Method Of Exam

• While the patient breathes normally with mouth open, auscultate the lungs, making sure to auscultate the apices and middle and lower lung fields posteriorly, laterally and anteriorly.
• Alternate and compare sides.
• Use the diaphragm of the stethoscope. Listen to at least one complete respiratory cycle at each site.
• First listen with quiet respiration. If breath sounds are inaudible, then have him take deep breaths.
• First describe the breath sounds and then the adventitious sounds.
• Note the intensity of breath sounds and make a comparison with the opposite side.
• Assess length of inspiration and expiration. Listen for the pause between inspiration, expiration and the quality of pitch of the sound
• Also compare the intensity of breath sounds between upper and lower chest in upright position. Compare the intensity of breath sounds from dependent to top lung in the decubitus position.
• Note the presence or absence of adventitious sounds.

Normal:

There are two normal breath sounds. Bronchial and vesicular. Breath sounds heard over the tracheobronchial tree are called bronchial breathing and breath sounds heard over the lung tissue are called vesicular breathing. The only place where tracheobronchial trees are close to chest wall without surrounding lung tissue are trachea, right sternoclavicular joints and posterior right interscapular space. These are the sites where bronchial breathing can be normally heard. In all other places there is lung tissue and vesicular breathing is heard.

The bronchial breath sounds over the trachea has a higher pitch, louder, inspiration and expiration are equal and there is a pause between inspiration and expiration.

The vesicular breathing is heard over the thorax, lower pitched and softer than bronchial breathing. Expiration is shorter and there is no pause between inspiration and expiration. The intensity of breath sound is higher in bases in erect position and dependent lung in decubitus position.

The breath sounds are symmetrical and louder in intensity in bases compared to apices in erect position. No adventitious sounds are heard.

Breath Sounds by Dr David W.Cugell NW University Chicago