Acute Respiratory Distress Syndrome and its effect on victims and
ARDS Support Center, Inc.7172 Regional Street, #278
Dublin, California 94568-2324
With special assistance from
Harborview Medical Center
ARDS Support Board of Medical Consultants
John Hansen-Flaschen M.D.
WHAT IS ARDS?
Acute Respiratory Distress Syndrome (ARDS):
Acute Respiratory Distress Syndrome (ARDS) is an
acute, severe injury to most or all of both lungs. Patients with ARDS
experience severe shortness of breath and often require mechanical
ventilation (life support) because of respiratory failure. ARDS is not
a specific disease; instead, it is a type of severe, acute lung
dysfunction that is associated with a variety of diseases, such as
pneumonia, shock, sepsis (a severe infection in the body) and trauma.
ARDS can be confused with congestive heart failure, which is another
common condition that can also cause acute respiratory distress.
The term Acute Lung Injury "ALI" is sometimes used in the
same setting as ARDS, but also includes less severe instances of
generalized, acute lung injury.
To understand ARDS, it is important to review
how the lungs work. Air, which contains oxygen, is inhaled through the
nose and mouth, and passes into the windpipe (trachea). From the
trachea, air flows through tubes called bronchi into microscopic air
sacs called alveoli. Very small blood vessels (capillaries) are
imbedded in the walls of these air sacs. Oxygen passes through the
thin walls of the alveoli into the
bloodstream. Carbon dioxide, a waste product of cellular function
throughout the body, passes from
the bloodstream into the alveoli and then is exhaled.
At the onset of ARDS, lung injury may first
appear in one lung, but then quickly spreads to affect most of both
When alveoli are damaged, some collapse and lose their ability to
receive oxygen. With some alveoli collapsed and others
filled by fluid, it becomes difficult for the lungs to absorb oxygen
and get rid of carbon dioxide. Within one or two days,
progressive interference with gas exchange can bring about respiratory
failure requiring mechanical ventilation.
As the injury continues over the next several days, the lungs, fill
with inflammatory cells derived from circulating blood and with
regenerating lung tissue. Fibrosis (formation of scar tissue)
begins after about 10 days and cam become quite extensive by the third
week after onset of injury. Excessive fibrosis further interferes with the exchange of oxygen and carbon
dioxide. The sequential stages of ARDS are described in further
WHAT CAUSES ARDS?
The cause of ARDS is not well known.
Current scientific information supports several theories about its development, but the precise reason ARDS occurs
remains unknown. What is known, however, is that ARDS can come about
by either of two basic mechanisms.
The first is a direct physical or
toxic injury to the lungs. Examples include inhalation of vomited
stomach contents (aspiration), smoke or other toxic fumes, and a
severe 'bruising' of the lungs that usually occurs after a severe blow
to the chest.
The second mechanism is more common,
but less understood. This is an indirect, blood-born injury to the
lungs. When a person is very sick or the body is severely injured, some
chemical signals are released into the bloodstream. These signals
reach the lung, and the lung reacts by becoming inflamed, thus causing
lung failure. Examples of this type of indirect lung injury include
the presence of severe infection (sepsis) and severe injury (trauma)
- the two most common factors in ARDS cases. Other examples
are severe bleeding (resulting in massive blood transfusions), severe
inflammation of the pancreas (pancreatitis) and some
types of drug overdoses.
Not everyone who has these problems,
however, develops ARDS, which is fortunate, since all of the above
problems are common. There are no easy answers as to why some patients
with sepsis or trauma develop ARDS and others do not.
Studies have identified that recent cigarette smoking and chronic
alcohol abuse may be associated with ARDS, but these actions are not
considered to be causative factors. The presence of other lung diseases
such as asthma, emphysema, chronic bronchitis or lung cancer, does not
seem to be a factor in causing ARDS, although these may complicate the
course of the syndrome.
No one can predict with any certainty who will
get ARDS and who will escape it. This unpredictable nature makes ARDS
a complication of other illnesses that may be serious enough by
THE STAGES OF ARDS
ARDS has generally been characterized into three
stages. In full-blown cases, these three stages unfold sequentially
over a period of several weeks to several months.
Exudative stage: Characterized by accumulation in the alveoli of excessive
fluid, protein and inflammatory cells that have entered the air spaces
from the alveolar capillaries. The exudative phase unfolds over the
first 2 to 4 days after onset of lung injury.
(or proliferative) stage: Connective
tissue and other structural elements in the lungs proliferate in
response to the initial injury. Under a microscope, lung tissue
appears densely cellular. Also, at this stage, there is a danger of
pneumonia sepsis and rupture of the lungs causing leakage of air into
and Recovery: During this
stage, the lung reorganizes and recovers. Lung function may continue
to improve for as long as 6-12 months and sometimes longer, depending on the precipitating condition
and severity of the injury. It is important to remember that there may
be and often are different levels of pulmonary recovery amongst
individuals who suffer from ARDS.
