Peak Flow Meters (PDF)
A peak flow meter measures how fast you can blow air out after taking a big breath in. The scores depend on how much effort you put into blowing. It is important to blow as hard as you can.
When you have asthma your airways narrow and you will have a lower score. When you don’t have asthma your airways are open wide and your score will be higher. Always use the same peak flow meter every time as readings may vary between meters.
What should you score?
This will depend on your height, age and sex. When you are well you should use your peak flow meter daily for 1 – 2 weeks to find your ‘personal best’ score. This is then recorded as a guide for you and your doctor.
Who should have a peak flow meter?
If you use asthma medications daily and are over 7 years of age your doctor may advise you to use a peak flow meter.
How do you use a peak flow meter?
1. Stand up
2. Hold the peak flow meter level, so the indicator faces upwards
3. Put the marker on zero or ‘start’
4. Take in as deep a breath as possible
5. Place your lips tightly around the mouthpiece
6. Blow as hard and fast as you can
7. Check your score
8. Repeat steps 1-7 two more times
9. Record your highest score; and
10. Do this every morning and night before you take your medication for 1 – 2 weeks.
Your doctor may also ask you to record your peak flow meter scores before and after your reliever medication (blue/grey) inhaler, e.g., Airomir, Asmol, Bricanyl, Epaq or Ventolin.
Why use a peak flow meter?
A peak flow meter tells you if your airways are wide open or narrowed. This information can be used with your personal written asthma action plan.
When should you use a peak flow meter?
You should use a peak flow meter to monitor your asthma when:
1. You leave hospital
2. You need to take your ‘reliever’ medication more often
3. You are getting a cold or you don’t feel as well as usual
4. You have been near a known ‘trigger’
5. Your medication is changed or new medication is commenced
6. You are visiting your doctor for an asthma check-up
7. You are waking at night with asthma symptoms (a sign of poorly controlled asthma); and
8. Ask your doctor for a written personal asthma action plan. Your Asthma Action Plan and Peak Flow Meter scores will help you know when to increase or decrease your medication.
How to look after your peak flow meter
Wash your peak flow meter mouthpiece in warm, soapy water after use. Leave it to drip dry. Do not take the peak flow meter apart.
For advice about monitoring your asthma with a peak flow meter, see your doctor.