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Fit the stethoscope earpiece to your ears. The tubing should angle
slightly upward and toward the front of your head.
Instruct the patient to take slow, deep breaths through the mouth
while you listen. The breaths should be deep so the air will
completely fill the lungs. They should be slow to prevent
hyperventilation. The mouth should be open to minimize the noisy
turbulence created whenever air moves quickly through the nose.
Listen to each lung in several areas of the back. Compare the left
side to the right side at the same level. Listen to
the apex of each lung over the anterior chest. Avoid trying to listen
through the scapula (shoulder blade) as sound does not conduct well
through the bone. Avoid listening through chest hair or clothing as
they introduce acoustic artifact.
Normal breath sounds are clear. Crackles
(rales) are high-pitched
sounds similar to the sound of hairs being rubbed together. Wheezes
have a musical quality to them, reflecting narrowed air passages
vibrating like the reeds on a musical instrument. Pleural friction
rubs are the soft sounds with each breath that resembles two pieces of leather
rubbing against each other. Stridor are the loud, coarse sounds coming
from the upper airway indicating swelling or obstruction. These can be
heard without a stethoscope, some distance from the patient.
Absent or significantly diminished breath sounds over part or all
of the lung fields may indicate fluid (pleural effusion, hemothorax)
in the chest, or a collapsed lung (air in the pleural space).
If
you are connected to the Internet, you can hear additional breath
sounds at this web site.
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Listen to each lung in several areas of the
back.
In this case of right hemothorax, the
left lung will be clear while the right
lung sounds will be muffled or absent
in the lower half of the lung fields. |