Some experts recognize a fourth phase of ARDS.
This is the period longer than six to twelve months after onset, when
some patients experience continued health problems caused by the acute
illness. These problems may include cough, limited
exercise tolerance and fatigue. Others experience anxiety, depression
and flashback memories of their critical illness, which are very
similar to post-traumatic stress disorder. This fourth phase is
incompletely characterized, and is very much in need of research.
Treatment primarily involves supportive care in
an intensive care unit (ICU), including use of a mechanical ventilator
(vent) and supplemental oxygen. The goal of
mechanical ventilation is to support the patient's breathing during
the time needed for the patient's lungs to heal. Good progress has
been made recently in improving the use of ventilators. For the most
recent information regarding lower tidal volumes used in ventilation
you will want to discuss with your physician an article titled, "Ventilation
with Lower Tidal Volumes as Compared with Traditional Tidal Volumes
for Acute Lung Injury and the Acute Respiratory Distress
Syndrome" which was provided by the ARDSNetwork. This article
was published in the New England Journal of Medicine in
the May 4, 2000 issue and you may find this journal in your hospital
library. Using this technique has shown a decrease in mortality.
ARDS patients frequently receive medications to
reduce anxiety and discomfort and help conserve energy. Sometimes,
these medications make patients very sleepy.
The use of paralytic drugs has been
substantially reduced in recent years. Only a small percentage of
ARDS patients need this treatment. The use of the many adjuncts to
ARDS management are tailored to the individuals and depend on severity
of illness and other factors.
Medications are used to reverse the underlying
condition if possible, to prevent and treat complications of critical
illness, and to alleviate patient distress, such as pain, air hunger,
anxiety and severe confusional states. Antibiotics are commonly used
to treat confirmed or suspected infections. Vasopressors (“pressors”)
such as dopamine or Neosynephrine may be needed to maintain adequate
blood pressure. Pain relievers such as morphine and fentanyl and
anti-anxiety drugs such as Ativan or Versed are usually required to
improve patient tolerance of mechanical ventilation. Other medications
may be used to prevent bleeding from the stomach or to reduce the risk
of blood clot formation in the veins of the legs or arms. After the
first 2 or 3 days, patient nutrition is resumed, if possible. Until
the patient can eat again by mouth, food is given in liquid form into
a central vein (total parenteral nutrition “TPN”) or into the
stomach or intestine through a feeding tube (total enteral nutrition
“TEN”) If liquid feeding is required for longer than one or two
weeks, a surgical procedure may be performed to place a tube through
the abdominal wall directly into the stomach or intestine (“G-tube”,
“J-tube”, or “PEG”).
MORE ABOUT VENTILATORS:
A mechanical ventilator delivers breaths of
oxygen-enriched air to the body and removes breaths of carbon dioxide
produced by the body, to help the body maintain enough oxygen in the
bloodstream while patients recover from ARDS and their other
or illness(es). A ventilator can breathe completely for a patient or
assist a patient's own breathing. The 'vent' delivers breaths through
an artificial airway or endotracheal tube. Since it passes between the
vocal cords, the tube interferes with the patient's ability to speak.
Positive end expiratory pressure (PEEP) is a special setting on the
ventilator that keeps the lungs expanded to help get oxygen from the
lungs into the bloodstream. Another important setting is tidal volume
control, which measures the amount of air used for inflating the
lungs. Usually the tube is inserted through the mouth or nose.
Sometimes, tracheostomy is performed (an opening is cut through the
neck into the trachea and the ventilation tube is inserted through
this opening), ensuring a safe airway. Many patients get
tracheostomies to avoid tracheal injury from an orotracheal or
nasotracheal tube. Although the timing and necessity of tracheostomy
for this purpose are controversial, oftentimes it is the practice to
undergo tracheostomy after several weeks on the vent if it appears
that the patient will require long-term ventilation.
A decision to proceed with a tracheostomy is not
an indication of a worsening of the patient's condition, but rather
that mechanical ventilation is not being optimized by other means. A
tracheostomy might afford the patient a better pattern of breathing,
hence a better possibility of surviving ARDS.
WHAT TO EXPECT
The seriousness and unpredictability of ARDS can
emotionally devastate patients, family, friends, as well as doctors
and nurses, especially since very few cases of ARDS are alike. Some
patients get better quickly within several days, and others take weeks
or months to improve. Some patients have no complications and others
seem to develop every possible complication of ARDS. Finally, some
victims die quickly, while others die after a long and trying illness.
