Peak expiratory flow is the measurement of the maximum airflow you exhale as you expel air from your lungs.
It is useful for screening and monitoring people with asthma, as the clinical signs are sometimes insufficient to assess the reduction in the caliber of the bronchi.
The measurement is carried out to determine the severity of asthma and define a treatment, monitor the evolution of asthma, evaluate the effectiveness of the treatment and adjust it in order to better control the disease,- assess the severity of a crisis and sometimes prevent its occurrence.
The values given are valid for ages between 6 and 15 years, the measurements not being reliable below 6 years. The values are however very variable according to the individuals.
In the event of an asthma attack, the severity is assessed based on the predicted percentage of PEFR.