Adult Respiratory Distress Syndrome Essay Research Paper

Adult Respiratory Distress Syndrome Essay, Research Paper

ARDS (adult respiratory distress syndrome) Disease

Table Of Contents:

? Alternative names

? Definition

? Pathophysiology

? Causes, incidence, and risk factors

? Prognosis / Mortality

? Prevention

? Symptoms

? Signs and tests

? Treatment

? Complications

? Calling your health care provider

Alternative names:

stiff lung; shock lung; pump lung; acute respiratory distress syndrome;

congestive atelectasis

Definition:

Adult (acute) respiratory distress syndrome (ARDS) is the rapid onset

of progressive malfunction of the lungs, especially with regard to

the ability to take in oxygen, usually associated with the malfunction

of other organs. The condition is associated with extensive pulmonary

inflammation and small blood vessel injury in all affected organs.

ARDS has a fatality rate of approximately 50% despite supportive therapy,

including assisted respiration. It is difficult to estimate the incidence

of ARDS because it is often associated with other severe illnesses. But

it is a common problem in hospital intensive care units. The incidence

of ARDS has been difficult to determine, due partly to the variety of

causes. Various published estimates have ranged from 1.5 to 71 cases

per 100,000 population. Other figures suggest the occurrence of 13,000

to 27,000 cases annually.

Pathophysiology ARDS is the end result of acute alveolar injury caused by

a variety of insults and probably initiated by different mechanisms. The

initial injury is to either the capillary endothelium or alveolar

epithelium. There is increased capillary permeability, Organization and

scarring follows. The capillary defect is produced by an interaction

of inflammatory cells and mediators, including leukocytes, cytokines,

oxygen radicals, complement and arachidonate metabolites, that damages the

endothelium and allows fluid and proteins to leak. Endotoxin, neutrophils

and macrophages may also play key roles in the pathogenesis of ARDS.

ARDS results from widespread acute injury to the alveolar capillary

membrane. This produces high permeability edema, visible on the chest

x-ray. It also inhibits surfactant function (especially fibrin monomers).

Epithelial injury also impairs new surfactant synthesis. Inflammation

may exacerbate the injury because of release of oxidants and lysosomal

enzymes from activated leukocytes. Lung compliance (delta V) / (delta

P) is decreased because many airspace?s contain edema (and hence cannot

accept air) and because abnormally high surface tension counteracts the

negative intrapleural pressure.

Causes, incidence, and risk factors: ARDS is a medical emergency. It may

be caused by a variety of conditions that directly or indirectly cause

the blood vessels to “leak” fluid into the lungs. The ability of the

lungs to expand is severely decreased and damage to the air sacs and

lining (endothelium) of the lung is extensive. Blood concentration of

oxygen remains very low in spite of high concentrations of supplemental

oxygen given to the patient. Systemic causes of lung injury include

trauma, head injury, shock, sepsis, multiple blood transfusions,

and medications. Pulmonary causes include pulmonary embolism, severe

pneumonia, smoke inhalation, radiation, high altitude, near drowning,

and more. Symptoms usually develop within 24 to 48 hours of the injury

or illness. Cigarette smoking may be a risk factor. The incidence is 1

out of 100,000 people.

ARDS is commonly precipitated by trauma, sepsis (systemic infection),

diffuse pneumonia and shock. It may be associated with extensive surgery,

and certain blood abnormalities. Less common causes include drowning

and inhalation of toxic gases. In half the cases, onset occurs within

24 hours of the original illness or injury; in nearly all, it occurs

within three days.

Prognosis / Mortality The death rate estimates a range from 30-70%

Although survivors usually recover normal lung function, some

individuals may suffer permanent lung damage, which can range from mild to

severe. Recent data suggests that on average more than 40 percent die from

ARDS. This data accounts for direct deaths resulting from not recovering

from ARDS. The data does not account for deaths among survivors which

may be causally related due to medical conditions arising or effected

by the encounter with ARDS.

Since ARDS was first described in 1967, the prognosis has

improved slightly despite rapid advancements in medical science and

technology. Statistical data reveals that approximately one half of

who develop ARDS each year will survive in the United States and other

countries which have well trained medical personnel and facilities for

treating ARDS patients.

Younger people and those who have fewer chronic health problems are more

likely to recover. It is known that people with a milder form of ARDS

tend to have a better chance of recovering than those with a more severe

form of the illness. It is also known that the cause of a patient’s

ARDS helps predict that patient’s chances for survival. For example,

patients who develop ARDS due to sepsis usually do not do as well as

patients whose ARDS is related to trauma. Finally, those patients who

do survive after developing ARDS usually improve over several months

with a return to normal or near normal lung function.