What is a peak flow meter?

The readings on a peak flow meter tell you how open your airways are, so you can manage your asthma¹.

What is a peak flow meter?

A peak flow meter is an inexpensive, portable, handheld device for people with asthma that is used to measure how well air moves out of your lungs. Measuring your peak flow using this meter is an important part of managing your asthma symptoms and preventing an asthma attack and should form part of your personal asthma action plan².

Why should I measure my breath strength?
Peak flow is a measure of how fast you can blow air out of your lungs when you exhale forcefully after inhaling fully. This measure is called a "peak expiratory flow" or "PEF." Keeping track of your PEF, is one way you can know if your asthma is in control or worsening¹. Then, in conjunction with your prescribed asthma treatment plan, you can take appropriate action to bring your asthma back under control.

Monitoring asthma
If your asthma isn’t affecting you, you will have airways that are open, so you’re able to blow air out of your lungs quickly, which will give you a high peak flow reading. However, if asthma is not controlled, the airways will narrow and you will not be able to blow air out so fast, which will give you a lower peak flow reading.

How is it measured²?
Peak flow is measured using a small handheld device called a peak flow meter. The scale is in units of litres per minute (lpm). When you blow into the mouthpiece the small marker will move depending on how fast you are blowing. Where the marker ends up is your peak flow reading. The highest reading from three attempts should be recorded as your personal best peak flow reading.

Your healthcare professional will set the colour zone indicators based on you or your child’s personal best peak expiratory flow rate (the best peak flow measurement achievable when asthma is under control). The peak flow measurement will fall into one of three zones, as shown below.

How is my personal best peak flow number determined?³

The "personal best" peak expiratory flow (PEF) is the highest peak flow number you or your child can achieve over a two to three week period when asthma is under good control. Good control means you feel good and do not have any asthma symptoms.

Your personal best PEF is important because it is the number to which all of your other peak flow readings will be compared. Your asthma action plan, developed along with your healthcare professional, is based on this number.

You should always use the same peak flow meter and write your readings in your peak flow chart. Then, continue to take peak flow readings each morning. Daily readings will help you to recognise early drops in airflow and changes with asthma control.

To find your personal best peak flow number, take peak flow readings:

Twice a day for two to three weeks when asthma is in good control

At the same time in the morning and in the early evening

As instructed by your healthcare professional

Get a Philips PersonalBest peak flow chart (133.0KB)

Learn about a personal asthma action plan

How often should I check my peak flow?

Peak flow values are best if they are checked at the same time each day, preferably once in the morning and again at night³. Ask your healthcare professional how often you should check your peak flow.

How to read a Philips PersonalBest peak flow meter

Three-zone traffic light system

Green zone

If the reading is above the green mark then your regular medication plan for use of controller medication should be followed

Yellow zone

If the reading is between the yellow markers, the asthma might be worsening. Follow your asthma action plan for instructions on how to use your reliever medication to get back into a green zone

Red zone

If the reading is below the red mark, then you should seek medical advice immediately.

How to buy a PersonalBest peak flow meter

Philips PersonalBest peak flow meter
Lightweight, self-contained and portable, PersonalBest puts peak flow monitoring at your fingertips whenever you need it.

Using and caring for a Philips PersonalBest peak flow meter

1. Remove the top cover

Step 3 of using and caring for a Philips PersonalBest peak flow meter

2. Fold the hinged bottom cover down and click the halves together so that they form a handle

Step 4 of using and caring for a Philips PersonalBest peak flow meter

3. Slide the red indicator to the bottom of the scale

Step 5 of using and caring for a Philips PersonalBest peak flow meter

4. Stand up and breathe in as deeply as you can. Place your mouth around the mouthpiece to form a tight seal. Blow as hard and as fast as you can

5. The number where the indicator stops is your peak flow measurement. Repeat from step 3 and take 3 measurements

Step 6 of using and caring for a Philips PersonalBest peak flow meter

6. Record the highest measurement in your daily record chart, noting the time and the date

How to use a peak flow meter

How to use a Philips PersonalBest peak flow meter - for children (2.24MB)

Record your peak flow readings on a Philips PersonalBest peak flow chart (133.0KB)

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Frequently asked questions

What are the asthma controller (preventer) medications and how do they work?
What are the asthma controller (preventer) medications and how do they work?

