IER Placement: Respirology

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As part of the McMaster Physician Assistant Education Program curriculum, each student shadows a professional in the field relevant to the unit being studied that month. These are called IER placements and students are assigned a half-day shift at a hospital in Hamilton. IER stands for Interviewing, Examining and Reasoning.

For this IER Placement:

  • Medical Foundation Unit: Respirology
  • Professional Shadowed: Respiratory Therapists (RT)
  • Date of Placement: Wed. Oct 8, 2014
  • Where: McMaster University Medical Centre

Read more about what I observed in my placement!

During my placement, I was able to observe three tests, briefly explained below. WARNING: I may not be good at explaining these tests…the following paragraphs are somewhat overwhelming to read but I will try my best to explain the tests I observed and what they test for.

1) Spirometry (or Pulmonary Function Test)

Spirometry is a simple breathing test to access how well you breath. You take a big breath in and then blow as hard, as fast and as long as you can into the spirometer. The machine measures how much air you can blow out from your lungs and how fast you can blow it out.

This test takes into account the person’s age, sex, and height to give a predicted baseline. This is because these are all factors that determine the size of a person’s lungs are (eg. Males have larger lungs than females). For example, I am a 22 year old female, 160 cm tall. The computer will give predicted values of what my results should be. How well I do on the test will be determined by comparing my measured values to the predicted value.

The set up is pretty much like the photo I attached here. You got the nose clip on the nose so that air is only entering and exiting through the mouth. The spirometer will measure the amount of air inspired and expired. The monitor will generate a “Flow Volume Loop” which is useful in seeing what conditions the person has.

People with normal breathing should have a loop like the one on the left. The loop on the right is suggestive of obstruction in airways, such as in Chronic Obstruction Pulmonary Disease (COPD). COPD is most common in people who smoke.

Kids are so cute when they do the test. The RT will be cheering on the side, encouraging them to blow out as fast and long as they can! They do multiple trials (at least 3) and they must all be around the same values (reproducible) in order for the results to be valid and acceptable.

My Own Spirometry Test

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At the end of my shift, I asked if I could do a Spirometry test just to know how it feels and they said YES! It was difficult for me when I had to exhale as long as I could so that all the air in my small airways were cleared. They want wanted me to force as much air out as I can. If it was hard on a person who has normal breathing, imagine having the test done on someone who has breathing difficulties.

Click to see my spirometry results! Clearly, I didn’t reach the predicted value for my Forced Vital Capacity (how much air I should be able to take in)…I only did 94% of predicted!

2) Methacholine Challenge

FEV 1= Forced Expiratory Volume = The amount of air forcefully blown out in the first second

If you ever wonder if you have asthma, this is the test doctors will get you to do. A 16 year old female patient came in with a referral for this test. The doctor wanted to know if her symptoms were attributable to asthma. The procedure was as follows:

  1. Do a flow-volume loop (to establish a baseline)…see “Spirometry” above
  2. Breathe in aerosol saline for 2 min –> Do a flow-volume loop (To see how irritated airway is by something neutral like saline)
  3. Breathe in lowest concentration of methacholine for 2 min (a bronchoconstrictor – it constricts airways) –> Do a flow-volume loop
  4. Repeat with increased doses of methacholine and do flow-volume loops until the FEV1 drops down to below 80% of predicted
  5. Administer Ventolin (a bronchodilator – dilates airways), wait 10 mins before doing a flow-volume loop (to see if FEV1 goes back to baseline)
    • If FEV1 returns to baseline after Ventolin administration, this person definitely has asthma!

Note that for healthy airways, our FEV1 should not drop under 80% at any given point in time. For the girl I was with, her FEV1 dropped down 14% with the saline solution (Step 2). It dropped another 10% with the lowest concentration of methacholine (0.125 mg/ml). In total, her FEV1 dropped down 24%, bringing her below the 80% of predicted FEV1. We stopped the test and gave her Ventolin (Step 5). After 10 mins, we had her do another flow-volume loop and her FEV1 was back at 100% of predicted. The RT said she definitely has asthma and it is severe asthma because her airway was constricted so much after such a small amount of methacholine!

3) Exercise Stress Test

It is difficult for me to explain this one because I am still unsure of all the components the test is looking for. The patient I saw was referred for an exercise stress test because she was having episodic chest pains. The exercise test puts the patient on a bike to put stress on the heart. She was hooked onto many things: ECG electrodes, spirometer mask, an oximeter, and a blood pressure cuff. The patient was instructed to pedal the bike, all the while having all these things monitored. The test stopped when she felt like she maxed herself out or if her vitals are unstable.

I got to see the results but I was not sure what the values or ECG interpretations meant. The RT told me not to worry because the Respirologist and Cardiologist (respectively) interprets it.

Overall Experience

My overall experience was great because I was able to observe the different tests done in the unit and the RTs were happy to explain everything to me. For example, without asking, they explained how a test was done, why it was done and what the results were suggesting.

Thank you for reading! This is my first time writing about my IER placement experience. Let me know in the comments below if anything I wrote down confused you or if there is anything I should add to my next IER placement experience post!

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