Are you ready to learn about breath sounds? I sure hope so because that is what this study guide is all about.

As a Respiratory Therapist (or student), it goes without saying that you must fully know and understand auscultation and listening to lungs sounds. The good news is — we created this study guide to help you do just that.

So if you’re ready, let’s go ahead and dive right in!

What are Breath Sounds?

Breath sounds are the noises that come from your lungs when you inhale and exhale. Any abnormality in breath sounds indicates a problem in the lungs such as:
  • Accumulation of fluid
  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Foreign body in the lungs or airways
  • Heart failure
  • Infection
  • Inflammation of the airways
  • Obstruction
  • Pneumonia

By listening to the quality, duration, and intensity of breath sounds, healthcare providers can come up with a proper diagnosis and medical management.

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What is Auscultation?

Auscultation is a simple, non-invasive procedure that involves the use of a stethoscope to listen to the sounds produced by the body. For the sake of this guide, we’re focusing specifically on the lungs.

This device amplifies the sounds within the lungs so that the healthcare provider can have an idea of what’s going on inside.

When performing lung auscultation, the bell or diaphragm of the stethoscope is placed on the patient’s chest and/or back. Both sides can be compared with one another. Also, the sounds within each lung should be compared as well.

Types of Breath Sounds:

As a medical professional, you have to be able to differentiate the difference between all the different types of breath sounds. 

Here are the lung sounds that you should be familiar with:

1. Vesicular (Normal)

Vesicular or normal breath sounds are usually soft and low-pitched and are heard during auscultation of the chest and lung surface of a healthy person. The sound has a rustling quality during inspiration. This is generated by turbulent airflow within the lobes of the lungs.

During expiration, the sound becomes softer as air flows within the larger airways. The inhalation process is normally 2-3 times the length of the exhalation process.

2. Crackles (Rales)

Crackles, also known as rales, are short, explosive, nonmusical sounds. They are heard in lung fields that have fluid in the small airways. Crackles can occur on both inspiration and expiration but are more common during the inspiratory phase.

There are two types of crackles:

  • Fine crackles
  • Coarse crackles

The difference between the two is that fine crackles have a higher frequency and a shorter duration and are caused by a sudden opening of a narrowed or closed airway. The sound of fine crackles can be compared to that of salt heated on a frying pan.

Coarse crackles, on the other hand, are louder, lower in pitch and last longer. They are caused by secretions in the airways. The sound of coarse crackles is like pouring water out of a bottle.

Crackles are often associated with lung inflammation or infection. If they do not clear after a cough, this may indicate fluid in the alveoli, acute respiratory distress syndrome, or pulmonary fibrosis.

3. Wheezes

Wheezes are defined as continuous tones that commonly occur at the end of the inspiratory phase or early expiratory phase as a result of the gradual opening or closing of a collapsed airway.

Wheezes are either high-pitched or low-pitched. They sound like a whistle when you breathe and are most audible during the expiratory phase. Wheezing is usually caused by bronchoconstriction but can also occur when the patient is fluid overloaded as well. 

Aside from narrowed airways, wheezes can also be caused by inflammation secondary to asthma and bronchitis.

4. Rhonchi

Rhonchi means that there is secretions in the large airways. As a Respiratory Therapist, when you hear rhonchi, you should recommend bronchial hygiene therapy or suctioning.

These lung sounds are often low-pitched and are audible during the expiratory phase. The main difference between rhonchi and wheezes is that rhonchi sounds are low and dull while wheezes are high and squeaky.

Rhonchi is mainly caused by either the accumulation of secretions, lesions, or foreign bodies. Rhonchi is common in certain medical conditions such as pneumonia, chronic bronchitis, and cystic fibrosis.

5. Stridor

Stridor, also known as “noisy breathing”, is a high-pitched sound caused by an upper airway obstruction. This sound is commonly heard during the inspiratory phase but can also be present during the expiratory phase.

