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Firstly, before we look at how to use this piece of equipment, we must first understand what is Peak Flow?

The Peak Flow is defined as “The maximum volume of air that can be expelled from the lungs during a vigorous exhalation. Its measurement is used to determine the degree of respiratory impairment in patients with obstructive lung diseases.” 

Further information: here

Now that we understand what Peak flow is, we can now look at what is a peak flow meter?

A peak flow meter looks like this and quite simply assesses how quickly a person can blow air out of their lungs. It is a vital assessment to make when trying to diagnose or monitor respiratory conditions such as Asthma. Gathering information such as this enables a clinician to identify whether an airway is narrowed, as we would expect to see in an asthmatic patient for example.

How to measure your peak flow using a peak flow meter:

Before you begin ensuring that your patient is in a comfortable position, either sitting or standing and reset your peak flow meter so the pointer is pushed back to the first line of the scale.

  • Hold the peak flow meter so it is horizontal and make sure that your fingers are not obstructing the measurement scale
  • Take a deep breath and place your lips tightly around the mouthpiece (ensure the patient has a good seal around the mouth piece)
  • Blow out as hard and quickly as you can into the meter
  • When finished breathing out, make a note of your reading (This should be repeated 3 times, and the highest of the 3 measurements should be recorded as your peak flow score.)

What does the meter reading mean?

Once you have a figure recorded using the above technique this can be recorded as Peak Expiratory Flow (PEF) this is the amount of air breathed out p/min. The reading will vary depending on various factors such as your age, gender, height etc. If your airways are tight and inflamed, you won’t be able to blow out so quickly and your score will be low. If you manage to blow out quickly and forcefully you should get a high score. This tells you that your airways are open and working well.

You may be asked to record the PEF in a diary that will look something like this:

Further information: here

PEF should be checked regularly, and all findings recorded. If your findings drop much lower than normal – ACT on it!!

What are the benefits of measuring your PEF?

If you suffer from a respiratory condition, then you may find that completing a daily PEF is a positive thing. You can monitor your condition; you will be able to identify any improvements and prepare for deterioration with an early warning of when your airways are compromised. All of this will be great information to feedback to your asthma nurse or GP at your regular review or post attack.

Written by Nina Preston (Trainer Engagement Officer), Friday 19th July 2019

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