Why use a peak flow meter
One of the uses for a peak flow meter is to measure if your asthma is under control. It measures the ‘openness’ of your upper airways. The small device measures air flowing out of the lungs as you blow into it as fast and as hard as possible.
A peak flow meter can reveal narrowing of the airways well in advance of a potential asthma attack. They are used by those with moderate to severe and persistent asthma.
Peak flow meters can often determine:
- When to seek more medical support
- Effectiveness of asthma management and a treatment plan
- When to stop or take extra medication, as directed by your Doctor
- What triggers the asthma attack such as exercise-induced asthma
With asthma, sometimes you may feel your breathing is okay but when measured with a peak flow meter, your lung function may have decreased.
A peak flow meter can help you determine airway changes and better manage your asthma. A peak flow meter can check healthy individuals quality and health of the upper airways.
You and your Asthma
Often those with asthma need to track asthma at least twice a day and have a plan of action to keep it under control. This leaflet provides detailed information on your Peak Flow Meter and how the Self-Management action plan works.
What is Peak Flow?
Peak Flow is a measurement that tells you how fast you can blow air out of your lungs. Your peak flow measurement will be better when you are well and lower when your airways are narrower.
Peak Flow levels are a guide to the openness of your airways and give an insight of your asthmatic status.
You should measure peak flow as soon as you wake up and in the evening. It may be best to do this before taking your bronchodilator, or as directed by your Doctor.
Although, how you feel and what you can do is important. Peak flow scores show how your breathing is changing. Modern asthma medicines aim to give you the best possible peak flow score. It is also important to aim for stable peak flow. For example, a small change between morning and evening levels and from day to day.
Why do I need to measure my peak flow?
Many people over the age of 5 will benefit by monitoring their asthma with a Peak Flow Meter. This can help to state when and how much to use their reliever medication. It also helps your doctor to see how you’re controlling your asthma or if medications may need to change.
How do I create an Action Plan?
Only a doctor can determine the best action plan that meets your needs. After an initial assessment, a diagnostic phase is undertaken. During this period you will need to record your peak flow levels and have your Action Plan checked against your peak flow scores over several days. Your treatment and action plan may be changed following the diagnostic phase. This procedure may be repeated until your action plan is proven.
What is my Normal Value?
Your “Normal Value” is the best Peak Flow value that you can achieve. This is then your 100% or ‘reference’ value. Often, population normative standards are not clinically useful in ongoing serial monitoring of your asthma.
How to use your Peak Flow Meter
- Stand up (unless your physician advises otherwise)
- Slide the point down to the bottom of the scale at the end where you blow in
- Hold the peak flow meter on its edge in front of you. With the scale away from your hand, inhale in as much as possible and hold your breath, then place the mouthpiece in your mouth creating a seal around the mouthpiece with your lips firmly around it
- Do not bend your neck down
- Exhale fast and as hard as you can for a second or more. Be careful not to block the mouthpiece with your tongue or teeth. A ‘spitting’ action will give falsely high readings
- The subject may experience side effects such as dizziness or fatigue during the test procedure if this occurs, stop the procedure
- Your peak flow level is shown on the scale against the pointer. Note where it is (colour band) then move the slider back to the bottom of the range
- Do this three times using the highest as your guide or best score
- During a diagnostic phase, you must record your highest peak flow reading or colour every morning and evening on a chart for your doctor. If you are not in the green zone most of the time, your management plan must be reviewed
Making sense of your peak flow levels
If you often fall below your usual peak flow, it may be a sign that your asthma is worsening. Similarly, larger differences between morning and evening scores may mean your asthma is getting worse, especially if you also begin waking at night with a cough or wheezing.