A preschooler using a peak flow meter, a time when most kids are too young to do correctly.
A Preschooler Using a Peak Flow Meter
(c) 2007 Vincent Iannelli, MD licensed to About.com, Inc.
Although some preschoolers can use a peak flow meter correctly, this is usually a time when you need to use a symptom based asthma management plan to understand how well your child's asthma is being controlled.
You can try using a peak flow meter under the guidance of your pediatrician though, and with some practice, you might get accurate readings and begin to use peak flows in your child's asthma management.