Registered Nurses' Association of Ontario

Nursing Best Practice Guidelines

Five Steps for Using a Peak Flow Meter
  1. Move the indicator to the bottom of the numbered scale.
  2. Stand up, or sit upright.
  3. Take a deep breath in, and fill lungs completely.
  4. Place the mouthpiece in mouth and close lips around it.
  5. Blow out as hard and fast as possible in a single blow
  • Write down the value. If coughing occurred, the value is inaccurate. Do not record. Repeat the test.
  • Repeat steps 1 through 5 two more times.
  • Take the highest result of the three, and record.

Finding the Personal Best Peak Flow Number

To identify the child’s personal best peak flow number, have the child take peak flow readings:

  • At least twice a day for 2 to 3 weeks. Document readings to observe trends.
  • Upon awakening and before bed.
  • Prior to and 15 minutes after taking a short-acting inhaled bronchodilator (reliever).