Pulmonary function tests
Pulmonary function tests are a group of tests for measuring the effectiveness of your lungs. This includes how well the individual is able to breathe and the effectiveness of the lungs to bring oxygen to the other parts of the body. It’s a noninvasive procedure, which means the doctor doesn’t need to cut you or put any tools inside your body.
Purpose
Testing your lungs can help your doctor to diagnose several lung diseases, which can include any of the following:
- Asthma
- Chronic Bronchitis
- Lung Cancer
- Allergies
- Chronic Obstructive Pulmonary Disease
- Damaged of Scarred Lung Tissue
- Saccoidosis, a collection of inflammatory cells around the body’s organs
- Infections
- Thickening or hardening of the connective tissues
- Thickened stretched or enlarged airways
- Weakness in the muscles in the walls of the chest
Preparation
If you’re on medications that open your airways, such as the ones used for chronic bronchitis or asthma, your doctor might ask you to stop taking them before your test. The results of the test can also be affected by pain medications, so you should discuss in detail with your doctor about the medications you need to avoid.
Before your testing, you need to consume a large meal. A full stomach helps in preventing your lungs from inhaling fully. However, keep in mind that you should avoid any kind of food or drink that contains caffeine, which includes coffee, tea and chocolate. Caffeine can lead your airways to become more open which might affect the test results. Also remember to avoid smoking at least one hour before your test, as well as any kind of strenuous exercise.
Make sure that you are wearing loose-fitting when you go for the test, as tighter clothing can restrict your breathing. Also, avoid wearing any kind of jewelry which can affect your breathing. If you wear dentures, you should wear them to the test in order to ensure that your mouth fits tightly around the mouthpiece used for the test.
If you have had abdominal surgery or any eye or chest test recently, you may need to delay the test until full recovery.
Procedures
Spirometry
Spirometry is considered the most common pulmonary function test. It can measure how much air you can breathe in as well as out. It also measures how fast you can empty the air out of your lungs. During this test, you will be breathing as much air as you can, and then you will quickly blow it out as much as possible, through a tube that will be connected to a machine known as a spirometer.
Body plethysmography
This is another test in which you can measure how much air is in your lungs when you are inhaling. In this test, you will need to breathe deeply and this will measure how much air is in the lungs after inhalation. It will also check how much air stays inside after you exhale as much as you can. This test is painless and requires only around 15 minutes.
Plethysmography is used for several reasons. Your doctor might order this test so that they can see how COPD or asthma affects your lungs. The test may also show if your treatment needs to be changed. This test can also help to confirm if you have a restrictive disease, which is a type of lung disease that reduces the space in your lungs.
This test can also show you if your airways have narrowed. Therefore, your doctor will be able to decide whether you need lung medications. The test can also help your doctor understand if you would be able to do well if you require surgery.
Bronchial Provocation Test
If you have asthma, you will know that there are various triggers such as exercise, dust or smoke which can suddenly make it hard for you to breathe. A bronchial provocation test will help in diagnosing asthma and how severe the condition is.
During the test, you will be inhaling a medication which narrows down your airways. After this, you take a Spirometry test. This continues several times. This will help your doctor know much your airways narrow down when you are having an asthma attack.
Lung diffusion capacity
Arterial Blood Gas Test
Pulse Oximetry Test
Cardiopulmonary exercise stress test
Fractional exhaled nitric oxide test
Risks
Though pulmonary function tests are considered safe, there are few small risks like dizziness, coughing, shortness of breath or an asthma attack.
If you had recent eye surgery or any surgery on your belly or chest, your doctor will not be recommending this test. He/she will also not recommend it if you are having chest pain, a recent heart attack or certain heart conditions. They are also likely not to recommend it if you have a bulging blood vessel in your belly, chest, brain, active tuberculosis or respiratory infection.