Lung Sounds—Differential Diagnosis
| Crackles (rales) | Simulated by rubbing hair between fingers, best heard on inspiration in lower bases, unrelieved by coughing:
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| Wheezes | High-pitched, squeaking sound, best heard on expiration over all lung fields, unrelieved by coughing (e.g., asthma, COPD, emphysema). |
| Rhonchi | Coarse, harsh, loud gurgling or rattling, best heard on expiration over bronchi and trachea, often relieved by coughing (e.g., bronchitis, pneumonia). |
| Stridor | Life-threatening! Harsh, high-pitched, easily audible on inspiration, progressive narrowing of upper airway requiring immediate attention (e.g., partial airway obstruction, croup, epiglottitis). |
| Unilaterally absent or diminished | Inability to hear equal, bilateral breath sounds (e.g., pneumothorax, tension pneumothorax, hemothorax, or history of pneumectomy). |
| Document | Rate, rhythm, depth, effort, sounds (indicate if sound is inspiratory and/or expiratory), and fields of auscultation. |