What To Expect During Lung Function Tests
Breathing Tests
Spirometry tests may be done in your doctor's office
or in a special lung function lab. Your doctor may ask you to use a peak flow
meter in the office and suggest that you also do the test at home. The lung
volume measurement and lung diffusion capacity tests are done in a special lab
or clinic.
For the lung volume measurement and lung diffusion
capacity tests, you sit in a chair next to a machine that measures your
breathing. For spirometry, you sit or stand next to the machine.
Before the tests, a technician places soft clips on
your nose. This allows you to breathe only through a tube that's attached to
the testing machine. The technician will tell you how to breathe into the tube.
For example, you may be asked to breathe normally, slowly, or rapidly.
The deep breathing done in some of the tests may
make you feel short of breath, dizzy, or lightheaded, or it may make you cough.
Spirometry
In this test, you take a deep breath and then exhale
as fast and as hard as you can into the tube. With spirometry, your doctor may
give you a medicine that helps open your airways. Your doctor will want to see
whether it changes or improves the test results.
Peak Flow Meter
In this test, you take a deep breath and then exhale
as fast and as hard as you can into a small, hand-held device that's connected
to a mouthpiece.
Lung Volume Measurement
For this test, you sit in a clear glass booth and
breathe through the tube attached to the testing machine. The changes in
pressure inside the booth are measured to show how much air you can breathe
into your lungs.
Sometimes you breathe in nitrogen or helium gas and
then breathe it out. The gas that you exhale is then measured.
Lung Diffusion Capacity
During this test, you breathe in gas through the
tube, hold your breath for 10 seconds, and then rapidly blow it
out. The gas contains a small amount of carbon monoxide, which won't harm you.
Tests To Measure Oxygen Level
Pulse oximetry is done in a doctor's office or
hospital. Arterial blood gas tests are done in a lab or hospital.
Pulse Oximetry
During this test, a small light is placed over your
fingertip, earlobe, or toe using a clip or flexible tape. It's then attached to
a cable that leads to a small machine called an oximeter. The oximeter shows
the amount of oxygen in your blood. This test is painless and no needles are
used.
Arterial Blood Gas
During this test, your doctor or technician inserts
a small needle into an artery, usually in your wrist, and takes a sample of
blood. You may feel some discomfort when the needle is inserted. The oxygen
level of the blood sample is then checked in a lab.
After the needle is removed, you may feel mild
pressure or throbbing at the needle site. Applying pressure to the area for 5
to 10 minutes should stop the bleeding. You will be given a small bandage to
place on the area. |