Encyclopedia of Health and Medicine

C–E
chest percussion and postural drainage A therapeutic
method for loosening and clearing mucus
from the LUNGS, used especially in CYSTIC FIBROSIS
and BRONCHIECTASIS, when there is ATELECTASIS, and
in other pulmonary disorders in which mucus collects
and blocks the flow of air. For this treatment,
a respiratory therapist or caregiver trained in the
method rhythmically claps, with cupped hands,
on the SKIN surfaces of the chest and back over the
thoracic cavity with the person receiving the treatment
in various postures, depending on the location
of the clapping. The therapist may choose
to use a mechanized percussor instead of the
hands, which allows longer and more intensive
percussion.
Clapping over the upper chest (near the collarbones)
and upper back (near the shoulder blades)
loosens secretions in the upper lobes. Clapping
over the midchest (nipple line) and midback
loosens secretions in the middle lobes. Clapping
over the lower chest (below the nipple line) and
lower back loosens secretions in the lower lobes.
Precise positioning of the hands when clapping
can further target specific segments of the lobes.
The percussion of the clapping loosens mucus and
secretions within the bronchi, which the person
then coughs up to remove from the respiratory
tract.
See also COUGH; CYSTIC FIBROSIS AND THE LUNGS.
Cheyne-Stokes respiration A pattern of BREATH-
ING in which periods of APNEA alternate with periods
of accelerated breathing. Cheyne-Stokes
respiration indicates damage to the brainstem or
other NERVOUS SYSTEM mechanisms that regulate
breathing. This breathing pattern also occurs in
severe HEART FAILURE. During the apneic periods,
which may last up to 60 seconds, breathing stops.
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During the accelerated periods, the RESPIRATORY
RATE rapidly increases in rate and depth (hyperpnea)
then abruptly stops as the cycle returns to
apnea. Cheyne-Stokes respiration may reflect an
end-stage (near death) breathing pattern in adults,
though may persist for an extended time in people
who are comatose.
See also DYSPNEA; TACHYPNEA.
chronic obstructive pulmonary disease (COPD)
A serious, often debilitating, and potentially fatal
condition in which INFLAMMATION and scarring
destroy alveoli, bronchioles, and bronchi. The
most common cause of COPD is cigarette smoking;
8 of 10 Americans who have COPD are smokers.
Uncontrolled ASTHMA and chronic lung diseases
such as ASBESTOSIS and SILICOSIS can also progress to
COPD. About 16 million people in the United
States have COPD and more than 100,000 of them
die from it each year.
COPD takes years to decades to develop, and its
damage is permanent. The most common presentation
is that of chronic BRONCHITIS, in which there
is repeated inflammation of the bronchi. Each
bout of inflammation results in the formation of
SCAR tissue as the damaged area heals. Over time
the scar tissue causes the bronchi to narrow, with
areas of constriction that severely limit the flow of
air. ATELECTASIS (collapse) may occur in affected
bronchial structures, reducing the ability of the
lung to diffuse oxygen into the bloodstream.
In about 10 percent of people who have COPD
the damage extends to the alveoli, the clusters of
air sacs where oxygen–carbon dioxide exchange
takes place. Repeated inflammation and scarring
causes the alveoli to enlarge and lose elasticity, a
state called emphysema. The damaged alveoli can
take in air but cannot collapse sufficiently to expel