Clinical meaning
Breath sounds are produced by air turbulence in the large airways and transmitted through lung tissue to the chest wall. Normal vesicular breath sounds are soft and low-pitched, heard over peripheral lung fields. Adventitious (abnormal) sounds occur when air flows through narrowed or fluid-filled airways, or when inflamed pleural surfaces rub together. Changes in breath sounds are often the earliest detectable sign of respiratory deterioration.
Exam relevance
Risk factors: - Smoking or history of tobacco use causing chronic airway inflammation and impaired mucociliary clearance - Recent general anesthesia or surgery increasing risk of atelectasis and diminished breath sounds - Immobility or prolonged bedrest reducing lung expansion and promoting mucus pooling - History of COPD, asthma, or chronic lung disease with ongoing adventitious breath sounds at baseline - Heart failure causing pulmonary congestion and bilateral crackles - Aspiration risk from impaired swallowing, decreased level of consciousness, or tube feeding
Diagnostics: - Auscultate with diaphragm of stethoscope - Listen to anterior, posterior, and lateral lung fields bilaterally - Compare side-to-side at each level - Note the location, timing, and quality of any abnormal sounds - Report all abnormal findings to the nurse promptly