A phase that drives fear into most medical students hearts. As they stand trying to figure out the difference between fineinspiratory crackles, wheeze, coarse crackles, reduced air entry. And then blurt out something that sounds kind of right?
But this shouldn’t have to be the case.
Examination stations are a gift as you can practice exactly what you are going to get in the exam!
We are going to run through everything you need to know to snatch top marks in your respiratory examination stations by focusing on auscultation sounds.
In reality there are only a number of stations that can come up in your OSCEs and we are going to cover them all.
We are going to assume that you know how to do a respiratory examination and we’ll just focus on the exciting bits.
Here’s what we are going to cover:
Main types of sound
In your exams you are going to be expected to know if lung sounds are normal or pathological.
Normal chest sounds are low in volume and a heard during inspiration. During expiration you should nearly be able to hear any sound.
Geeky bit: Inspiratory component is created in the lobar and segmental airways. The expiratory component is created from proximal airways.
Here are some examples of normal chest sounds (remember there is variation between individuals):
Listen to this a few times, so you have a baseline for what a ‘normal’ chest sounds like!
Main types of sounds
You’ve probably noticed doctors like to make simple things confusing. When it comes to chest sounds it’s pretty simple.
Chest auscultation sounds are divided into two broad categories: Continuous (wheezes) and Discontinuous sounds (crackles)
You are able to hear these differences because of the: frequency, duration ect. But we are going to show you what these sound like and not bore you with the physics of generation of sounds.
Discontinuous Fine crackles = fine, high pitched, low aptitude, short duration
I know this tutorial is about auscultation sounds, but we might as well throw in some Respiratory OSCEs tips whilst you’re here.
If I can give one piece of advice it’s this.
Use all the clues in the room to help you.
In COPD patients you will see on observation: ‘barrel shaped chest’, shortness of breath, pursed lips breathing, inhalers on the side table and coughing
Please remember COPD is NOT a cause of clubbing!
When you listen to the chest breath sounds can be diminished and expiration is prolonged.
You might be able to hear coarse crackles at the beginning of inspiration (most of the time you can also hear this during expiration). These have a “popping” quality and should be heard over the whole chest.
Your patient may have a degree of mucus plugging, if they cough, the crackle might disappear, so don’t be alarmed by this in your exam (or in hospital) if you get different findings to other people.
Geeky bit: coarse crackles are caused by gas moving through an intermittently obstructed airway
These coarse crackles are caused by the movement of boluses of gas through an intermittently occluded airway.
Here are some examples of patients with COPD:
Interstitial pulmonary fibrosis (IPF)
Patients with interstitial pulmonary fibrosis are really common during OSCEs, they are relatively stable patients and have consistent signs. There are lots of professional patients, who come to exams with this condition, so make sure you understand the auscultation.
Remember Interstitial Pulmonary Fibrosis IS a cause of clubbing!
You should hear bilateral fine crackles during middle to late inspiration
Some people describe this as “treading through snow”, “velcro” or “rubbing hair together”. Think which one it sounds like most to you – for me its the snow one. And just think of what when you are listening.
Geeky bit: fine crackles are created when a collapsed alveoli is opened when breathing in