Controller medications may also be called preventers. These are medications that are prescribed by your healthcare professional to take daily to control the inflammation (swelling) in your lungs and to prevent asthma attacks. There are several different types of controller medications but the most common are inhaled corticosteroids (steroids) or combination inhaled steroid and long-acting bronchodilators. Long-acting bronchodilators are not prescribed alone for asthma but may be prescribed with an inhaled steroid. This is a medication to keep airways open over a long period of time. Controller medications and combination controller medications should not be used to relieve symptoms during an asthma attack.

References:

asthma.org.uk Advice/inhalers-medicines-treatments. Accessed October 2017
What are the asthma reliever (rescue) medications and how do they work?
What are the asthma reliever (rescue) medications and how do they work?

Reliever medications are short-acting bronchodilators. They may also be called rescue medications. These are medications that act very quickly to relax the muscles surrounding tightened airways and relieve asthma symptoms.

References:

asthma.org.uk Advice/inhalers-medicines-treatments. Accessed October 2017
Are you worried that your child's controller medication is not helping?
Are you worried that your child's controller medication is not helping?

Controller medications work differently than reliever medications and must be taken even when symptoms may not be present. The controller medications reduce inflammation but they take time to start working. Your child may need to take them for several days or weeks before you and your child notice an improvement. Your child will not feel that immediate relief that they may feel after taking a reliever medication. Instead they will know that they are working because over time, they will have fewer symptoms and they will need to use their reliever medication less.

References:

asthma.org.uk Advice/inhalers-medicines-treatments/inhalers-and-spacers/preventer. Accessed October 2017.
What will happen if my child doesn't take their controller medication?
What will happen if my child doesn't take their controller medication?

If the inflammation in asthma is not controlled, it will be difficult to manage your child's asthma symptoms. Also over time the inflammation may permanently damage your child's airways.

References:

webmd.com Asthma/features/preventing-permanent-damage#1. Accessed October 2017
What are the possible side effects of inhaled steroids?
What are the possible side effects of inhaled steroids?
If your child uses their inhaler correctly, they are less likely to have side effects. This is because more of the inhaled medicine goes down to the lung where it’s needed. If your child uses inhaled steroids, which is a type of contoller medication, some of the side effects that may occur due to poor inhaler technique include:

a sore tongue

a sore throat

a mouth infection called thrush

These side effects could easily be prevented by rinsing their mouth after inhaling the medication and using a spacer or valved holding chamber when using a metered dose inhaler (MDI).

References:

asthma.org.uk Advice/inhalers-medicines-treatments. Accessed October 2017.
Can I stop giving my child controller medication if she/he shows no asthma symptoms for some time?
Can I stop giving my child controller medication if she/he shows no asthma symptoms for some time?

Remember that your child’s asthma changes over time, and some degree of inflammation or swelling is usually present, even when they are not having any symptoms. Generally, the benefit of the treatment is much greater than any risk associated with taking the medication, even in periods where your child seems to be ok. You should not stop your child's inhaled steroid (controller medication) unless you have discussed this with the healthcare professional first.

References:

asthma.org.uk Advice/inhalers-medicines-treatments. Accessed October 2017.
How long does my child have to take a controller medication before it starts working?
How long does my child have to take a controller medication before it starts working?

It may take several days or a couple of weeks before the medications are effective. Your child may not feel different at the very beginning, but they need to take it every day so its protective effects can build up. Your child should not stop taking it unless you have discussed this with the healthcare professional.

References:

asthma.org.uk Advice/inhalers-medicines-treatments. Accessed October 2017.
How can I be sure I am getting the medication from my inhaler down into my lungs?
How can I be sure I am getting the medication from my inhaler down into my lungs?

When you press down on the top of your inhaler, it creates an aerosol mist traveling very fast. Because the medication mist is moving quickly, timing is important. This means that you should start breathing before you press down on the inhaler and breath in slowly and deeply. Therefore, it is important that you use your inhaler perfectly. Both spacers and Valved Holding Chambers (VHC's) are devices that may be used to overcome these timing issues and help you get more medication where you need it. These are simple devices that attach to your inhaler. When you push down on the inhaler, the mist is dispensed into the device where it is held temporarily until you inhale. This gives you the time to breathe in the medication slowly and deeply into your lungs.

