Bronchial Breath Sounds

Breath sounds, in general, are of two types: normal and abnormal breath sounds. Normal sounds are the ones produced during breathing, till the air reaches the bronchioles, and not when the air reaches the terminal bronchioles or alveoli. When there is a disease or disorder, there are different kind of sounds produced in the alveolar zone.

Normal breathing sounds can be heard along different parts of the respiratory system. These include tracheal, bronchial, bronchovesicular, and vesicular sounds.

Sounds of bronchial breathing are heard over the large airways present in the anterior portion of the chest, close to the second and third intercostal space. As the air is passing through the empty and wide airway at this time, these sounds are hollower than the next type of sound, which is vesicular. These are not as harsh as tracheal sounds, but are loud and high pitched, with a slight palpable pause between inspiration and expiration.

Although these breath sounds are audible during inspiration and expiration, the expiratory sounds are louder when the patient is in a non-supine position, i.e., when the patient is now lying down. The ratio of the duration of inspiration to expiration is typically 1:2, when the person is in a resting stage.

These sounds are not generally heard over the thorax when a person is in a calm and resting stage. When a person has done physically exerting work, bronchial sounds can be heard over the hilar region.

If these sounds are heard anywhere else besides between the intercostal region of the second and third rib, then it is indicative of consolidation in that region. Consolidation is a condition of a air pocket being filled by fluid or solid lung tissue.

This heavy and dense lung tissue creates an obstruction to the air, due to which the sounds travel more readily to the chest wall, and the filtering of sounds that usually take place is not seen.

Due to this, loud and tubular sounds are heard over this region, mimicking bronchial breathing. This consolidation may be seen in cases of emphysema or in cases where there is a large amount of pleural effusion.

With the help of a stethoscope, these sounds can be heard. If abnormal bronchial breath sounds are heard, then further tests and investigations need to be done to reach a diagnosis regarding the condition.