How to use a peak flow meter

Your health care provider may prescribe a peak flow meter to monitor your breathing. A peak flow meter is a simple device that measures air flow. It can be used as a tool to assess the severity of your asthma, to check your response to treatment or to monitor lung function when your asthma symptoms flare up.

The following are steps that you should follow to properly using a peak flow meter:

1. Move the marker on the peak flow meter to the bottom of the scale so that it reads zero or is at base level.
2. Stand up straight.
3. Take a deep breath and fill your lungs all the way.
4. Hold your breath while you place the device in your mouth, and close your lips around the mouthpiece. Do not put your tongue inside the hole.
5. Blow out as hard and as fast as you can for one to two seconds. You want to move the marker as far as you can.
6. Write down the number you receive.
7. Repeat steps one to six for a total of three times. Record the highest of the three numbers — this is your peak flow number.
8. Check to see which peak flow zone your peak flow number is in. Follow the plan developed by you and your health care provider for the appropriate zone. (This information was excerpted from NHLBI Practice Guide).

Determining a 'Personal Best'

Establishing your personal best peak flow reading is a key part of monitoring your asthma. A drop in your personal best peak flow can help you identify problems with your lungs before symptoms appear. Measuring peak flow before and after taking a rescue medication can help you determine the effectiveness of the medication and indicate if additional actions are needed. Your asthma must be under control when you establish your personal best.

To determine your personal best:

• Use the same peak flow meter for each reading.
• Record your reading twice a day for two weeks. Take the reading at approximately the same time each day. The first reading should be taken upon rising in the morning and the second one in the late afternoon.
• At the end of two weeks, review the readings. The highest reading you recorded during that period is your "personal best."
• Work with your provider by using your personal best to determine your green, yellow and red zones in your asthma action plan.
• Personal best values will need to be recalculated as a child grows and when disease status changes.

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