What is breath sound assessment?

Clinical evaluation of breath sounds is the first and most common method of assessing lung health. The stethoscope placed on the back and chest lets the physician listen to the breath sounds. This process is called auscultation.
Assessment of breath sounds is a routine part of a clinical examination. If a pathology of the lung is suspected, assessing the breath sounds helps identify probable causes. The type and location of certain breath sounds can help make a diagnosis.
What are normal breath sounds?
There are two types, normal and abnormal (adventitious) breath sounds:
Normal breath sounds are divided into two subcategories:
- Vesicular breath sounds: Sounds heard during auscultation of the chest of a healthy person. They can be heard all over the chest and the back.
- Tracheal sounds: Sounds heard over the sternum. They are louder and higher pitched than vesicular sounds are.
What are the types of abnormal breath sounds?
The type and location of the abnormal breath sounds can help make a diagnosis. In the presence of abnormal breath sounds, the doctor will advise a management plan for further investigations and treatment. The types of abnormal breath sounds include the following:
Wheezing
This is a high-pitched whistling sound that occurs breathing in or out. It’s usually a sign that there is narrowing of the airways, preventing air from flowing through freely.
The most common causes of wheezing are asthma and a group of lung diseases called chronic obstructive pulmonary disease (COPD). Other conditions that can cause wheezing include:
- Allergies
- Epiglottitis (when the “lid” of cartilage that covers the trachea swells and obstructs air entry to the lungs)
- Vocal cord problems
- A foreign body stuck in stuck in throat or trachea (windpipe)
- Infections
- Smoking
- Side effect of some medications
- Laryngeal or tracheal tumors
- Tracheal stenosis
- Tracheomalacia
- Foreign body aspiration
- Occupational exposure to certain chemicals and irritants
- Cystic fibrosis
- Bronchiectasis
- Hypersensitivity pneumonitis
- Pulmonary edema
- Reactive Airway Disease Syndrome
Crackling (rales)
This is a series of short, explosive sounds. They may sound like bubbling, rattling or clicking. They mostly occur during inhalation and sometimes during exhalation.
Crackles can be a sign that there’s fluid in the lungs.
They can be caused by:
- Pneumonia
- Heart disease
- Lung fibrosis
- Cystic fibrosis
- COPD
- Lung infections
- Asbestosis (caused by breathing in asbestos)
- Pericarditis (infection of the covering of the heart)
Stridor
This a harsh, noisy, squeaking sound happens with every breath. It can be high or low and usually a sign that there is obstruction of the airways. It may be present during inhalation or exhalation. It can be a sign of a life-threatening problem that needs medical attention right away.
The causes of stridor are:
- Laryngomalacia (softening of the vocal cords in babies)
- Paralyzed vocal cord
- Narrow voice box
- Hemangioma (unusual growth of blood vessels) just below the vocal cords
- Infection of the trachea (windpipe)
- Epiglottitis
- Foreign body stuck in the trachea
Rhonchi
These are low-pitched wheezing sounds that sound like snoring. They usually occur during exhalation. They can be a sign that the bronchial tubes (the tubes that connect the trachea to the lungs) are thickened because of mucus.
Rhonchi sounds can be a sign of bronchitis or COPD.
Whooping
This is a high-pitched gasp that typically follows a long bout of coughing. It may be a symptom of whooping cough (pertussis), a contagious infection in the respiratory system.
Pleural friction rub
The membranes that cover the walls of the chest cavity and the outer surface of the lungs are called pleura. If they get inflamed and rub together, it produces a rough, scratchy sound.
It can be a sign of pleurisy (inflammation of the pleura), fluid in the lungs, pneumonia or lung tumors.
Mediastinal crunch
This sound, also called Hamman’s sign. It indicates that air is trapped in the space between the lungs (the mediastinum). It’s a crunchy, scratchy sound and occurs along with the heartbeat.
The sound can occur in lung diseases like COPD, pneumonia or cystic fibrosis.

QUESTION
COPD (chronic obstructive pulmonary disease) is the same as adult-onset asthma. See AnswerHealth Solutions From Our Sponsors
Top What Is Breath Sound Assessment Related Articles
Respiratory Illnesses: 13 Types of Lung Infections
Is your cough caused by a cold, flu, pneumonia or something else? Learn causes of respiratory infection like bronchitis, pneumonia, SARS, Coronavirus COVID-19 bird flu, and more.COPD Lung Symptoms
COPD is a pulmonary disorder caused by obstructions in the airways of the lungs leading to breathing problems. Learn about COPD symptoms, diagnosis, and treatment options.Emphysema
Emphysema is a COPD (chronic obstructive pulmonary disease) that often occurs with other obstructive pulmonary problems and chronic bronchitis. Causes of emphysema include chronic cigarette smoking, exposure to secondhand smoke, air pollution, and in the underdeveloped parts of the world. Symptoms of emphysema include chronic cough, chest discomfort, breathlessness, and wheezing. Treatments include medication and lifestyle changes.How Serious Is a Blood Clot in the Lungs?
