Table 16-2.

Classification of Common Lung Sounds

	Acoustic Characteristics	American Thoracic Society Nomenclature	Common Synonyms
Normal	200-600 Hz Decreasing power with increasing Hz	Normal	Vesicular
	75-1600 Hz Flat until sharp decrease in power (900 Hz)	Bronchial	Bronchial Tracheal
Adventitious	—	Adventitious	Abnormal
	Discontinuous, interrupted explosive sounds (loud, low in pitch), early inspiratory or expiratory	Coarse crackles	Coarse crackles
	Discontinuous, interrupted explosive sounds (less loud than above and of shorter duration; higher in pitch than coarse crackles or crackles), mid- to late inspiratory	Fine crackles	Fine crackles, crepitation
	Continuous sounds (>250 msec, high-pitched; dominant frequency of 400 Hz or more, a hissing sound)	Wheezes	Sibilant rhonchus, high-pitched wheeze
	Continuous sounds (>250 msec, low-pitched; dominant frequency < 200 Hz, a snoring sound)	Rhonchi	Sonorous rhonchus, low pitched wheeze