If heard during inhalation, the airway obstruction is typically at the level of the vocal cords or just below the windpipe. If heard during exhalation, the airway obstruction might be in the lower trachea or the bronchi.

Several medical conditions can cause stridor including vocal cord abnormality, narrowing of the larynx (voice box), abnormal growth of blood vessels, lesions, infection, and foreign bodies. When heard in adults, it’s usually caused by post-extubation laryngeal edema.

6. Pleural friction rub

A pleural friction rub is a loud grating sound that is usually heard over the lower lung lobes when inflamed pleura rub together. It is heard in patients with pleurisy. 

Because these sounds occur whenever the chest wall moves, they are generally heard throughout inhalation and exhalation. This lung sound is almost always associated with inflammation of serous membrane lining in the thorax known as pleurae.

What are Vesicular Breath Sounds?

Vesicular breath sounds are another name for normal breath sounds. They are low-pitched and sounds like you would expect air to sound as it flows through an airway. 

The sounds are usually soft and can be heard throughout the inspiratory and expiratory phase.

What are Adventitious Breath Sounds?

Adventitious breath sounds are abnormal sounds that occur over the lungs and airways. The term “adventitious” breath sounds describe the additional audible lung sounds during auscultation.

This includes abnormal lung sounds such as crackles (rales), wheezes, rhonchi, stridor, and pleural friction rubs — just as I mentioned earlier in this guide. 

Adventitious breath sounds are commonly associated with a wide array of heart and lung conditions. The type, duration, location, and intensity of each adventitious breath sounds can help the healthcare provider determine the root cause of the medical condition.

Causes of Abnormal Breath Sounds:

There are several causes of abnormal breath sounds. Each of which is specific to the type of breath sound the patient is experiencing:

  • Air moving through narrowed airways due to swelling or obstruction causes wheezes.
  • Airway obstruction due to the accumulation of mucus secretions, lesions, or foreign bodies causes rhonchi.
  • Fluid accumulation in the small airways or atelectasis (lung collapse) causes crackles.
  • Obstruction of the upper airway causes stridor.
  • Rubbing of inflamed pleural surfaces against each other during respiration causes pleural friction rub.

There are hundreds of causes of abnormal breath sounds — these are just a few of the common examples that you should be familiar with. 

Treatment for Abnormal Breath Sounds

Abnormal breath sounds are often associated with common and treatable medical conditions. As a Respiratory Therapist or medical professional, you will be required to recommend the proper medication or treatment for each abnormal breath sound. 

Here are the common treatment strategies for abnormal breath sounds:

1. Metered-Dose Inhaler (MDI)

This is a pressurized inhaler that delivers a bronchodilator (dilates the airways), corticosteroid (suppresses inflammation), or a combination of both.

By opening the airways and suppressing the inflammatory process, it can help restore breath sounds to normal.

2. Nebulizer

This delivers an aerosolized form of medication into the alveoli via inhalation. They are commonly used to deliver bronchodilator medications, like albuterol, which can alleviate bronchoconstriction. 

Nebulizers can help deliver other medications as well which can treat other types of abnormal breath sounds.

3. Incentive spirometry

This is a simple, inexpensive, and effective tool that is useful in helping a patient achieve normal lung function. This device mimics natural sighing or yawning, which in turn improves lung expansion and gas exchange.

To use the device, the patient needs to place the mouthpiece spirometer in their mouth and do deep breathing exercises.

4. Chest physiotherapy (CPT)

This is also considered a simple and effective method of normalizing abnormal breath sounds. CPT includes various techniques in order to naturally clear lung secretions through the use of vibration or shaking, proper positioning, breathing exercises, and coughing techniques.

5. Antibiotics

Antibiotic therapy is designed to fight infection and destroy microorganisms that affect lung function. By fighting the infection, antibiotics also help with airway inflammation and secretions which can improve abnormal breath sounds.

What are Bronchial Breath Sounds?

Bronchial breath sounds are tubular, hollow sounds that occur as a result of an abnormal increase in the transmission of airway sounds to the chest surface. The sound is very similar to the sound produced by blowing through a hollow tube.

