What Is ARDS?
ARDS, or acute respiratory distress syndrome, is a
lung condition that leads to low oxygen levels in the blood. ARDS can be life
threatening. This is because your body's organs, such as the kidneys and brain,
need oxygen-rich blood to work properly.
ARDS usually occurs in people who are very ill with
another disease or who have major injuries. Most people are already in the
hospital when they develop ARDS.
Overview
When you breathe, air passes through your nose and
mouth into your windpipe. The air then travels to your lungs' air sacs. These
sacs are called alveoli (al-VEE-uhl-eye).
Small blood vessels called capillaries run through
the walls of the alveoli. Oxygen passes from the alveoli into the capillaries
and then into the bloodstream. Blood carries the oxygen to all parts of the
body, including the body's organs.
In ARDS, infections, injuries, or other conditions
cause the lung's capillaries to leak more fluid than normal into the alveoli.
This prevents the lungs from filling with air and moving enough oxygen into the
bloodstream.
When this happens, the body's organs don't get the
oxygen they need. Without oxygen, the organs may not work properly or may stop
working completely.
Most people who develop ARDS are in the hospital for
another serious health problem. Rarely, people who aren't hospitalized have
health problems (such as severe pneumonia) that lead to ARDS.
If you have trouble breathing, call your doctor
right away. If you have severe shortness of breath, call
911.
Outlook
ARDS treatment has improved in recent years. As a
result, more people are surviving ARDS. This condition affects about 190,000
people in the United States each year. About 7 out of 10 people who get prompt
and proper treatment for ARDS survive it.
Some people who survive recover completely. Others
may have lasting damage to their lungs and other health problems.
Researchers are studying new treatments for
ARDS.
Other Names for ARDS
- Acute lung injury
- Adult respiratory distress syndrome
- Increased-permeability pulmonary edema
- Noncardiac pulmonary edema
ARDS used to be called stiff lung, shock lung, and
wet lung.
What Causes ARDS?
Many conditions or factors can directly or
indirectly injure the lungs and lead to ARDS. Some common ones are:
- Sepsis. This is a condition in which bacteria
infect the bloodstream.
- Pneumonia. This is an infection in the
lungs.
- Severe bleeding due to an injury to the
body.
- An injury to the chest or head, like a severe
blow.
- Breathing in harmful fumes or smoke.
- Inhaling vomited stomach contents from the
mouth.
It's not clear why some very sick or seriously
injured people develop ARDS and others don't. Researchers are trying to find
out why ARDS develops and how to prevent it.
Who Is At Risk for ARDS?
People at risk for ARDS have a condition or illness
that can directly or indirectly injure their lungs.
Direct Lung Injury
Conditions that can directly injure the lungs
include:
- Pneumonia. This is an infection in the
lungs.
- Breathing in harmful fumes or smoke.
- Inhaling vomited stomach contents from the
mouth.
- Severe acute respiratory syndrome (SARS). This is
a type of pneumonia.
- Using a ventilator. This is a machine that helps
people breathe, but, rarely, it can injure the lungs.
- Nearly drowning.
Indirect Lung Injury
Conditions that can indirectly injure the lungs
include:
- Sepsis. This is a condition in which bacteria
infect the bloodstream.
- Severe bleeding due to an injury to the body or
having many
blood
transfusions.
- An injury to the chest or head, like a severe
blow.
- Pancreatitis (PAN-kre-a-TI-tis). This is a
condition in which the pancreas becomes irritated or infected. The pancreas is
a gland that releases enzymes and hormones.
- Fat embolism (EM-bo-lizm). This is a condition in
which fat blocks an artery. A physical injury, like a broken bone, can lead to
a fat embolism.
- Drug overdose.
What Are the Signs and Symptoms of ARDS?
The first signs and symptoms of ARDS are feeling
like you can't get enough air into your lungs, rapid breathing, and low oxygen
levels in the blood.
Other signs and symptoms depend on the cause of the
condition. They may occur before ARDS develops. For example, if pneumonia is
causing ARDS, you may have a cough and fever before you feel short of
breath.
Sometimes, people with ARDS develop signs and
symptoms such as
low
blood pressure, confusion, and extreme tiredness. This may mean that the
body's organs, such as the kidneys and heart, aren't getting enough oxygen-rich
blood.
Most people who develop ARDS are in the hospital for
another serious health problem. Rarely, people who aren't hospitalized have
health problems (such as severe pneumonia) that lead to ARDS.
