Unless you or someone you know has asthma, you have probably never heard of a peak flow meter. A peak flow meter is a small instrument used by people who suffer from asthma to measure their ability to breath out air. It does this by calculating airflow through the bronchi.
The primary use of a peak flow meter is to measure an individual’s maximum ability to exhale, also known as peak expiratory flow rate. In a healthy person who does not suffer from asthma the readings will most often be higher than an asthmatic or someone who has constricted airways.
The height, age and sex of a a person greatly affects the normal value returned from a peak flow meter. Usually peak flow meters output two ranges of measurement that determine the peak expiratory flow rate of an individual. Since adults and teens have larger airways than children, they each need to be monitored using a specific range. Standard range is used for teens and adults while low range is reserved for small children.
While peak flow is being monitored the results should be saved in a peak flow chart. The asthma symptoms as well as the amount and frequency of reliever medication taken should also be noted. The same peak flow meter should also be used to keep consistent results.
Though peak flow meters can be useful for people already diagnosed with asthma, they are not a recommended test to diagnose asthma due to variability and the wide range of normal values of air volume from person to person.