What is an Asthma Action Plan?
What is an Asthma Action Plan?
An asthma action plan (also known as a treatment plan) is a plan for managing your child's asthma. The goal of this plan is to reduce symptoms, prevent serious asthma flare-ups and emergency trips to the hospital. The plan includes written instructions so you and your child can:

identify early symptoms of an asthma flare-up and treat them with the proper medication to prevent them from getting worse

know how to use the medications to manage a full-blown flare-up

know when to call the doctor or seek emergency care

Make sure to bring the asthma action plan on each doctor visit to review and update as necessary. If your child doesn’t have a personal asthma action plan yet, make an appointment with their doctor to create one.

References:

asthma.org.uk. Advice/manage-your-asthma/action-plan. Accessed October 2017
Know your child’s Asthma Action Plan – Green Zone
Know your child’s Asthma Action Plan – Green Zone
A personalised asthma action plan is a written plan designed by you and your doctor that provides instructions on how to control your or your child's asthma. Because everyone's asthma symptoms and triggers may be different, the action plan should be personalised or customised to the individuals asthma. Contact your doctor and set up an appoitnment to develop an asthma action plan.

The green zone in your child's asthma action plan shows what they should be doing when things are going well to prevent asthma symptoms.

The Green Zone means:

Breathing is good

No cough, wheeze, chest tightness or shortness of breath

Sleeping through the night without symptoms

Can play and participate in sports

Peak flow above 80% of personal best

References:

mayoclinic.org. Diseases-conditions/asthma/in-depth/asthma/art-20044888. Accessed October 2017.
Know your child’s Asthma Action Plan – Yellow Zone
Know your child’s Asthma Action Plan – Yellow Zone
The yellow zone in your child's asthma action plan shows what they should be doing when they start to have symptoms or are exposed to a trigger that is likely to cause symptoms.

The Yellow Zone means:

First sign of cold symptoms

Exposure to known triggers

Peak flow between 50% and 80% of personal best

Symptoms may include:

- Cough

- Some wheezing

- Tight chest or shortness of breath

- Coughing at night or wakening at night with asthma symptoms

- Decreased ability to play or do usual activities

References:

aafa.org Page/asthma-treatment-action-plan. Accessed October 2017.
Know your child’s Asthma Action Plan – Red Zone
Know your child’s Asthma Action Plan – Red Zone
The red zone in your child's asthma action plan shows what they should be doing when they have an asthma medical alert. Urgent action is necessary if you child is in the Red Zone.

Red Zone means:

Wheezing, coughing and shortness of become worse after giving yellow zone medicine.

Shortness of breath while walking, talking or resting.

Use of chest muscles while breathing.

Wheezing may be absent if symptoms are very severe.

Child is unable to sleep or do usual activities or play because of trouble breathing.

Peak flow below 50% of personal best

References:

aafa.org Page/asthma-treatment-action-plan. Accessed October 2017.
How to perfom a peak flow measurement using the Philips PersonalBest peak flow meter.
How to perfom a peak flow measurement using the Philips PersonalBest peak flow meter.
The peak flow meter is a simple, hand-held device which is used for measuring your child's peak flow value.

Guide your child to measure their peak flow value with a peak flow meter by following these steps:

Slide off the top cover and unfold the bottom cover into a handle.

Move the red indicator to the bottom of the scale.

Stand up, if possible.

Instruct your child to breathe in as deeply as they can, and put their lips and teeth around the mouthpiece.

Blow out as hard and fast as they can, staying straight. They should not bend over as they blow.

Read the peak flow measurement next to the indicator, and see what colour-coded section their reading is in (if their peak flow zones have been established). Write down the reading. Then slide the indicator back down to the bottom of the scale.

Repeat steps 4 and 5 two more times and write down the reading each time.

Then, the highest reading from three attempts should be recorded as your children's peak flow reading. It's a good idea to let your children practice using the peak flow meter in front of their healthcare professional.

What is a peak flow meter?
Daily peak flow measurements
Daily peak flow measurements

Daily peak flow monitoring using a diary or chart can help you to determine whether your child's asthma is stable or worsening. In conjunction with their prescribed asthma action plan, you can take appropriate action to bring your child's asthma back under control.

What is a peak flow meter?

Personalised Asthma Action Plan

References:

lung.org. Lung-health-and-diseases/lung-disease-lookup/asthma/living-with-asthma/managing-asthma/measuring-your-peak-flow-rate. Accessed October 2017.

What should I consider when selecting a spacer or valved holding chamber?
What should I consider when selecting a spacer or valved holding chamber?