These sounds are normal when heard over the trachea, but abnormal when heard over the lungs.

Let’s break down a practice question about bronchial breath sounds:

Example TMC Practice Question:

A 63-year-old male patient was recently admitted to the ICU. While auscultating the lungs, you hear bronchial breath sounds over the right lower lobe. This would indicate which of the following?

A. The patient has normal lungs
B. Pneumothorax in the right lung
C. Pleural effusion in the patient’s right lower lobe
D. Consolidation in the patient’s right lower lobe

Bronchial breath sounds are normal when heard over the trachea. However, if you hear bronchial breath sounds over the lung periphery, this is an abnormal finding.

To get this one right, you had to know that bronchial breath sounds are sometimes heard in patients with pneumonia. And for the TMC Exam, you must remember that patient with pneumonia have consolidation.

A pneumothorax or pleural effusion are not identified by bronchial breath sounds, so we can rule those out immediately.

So by using what we know about breath sounds, as well as the process of elimination, you can easily determine that the correct answer has to be D. 

The correct answer is: D. Consolidation in the patient’s right lower lobe

This practice question was taken straight from our TMC Test Bank. It’s one of our bestselling packages where we break down hundreds of these practice questions that cover every topic you need to know for the TMC Exam.

Each question comes with a detailed rationale that explains exactly why the answer is correct.

So if you thought this was helpful, definitely consider checking it out. Click Here to learn more. 

What are Bronchovesicular Breath Sounds?

Bronchovesicular breath sounds are normal sounds that are heard in the mid-chest area or over the scapula. Unlike other normal breath sounds, bronchovesicular breath sounds have tubular quality.

These sounds are the combination of bronchial breath sounds heard near the trachea and vesicular sound in the alveoli.

Bronchovesicular breath sounds have equal periods of inhalation and exhalation, so the I:E ratio is 1:1. However, the differences in pitch and intensity are often audible during the expiratory phase.

What are Diminished Breath Sounds?

Diminished breath sounds are soft, distant lung sounds with a lower intensity. These sounds are normally heard in patients with decreased lung volumes.

They can be heard in patients with a life-threatening obstructive condition, but they’re also heard in other types of patients as well.

Here are some example of when breaths sounds may be diminished:

  • Obese patients
  • Patients with increased muscle mass
  • Patients air or fluid around the lungs
  • Patients with an increased chest wall thickness
  • Patients with lung hyperinflation

During diminished breath sounds, the inspiratory phase is usually much longer than the expiratory phase. This means that patient with diminished breath sounds will have an I:E ratio of 3:1.

When are Coarse Breath Sounds Heard?

Coarse breath sounds are actually a type of crackles/rales. These sounds are clicking, bubbling, or rattling sounds that occur during the inspiratory process when air opens closed spaces in the lungs. Coarse breath sounds are louder, low-pitched and have longer duration.

Most patients with copious amounts of secretions exhibit coarse breath sounds during auscultation of the affected lung area.  

When are Pneumonia Breath Sounds Heard?

Pneumonia is a respiratory infection caused by harmful microorganisms and is characterized by a productive cough. Patients with pneumonia often have greenish or yellowish secretions.

If a patient has pneumonia, you will likely hear crackling, bubbling, or rumbling sounds. Wheezing is also a possibility is some areas of the lungs as well.

Crackles in patients with pneumonia are often heard only on one side of the chest or when the patient is lying down. In addition to crackles and wheezes, low-pitch rhonchi sounds may also be audible during the expiratory phase of breathing.

What are Stridor Breath Sounds?

Stridor is a high-pitched lung sound that is created by an airway obstruction. It is mostly audible during inhalation but can also be heard during exhalation in patients with a deteriorating condition.

These sounds commonly occur in extubated patients as a complication of endotracheal intubation. In children, stridor is very audible when lying on the back in the supine position.

