What is a peak flow meter?
A peak flow meter is a device that measures how well air is moving in your child’s lungs. Using a peak flow meter can help you monitor your child’s asthma.
Measuring peak flow regularly can help you do the following things:
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tell if your child is having difficulty with their asthma
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see if your child’s medicines are working well
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see if your child is getting better after an asthma episode
To measure peak flow, your child breathes in and then blows as hard and as quickly as she can into the meter. This gives a reading that you can compare with your child’s normal ( baseline) reading or with the normal range for your child’s height. Many peak flow meters are colour-coded or come with a chart so that you can easily compare the readings.
The peak flow meter is very dependent on your child's effort. To use a peak flow meter effectively, your child must be old enough to follow instructions and to make a consistent effort even when she is sick. Your child should also understand that her peak flow readings are an important part of monitoring asthma control, especially if she does not always notice her asthma symptoms.
What peak flow readings mean
Ask your child's doctor what peak flow readings are normal for your child. Peak flow is predicted based on average readings for your child’s height. So normal peak flow will change as your child grows.
These are the three colour-coded areas on a peak flow meter:
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Green means “go.” Congratulations! Your child’s asthma is well controlled. Follow the regular asthma medicine plan.
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Yellow means “caution.” Your child’s asthma may be getting worse. Your child needs to add controller and/or reliever medicine.
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Red means “stop.” Your child needs to see a doctor right away. Go to the closest emergency department and give your child extra reliever medicines every 10 minutes.
Your child’s doctor will give you specific instructions for each reading on your child’s asthma action plan.
When to use the peak flow meter
Your child’s doctor will explain when to use the peak flow meter. These are some times to use the peak flow meter:
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before and after giving reliever medicine
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when an asthma episode happens
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one or two times a day, every day, to keep track of how well your child’s controller medicine is working
How to use the peak flow meter
There are different brands of peak flow meter, and each one is a bit different. Read and follow the instructions for your meter.
Here are some general instructions:
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Attach the mouthpiece to the peak flow meter, if there is one.
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Put the marker at the bottom of the scale. |
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Hold the peak flow meter upright. Do not block the opening with your fingers.
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Ask your child to stand up and breathe in as deeply as he can. Your child should put the mouthpiece into his mouth and close his lips tightly around the mouthpiece. |
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Ask your child to blow out as hard and as fast as he can. The marker will move up the scale to the number that is the peak flow measurement.
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Write down the measurement. Put the marker back down to the bottom of the scale.
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Do steps 3 through 6 again.
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In your child’s asthma diary, write down the date, the time, and the higher of the 2 measurements. |
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Cleaning the peak flow meter
If your child’s meter has a separate mouthpiece, you should clean it once a week. Wash it with warm water and let it air dry thoroughly.