You know that feeling… maybe you’re just walking up a flight of stairs, something you’ve done a thousand times. But lately, you find yourself huffing and puffing more than usual. Or perhaps there’s this nagging cough that just won’t seem to go away. It’s moments like these, when something just feels a bit off with your breathing, that we doctors start thinking about getting a closer look at how well your lungs are doing their job. And one of the best ways we have to do that is with something called a Pulmonary Function Test, or PFT for short. It sounds a bit technical, I know, but it’s really just a series of breathing tests.
So, What Exactly is a Pulmonary Function Test?
Think of Pulmonary Function Tests (PFTs) as a check-up for your lungs. They help us understand how well your lungs are taking in air, moving it, and then getting oxygen into your blood. They’re safe, and we don’t need to put any instruments inside your body, which is what we call “noninvasive.” Some folks also call them lung function tests.
There are a few different kinds of PFTs, each telling us something specific:
- Spirometry: This is the one we do most often. It measures how much air you can breathe in and out, and how fast you can blow it out. It also gives us a good idea of the total amount of air your lungs can hold.
- Lung Volumes (or Body Plethysmography): This one sounds a bit like a mouthful! It measures the different amounts of air in your lungs at various points – like after a normal breath in, or after you’ve breathed out completely.
- Gas Diffusion Study: This test looks at how well gases, especially oxygen, pass from your lungs into your bloodstream.
- Cardiopulmonary Exercise Test (CPET): This test sees how your heart, lungs, and muscles work together when you’re exercising, like on a treadmill.
When Might We Suggest a PFT?
I might suggest a PFT if you’ve been experiencing things like:
- A feeling of tightness, pain, or pressure in your chest.
- A persistent cough, especially if you’re bringing up mucus.
- Trouble breathing deeply or catching your breath (what we call dyspnea).
- Wheezing, which is that whistling sound when you breathe.
Sometimes, even if you feel perfectly fine, we might do a PFT as part of a regular check-up, especially if you smoke or are going to have surgery. These tests are super helpful for us to:
- See if the airways in your lungs are narrowed.
- Catch early changes in how well your lungs are working.
- Understand if things in your environment, like dust or chemicals, might be affecting your lungs.
- Figure out if certain medications could help you breathe easier.
- Diagnose conditions like asthma, chronic obstructive pulmonary disease (COPD), or pulmonary fibrosis (scarring in the lungs).
- Check for issues like weakness in your breathing muscles or a narrowing of your windpipe (trachea).
Usually, a specially trained respiratory therapist, someone who’s an expert in lung health and breathing treatments, will be the one to guide you through the tests.
Getting Ready for Your PFT: What to Expect
The good news is, preparing for a PFT is pretty straightforward.
Before Your Test
We’ll give you specific instructions, but generally, we might ask you to:
- Hold off on taking certain breathing medications for a little while before the test. Don’t worry, we’ll tell you exactly which ones and for how long.
- Wear loose, comfy clothes. Nothing that will squeeze your chest.
- Avoid any really strenuous exercise right before.
- Steer clear of smoking for a bit before the test.
- It’s also a good idea not to eat a big, heavy meal right before, and maybe skip that coffee or tea.
These little steps help us get the most accurate results.
On the Day of Your Test
When you come in, we’ll first note down a few things like your height, weight, age, and a couple of other details. This helps us compare your results to what’s typical for someone like you.
Then, the respiratory therapist will take you to a room with the PFT equipment. It usually involves a clear, airtight box (for one of the tests), some soft clips for your nose, a mouthpiece, and a small electronic machine called a spirometer that measures your airflow.
Here’s a little peek at what happens during the common tests:
- Spirometry: You’ll have soft clips on your nose (so all your breathing is through your mouth). You’ll then seal your lips around a mouthpiece connected to the spirometer. The therapist will guide you – you might breathe normally, take some deep breaths, or blow out as hard and fast as you can. It’s all about following their instructions.
- Body Plethysmography: For this one, you’ll sit inside that clear, phone-booth-like box. The door will be closed for about five minutes. If you ever feel a bit anxious in small spaces (claustrophobic), please let the therapist know! They can help you feel more comfortable. You’ll breathe into the mouthpiece, and as you do, the machine measures tiny pressure changes in the box to figure out your lung volumes.
- Gas Diffusion Study: Again, nose clips and the mouthpiece. You’ll breathe in a tiny, perfectly safe amount of a gas called carbon monoxide. When you breathe out, the machine measures how much of it comes back out. This tells us how much your lungs absorbed, which shows how well gases are transferring to your blood.
- Cardiopulmonary Exercise Test (CPET): If you’re having this one, we’ll hook you up to monitors for your heartbeat, blood pressure, and oxygen levels. Then, you’ll walk on a treadmill or ride a stationary bike while the machines keep track of how your body is responding.
How Long Does It Take? And Does It Hurt?
Most PFTs take about 15 to 45 minutes. If you feel tired or need a breather (pun intended!), just let the therapist know. You can definitely take breaks.
And no, the tests themselves aren’t painful. Sometimes, all that deep breathing can make you feel a bit dizzy, lightheaded, or tired. You might even cough a bit from blowing into the mouthpiece. These feelings usually pass very quickly once the test is over.
After Your Test and Understanding Your Results
Once you’re done, you can usually go back to your normal activities and restart any medications we asked you to pause. If you felt a bit woozy during the test, the therapist will make sure you’re feeling okay before you head home.
There are some very small risks, like with any procedure. Rarely, all that effort in breathing could, in theory, cause a collapsed lung (we call this a pneumothorax), but this is extremely uncommon. The tests can also make your heart rate go up a bit, so if you’ve had a recent heart attack or have other heart concerns, please make sure we know beforehand.
Your results will be compared to what’s considered typical for your age, height, and other factors. There’s no “failing” a PFT. If your results are outside the usual range, it just means we need to talk more about what might be going on and figure out the next steps for your care. We usually get the results back within a few days, and we’ll be in touch to discuss them with you.
Key Things to Remember About Your Pulmonary Function Test
- PFTs are safe, non-invasive breathing tests that check how well your lungs are working.
- They help us diagnose conditions like asthma or COPD and see if treatments are helping.
- Preparation is simple: usually involves avoiding some meds, heavy meals, and smoking before the test.
- The tests aren’t painful, though you might feel a bit lightheaded or tired from the breathing maneuvers.
- Your results from a Pulmonary Function Test help us understand your lung health better and plan the best care for you.
We’ll always discuss all the options and results with you. The goal is to help you breathe easier and feel your best. You’re not alone in this, and we’re here to help figure things out.
