Acute respiratory distress
syndrome, commonly called ARDS, is a sudden failure of the respiratory
system that occurs when fluid builds up in the tiny, elastic air sacs in
your lungs. In a short time, breathing becomes difficult, depriving
your organs of the oxygen they need to function.
ARDS usually occurs in people who are already critically ill or who have
significant injuries. Severe shortness of breath — the main symptom of
ARDS — usually develops within a few hours to a few days after the
original disease or trauma.
ARDS is fatal in 25 to 40 percent of the people who develop it. Some
people who survive ARDS recover completely, though they may not regain
full lung function for a year or more.
The signs and symptoms of ARDS can vary in intensity, depending on its cause and severity. They include:
* Severe shortness of breath
* Labored and unusually rapid breathing
* Low blood pressure
* Confusion and extreme tiredness
* Cough or fever, in some cases
When to see a doctor
ARDS usually follows a major illness or injury, and most people who are
affected are already hospitalized. Still, if you develop any serious
breathing problem, see your doctor or get emergency care right away.
Several disorders that require immediate treatment, including heart
problems, have signs and symptoms similar to those of ARDS. In the case
of ARDS, the need for medical treatment is urgent.
The mechanical cause of ARDS is fluid leaked from the smallest blood
vessels in the lungs into the tiny air sacs where blood is oxygenated.
Normally, a protective membrane keeps this fluid in the vessels. Severe
illness or injury, however, can cause inflammation that undermines the
membrane's integrity, leading to the fluid leakage of ARDS.
A number of conditions can injure your lungs and lead to inflammation, including:
* Severe viral or bacterial pneumonia
* Infection spreading through your bloodstream (sepsis)
* Heart failure with fluid in your lungs
* Multiple or massive blood transfusions
* A serious head or chest injury
* Fractures of long bones, such as the femur, which can release fat
particles that are carried through your bloodstream to your lungs (fat
* Prolonged use — from several days to a week — of large volumes of supplemental oxygen
* Accidental inhalation of vomit or chemicals, such as ammonia or chlorine
* Smoke inhalation
* Near drowning
* An adverse reaction to cancer drugs or other medications
* Drug overdose, most commonly with heroin
* Inflammation of your pancreas (pancreatitis)
* Shock from any cause
If possible, it's important to find the cause behind ARDS, because it
can determine treatment and can predict your chances for survival. In
some cases, though, the cause of ARDS is never found.
Most people who develop ARDS are already hospitalized for another
condition, and many are critically ill. You're especially at risk if
* Have a widespread infection in your bloodstream (sepsis)
* Have chronic liver disease (cirrhosis)
* Use a breathing machine (mechanical ventilator)
* Have had certain types of surgery recently
* Are a heavy drinker
* Are a current or former smoker
ARDS is extremely serious, but thanks to improved treatments, more
people are surviving it. However, many survivors end up with potentially
serious — and sometimes lasting — complications, including:
* Pulmonary fibrosis. Scarring and thickening of the tissue between
the air sacs (interstitium) can occur within a few weeks of the onset of
ARDS. This stiffens your lungs, making it even more difficult for
oxygen to flow from the air sacs into your bloodstream.
* Collapsed lung (pneumothorax). Usually, a breathing machine called
a ventilator is used in the treatment of ARDS to increase oxygen in the
body and force fluid out of the lungs. However, the ventilator can
cause its own problems. The pressure and air volume of the ventilator
can force gas to go through a small hole in the very outside of the lung
and out into the pleural space in your chest, causing your lung to
collapse. If this happens, your doctor will insert a tube between your
ribs into the pleural space to remove the excess air, allowing your lung
* Bacterial infections. Sometimes, the ventilator is attached
directly to a tube inserted in your trachea to assist breathing. But
this can also make you more susceptible to bacterial infections like
pneumonia, which can further injure your lungs. Infections can also
occur in other parts of your body, including in your bloodstream,
urinary tract and spinal fluid. Some of these infections may be
difficult to control if the bacteria have become resistant to commonly
used antibiotics. The problem may be compounded even further if ARDS was
initially caused by a bacterial infection.
* Abnormal lung function. Many people with ARDS recover most of
their lung function within several months to two years, but others may
have breathing problems for the rest of their lives. If you have other
lung diseases, such as emphysema, you're especially likely to have a
difficult time recovering from ARDS. Even people who do well usually
have shortness of breath and fatigue and may even need supplemental
oxygen in the first months after they leave the hospital.
