The most effective treatment for chronic bron-
chitis is removing the cause of the symptoms,
which most often is cigarette smoking. Chronic
bronchitis becomes inevitable at some point in
everyone who smokes. People who work in envi-
ronments with high exposures to fumes, dust, or
pollutants should use appropriate protective gear
including masks or respirators. Chronic bronchitis
that continues unchecked results in permanent
damage to the bronchial structures.
Risk Factors and Preventive MeasuresFrequent HAND WASHINGis the best defense against
viral infections of any sort. Upper respiratory
viruses spread through droplet contamination,
which may occur through direct touch (such as
shaking hands) or breathing droplets coughed or
sneezed into the air by those who have upper res-
piratory viruses. In epidemic circumstances, doc-
tors may prescribe antiviral medications such as
rimantadine to reduce the risk or severity of infec-
tion. Removal from the source of irritation
reduces symptoms to improve chronic bronchitis.
People who have high risk of respiratory infection,
such as those who have chronic lung disease or
other chronic health conditions, should receive
influenza vaccination (flu shot) every year and
pneumonia vaccination every five years.
See also ANTIBIOTIC RESISTANCE; CROUP; HEMOPTY-
SIS; PNEUMONITIS; SMOKING AND PULMONARY DISEASE.
bronchoalveolar lavage A diagnostic procedure
that washes cells from the bronchi and alveoli for
laboratory examination. The doctor does bron-
choalveolar lavage during BRONCHOSCOPY, blocking
a small section of the bronchial segment to instill
and then withdraw sterile saline. The solution
contains cells from the inner lung structures that
can provide diagnostic information. The doctor
may also use bronchoalveolar lavage therapeuti-
cally, to irrigate (rinse away) thickened mucus or
other deposits from the LUNGSin conditions when
thick plugs of mucus block the airways and do not
respond to other treatments.
See also ALVEOLUS; BRONCHUS.
bronchoscopy A diagnostic procedure in which
the doctor uses a flexible, lighted endoscope,
inserted through the THROATand into the airways
under sedation or ANESTHESIA, to view the TRACHEA,
bronchi, and other structures of the respiratory
tract. The doctor also can watch the LUNGS in
motion, assessing air movement and filling. Bron-
choscopy is an outpatient procedure that takes
about an hour. Many people receive mild sedation
before the bronchoscopy to help them relax and
be more comfortable.
The bronchoscope is a thin, flexible, lighted
tube with a tiny camera on the tip. The pulmo-
nologist sprays a topical anesthetic on the back of
the throat to block the GAG REFLEXand numb the
throat, then inserts the bronchoscope through the
MOUTH(or the NOSE, with lubrication) and throat
into the trachea. The pulmonologist guides the
bronchoscope into the bronchi, which enables
examination of the lung to a moderate depth of
about four or five branchings of the bronchus. The
pulmonologist may use bronchoscopy to obtain
tiny tissue samples for biopsy or to perform BRON-
CHOALVEOLAR LAVAGEto obtain bronchial and alveo-
lar cell samples. Bronchoscopy may also be
therapeutic, allowing the pulmonologist to rinse
accumulated mucus and debris from the bronchi.
It is common to feel some discomfort after the
topical anesthetic wears off, similar to a sore
throat. The discomfort generally does not last
more than a day or two. Rarely after a biopsy,
bronchoscopy may cause a PNEUMOTHORAX, a con-
dition in which air gets in the pleural space (a
small area around the lung) and the lung col-
lapses. The risks of bronchoscopy for most people
are minimal.
See also ALVEOLUS; BRONCHUS; ENDOSCOPY.bronchus A secondary branch of the airways
that connect the LUNGSand the primary airway,
the TRACHEA. The main bronchi branch directly
from the trachea at about mid-lung, with the right
main bronchus channeling air to the right lung
and the left main bronchus directing air to the left
lung. Each main bronchus nearly immediately
branches into lobular bronchi, three in the right
lobe and two in the left lobe. Bronchi become
diminishingly smaller as they branch deeper into
the lungs. Rings of CARTILAGEgive larger bronchi
rigidity and support. Smaller bronchi have fewer
and thinner cartilage rings, and bronchioles, the
tiniest of the bronchi, have thin walls of onlybronchus 197