Common causes of stridor are croup, pertussis, aspiration, epiglottis, choking, severe anaphylactic shock, tonsillitis, laryngitis, lung cancer, deviated septum, and blood transfusion reactions.

How to Perform Auscultation?

Auscultation is used to examine the heart and lungs but can also be used in the abdomen and other areas of the body with major blood vessels. But for the sake of this article, we’re focusing strictly on the lungs.

In order to assess a patient’s breath sounds, auscultation must be performed using a stethoscope to hear the lung sounds. Let’s go through the process of auscultating a patient.

Here are the Steps for Performing an Auscultation:

1. Explain the procedure to the patient to establish trust and rapport.
2. Stand close to the patient to gain access to the target area. In this case, the lungs.
3. If the diaphragm is cold, warm it by rubbing the surface to avoid startling the patient.
4. Place the eartips of the stethoscope in your ears and adjust them as desired.
5. Hold the diaphragm firmly against the patient’s skin with enough pressure and have the patient take slow, deep breaths through an open mouth.
6. Listen to the sounds and try to identify their intensity, location, strength, pattern, and duration.
7. Always listen to the patient’s anterior side first. Start at the apices and then move downward to the lung bases. Then proceed to do the same on the posterior side.
8. Compare the right lung to the left lung. Also compare the anterior to the posterior side.
9. Document the findings in the patient’s chart.

What is the Best Stethoscope for Auscultation?

In order to perform auscultation and listen to breath sounds the right way, you need the right stethoscope. Here’s our favorite:

When it comes to getting great value at an affordable price, this stethoscope is the best.

As an affiliate, we receive compensation if you purchase through this link.

While the 3M Littmann Classic III is our favorite, there are plenty of other high-quality stethoscopes as well. Visit this link to see our Full List of Best Stethoscopes.

Now that you have a good understanding of breath sounds and auscultation, let’s take it a step further by going through some practice questions on this topic.

Practice Questions about Breath Sounds for Respiratory Therapy Students:

1. What are fine crackles?
They are high-pitched, discrete, discontinuous crackling sounds heard during the end of respiration; not cleared by a cough.

2. What are medium crackles?
They are lower, moist sounds that are heard during the mid-stage of inspiration; not cleared by a cough.

3. What is rhonchi?
It’s a loud, low, coarse breath sound that sounds like a snore and is most often heard continuously during inspiration or expiration. Coughing may clear this sound and it usually means that there is a mucus accumulation in the trachea or large bronchi.

4. What are coarse crackles?
They are loud, bubbly noises heard during inspiration. They are not cleared by a cough

5. What are wheezes?
They make a musical noise that sounds like a squeak. They are most often heard continuously during inspiration or expiration but are usually louder during expiration.

6. What is a pleural friction rub?
It is a dry, rubbing, or grating sound, usually caused by inflammation of the pleural surfaces. This sound can be heard during inspiration and expiration. It is usually the loudest over the lower lateral anterior surface.

7. What is stridor?
It’s a harsh or high-pitched respiratory sound that is caused by an obstruction of the upper airway.

8. What are vesicular breath sounds?
These are normal breath sounds. They are heard over most lung fields. They are low pitch, soft, and usually have short expirations. They are more prominent in thin people or child and can be diminished in the overweight or very muscular patients.

9. What are bronchovesicular breath sounds?
They are heard over the main bronchus area and over the upper right posterior lung field. They have a medium pitch and the expiration usually equals the inspiration phase.

10. What are bronchial breath sounds?
They are heard only over the trachea in healthy patients. They have a high pitch with loud and long expirations. The expiratory phase is sometimes a bit longer than the inspiratory phase.

11. What is auscultation?
It is the process of listening to sounds of the body with the aid of a stethoscope. As Respiratory Therapists, we are particularly focuses on the lungs.

