS
On this page:
ARDS (Acute Respiratory Distress Syndrome) is breathing failure that can occur
in critically ill persons with underlying illnesses. It is not a specific disease.
Instead, it is a life-threatening condition that occurs when there is severe
fluid buildup in both lungs. The fluid buildup prevents the lungs from working
properly—that is, allowing the transfer of oxygen from air into the body and
carbon dioxide out of the body into the air.
In ARDS, the tiny blood vessels (capillaries) in the lungs or the air sacs
(alveoli) are damaged because of an infection, injury, blood loss, or inhalation
injury. Fluid leaks from the blood vessels into air sacs of the lungs. While
some air sacs fill with fluid, others collapse. When the air sacs collapse
or fill up with fluid, the lungs can no longer fill properly with air and the
lungs become stiff. Without air entering the lungs properly, the amount of
oxygen in the blood drops. When this happens, the person with ARDS must be
given extra oxygen and may need the help of a breathing machine.
Breathing failure can occur very quickly after the condition begins. It may
take only a day or two for fluid to build up. The process that causes ARDS
may continue for weeks. If scarring occurs, this will make it harder for the
lungs to take in oxygen and get rid of carbon dioxide.
In the past, only about 4 out of 10 people who developed ARDS survived. But
today, with good care in a hospital's intensive or critical care unit, many
people (about 7 out of 10) with ARDS survive. Although many people who survive
ARDS make a full recovery, some survivors have lasting damage to their lungs.
Return to top 
To understand ARDS, it is helpful to understand how your lungs work.
Normal lung function. A slice of normal lung looks like a pink sponge—filled
with tiny bubbles or holes. Around each bubble is a fine network of tiny blood
vessels. These bubbles surrounded by blood vessels give the lungs a large surface
to exchange oxygen (into the blood where it is carried throughout the body)
and carbon dioxide (out of the blood). This process is called
gas exchange.
Healthy lungs do this very well.
Here's how normal breathing works:
- You breathe in air through your nose and mouth. The air travels down
through your windpipe (trachea) through large and small tubes in your lungs
called bronchial (BRON-kee-ul) tubes. The larger ones are bronchi,
and the smaller tubes are bronchioles. Sometimes we use the word "airways" to
refer to the various tubes or passages that air must travel from the nose
and mouth into the lungs. The airways in your lungs look something like
an upside-down tree with many branches.
- At the ends of the small bronchial tubes, there are groups of tiny bubbles
called air sacs or alveoli. The bubbles have very thin walls, and
small blood vessels called capillaries are next to them. Oxygen passes
from the air sacs into the blood in these small blood vessels. At the same
time, carbon dioxide passes from the blood into the air sacs.
Effects of ARDS. In ARDS, the tiny blood vessels leak too much fluid
into the lung. This results from toxins (poisons) that the body produces in
response to the underlying illness or injury. The lungs become like a wet sponge,
heavy and stiffer than normal. They no longer provide the effective surface
for gas exchange, and the level of oxygen in the blood falls. If ARDS is severe
and goes on for some time, scar tissue called fibrosis may form in the lungs.
The scarring also makes it harder for gas exchange to occur.
People who develop ARDS need extra oxygen and may need a breathing machine
to breathe for them while their lungs try to heal. If they survive, ARDS patients
may have a full recovery. Recovery can take weeks or months. Some ARDS survivors
take a year or longer to recover, and some never completely recover from having
ARDS.
Return to top
The causes of ARDS are not well understood. It can occur in many situations
and in persons with or without a lung disease.
There are two ways that lung injury leading to ARDS can occur: through a direct
injury to the lungs, or indirectly when a person is very sick or has a serious
bodily injury. However, most sick or badly injured persons do not develop ARDS.
Direct lung injury. A direct injury to the lungs may result from breathing
in harmful substances or an infection in the lungs. Some direct lung injuries
that can lead to ARDS include:
- Severe pneumonia (infection in the lungs)
- Breathing in vomited stomach contents
- Breathing in harmful fumes or smoke
- A severe blow to the chest or other accident that bruises the lungs.
