Pulmonary Function Tests

One of the most fun things I got to do on this rotation was take my own pulmonary function tests (PFTs). PFTs are a battery of breathing tests commonly ordered to characterize asthma, chronic obstructive pulmonary disease, and other lung abnormalities. At its most complex form, the set-up is the one shown above. There is a "body box" which can be completely sealed so the machine can precisely measure changes in volume and pressure.

You put your mouth on the device shown above which can deliver various combinations of gases and measure pressures, flow, and volume of breathing. We went through basic spirometry as it is taught in medical school; I breathed normally, then inhaled to my maximum and exhaled as quickly and completely as I could. I then did a handful of other maneuvers from inhaling and exhaling as hard as I could against a closed valve (calculating maximum inspiratory and expiratory pressures) to breathing in large volumes as rapidly as I could (to test for diaphragm weakness). I also breathed in a whole bunch of different gases: carbon monoxide to calculate diffusing capacity, methane, and 100% oxygen as two separate methods of calculating total lung capacity. The data generated included graphs like this:

Overall, it was a great way to spend the afternoon. It was highly educational, both in reviewing basic lung physiology, formulas, and relationships, but also in interpreting data. Seeing my own graphs and numbers was far more fascinating and relevant than reading a textbook chapter. But moreover, I found it really important to learn what a patient experiences when we ask him to do pulmonary function tests. It wasn't as easy as I thought it would be, and I'm a healthy person. I can't imagine how hard it must be for someone with lung problems. I think it's educational, fun, and important for providers to undergo some of the tests their patients have to take, and this was a great experience for me to do so.

All three images are shown under GNU Free Documentation license, from Wikipedia.