While ARDS is a very serious syndrome, people
can and do survive! It is important family and friends of the patient
remain hopeful, and seek guidance from others, including ARDS
survivors, families and friends of survivors.
The course of events after ARDS has developed is
determined, in part, by the degree of abnormality in lung function and
by the illness or injury that led to the development of ARDS. If the
underlying medical condition(s) stabilize(s) and no new complications
develop, the lungs may begin to heal, allowing the patient to breathe
more on his/her own. In about one third of ARDS cases, the ventilator may
be removed within a week. In another third of ARDS cases, the
underlying conditions are so severe that even treatment is unable to
reverse the abnormalities. Such patients may have or develop,
progressive or irreversible damage to other vital organs. Sometimes
the healing process is further compromised by chronic illnesses or
advanced age. Although intensive medical care is sometimes able to
prolong survival by a few days, such patients often die within the
first week. Those who survive the first week, but whose ARDS has not
yet improved, usually remain on the 'vent' for an average of 2-4
weeks, though it could be significantly longer. Even upon satisfactory
response to treatment of the underlying conditions, a small number of
patients have persistent inflammation in the lung(s) and seem unable to
begin the healing process. The outcome of patients who enter this
chronic stage is dependent on reversing the inflammation and
preventing or treating complications, especially infection. In any
case, unusual or experimental treatments may be considered. About one
half of patients with extreme cases of ARDS get better and leave the
hospital, but recovery is slow and may be incomplete.
Each patient's course with ARDS will be an
individualized process. The following are some of the
complications which may be encountered:
caused by pressure), or
caused by volume of air used for inflating the lungs.) In ARDS, the
lungs are weakened, making them at risk of a rupture (pneumothorax).
This leads to accumulation of air in the pleural cavity, partially
collapsing the lung(s). A chest tube (sometimes more than one) is
inserted to remove the air, allowing the lung(s) to re-inflate.
Bacterial infections are
a common complication of ARDS and contribute to continued lung injury.
Lung infection or pneumonia may be difficult to diagnose in a patient
with ARDS because the chest X-ray is already very abnormal.
Abnormal organ function may
involve the liver, kidney(s), brain, blood or immune system. Organ
dysfunction may be related to the underlying illness, to treatment, or
may occur through the same inflammatory process which injured the
lungs. If kidney failure occurs, the patient is given dialysis
(treatment to remove waste products from the blood by circulating the
blood through a special machine). Liver failure is a difficult problem
to treat, since there is no replacement for the many functions the
liver performs. Ongoing infections, despite appropriate antibiotic
therapy, may be due to dysfunction of the immune system. Patients may
become unconscious or confused when they previously have been alert
and oriented due to dysfunction of the brain or central nervous
or replacement of certain elements of the blood, such as platelets,
which are needed for clotting of the blood, may be required.
Delirium (also sometimes known as “ICU
psychosis”). The process that injures the lungs in ARDS also often
affects brain function. Many medications, including pain relievers and
anti-anxiety drugs, also adversely affect thought and behavior. As a
consequence, many victims of ARDS become agitated and confused or
disoriented after several days, especially as they reawaken. Severe
episodes are called delerium. In this condition, memory and
concentrating ability are impaired and awareness of time and place may
be lost. Many patients experience visual or auditory hallucinations.
Consciousness and confusion typically fluctuate over the course of the
day. For unknown reasons many patients are most agitated and confused
in the evening. Physical restraints and certain medications such as
Haldol are used to protect patients from themselves during periods of
severe agitation. Delirium generally resolves after several days as a
patient continues to recover from ARDS.
SURVIVAL AND MORTALITY
Thousands and thousands of Americans suffer from
ARDS each year. Many more suffer throughout the world. Until the
recent past, this devastating condition was uniformly fatal. However,
since ARDS was first described in 1967, steady progress has been made
in reducing mortality. Today, as many as 60% of ARDS victims recover
to leave the hospital. More than ever before, survivors are returning
to productive and rewarding lives. Medical doctors and scientists
still have more work to do to further improve mortality and functional
independence after recovery.
FAMILY AND FRIEND SUPPORT
Choose the Doctor and Hospital
Carefully. Hospitals differ in their ability to care for patients
who require intensive care. The best-equipped regional referral
hospitals have specialized ICUs for patients in severe respiratory
failure. These ICUs are staffed with around the clock and calendar by
doctors, nurses and therapists who are devoted exclusively to the care
of critically ill patients. These hospitals accept patients in
transfer by ground or air ambulance from other, smaller hospitals.
Thus, it is important to consider carefully the most appropriate place
for the care of a loved one in ARDS.