* Muscle wasting and weakness. If you need to use a ventilator for
longer than a week, it can begin weakening your muscles because of
nutritional deficiency. Many people recovering from ARDS require
physical therapy, both in the hospital and once they're at home, to
restore strength and stamina. The extent to which you'll regain full
functioning depends on many factors, including weight loss, the length
of time you were sedated, the length of time on the ventilator, and the
amount of damage to your lungs and other organs.
* Memory, cognitive and emotional problems. Sedatives and low levels
of oxygen in the blood can lead to memory loss and cognitive problems
after ARDS. In some cases, the effects may lessen over time, but in
others, the damage may be permanent. Most ARDS survivors also report
going through a period of depression, which for some people is quite
severe. If you are a friend or family member of someone who has had
ARDS, be alert to symptoms of depression and urge him or her to seek
professional help as soon as possible.
Tests and diagnosis
Tests to confirm ARDS may include:
* Chest X-ray
* Arterial blood gas analysis
* Computerized tomography (CT) scan
* Blood tests to determine infection
* Heart tests to rule out heart problems that can cause fluid to build up in your lungs
Treatments and drugs
The first goal in treating ARDS is to get oxygen flowing to your lungs
and organs until the fluid is cleared out of the lungs and they can
function more normally. Treating the underlying condition then becomes
To get more oxygen into your bloodstream, your doctor will likely use supplemental oxygen and mechanical ventilation.
* Supplemental oxygen (noninvasive positive pressure ventilation).
For milder symptoms or as a temporary measure, oxygen may be delivered
through a mask that fits tightly over your nose or your nose and mouth.
Mechanical ventilation, or breathing machine (positive pressure
mechanical ventilator). Most people with ARDS also will need assisted
breathing. A positive pressure mechanical ventilator pushes air into
your lungs, forcing the fluid out of your air sacs. Air flows from a
bedside ventilator into your windpipe (trachea) through a tube placed in
your nose or mouth. If you need help breathing for more than several
days, it's likely that the breathing tube will be inserted directly into
your trachea through an incision in your neck (called a tracheotomy).
You remain on a ventilator until you can breathe on your own. For
some people, this may be a matter of days. For others it may take weeks
or even months. The longer you remain on a ventilator, the greater the
chances of serious complications, including pneumonia and further lung
damage. The first week of treatment is critical. People who are weaned
from the ventilator within a week have the best chance of a complete
Managing fluids carefully is crucial. In the past, doctors gave people
with ARDS large amounts of fluids through an IV to keep oxygen flowing
to other parts of the body. Now, doctors know that too much fluid can
increase the fluid buildup in the lungs. However, depriving your body of
fluids can put a strain on your heart and other organs that depend on
adequate volumes of blood and oxygen to function properly. Your doctor
will likely closely monitor the amount of fluids you receive so that you
get just the right balance to regain lung function but protect your
People with ARDS are also given medication to prevent and treat
infections, as well as relieve pain and discomfort. All people on
mechanical ventilation are given comfort sedation. Sometimes it is
necessary to paralyze the skeletal muscles to relax them and prevent
them from "fighting" the respirator. You may also be given an
anticoagulant to prevent blood clots (deep venous thrombosis) and
In the past, corticosteroids — meant to reduce lung inflammation — were a
routine part of managing ARDS. Several studies, however, have found
that corticosteroid treatment has no effect on survival rates among
people with ARDS.
Coping and support
Recovery from ARDS can be a long road, and you'll need plenty of
support. Although everyone's recovery is different, being aware of
common physical and mental difficulties encountered by others with the
disorder can help. Consider these tips:
* Ask for help. Particularly after you're released from the
hospital, be sure you have help with everyday tasks until you know what
you can manage on your own.
* Attend pulmonary rehabilitation. Many medical centers now offer
pulmonary rehabilitation programs, which incorporate exercise training,
education and counseling to help you learn how to return to your normal
activities and achieve your ideal weight.
* Join a support group. There are support groups for people with
chronic lung problems. Discover what's available in your community and
consider joining others with similar experiences.
* Seek professional help. If you have symptoms of depression, such
as hopelessness and loss of interest in your usual activities, tell your
doctor or contact a mental health professional. Depression is common in
people who have had ARDS, and treatment can help.
* Quit smoking. If you smoke, seek help to quit, and avoid secondhand smoke whenever possible.
* Get vaccinated. To prevent future complications, be sure to get
the yearly influenza shot, as well as the pneumonia vaccine every five