Pulmonary function testing

Mark:  My doctor is crazy.

Barbara: Why do you say that? I’ve always found him to be great.

Mark: Well he told me it was time to do a pulmonary function test. 

Barbara: Yeah, I’ve done it before. You breathe into a tube for them to find out your breathing capacity.

Mark: Yeah, that’s what he told me. And when I told him that I just did one, he asked me the name of the doctor who did it. I told him it wasn’t a doctor, but the police.

Barbara: The police don’t do pulmonary function tests.

Mark: Yes, they do.  They had me do one when they pulled me over after leaving the bar. And that is the same look the doctor gave me when I told him the same thing.

“So what exactly is a pulmonary function test?  I’ve never had to have one, but I’ve heard some people have to do them for their jobs.”

Pulmonary function tests, also called PFTs, are basically what they sound like; they test the function of your lungs (pulmonary system).  People with weakened lungs, like those with asthma or emphysema, or smokers have to have regular monitoring of their lungs to help the doctors detect changes.  If you have heard of people doing them for jobs, it’s the same concept, except it’s also to help ensure that the person doing the testing is capable of wearing respirators. We see how much air your lungs can expel within one second, and then how much air can be expended until your lungs are almost completely empty. This is compared to norms of the same age, height, weight and ethnicity.

“Why would someone need a pulmonary function test, if they have to wear a respirator?”

Have you ever worn even just a basic face mask for simple jobs at home, or even the paper ones a doctor typically wears in the hospital?  If you have done so, did you notice that it’s just slightly harder to breathe with it on that without it?  Respirators work by filtering the air that passes through the filters, with no other air coming through. The process of filtering makes a slight change in how much air you receive, so you work a bit harder to get all of the air you need.  People with weakened lungs already work harder than people with normal lung function, so to make sure that you have the lung function necessary to wear the device, a PFT would be conducted to make sure that you can handle the lower air volume. If your lungs are already restricted enough to not pass the PFT, your employer cannot take the responsibility of putting you into a respirator. Lack of enough air can cause a heart attack.

“What does a PFT entail?  Are there any special guidelines I have to follow before getting one done?”

The PFT will be completed by a specially trained respiratory therapist or technician in their office.  What the technician will do is ask you a series of questions before you begin the test. Those questions include if you have smoked in the last hour, have you had any recent surgeries, are you being treated for high blood pressure, and if you have anything in your mouth like piercings or dentures.  So there are some things you should avoid before having a PFT; eating a heavy meal (you can eat something, but don’t overstuff yourself), do not smoke or do serious exercising (waking a few blocks is ok, but don’t run 2 miles) for 6 hours before the test, avoid food or drinks that are caffeinated (caffeine can skew the test results), wear loose fitting clothing to allow your body room for that extra deep breath, and take all piercings and gum out of your mouth before the test.  If you have dentures, you can still wear them, but only if they are tight fitting in your mouth.

“Wow! So many requirements for one test.  What if I have medications I have to take?”

You can still take your medications. Just be sure to let the technician know that you are, so they can make sure they don’t interfere with the test results.

“Ok, that’s good to know.  But, I have also heard from my buddy he passed out when he did his.  Is that normal?”

Passing out (fainting) or a feeling of being lightheaded is a slight risk for anyone doing a PFT, but only because you have to inhale and exhale rapidly (think of someone who is hyperventilating). The technician will take precautions to prevent you from falling, especially if you are standing during the test. This is the reason it is recommended to remain seated during the test. If light-headedness occurs, it is up to you to let the technician know.  And if you have had a recent heart attack, heart disease, recent eye, chest, or abdominal surgery (within the last 3 months), or any respiratory infections you have to let the technician know before the test begins, because there are more risks involved with people with those issues. You may be referred to your family doctor for greater support during the test.

“Well that’s good know, at least I now know that I’ll be ok, if I ever have to take one of those tests.“

Yes, a PFT is really an easy test to take. It can also help your doctor monitor you, if you have any lung issues, and can help determine if you are able to wear respirators safely on a job.  If ever find out you have to take a PFT, present any questions to the technician. They will do their best to answer your questions, and try to make you feel as comfortable as possible for the test.