Lung Sounds:
There are several lung sounds we need to be aware of as paramedics, all of which indicate potential pathologies that are occurring with our patients. Being able to discern between healthy lungs and those of a patient with, for example, CHF, or COPD is a key skill in this profession.
So what are we listening for?
Well, what we are hoping to hear are “happy lungs”, that is: clear air entry from the apices to the bases. What we don't want to hear are ADVENTITIOUS lung sounds. These indicate lungs that are not effectively participating in ventilation. These sounds include:
Wheezes
Rales
Rhochi
Stridor
Wheezes: These are “musical” sounds, high pitched, heard during expiration. They indicate bronchoconstriction. Narrowing of the lower airways, due to obstructive lung disease (Asthma, or COPD), or inflammatory causes such as anaphylaxis.
Rales: These are course “crackles” usually heard at the end of inspiration. The sound is best compared to rubbing hair together next to your ear. They indicate fluid in the alveoli. The most common cause is left sided heart failure due to CHF or SCAPE.
Rhonchi: These are “wet” course crackles usually heard in patient's with pneumonia. They tend to be localized to an area of consolidation. They are usually louder than the clear breath sounds entering unaffected areas of the lung.
Stridor: This is an upper airway sound that indicates constriction of the mainstem bronchi or the trachea itself. It presents as a high pitched wheeze that is audible without having to auscultate. Common causes are croup, upper airway burns, anaphylaxis, or severe asthma.
Another sound we want to be aware of is NOTHING. A silent chest indicates massive bronchoconstriction and is usually heard in patients with severe asthma or anaphylaxis. It occurs just before respiratory arrest.
Know what to listen for and you will be able to narrow your differential fairly quickly, BUT be aware that in some patients (such as the COPD exacerbation patients), you may here more than one type of sound. Use patient presentation to gain an overall picture of the problem before you jump to a specific protocol.
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