If you have trouble breathing, call your doctor
right away. If you have severe shortness of breath, call 911.
How Is ARDS Diagnosed?
Your doctor will diagnose ARDS based on your medical
history, a physical exam, and results from tests.
Medical History
Your doctor will ask about conditions you may have
or have recently had that can lead to ARDS. For a list of these conditions, see
"Who Is At Risk for ARDS?" Your doctor also
will ask whether you have heart problems, such as
heart
failure, which can cause fluid to build up in your lungs.
Physical Exam
ARDS may cause abnormal breathing sounds, such as
crackling. Your doctor will listen to your lungs with a stethoscope to hear
these sounds.
He or she also will listen to your heart and look
for signs of extra fluid in other parts of your body. Extra fluid may mean you
have heart or kidney problems.
Your doctor will look for a bluish color on your
skin and lips. A bluish color means your blood has a low level of oxygen. This
is a possible sign of ARDS.
Diagnostic Tests
Diagnostic tests are used to find the cause of your
symptoms. You may have ARDS, or you may have another condition that causes
similar symptoms.
Initial Tests
The first tests done are:
- An arterial blood gas test. This blood test shows
the oxygen level in your blood. A low level of oxygen in the blood may be a
sign of ARDS.
- Chest x ray. This test is used to take a picture
of your lungs. It can show whether you have extra fluid in your lungs.
- Blood tests, such as a complete blood count,
blood chemistries, and blood cultures. These tests help find the cause of ARDS,
such as an infection.
- Sputum cultures. This test looks at the spit
you've coughed up from your lungs. It can help find the cause of an
infection.
Other Tests
Other tests used to diagnose ARDS include:
- Computed tomography (to-MOG-rah-fee), or CT,
scan. This test uses a computer to take detailed pictures of your lungs. It may
show lung problems, such as fluid in the lungs, signs of pneumonia, or a lung
tumor.
- Heart tests that look for signs of heart failure.
Heart failure is a condition in which the heart can't pump blood the way it
should. This condition can cause fluid to build up in your lungs.
How Is ARDS Treated?
ARDS is treated with oxygen, fluids, and medicines.
Treatments are done in a hospital's intensive care unit.
The main goals of treating ARDS are to get oxygen to
your lungs and organs (like the brain and kidneys) and treat the underlying
condition that's causing ARDS.
Oxygen
First, your doctor will try to give you extra oxygen
through soft, plastic prongs that fit into your nose, or through a mask that
fits over your mouth (or mouth and nose).
If your oxygen level doesn't increase or it's still
hard for you to breathe, your doctor will give you oxygen through a breathing
tube. The flexible tube will be inserted through your mouth or nose and into
your windpipe.
Before inserting the tube, your doctor will squirt
or spray a liquid medicine into your throat (and possibly your nose) to make it
numb. This helps prevent coughing and gagging when the tube is inserted. Your
doctor also will give you medicine, through an intravenous (IV) line into your
bloodstream, to make you sleepy and relaxed.
The breathing tube will be connected to a machine
that helps you breathe (a ventilator). The ventilator will fill your lungs with
oxygen-rich air.
Your doctor will adjust the ventilator often to help
your lungs get the right amount of oxygen. This also will help prevent any
further injury to your lungs from the pressure of the ventilator.
The breathing tube and ventilator are used until you
can breathe on your own. If you need a ventilator for more than a few days,
your doctor may do a tracheotomy (tra-ke-OT-o-me). This involves making a small
cut in your neck to create an opening to the windpipe. Your doctor will place
the breathing tube directly into the windpipe. The tube is then connected to
the ventilator.
Fluids
Fluids may be given to improve the flow of blood
through your body and to provide nutrition. Your doctor will make sure you get
the right amount of fluids.
Too much fluid can fill the lungs, making it harder
to get the oxygen you need. Not enough fluid can limit blood and oxygen flow to
the body's organs. Fluids usually are given through an IV line inserted in one
of your blood vessels.
Medicines
Your doctor may give you medicines to prevent and
treat infections and to relieve discomfort.
Complications From ARDS
If you have ARDS, you can develop other medical
problems while in the hospital. The most common are infections,
pneumothorax
(noo-mo-THOR-aks; collapsed lung), lung scarring, and blood clots.
- Infections. Being in the hospital and lying down
for a long time can make you prone to infections, such as pneumonia. Being on a
ventilator also can put you at higher risk for infections. Infections can be
treated with antibiotics.
