Breath Sounds Tutor

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.

Respiratory Cycle

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**

Airflow

Adventitious sounds

Wheezing: musical, whistling sound

  1. Usually more pronounced during expiration
  2. From narrowed airways
  3. Interventions:

Rales: crackling sound

  1. Heard at the end of inspiration
  2. From collapsed or waterlogged alveoli
  3. Fine: beginning of fluid buildup / or atelectasis
  4. Coarse: greater volume of fluid buildup

Rales

  1. Interventions:
    Manage fluids

Expectorate

Rhonchi: bubbling

  1. The sound will be heard throughout inspiration and expiration.
  2. Louder than rales due to larger secretions
  3. Results from air bubbling past secretions in the airways

Rhonchi

  1. Interventions:

Friction rub: creaking, leathery sound

  1. End of inspiration and beginning of expiration
  2. Caused by rubbing of inflamed pleural surfaces against lung tissue.

Friction rub

  1. Interventions:

To listen to examples of these breath sounds check out the link below:

The RALE repository

For more information about breath sounds and respiratory treatments, see Mechanical Ventilation for Nurses, Pulmonary Interventions, or Pulmonary Emrgencies.

©2003 Ed4Nurses, Inc. All rights reserved.