Peak Expiratory Flow Meters

'Peak Expiratory Flow Meters are available in several variations.


The one currently in use by the Respiratory Services department of LSUHSC is:

Respiratory Services should be consulted to provide each asthma patient with a peak flow meter and instruction in its use at the time the diagnosis of asthma is made.

Instructions on use of a peak flow meter:

Expected values of peak expiratory flows based on gender, height, and weight can be found here.

Patients should be reminded to keep a log of peak expiratory flows at home. Review of these readings can provide the physician with important information at clinical visits. Even more importantly, the patient can be educated to take action in managing their asthma based on the peak flow readings.

A patient's best peak expiratory flow is determined by use of the peak flow meter twice daily when the patient's lung function is at its best. From that baseline, the patient's 'zones' are determined.

                                           Green Zone - 80 - 100 % of patient's personal best PEF
                                                Yellow Zone - 50 - 80 % of patient's personal best PEF
                                                 Red Zone - less than 50 % of patient's personal best PEF

Once the patient's zones have been defined, they can be instructed on actions to take for each zone. The patient should be provided with a written record of their action plan. Some examples can be seen here.