- Pneumothorax. This is a condition in which air or
gas collects in the space around the lungs, which can cause one or both lungs
to collapse. The pressure of the air from a ventilator can cause this
condition. Your doctor will put a tube into your chest to remove the air and
let your lung(s) expand again.
- Lung scarring. ARDS causes the lungs to become
stiff (scarred) and makes it hard for them to expand and fill with air. Being
on a ventilator also can cause lung scarring. Often, lung scarring heals before
you leave the hospital.
- Blood clots. Lying down for long periods can
cause blood clots to form in your body. A blood clot that forms in a vein deep
in your body is called a
deep vein thrombosis. This type of blood clot can break off, travel through
the bloodstream to the lungs, and block blood flow. This is called
pulmonary
embolism.
Living With ARDS
Some people fully recover from ARDS. Others continue
to have health problems. After you go home from the hospital, you may have one
or more of the following problems:
- Shortness of breath. After treatment, lung
function in most people who have ARDS improves within 3 months and is back to
normal within 6 months. For others, it may take up to a year or more. Some
people have breathing problems for the rest of their lives.
- Tiredness and muscle weakness. Being in the
hospital and on a ventilator (a machine that helps you breathe) can cause your
muscles to feel weak. You also may feel very tired following treatment.
- Depression. Many people who've had ARDS say that
they were depressed for a while after treatment.
- Problems with memory and thinking clearly.
Certain medicines and a low oxygen level in your blood can cause these
problems.
These health problems may go away within a few weeks
or they may last longer. Talk to your doctor about how to deal with these
problems. Also, see the suggestions below.
Getting Help
You can take steps to recover from ARDS and improve
your quality of life.
- Ask your family and friends for help with
everyday activities.
- Go to pulmonary rehabilitation (rehab). A rehab
program can show you how to return to normal activities and stay active. Rehab
may include exercise training, education, and counseling. Your rehab team may
include doctors, nurses, and other specialists. They will work with you to
create a program that meets your needs.
- Join a support group for ARDS. The
ARDS Support Center, the
American Lung Association's Better Breathers Clubs, and the
ARDS Foundation are examples of support networks that can help
you learn about and cope with your condition.
- Seek help from a mental health professional if
you feel depressed.
- Don't smoke, and avoid secondhand smoke.
Key Points
- ARDS, or acute respiratory distress syndrome, is
a lung condition that leads to low oxygen levels in the blood. ARDS can be life
threatening. This is because your body's organs, such as the kidneys and brain,
need oxygen-rich blood to work properly.
- Most people who develop ARDS are in the hospital
for another serious health problem. Rarely, people who aren't hospitalized have
health problems (such as severe pneumonia) that lead to ARDS. If you have
trouble breathing, call your doctor right away. If you have severe shortness of
breath, call 911.
- In ARDS, infections, injuries, or other
conditions cause the lung's tiny blood vessels to leak more fluid than normal
into the lungs' air sacs. This prevents the lungs from filling with air and
moving enough oxygen into the bloodstream.
- Some common conditions and factors that can lead
to ARDS are sepsis, pneumonia, severe bleeding due to an injury, an injury to
the chest or head, breathing in harmful fumes or smoke, and inhaling vomited
stomach contents from the mouth.
- People at risk for ARDS have a condition or
illness that can directly or indirectly injure their lungs.
- The first signs and symptoms of ARDS are feeling
like you can't get enough air into your lungs, rapid breathing, and low oxygen
levels in the blood. Other signs and symptoms depend on the cause of the
condition. They may occur before ARDS develops.
- Your doctor will diagnose ARDS based on your
medical history, a physical exam, and results from tests.
- ARDS is treated with oxygen, fluids, and
medicines. Treatments are done in a hospital's intensive care unit. Patients
who have ARDS can develop other medical problems while in the hospital. The
most common problems are infections,
pneumothorax (collapsed lung), lung scarring, and blood clots.
- Some people fully recover from ARDS. Others
continue to have health problems. These problems may include shortness of
breath, tiredness and muscle weakness, depression, and problems with memory and
thinking clearly.
- You can take steps to recover from ARDS and
improve your quality of life. Ask you family and friends to help with everyday
activities. Go to pulmonary rehabilitation if you doctor recommends it. Join a
support group for ARDS. Seek help from a mental health professional if you feel
depressed. Don't smoke, and avoid secondhand smoke.
- ARDS treatment has improved in recent years. As a
result, more people are surviving ARDS. Researchers are studying new treatments
for the condition.
Links to Other Information About ARDS
Non-NHLBI Resources
Clinical Trials
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