Participate actively in
Medical Decision Making. Get to know the doctor in charge early
on. Convey your desire to remain informed and to participate in
medical decision making as appropriate. Many experienced doctors admit
that they work hardest for patients who are closely accompanied by
concerned family members who are constructively engaged in critical
Do They Know We're Here? Always
gain permission from doctors and nurses before attempting to interact
with an ARDS patient. Many ARDS survivors attest that even though they
were on a 'vent', in a sleep-induced state, they were, on some level,
aware of the people and events around them. Many family members and
practitioners find that triggering the patient's senses plays an
important role in his/her recovery (i.e., talking, bringing in
pictures, playing soothing music, aroma therapy - if conducive to
environment, and touch; such as rubbing lotion on the patient's body).
Dreams: Many ARDS survivors recall vivid
dreams, while in the sleep-induced state. By stimulating the senses
the dreams may be based on reality, which might be helpful. Some
dreams can be calming and others frightening. Talk to your loved one
about fun things you did together, laugh with your loved one about
silly things you did. Request that nurses explain to the patient
exactly what they are doing and why, when they clean the 'vent' and
perform other procedures.
Ban Negativity! It
is vitally important that family and friends remain positive in the
patient's presence - leave fears and worries at the door. Conduct all
consults with the doctors/nurses away from the patient's hospital room
since patients may sense and be affected by stress dispersed in their
presence. Keep your faith and your hope strong, making sure that
everybody is encouraging and hopeful while with your loved one.
However, it is also important to be realistic. The mortality rate of
ARDS has been reduced in recent years but a significant number of ARDS
patients succumb to the syndrome.
Prepare to Tell Them. Start
a journal. ARDS survivors have a great need to know every detail of
what happened while they were asleep. All family members can
contribute. A separate journal of 'good things' that are happening in
each person's life can also be used to read back to the patient when
he/she shows signs of alertness.
Prepare Yourself Daily. Prepare
yourself for setbacks. ARDS is a roller coaster ride. Like the
patient, it is normal for family and friends to have both good and bad
days. Concentrate on the steps taken forward and view the steps
backwards as hurdles that can be overcome.
Take care of yourself. While a family
member or close friend requires intensive care, be sure to get enough
sleep. Eat well. Attend to the basic and emotional needs of others in
the family. Preserve yourself for a prolonged period of recovery when
your critically ill love one will especially need your strength and
A WORD ABOUT TERMINAL WITHDRAWAL
OF LIFE SUPPORT.
Despite the best effort of the
best doctors, nurses and family members, approximately 40% of ARDS
victims succumb to their acute illness. In most instances, death can
be anticipated. The patient does not heal from acute lung injury.
Multiple organ failure may ensue. Sepsis may becomes refractory to
antibiotic therapy. The brain may be irreversibly damaged by stroke or
other injury. Today, terminal withdrawal is a legal and medically
appropriate alternative to indefinite intensive care for some patients
who cannot recover from ARDS. By this approach, intensive efforts to
forestall death are replaced by comfort care aimed at allowing a
peaceful, dignified death. At some point, either you or the doctor may
raise the question as to whether continuation of life support best
serves the wishes and interests of the patient. Frank, open
discussions should follow focused on the question: “what would the
patient want us to do now?” In search for answers to that difficult
question, turn first to written documents such as living wills and
medical advanced directives that the person may have written. Consider
also conversations they may have had with others about continuation of
life support. Engage close family members in these discussions. Many
hospitals also have Ethics Committees to assist families and care
givers in considering difficult decisions. Hospital chaplains or other
members of the clergy can be helpful as well.
RESEARCH ON ARDS:
Clinical and laboratory
scientists around the world are engaged in research aimed at improving
the survival and functional recovery of patients who are victimized by
ARDS. Family members of patients in ARDS and survivors can support the
research effort by considering carefully requests to participate in
clinical research trials and requests for information. Some may wish
to contribute money to the research effort as well.
FOR MORE INFORMATION:
Please visit the web site of ARDS Support
Center, Inc. at http://www.ards.org
(This site includes articles, FAQs, memorials,
stories and journals, links, and much more.)
The ARDS Support brochure was revised on October
3, 2001 to reflect the latest scientific research provided by
doctors/researchers who serve on the ARDS Support Center Board of
Medical Consultants. The consultants who assisted with the revision
Dr. John Hansen-Flaschen
Dr. Jason Christie
Dr. William Shull, Jr.
Hospital of the University of Pennsylvania
Dr. Roy Brower
Johns Hopkins University Hospital
Dr. Art Wheeler
Vanderbilt University Hospital
Also reviewed by:
Dr. Kenneth Steinberg
Dr. Leonard Hudson
Harborview Medical Center/University of Washington