Qualitative differences in breath sounds are collectively called adventitious breath sounds. The inspiratory:expiratory ratio (1:3) heard over the central airways better approximates the actual time spent in each phase of the respiratory cycle ( Figure 5–1).Ībnormal breath sounds include sounds of differing intensity, duration, or quality when compared to those of the normal respiratory cycle. Listening to alveolar breath sounds (also called vesicular sounds), the expiratory phase sounds shorter (a 3:1 inspiratory:expiratory ratio) because expiration is a passive process resulting in lower flow rates and less turbulence. In the periphery of the lung, higher pitched components are more attenuated than lower pitched ones, resulting in the muffled quality of normal alveolar breath sounds.

These sounds, appropriately named tracheal or bronchial breath sounds, consist of high- and low-frequency sounds. During respiration, this can occur when airflow reaches a critical velocity such as during forced expiration or when airflow is physically disrupted as occurs at airway branch points.ĭuring auscultation, breath sounds are heard best over the trachea and central airways. Turbulent airflow occurs when the orderly arrangement of particles in laminar flow becomes disrupted. Recognize the implications of abnormal sounds in individuals with specific lung disease.įormulate a differential diagnoses for the causes of various abnormal lung sounds.īreath sounds result, in large part, from turbulent airflow. Understand the pathogenesis and pathophysiology of normal and abnormal breath sounds.

Auscultating lung sounds