Indirect lung injury. Most cases of ARDS happen in people who are very
ill or who have been in a major accident. This is sometimes called an "indirect
lung injury." Less is known about how indirect injuries lead to ARDS than about
how direct injuries to the lungs cause ARDS. Indirect lung injury leading to
ARDS sometimes occurs in cases of:
- Severe and widespread bacterial infection in the body (sepsis)
- Severe injury with shock
- Severe bleeding requiring blood transfusions
- Drug overdose
- Inflamed pancreas.
It is not clear why some very sick or seriously injured people develop ARDS,
and others do not. Researchers are trying to find out why ARDS develops and
how to prevent it.
Return to top
ARDS usually affects people who are being treated for another serious illness
or those who have had major injuries. It affects about 150,000 people each
year in the United States. ARDS can occur in people with or without a previous
lung disease. People who have a serious accident with a large blood loss are
more likely to develop ARDS. However, only a small portion of people who have
problems that can lead to ARDS actually develop it.
In most cases, a person who develops ARDS is already in the hospital, being
treated for other medical problems. Some illnesses or injuries that can lead
to ARDS include:
- Serious, widespread infection in the body (sepsis)
- Severe injury (trauma) and shock from a car crash, fire, or other cause
- Severe bleeding that requires blood transfusions
- Severe pneumonia (infection of the lungs)
- Breathing in vomited stomach contents
- Breathing in smoke or harmful gases and fumes
- Injury to the chest from trauma (such as a car accident) that causes
bruising of the lungs
- Nearly drowning
- Some drug overdoses.
Return to top
The major signs and symptoms of ARDS are:
- Shortness of breath
- Fast, labored breathing
- A bluish skin color (due to a low level of oxygen in the blood)
- Lower amount of oxygen in the blood.
Doctors and other health care providers watch for these signs and symptoms
in patients who have conditions that might lead to ARDS. People who develop
ARDS may be too sick to complain about having trouble breathing or other related
symptoms. If a patient shows signs of developing ARDS, doctors will do tests
to confirm that ARDS is the problem.
ARDS is often associated with the failure of other organs and body systems.
They include the liver, kidneys, and the immune system. Multiple organ failure
often leads to death.
Return to top
Doctors diagnose ARDS when:
- A person suffering from severe infection or injury develops breathing
problems
- A chest x-ray shows fluid in the air sacs of both lungs
- Blood tests show a low level of oxygen in the blood
- Other conditions that could cause breathing problems have been ruled
out.
ARDS can be confused with other illnesses that have similar symptoms. The most
important is congestive heart failure. In congestive heart failure, fluid backs
up into the lungs because the heart is weak and cannot pump well. However,
there is no injury to the lungs in congestive heart failure. Since a chest
x-ray is abnormal for both ARDS and congestive heart failure, it is sometimes
very difficult to tell them apart.
Return to top
Patients with ARDS are usually treated in the intensive or critical care
unit of a hospital. The main concern in treating ARDS is getting enough oxygen
into the blood until the lungs heal enough to work on their own again. The
following are important ways that ARDS patients are treated.
Extra oxygen. The main treatment is giving a higher concentration
of oxygen than that found in normal air, enough to raise blood levels of
oxygen to safe levels. At first, this can sometimes be done with a face mask.
A face mask can deliver oxygen at a concentration of 40-60 percent. As the
ARDS progresses over hours or days, the patient may need a higher level of
oxygen than a face mask can give.
As the patient becomes tired from breathing so hard, it may become necessary
to connect the patient a breathing machine (ventilator). This can
be done by placing a tube through the mouth or nose into the windpipe (trachea)
in a procedure called endotracheal intubation (or just intubation)
and connecting the tube to the ventilator. Sometimes the connecting tube
is inserted through a surgical opening in the neck (tracheotomy).
The breathing machine can be set to help or completely control breathing.
It will deliver the minimum amount of air every minute. If the extra oxygen
and help with breathing are not enough, the breathing machine can be set
to Positive End Expiratory Pressure (PEEP) to maintain the surface
for gas exchange.
