Wednesday, December 9, 2009

Lungsound lexicon

As an RT I've done a lot of bronchodilator breathing treatments on patients just because a doctor, nurse, or fellow RT heard a wheeze and made the suggestion. What many of us fail to realize is that not all that wheezes is bronchospasm.

What follows are the five types of wheezes:

1. Expiratory wheezes: This is a continuous high pitched whistling sound heard only by auscultation. It is caused by an obstruction caused by narrowing of the air passages in the lungs due to bronchospasm, secretions or inflammation. Generally, if the expiratory wheeze is heard throughout the lungfields you have bronchospasm. This is indicitive of bronchospasm, and the main therapy for this is a bronchodilator breathing treatment. Bronchospasm may also be associated with diminished lungsounds, distant wheezes that you have to listen real closely to hear, or no wheeze at all. You can read more by clicking here.

2. Inspiratory Wheezes: This is a continuous high pitched whistling souind heard only by auscultation. It is caused by bronchitis, foreign body obstruction, tumors, and fibrosis. Differential diagnosis can further be made by isolating the location of the wheeze. If it is isolated to one part of the lobe it can be indicitive of foreign body obstruction and tumors.

3. Audible wheeze: It's low pitched noise you hear as soon as you enter the patient's room. It is most commonly associated with upper airway secretions or dehydration. It is often heard radiating throughout the lungfields. Pay close attention. If you auscultate the throat and hear it resonating there, chances are it is an upper airway wheeze. Audible wheezes are also caused by cardiac failure, pulmonary edema and pneumonia (see below).

4. Upper airway wheeze (cardiac wheeze): This is a low pitched noise that might be audible and can usually be heard resonating throughout the lungfields by auscultation. Pay close attention. If you auscultate the throat and hear it loud the chances are you are hearing this type of wheeze. It is usually associated with fluid around the vocal cords and/ or fluid build up in the lungs caused by pneumonia or heart failure (CHF). Increased pressure and fluid in the lungs squeezes the bronchioles from the outside causing the wheeze. It may also be associated with a forced or prolonged expiration that mimics bronchospasm. An X-Ray and labs are best used to differentiate between CHF or pneumonia. It is important to note that this wheeze mimics bronchospasm, yet treatment for it is completely different. It is also important to consider dehydration as a possible diagnosis as well (check the labs for signs of dehydration).

5. Rhonchi: Low pitched continuous sounds that are similar to wheezes, although they really aren't. Sometimes they are referred to as Coarse lungsounds. They actually sound somewhat like snoring. It is not caused by bronchospasm. This lung sound is caused by air trying to get through the partially obstructed, inflammed and thick secretion filling the airways. This is indicitive of COPD, increased or thick secretions, inflammation, bronchospasm, and bronchitis (inflammed airways).

6. Stridor: This is a noise heard only on inspiration. It is not a wheeze but sometimes can be confused for one. It is generally caused by swelling or similar obstruction around the vocal cords, and as air rushes it it can make the harsh vibrating noise. It may also be associated with a harsh barky cough. Common cuases are croup in children and post extubation in adults. Since children with this condition often present appearing as asthmatics, they are often mistakenly treated as such. Quite often you'll hear good air movement in the lungfields (the exception will be an underlying condition such as COPD). Stridor heard on expiration may be indicitive of obstruction in the air passeges of the lungs (lower airway) caused by a forein body such as a coin or a hotdog.

7. Rub: This is a continuous or discontinuous"creaking sound" caused by the inlfammed pleural spaces around the lungs rubbing against oneanother. The main cause of this is pleuritis, pneumothorax (collapsed lung), or pleural effusion (fluid in the lung spaces). They are usually isolated to the infected part of the lung. Otherwise you should hear normal air movement in the lung fields unless the patient has an underlying condition. It is very rare to hear this and takes a trained ear, however you can become a hero if you pick up on it.

8. Fine crackles or dry crackles: This is the sound you hear as the alveolar sacs in the lungs pop open with inspiration. They are usually heard on end inspiration and sound like hair when you rub it together or when you pull velcro apart. The location of these crackles can help with difinitive diagnosis. If it is isolated to one lobe, it can be caused by pneumonia. If it is heard in both bases it can be indicitive of COPD or atelectasis or pulmonary fibrosis. They also do not clear with cough.

9. Coarse or wet crackles: This is crackles that sound wet and usually fill both bases of the lungs and sometimes all the lungfields. They are discontinuous and start at early inspiration and continue through expiration. It can only be heard by auscultation. These crackles are caused due to fluid buildup in the alveolar sacs. Coarse crackles that clear with a cough may be caused by secretions in the lungfields. Coarse crackles that do not clear with cough may be indicitive of bronchiectasis, pneumonia or cardiac failure. If it's caused by pulmonary edema it may also be audible.

(Check out the Crackles Lexicon by clicking here)

10. Rales: (Pronounced Raahls): See coarse or wet crackles above. Rale comes from the French word rale which means rattle. This term is not used much anymore. May be audible.  This term was first used by Rene Laennec when he invented the stethescope and is a retired term generally replaced with coarse crackles.

11. Crepitance: Although not a lung sound, it is something all RTs should be familiar with. It refers to air under the surface of the skin. It sounds like crackling or bubbling sound similar to the noise heard when pulling velcro apart or salt being poured on paper. You may also be able to feel the air bubbles with your fingers. Causes of this are pneumothorax or trachs.

12.  Cardiac Wheeze:  It usually sounds like a coarse wheeze or rhonchi and is generally heard over the upper airways.  It's caused not by bronchospasm but due to increased pulmonary pressures due to heart failure and fluid squeezing the air passages.  It's often confused for a bronchospasm wheeze.

The following articles were used as references for this post:
For further reading, click here
Related links:

3 comments:

Pissed Off Patient said...

This was super helpful for me as a layperson.

Great articles!

M

Rick Frea said...

Thanks.

akay said...

Very informative. Thanks for sharing