What is Spirometry?
Spirometry is the most accurate breathing test for asthma and many other lung conditions. It is a safe, simple and painless test using a machine called a spirometer. The spirometer measures how much air you can breathe in and out of your lungs, and how fast and hard you can breathe out.
Why am I having this test?
Spirometry is an important part of your doctor’s assessment of your lung condition.
It helps your doctor to:
- diagnose your condition
- identify how severe your condition is
- decide which treatment to trial first
- measure improvements or changes in your condition.
Is there any risk to having spirometry?
Spirometry is a very low risk test.
When you are blowing out as hard and fast as you can, for as long as you can, you increase the pressure in your eyes, head, chest and abdomen.
It is normal to feel breathless, dizzy and some people cough when doing the test. These feelings pass very quickly. We do the testing at your pace between blasts, making sure you have time to recover before we continue.
It is not safe for us to perform spirometry if you have:
- had any surgery in the last six weeks to your eye, chest or abdomen;
- unstable heart conditions, including unstable high blood pressure;
- blood nose, or blood-stained phlegm;
- blood clots in your lungs;
- infectious diseases such as TB or influenza;
- recent rib fracture.
Spirometry can be done safely once you have recovered from these conditions.
What do I need to do before a spirometry test?
Bring any medicines you are using with you, including inhalers and spacers.
Wear loose comfortable clothing to the test so that you can take a deep breath
Some medications can change the results of the test.
- 24 hours before the test - don't take daily inhalers.
- 12 hours before the test - don't take twice daily inhalers.
If you need to use your blue puffer, Asmol or Ventolin, 4 hours before the test, the test will need to be rescheduled. If you are having asthma symptoms before the test, you must take your blue puffer.
Do not delay treating your symptoms just to take the test.
- 4 hours before the test - don't drink alcohol
- 2 hours before the test - don't eat a large meal
- 1 hour before the test - don't smoke
- 30 minutes before the test - don't do any heavy exercise.
What happens in a spirometry test?
The test is done sitting down. If we are doing spirometry on your child who can’t touch the floor when sitting on the chair, we will need them to stand.
You will be asked to do up to eight blasts into the spirometer. A blast is where you take a deep breath in, put the spirometer tube into your mouth, and blow out as hard and fast as you can until you feel like your lungs are empty. It is important each blast has the most amount of effort you can give. Some people can find this difficult, but we are there to help coach you.
We need at least three good blasts.
Once we have three blasts which show similar results we will give you 4 puffs of salbutamol. Salbutamol is the medicine in the blue puffer, also known as Ventolin or Asmol. This is a very safe medicine.
After 20 minutes we will repeat the blasting. This will help your doctor see if the medication effected your lungs, and if so, how much.
What happens after the spirometry test?
There are no side effects from spirometry. After the test is completed you will be fine to drive home.
We will send your results through to your doctor within 24 to 48 hours. Your doctor will discuss with you what your test results mean and what type of treatment they recommend, or further investigations needed.
From what age can spirometry to done?
Chrildren from 6 years of age can attempt spirometry. Doing the test with children can be tricky. They often need intense coaching and most likely will need to repeat blasting up to 8 times to get the 3 good blasts. This can be tiring. They also need to stay focused and motivated to continue with testing after waiting for the salbutamol to work. Even some adults can struggle with this.
If we can not get 3 blasts which show similar results it is important we don’t give these results to the doctor. If we give inconsistent test results to doctors they may misdiagnose or they may make the wrong decision about treatment options.
If we do not get consistent results with spirometry your doctor will receive a report to let them know. Often repeating the test in a couple of months is more successful. The children are more familiar with the procedure, our asthma educators and our office environment.