Peak Flow Meters for Children

An asthma peak flow meter is a tool that measures how fast air moves out of your child's lungs. When asthma symptoms worsen, the airways tighten and become more narrow. The peak flow meter can show if your child's airways are getting more narrow. This is why it is important for your child to use a peak flow meter as directed by his or her doctor so you can monitor your child's status.

An asthma peak flow meter may help you:

Learn what makes your child's asthma worse

Decide when to seek emergency care

Decide if your child's asthma symptoms have been brought under control

General guidelines for using a peak flow meter:

Move the marker to 0 or to the lowest point/position on the scale.

Have your child stand up. If she can't stand, be sure she is sitting up straight, and make sure she is in the same position each time she tests.

Have your child take in as deep a breath as possible.

Put the mouthpiece of the peak flow meter in the child's mouth between the teeth, and have your child close the lips tightly around it. Be sure the tongue does not block the opening.

Have your child blow into the mouthpiece once, as hard and as fast as possible, as if blowing out candles on a birthday cake. Remember, it is the speed of the blow that is being measured.

Take the peak flow meter out of the child's mouth and look at the marker. It will have moved along the numbered scale. Write this number down. Then move the marker back to 0 or to the lowest point/position on the scale.

Repeat the test 2 more times.

Record the highest of the 3 readings.

Based on the Asthma Action Plan developed by your child's doctor, you can use the peak flow readings to help tell what asthma zone your child is in: green (asthma is under control), yellow (caution), or red (danger—get help from a healthcare professional). If you keep track of what zone your child is in, you can tell when her asthma is getting out of control so you can do something about it.