Encyclopedia of Health and Medicine

A
acute respiratory distress syndrome (ARDS) A
complex of symptoms, formerly called adult respiratory
distress syndrome, in which respiratory
distress and RESPIRATORY FAILURE develop accompanying
severe illness or trauma. ARDS involves the
whole of both LUNGS, as the lungs become
inflamed and fill with fluid. ARDS may develop as
a consequence of injury that directly affects the
lungs (notably blunt trauma to the chest, near
drowning, PNEUMONIA, and smoke inhalation) or
when the injury or illness affects other parts or
systems of the body. Systemic INFECTION (SEPSIS),
DRUG OVERDOSE, and BLOOD TRANSFUSION may also
result in ARDS. ARDS can affect people of any age
and is life-threatening. Because people who
develop ARDS are already very ill, ARDS has a
high death rate (about 40 percent). The syndrome
may cause complete respiratory failure or lead to
total system failure, either of which presents significant
challenge for recovery.
Symptoms and Diagnostic Path
People who develop ARDS have generally sustained
severe trauma or infection and most are
already in the hospital when their symptoms begin.
Early symptoms of ARDS include restlessness,
TACHYPNEA (rapid, shallow breathing), and HYPOXIA
(reduced oxygen to the body’s tissues). ARDS progresses
rapidly to full involvement of the lungs.
Chest X-rays show the filling of the lungs with
INFLAMMATION and fluid (called diffuse infiltration).
Arterial BLOOD gases show the decreased percentage
of oxygen in the blood. Doctors often perform tests
on SPUTUM and fluid from the lungs to identify any
pathogens, notably BACTERIA, that may be present.
Treatment Options and Outlook
Immediate oxygen supplementation is essential.
Many people require MECHANICAL VENTILATION with
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positive end expiratory pressure (PEEP) to
increase the amount of oxygen entering the lungs.
Doctors generally administer sedation while the
person is on mechanical ventilation, to provide
comfort and to prevent the natural tendency to
fight the intervention. Treatment primarily is supportive,
including close monitoring of cardiovascular
and renal (kidney) functions. Because
infection, either in the lungs or elsewhere in the
body, is often present, many people may also
receive intravenous (IV) ANTIBIOTIC MEDICATIONS.
The outlook for full recovery depends on
numerous factors including the person’s age, general
health status, and the ability to reverse the
circumstances responsible for the initial development
of ARDS. Even medical intervention that
begins early in the course of ARDS cannot predict
the success of treatment. About 60 percent of people
survive the ARDS episode, though the severity
of illness can require extensive recuperation.
Risk Factors and Preventive Measures
The primary risk factors for ARDS are sepsis
(severe infection) and major trauma, either to the
lungs or to the body in general. Though such
infection or trauma alerts doctors to the grave risk
for ARDS, there are no known measures that can
head off the development of ARDS. Public health
measures to minimize the risk factors (trauma and
infection) are critical. Once ARDS occurs, however,
aggressive medical intervention and support
provide the best chance for survival.
See also HEART FAILURE; SEVERE ACUTE RESPIRATORY
SYNDROME (SARS).
aging, pulmonary changes that occur with The
LUNGS and tracheobronchial structures undergo few
but significant changes over the course of the life-