12. Where are bronchovesicular breath sounds heard?
They are heard around the sternum or center of the chest.

13. What breath sound is common with a pleural effusion?
Decreased or absent breath sounds.

14. What do fine crackles sound like?
The make a popping sounds and are higher pitched.

15. What do coarse crackles sound like?
Bubbling/rumbling, discontinuous, not as sharp as fine crackles.

16. What should be noted when listening to crackles?
The location of the sound, duration, pitch, and when the sound occurs (inspiration or expiration).

17. What is the mechanical cause of crackles?
The small airways opening during inspiration and collapsing during expiration. They can also occur when air bubbles go through secretions or incompletely closed airways during expiration.

18. What does a wheeze sound like?
It is a continuous, high pitched, hissing sound. Wheezes tend to be longer than crackles and they occur on expiration.

19. What does rhonchi sound like?
It has a much lower pitch than a wheeze. It tends to be longer than crackles.

20. What does rhonchi normally imply?
It implies that a larger airway is obstructed by secretions.

21. What makes stridor sound different than others sounds?
It can usually be heard without a stethoscope.

22. If stridor does exist, what does it mean?
It usually means that there is a medical emergency that requires immediate attention.

23. What does a pleural rub sound like?
Brushing, similar to coarse crackles. In this case, the patient will likely be in pain, and be able to localize it to where the sound can be heard.

24. What is the mechanical main cause of a pleural rub?
The pleural surfaces are inflamed or roughened and are rubbing each other which is why the sound can be heard.

25. How should a patient be positioned before auscultation?
They should preferably be sitting up. Ensure they are not leaning against anything.

26. What are the normal breath sounds?
Tracheal, Vesicular, Bronchial, and Bronchovesicular.

27. Breath sounds can be classified into what three categories?
Normal, Abnormal, and Adventitious.

28. What are bronchovesicular breath sounds?
They are heard over the main bronchus area and upper right posterior lung fields. They are intermediate in intensity and pitch. The expiration phase is usually equal to the inspiration phase. They are normally heard in the 1st and 2nd intercostal spaces.

29. What are vesicular breath sounds?
Vesicular breath sounds are soft and low pitched lung sounds. They consist of a quiet, wispy inspiratory phase followed by a short, almost silent expiratory phase. They are heard over most of the lung fields. They are more prominent in children and thin adults.

30. What are the abnormal breath sounds?
Rales, Crackles, Rhonchi, Wheezes, and Absent.

31. What are the adventitious (abnormal) breath sounds?
Crackles, Rales, Rhonchi, Wheezes, and Pleural friction rub.

32. What is the sequence of steps in the examination of the chest and lungs?
Inspection, Palpation, Percussion, then Auscultation.

33. What is the difference in medium crackles and coarse crackles?
Medium crackles are lower, more moist, and are heard during the mid-stage of inspiration. They are not cleared with a cough. Coarse crackles are loud, bubbly noises heard during inspiration. Also, they are not cleared with a cough.

Final Thoughts

So there you have it. That wraps up our massive study guide on breath sounds and auscultation. I hope that this information was helpful for you.

Again, knowing the ins and outs of breath sounds is (obviously) very important for Respiratory Therapists and students. Hopefully this guide can help you increase your knowledge of this topic.

Thank you so much for reading and as always, breathe easy my friend. 


The following are the sources that were used while doing research for this article:

  • —. Workbook for Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020. [Link]
  • Faarc, Heuer Al PhD Mba Rrt Rpft. Wilkins’ Clinical Assessment in Respiratory Care. 8th ed., Mosby, 2017 [Link].
  • Rrt, Des Terry Jardins MEd, and Burton George Md Facp Fccp Faarc. Clinical Manifestations and Assessment of Respiratory Disease. 8th ed., Mosby, 2019 [Link].
  • Zimmerman, Barret. “Lung Sounds – StatPearls – NCBI Bookshelf.” NCBI Bookshelf, 27 Sept. 2019,
  • “Wheezes, Crackles and Rhonchi: Simplifying Description of Lung Sounds Increases the Agreement on Their Classification: A Study of 12 Physicians’ Classification of Lung Sounds from Video Recordings.” PubMed Central (PMC), 22 June 2020,

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