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Clinical Reference Systems: Pediatric Advisor 10.0

Peak Flow Meter: How to Monitor Asthma

What is the purpose of the peak flow meter?

The peak flow meter measures how fast air can be exhaled in one breath. Measuring the peak flow regularly can help predict early signs of an acute asthma episode and how well medications are working.

When should the peak flow meter be used?

Ideally, measure the peak flow before and after each bronchodilator treatment and when an acute asthma episode occurs. Record the measurements in a daily log to help your doctor know how well medications are working.

What is normal peak flow?

A peak flow is generally considered normal when it is within 20% of the peak flow predicted for your child's age, sex, and size.

How is the peak flow meter used?

Each brand of peak flow meter works a little differently. Carefully read the instructions included with your meter.

General instructions are:

  1. Place the mouthpiece on the peak flow meter. (Some meters have different sizes of mouthpieces for younger and older children.)

  2. Place the indicator at the bottom of the scale close to the mouthpiece.

  3. Hold the peak flow meter upright, being careful that fingers do not block the opening.

  4. Inhale as deeply as possible. Place the mouth firmly around the mouthpiece beyond the teeth, making a tight seal with the lips.

  5. Blow out as hard and fast as possible.

  6. The marker will move and indicate the peak flow measurement. Note the measurement, return the marker to the base of the scale, and repeat steps 3 through 5.

  7. Write down the date, time, and higher of the two measurements in the log.

When and how should the peak flow meter be cleaned?

Once a week clean the mouthpiece of the meter with warm water and dry it thoroughly.

Written by the Asthma Task Force at The Children's Hospital, Denver.
Copyright 1999 Clinical Reference Systems