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,
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:
- Place the mouthpiece on the peak flow meter. (Some
meters have different sizes of mouthpieces for younger
and older children.)
- Place the indicator at the bottom of the scale close to
- Hold the peak flow meter upright, being careful that
fingers do not block the opening.
- Inhale as deeply as possible. Place the mouth firmly
around the mouthpiece beyond the teeth, making a tight
seal with the lips.
- Blow out as hard and fast as possible.
- 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.
- 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.