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So there are four main normal lung sounds. What’s important to know here is that each area of the lung should sound a certain way. If it doesn’t, we know there’s a problem. Tracheal lung sounds, as you would assume, are heard over the trachea. They’re harsh and hollow, like blowing through a big pipe, which is exactly what the trachea is. Then you have bronchial breath sounds. These are heard over the bronchi, so you’d hear them right at the top of the sternum below the clavicle. They’re high-pitched, loud, and also sound hollow. Then you have bronchovesicular - these are heard over the smaller bronchioles and can be heard along the sternum in the center of the chest, as well as between the shoulder blades on the back. They’re lower pitched, but still hollow sounding. Then you have vesicular - these are heard everywhere else in the majority of your lung fields, anteriorly, posteriorly, and laterally. They’re a low-pitched blowing or rustling noise. You should be able to hear them all the way into the bases when the patient takes a deep breath.
So, what does it mean when we hear something different, or nothing at all? We’re gonna cover the 4 main breath sounds you’ll encounter, as well as talk about why they might be absent. First is crackles. Crackles are a fine popping noise that is caused by fluid in the alveoli. So when your little alveoli get filled with fluid, they tend to stick and when the patient breathes deep that pressure pops them open - that’s the noise you’re hearing. If you take a section of hair and rub it between your fingers next to your ear, you can hear what this should sound like. If you have short hair, find a friend with hair you can borrow - just be sure to give it back. Rhonchi are a harsh gurgling noise that are indicative of fluid or sputum in the air passages. Think about the sound of sputum in the back of your throat - it’s that *** sound. It’s liquid being pushed around in the airways by the air. Now rhonchi and crackles get confused sometimes, so just remember crackles are fluid in the alveoli so it’s a smaller, finer sound, rhonchi is fluid in the airway so it’s more harsh sounding. One thing to note here is that the lungs are like a sponge. If you fill a sponge with water, then hold it vertically - where does the water go? It goes down, right? So if the patient has fluid in their lungs, you are more likely to hear it in a dependent area. So if they’re sitting up it would be at the bases and if they’re bedridden and supine, it would be posterior. So it’s SO important that you actually listen to all lung fields, otherwise you might miss it.
Wheezing happens when the small airways in the lungs are narrowed. When we talk about Asthma or COPD we’ll discuss what makes them narrow. Think about blowing through a large milkshake straw versus a small soda straw - the pressure increases in the smaller straw. The same thing happens in the airways and we hear a whistling sound. This could be either on inspiration or expiration. Now, stridor is also caused by narrowing airways, but this time it’s the large airways like the trachea or bronchi. It’s usually heard on inspiration and it’s a loud, high-pitched almost musical sound, like this ***. This is a medical emergency - their air passages are closing up and they need intervention!
If you don’t hear any breath sounds at all, even when the patient takes a super deep breath, this might indicate there’s fluid or air around the lungs or a mass that’s preventing the lung from expanding. Remember it’s moving air that we are hearing, so if the air isn’t moving, we’ll hear nothing. When we look at hemo and pneumothorax we’ll talk about this more.
So remember there are 4 normal sounds, tracheal, bronchial, bronchovesicular, and vesicular, and they all have a place. Hearing bronchial sounds where you should hear vesicular might mean there’s fluid buildup there. Remember that absent or adventitious or abnormal lung sounds indicate some some sort of disease process that needs to be addressed. And remember to listen in ALL lung fields to make sure you don’t miss any abnormal sounds.
Keep these sounds in mind as we talk through disease processes - try to picture in your mind what the patient looks like and what you might hear! Now, go out and be your best self today! And, as always, happy nursing!
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