Definition

Breath sounds are the noises produced by the structures of the lungs during breathing.

Alternative Names

Lung sounds; Breathing sounds

Considerations

The lung sounds are best heard with a stethoscope. This is called auscultation.

Normal lung sounds occur in all parts of the chest area, including above the collarbones and at the bottom of the rib cage.

Using a stethoscope, the health care provider may hear normal breathing sounds, decreased or absent breath sounds, and abnormal breath sounds.

Absent or decreased sounds can mean:

• Air or fluid in or around the lungs (such as pneumonia, heart failure, and pleural effusion)
• Increased thickness of the chest wall
• Over-inflation of a part of the lungs (emphysema can cause this)
• Reduced airflow to part of the lungs

There are several types of abnormal breath sounds. The four most common are:

• Rales. Small clicking, bubbling, or rattling sounds in the lungs. They are heard when a person breathes in (inhales). They are believed to occur when air opens closed air spaces. Rales can be further described as moist, dry, fine, and coarse.
• Rhonchi. Sounds that resemble snoring. They occur when air is blocked or air flow becomes rough through the large airways.
• Stridor. Wheeze-like sound heard when a person breathes. Usually it is due to a blockage of airflow in the windpipe (trachea) or in the back of the throat.
• Wheezing. High-pitched sounds produced by narrowed airways. They are most often heard when a person breathes out (exhales). Wheezing and other abnormal sounds can sometimes be heard without a stethoscope.

Causes

Causes of abnormal breath sounds may include:

• Acute bronchitis
• Asthma
• Bronchiectasis
• Chronic bronchitis
• Congestive heart failure
• Emphysema
• Interstitial lung disease
• Foreign body obstruction of the airway
• Pneumonia
• Pulmonary edema
• Tracheobronchitis

When to Contact a Medical Professional

Seek medical care right away if you have:

• Cyanosis (bluish discoloration of the skin)
• Nasal flaring
• Severe trouble breathing or shortness of breath

Contact your provider if you have wheezing or other abnormal breathing sounds.

Your provider will do a physical exam and ask you questions about your medical history and your breathing.

Questions may include:

• When did the breath sound start?
• How long did it last?
• How would you describe your breathing?
• What makes it better or worse?
• What other symptoms do you have?

The provider usually discovers abnormal breath sounds. You may not even notice them.

The following tests may be done:

• Analysis of a sputum sample (sputum culture, sputum Gram stain)
• Blood tests (including an arterial blood gas)
• Chest x-ray
• CT scan of the chest
• Pulmonary function tests
• Pulse oximetry

References

Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW. Chest and lungs. In: Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW, eds. Siedel's Guide to Physical Examination. 10th ed. St Louis, MO: Elsevier; 2023:chap 14.

Kraft M. Approach to the patient with respiratory disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier ; 2020:chap 77.