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

Your test will be chosen by your doctors based on what they need to find out. It is also important to note that each test works differently.

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

A lung diffusion capacity test helps in measuring how well oxygen can move into your blood from the lungs. This test has some similarities with Spirometry. You will be breathing into a tube that will be attached to a machine. This test will help in diagnosing the disease of the blood vessels between the heart and the lungs. It can also show if there has been any damage done by a disease such as emphysema.

Arterial Blood Gas Test

This test can measure the levels of gases like oxygen and carbon dioxide in your blood which is taken from one of your arteries. You need to go to the hospital after which a nurse or technician will take your blood using a needle from the wrist. It might hurt a little and you might bleed a bit where the needle went in.

Pulse Oximetry Test

This painless test can measure how much oxygen is in your blood. The doctor will clip a probe to your finger, your earlobe as well as another part of your skin. The device uses light for measuring the level of oxygen available in your red blood cells.

Cardiopulmonary exercise stress test

The purpose of this test is to measure lung and heart strength. It’s usually for people who might be having heart disease or lung problems. Sometimes, these conditions show up only while exercising. During this test, you will walk on a treadmill or will ride a stationary bicycle. The doctor keeps will be keeping an eye on your heart rate as your heart starts to beat faster and faster. You’ll breathe into a tube that will be monitoring your lungs as they work harder.

Fractional exhaled nitric oxide test

When you have certain kinds of asthma, you might be having high levels of nitric oxide in your body. The fractional exhaled nitric oxide test can measure how much of it is in the air you exhale. For this test, you are required to breathe out slowly and steadily into a tube that will be connected to a portable device.

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.

Pulmonary Function Tests