PEEP keeps some air in the lungs at the end of each breath. It helps keep
the air sacs open instead of collapsing. The setting can be adjusted to fit
the needs of the patient. There are other settings on the ventilator that
control the number of breaths per minute (rate control) and the amount of
air the ventilator uses to inflate the lungs in each breath (tidal volume).
Medicines. Many different kinds of medicines are used to treat ARDS
patients. Some kinds of medicines often used include:
- Antibiotics to fight infection
- Pain relievers
- Drugs to relieve anxiety and keep the patient calm and from "fighting" the
breathing machine
- Drugs to raise blood pressure or stimulate the heart
- Muscle relaxers to prevent movement and reduce the body's demand for
oxygen.
Other treatment. With breathing tubes in place, ARDS patients cannot
eat or drink as usual. They must be fed through a feeding tube placed through
the nose and into the stomach. If this does not work, feeding is done through
a vein. Sometimes a special bed or mattress, such as an airbed, is used to
help prevent complications such as pneumonia or bedsores. If complications
occur, the patient may require treatment for them.
Results. With treatment:
- Some patients recover quickly and can breathe on their own within a week
or so. They have the best chance of a full recovery.
- Patients whose underlying illness is more severe may die within the first
week of treatment.
- Those who survive the first week but cannot breathe on their own may
face many weeks on the breathing machine. They may have complications and
a slow recovery if they survive.
Return to top
Some people who survive ARDS heal quickly and recover completely in a relatively
short time. Some are able to have the breathing tube and breathing machine
removed in a week or so. Survivors often recover much of their lung function
in the first 3-6 months after leaving the hospital and continue to recover
for up to a year or more.
However, others recover more slowly. Some ARDS survivors never recover completely
and have continuing problems with their lungs. Every case is different. People
who are younger and healthier when they develop ARDS are more likely to recover
quickly than those who are older or who have more health problems.
ARDS patients who survive the first week but cannot breathe on their own may
have to be on a breathing machine for several weeks or longer. These patients
often develop complications such as infections or air leaks . While some of
these patients will die, others will get better and be able to breathe on their
own again. Their recovery is usually slow, and they may have continuing problems.
After leaving the hospital, ARDS survivors need to visit a doctor during recovery
to check how well their lungs are doing. Doctors use lung function tests to
check the lungs.
Spirometry is the most commonly used lung function
test. It involves taking a deep breath and blowing hard into a plastic tube.
The doctor will also do an oxygen saturation (oximetry) test or a blood test
to check the amount of oxygen in the blood.
After going home from the hospital, the ARDS survivor may need only a little
or a lot of help. While recovering from ARDS at home, a person may:
- Need to use oxygen at home or when going out of the home, at least for
a while
- Need to have physical, occupational, or other therapy
- Have shortness of breath, cough, or phlegm (mucus)
- Have hoarseness from the breathing tube in the hospital
- Feel tired and not have much energy.
- Have muscle weakness.
Return to top
Anyone who stays in the hospital for a long time can get complications. Common
complications in ARDS patients are infections with hospital-acquired bacteria
and leaks of air out of the lungs into other body spaces.
- Bacterial infections. The lungs or other parts of the body may
become infected. These infections are usually treated with antibiotics
after a test to see what kind of bacteria is causing the infection.
- Air leaks. Leaks of air through holes in the lungs are caused
by pressure from the breathing machine that is needed to be sure the patient
gets enough air and from the very stiff lungs. Air from the injured lungs
may enter the space between the lungs and the lining around the lungs (the
pleura) and cause a pneumothorax (collapsed lung). Treatment involves
using a chest tube and suction to remove the air and help the lungs reinflate.
Air may also enter the space between the membranes that line the abdomen
(pneumoperitoneum) or the soft tissue under the skin (subcutaneous emphysema).
These are not usually treated.
Each complication is treated as it arises. Careful hand washing by hospital
staff and visitors helps reduce infections, and new breathing machine methods
help reduce air leaks.
