Wednesday, February 04, 2009

An Artificial Asthma Attack

Over the last couple of weeks, I've been getting increasingly short of breath while walking. Now granted, I'm not currently in nearly as good of shape as I was before med school, but I'm still in good enough shape that I should be able to walk a mile without getting short of breath!

So I went to the doctor, and I ended up getting some lab work, a chest x-ray, an echo, an albuterol inhaler, and an appointment for lung function tests. These tests measure how much air you can inhale and exhale by having you breathe a full breath of air in and out of a machine with your nose pinched shut. The machine measures the speed and amount of air you're moving.

Today was the day that I took the lung function tests. One of these tests is called a methacholine challenge, and its purpose is to see if the patient has asthma. How, you may ask, is the test performed? Well, the patient inhales a drug (methacholine) in periodically increasing amounts. After each dose, they have to keep inhaling and exhaling air into the machine to measure their lung function. Meanwhile, the tech administering the test watches to see if the patient's airways close up enough to diagnose them with asthma.

When I tried it, the first few doses weren't that bad. By the fourth dose, my chest was starting to feel a little tight. The fifth dose was absolute agony. The woman giving me the test asked if I thought I could still hang on long enough to inhale and exhale into the machine. I felt like I was seeing stars a little, but I nodded and did what I could. She then gave me albuterol, which is a medication that opens the patient's airways again. If they have asthma, this should lead to a recovery of lung function to the level it was at before starting the methacholine challenge.

Inhaling that albuterol helped me tremendously. It also made my heart start pounding (side effect), but being able to move air in and out of my lungs freely was more than worth a few palpitations. When the entire test was over, the tech showed me the graph of my lung function test, which was textbook beautiful for asthma.

Now that I've been officially diagnosed with asthma, I have to start using an inhaled steroid and taking a pill, both for prophylaxis. In other words, these medications won't stop an asthma attack that is already taking place, but they will prevent future attacks. I'll still have the albuterol inhaler to use in case I have more attacks.

The most indelible impression that this test made on me is that I will never order a methacholine challenge for a patient unless I think it's absolutely necessary. Feeling like you can't breathe is extremely unpleasant.

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