Normal Breath Sounds
To be able to distinguish between types of abnormal breath sounds and their location, it is important to understand normal respiration and its effect on airway noises that make up breath sounds. Normal breath sounds are bronchovesicular in nature. They are loud pipe-like sounds in the large airways, and softer blowing-like sounds in the small airways. Normal breath sounds are loudest during inspiration and softest during expiration. The inspiratory phase is shorter with faster airflow. Although abnormal sounds may be louder during inspiration, they may be difficult to distinguish due to their short duration.
Normal Air Flow through the Lungs
Flow is greatest in the trachea and diminishes in the distal lung fields, until it reaches the alveoli, where there is no flow. Breath sounds are loudest over areas with greater flow, and distal pathology may be communicated to these areas. Therefore, auscultation over the trachea may reveal pathology there or communicated from distal regions of the lung.
**If breath sounds are really diminished, listen over the trachea**

Adventitious sounds
Wheezing: musical, whistling sound
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Usually more pronounced during expiration
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From narrowed airways
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Bronchoconstriction
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Secretions
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Interventions:
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Bronchodilation
- Hydration
- Coughing
Rales: crackling sound
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Heard at the end of inspiration
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From collapsed or waterlogged alveoli
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Fine: beginning of fluid buildup / or atelectasis
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Coarse: greater volume of fluid buildup
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Interventions:
Manage fluids
- Budget volume resuscitation
- Diuretics
Expectorate
- Turn & position
- Deep breathing
- Forced expiration
- Vibration & percussion
Rhonchi: bubbling
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The sound will be heard throughout inspiration and expiration.
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Louder than rales due to larger secretions
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Results from air bubbling past secretions in the airways
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Interventions:
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Deep breathing
- Coughing
- Hydration (encourage fluids, if no restriction)
- Humidify air
- Mobilize
Friction rub: creaking, leathery sound
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End of inspiration and beginning of expiration
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Caused by rubbing of inflamed pleural surfaces against lung tissue.
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Interventions:
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Chest x-ray
- Anti-inflammatory medications