Adventitious breath sounds are abnormal sounds that are superimposed over normal breath sounds. Detection of these sounds can aid in the diagnosis of various pulmonary and cardiac conditions.
Crackles (Rales) are discontinuous, intermittent, “popping” sounds. Fine crackles are soft, high-pitched, and very brief. Coarse crackles are louder, lower-pitched, and last longer. Crackles may be heard with bronchiectasis, bronchitis, pneumonia, fibrosis, and congestive heart failure.
Wheezes are continuous, high-pitched, musical sounds that most often accompany asthma and COPD. However, it is important to remember the adage, “All that wheezes is not asthma (or COPD).” A variety of other conditions can produce airflow obstruction with inspiratory and/or expiratory wheezing.
Rhonchi are continuous, low-pitched sounds with a “snoring” quality. These sounds suggest secretions in the large airways.