The purpose of a peak flow meter
The amount of air you can blow out changes depending on how healthy your lungs are. Peak flow meters measure how fast you can blow air from your lungs.
Your peak flow score shows how well your lungs are working at a particular time.
Peak flow meters give you a reading or "score" (peak expiratory flow rate, also called PEFR or PEF). If you have an asthma flare-up, you will not be able to blow out as much air as usual. This will make your peak flow score go down.
Using your peak flow meter
To use a peak flow meter, follow the instructions on the package. In general, these are the steps you can follow:
- Stand up or sit up with a straight back.
- Make sure the indicator is at zero.
- Take a deep breath, seal your lips around the mouthpiece, and blow as hard and as fast as you can into the peak flow meter.
- Write down the reading (your score).
- Set the marker back to zero. Take your peak flow reading two more times. Write down your readings (your score).
- Each time you test your peak flow, do three blows. The best of the three scores is your actual score. That's the score you should write down and show the doctor.
- Check with your asthma action plan to see if you need to make any adjustments to your daily care.
You can buy a peak flow meter at your drugstore.
Ask your doctor, certified respiratory educator or pharmacist to show you how to use your peak flow meter and to explain what your peak flow scores mean.
Use the same peak flow meter consistently — different peak flow meters might take different readings.
How to clean your peak flow meter
Dirt and dust can get trapped in your peak flow meter, which can change the readings. That is why it's important to clean it regularly.
Follow the manufacturer’s instructions to clean your peak flow meter. In general, you should wash your peak flow meter in warm, soapy water. Rinse it gently in clear water, then let it air dry.
If you have a virus (cold, flu, etc), wash your peak flow meter after every use.
Make sure your peak flow meter is completely dry before using it.
Why peak flow scores are important
Your peak flow score shows how your lungs are working at a particular time. They also can help you keep track of how your lungs are doing over time.
Taking your peak flow regularly can help you notice changes in your airflow, and can help you catch asthma flare-ups before they get out of control. Using your peak flow scores, you can check your asthma action plan to see if you need to make any adjustments to your daily care.
Doctors often ask people to take peak flow readings every day and to write down their scores. You can use an asthma diary card to record your readings. These scores can help you and your doctor see if your asthma symptoms are getting better or worse.