Return to top
While your family member or friend is in the hospital being treated for ARDS,
you will feel a lot of stress. One day the patient may seem to be recovering,
and the next day things may take a turn for the worse. It can be a scary experience
to see someone you care about on a breathing machine. Several doctors work together
to give care to your family member. These doctors are often specialists who
are treating different concerns of the patient. For example, an infectious disease
specialist might be involved to help make sure that the initial infection or
an infectious complication is properly treated. A lung specialist may be adjusting
the settings on the breathing machine and a kidney specialist may be required
if kidney failure occurs. These doctors talk to each other regularly to make
sure that care is given in a coordinated manner. There are some things you can
do to help, even though you may feel very helpless:
- Talk to the doctors, nurses, and other health care providers. Ask questions
about the patient's condition and care, and ask how you can support your
loved one.
- Talk to the patient, even if he or she is in a drug-induced sleep. Talk
about fun things you did together and laugh with them about silly things
that you did. Many survivors say they were, at some level, aware of the
people and things around them. They also recall dreams they had while in
the sleep-induced state. The dreams can be calming or frightening. Talking
to the patient about happy and fun things may help make the dreams more
positive.
- Ask the hospital staff if you can put family photos near the patient,
play music at low volume, or rub lotion into the patient's feet and hands.
Many survivors are aware of people and things around them. This may help
to trigger their senses of hearing, touch, and seeing.
- Leave fears and worries at the door. Always go outside the patient's room
to talk with the doctor or nurse about the patient's condition. Make sure
everyone is encouraging and hopeful while with the patient. The patient
may sense stress in their presence.
- Keep a journal or record of events for the patient to read after leaving
the hospital. ARDS survivors want to know every detail of what happened
while they were asleep.
- Remember to take care of yourself, too. Try to get enough rest and sleep,
eat well, and get some exercise. Call on other family members and friends
to sit with the patient so you can have a break. Your very sick loved one
will need your strength and support over what may be a long recovery period.
The family members and friends of people who have had ARDS often are deeply
affected by the experience. The "roller-coaster" ride of emotions while the
ARDS patient is in the hospital is exhausting and stressful. Caring for the
ARDS survivor at home can also be stressful and tiring. Ask for help from others
or your health care providers if you need it. Most hospitals have individuals
such as social workers who can help family member cope with these issues.
Return to top
- ARDS is breathing failure that can occur in critically ill persons with
underlying illnesses. It is a life-threatening condition that occurs when
there is severe fluid build-up in both lungs.
- At one time, about 6 out of 10 people who developed ARDS died. But today,
with good care in a hospital's intensive or critical care unit, about 1
out of 3 dies.
- The cause of ARDS is not well known. It can occur in many situations and
in persons with or without a lung disease. Lung injury leading to ARDS can
occur through a direct injury to the lungs, or indirectly when a person
is very sick or has a serious bodily injury.
- ARDS usually affects people who are being treated for another serious
illness or those who have had major injuries. It affects about 150,000 people
each year in the United States.
- The major signs and symptoms of ARDS are rapid onset; shortness of breath;
fast, labored breathing; high blood pressure in the pulmonary arteries;
a bluish skin color (due to a low level of oxygen in the blood); and lower
amount of oxygen in the blood.
- Doctors diagnose ARDS when:
- A person suffering from severe infection or injury develops breathing
problems
- A chest x-ray shows fluid in the air sacs of both lungs
- Blood tests show a low level of oxygen in the blood
- Other conditions that could cause breathing problems have been ruled
out.
- Patients with ARDS are usually treated in the intensive or critical care
unit of a hospital. The main treatment is giving extra oxygen to raise the
amount of oxygen breathed in above that of normal air so that the oxygen
blood levels are safe. This can sometimes be done with a face mask but often
a breathing machine is needed.
- Some people who survive ARDS heal quickly and recover completely in a
relatively short time. Others recover more slowly and some never recover
completely. About 1 in 3 will die.
- Anyone in the hospital for a long time can get complications. Common complications
in ARDS patients are infections with hospital-acquired bacteria and air
leaks into other body spaces.
- Although you may feel very helpless, there are things family member and
friends can do to help.
Return to top