A blood clot is a solid or semisolid clump of blood. When the tissues of our body are injured, excessive blood loss is prevented by the clotting of blood. When a blood clot occurs inside the blood vessels it may lead to serious medical conditions. When a blood clot occurs inside the arteries to the lungs, the condition is called pulmonary embolism (PE).Interstitial Lung Disease (Interstitial Pneumonia)
Interstitial lung disease refers to a variety of diseased that thicken the tissue between the lungs' air sacks. Symptoms of interstitial lung disease include shortness of breath, cough, and vascular problems, and their treatment depends on the underlying cause of the tissue thickening. Causes include viruses, bacteria, tobacco smoke, environmental factors, cancer, and heart or kidney failure.Lung Cancer
Lung cancer kills more men and women than any other form of cancer. Eight out of 10 lung cancers are due to tobacco smoke. Lung cancers are classified as either small-cell or non-small-cell lung cancers.Lung Cancer Myths/Facts
Learn about lung cancer myths and facts. Explore how cigar smoke, menthol, and pollution can increase your risk of lung cancer and learn what to avoid.Lung Cancer Slideshow
Learn about lung cancer early warning signs, symptoms and treatments. What causes stage IV lung cancer? Get more information on small cell lung cancer, non-small cell lung cancer, and the diagnosis of lung cancer stages.Know Your Lung Cancer Facts Quiz
Lung cancer is the number one cause of cancer deaths in both men and women in the U.S. and worldwide. Get the facts about lung cancer with this quiz.Lung Anatomy
The lungs are primarily responsible for the exchange of oxygen and carbon dioxide between the air we breathe and the blood. Eliminating carbon dioxide from the blood is important, because as it builds up in the blood, headaches, drowsiness, coma, and eventually death may occur. The air we breathe in (inhalation) is warmed, humidified, and cleaned by the nose and the lungs.Lungs Picture
The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). See a picture of the Lungs and learn more about the health topic.Pleural Effusion (Fluid in the Pleural Space)
Pleural effusion is a buildup of fluid in the chest or on the lungs. There are two types of pleural effusion, transudate and exudate. Causes of transudate pleural effusion include congestive heart failure, kidney failure, and cirrhosis. Exudate pleural effusion can be caused by malignancy (cancer) or lung infection. Typically, transudate pleural effusion is more easily treatable. Symptoms of pleural effusion include chest pain, pain when breathing, difficulty breathing, and cough. Treatment depends on the source or cause of the pleural effusion.Pulmonary Embolism (Blood Clot in the Lung)
A pulmonary embolism (PE) occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks the artery and damages the lung. The most common symptoms of a pulmonary embolism are shortness of breath, chest pain, and a rapid heart rate. Causes of pulmonary embolism include prolonged immobilization, certain medications, smoking, cancer, pregnancy, and surgery. Pulmonary embolism can cause death if not treated promptly.Smoker's Lung: Pathology Photo Essay
Smoker's lung photo essay is a collection of pictures and microscopic slides of lung disease caused by cigarette smoking. Smoker's lung refers to the diseases and structural abnormalities in the lung caused by cigarette smoking.What Is a Laryngeal Mask Airway (LMA) Used For?
A laryngeal mask airway (LMA) is a device inserted into the area behind the mouth and nose, connecting them to the food pipe (the pharynx) to allow ventilation, oxygenation, and administration of anesthetic gases, without the need for inserting a tube in the windpipe (endotracheal intubation). It was initially used mainly in an operating room setting, but is also used in the emergency setting. Complications include aspiration of stomach contents, local irritation, upper airway injuries, mild sympathetic response, obstruction, laryngospasm, pulmonary edema, and bronchoconstriction.What Is a Plication of the Diaphragm Procedure?
A surgical plication of the diaphragm treats paralysis or abnormally shaped diaphragm. This condition usually leads to breathing difficulties. Diaphragm paralysis is typically due to damage to the phrenic nerve. Abnormality of the diaphragm may be birth related. Surgical plication to stabilize the diaphragm is needed to prevent the lungs from ballooning outward during expiration (breathing out).