Look for an enhanced type of spacer that has a valve - this is called a valved holding chamber. This chamber has a one way valve that only opens during inspiration which prevents you from exhaling or pushing the drug out of the chamber. You should also select one that is made of anti-static material. This material keeps the mist in the air longer and the one way valve holds it for a short period of time in the chamber so you have the time to inhale into your lung. Ideally the chamber should also have an audible flow signal, which will alert you if you are breathing too fast.

References:

lung.org. Lung-health-and-diseases/lung-disease-lookup/asthma/living-with-asthma/managing-asthma/valved-holding-chambers. Accessed October 2017
What should I consider when selecting a face mask?
What should I consider when selecting a face mask?

Babies and all young children who cannot use the mouthpiece of the spacer should be encouraged to use a face mask. It is important that the face mask fits comfortably on the face providing a good fit, to help them receive the proper dose of inhaler medication¹. Philips LiteTouch mask with its soft sculpted patient seal contours to a patient's facial landscape making it easy to fit with less discomfort².

References:
[1] Erzinger, S. et al. Face mask and aerosol delivery in vivo. Journal Aerosol Medicine 2007; 20 (Suppl 1):S78-S84
[2] Tong, K. et al. An Instrumented Valved Holding Chamber with facemask to measure application forces and flow in young asthmatic children. Journal of Aerosol Med and Pulm Drug Del. 2014; 27 (Suppl 1): S55-62.
I use a spacer with mask for delivery of inhaled medication to my child. How do I know when she is breathing the medication in from the spacer?
I use a spacer with mask for delivery of inhaled medication to my child. How do I know when she is breathing the medication in from the spacer?

Make sure you are using a spacer or valved holding chamber that has some type of indicator that you can monitor when your child is breathing in¹. The Philips OptiChamber Diamond has an exhalation valve that you can see moving upon exhalation. This allows you to time the release of medication when the valve goes from open to flat. You can also count the number of breaths he/she takes from the chamber.

References:

[1] lung.org Lung-health-and-diseases/lung-disease-lookup/asthma/living-with-asthma/managing-asthma/valved-holding-chambers. Accessed October 2017
My two year old fights me when I try to use a mask to give her a puffer. What can I do to make treatment time less of a struggle?
My two year old fights me when I try to use a mask to give her a puffer. What can I do to make treatment time less of a struggle?

Children up to 3 years of age cannot use a mouthpiece, so treatment with a spacer should be given with a face mask¹. Leaks around the face mask can result in decrease medication being inhaled³. To prevent leaks, you may need to hold the face mask on your child's face tightly. This causes the child to cry and fuss during the treatment. Crying causes more of their medication to be inhaled into the stomach and less in the lungs where it is needed. Philips LiteTouch mask with its soft sculpted patient mask seal requires less pressure to contour to patient’s facial landscape - making it easy to fit with less discomfort, especially for small children than conventional VHC masks². Also select a low volume chamber (less then 350 mL) like the OptiChamber Diamond. The larger chambers require more breaths and more time to get all the medication from a single dose⁴. This LiteTouch mask and a low volume spacer such as the OptiChamber Diamond may help you deliver the medication quickly and comfortably to your child.

References:
[1] Global Initiative for Asthma(GINA). Global strategy for asthma management and prevention. ginasthma.org updated Dec 2010. Accessed 13 January 2016.

[2] Tong, K. et al. An Instrumented Valved Holding Chamber with facemask to measure application forces and flow in young asthmatic children. Journal of Aerosol Med and Pulm Drug Del. 2014; 27 (Suppl 1): S55-62.

[3] Erzinger, S. et al. Facemasks and aerosol delivery in vivo. Journal Aerosol Medicine 2007; 20 (Suppl 1):S78-S84
[4] Nikander, K. The evolution of spacers and Valved Holding Chambers. Journal of Aerosol Med and Pulm Drug Del. 2014; 27 (Suppl 1): S4-24.
How can I objectively monitor my child’s asthma?
How can I objectively monitor my child’s asthma?

From age 5+ monitoring your child’s peak flow readings with a peak flow meter and tracking them with a diary or chart can help you to objectively determine whether your child's asthma is stable or worsening. In conjunction with their prescribed asthma action plan, you can take appropriate action to bring your child's asthma back under control.

References:

lung.org Lung-health-and-diseases/lung-disease-lookup/asthma/living-with-asthma/managing-asthma/assess-and-monitor-your. Accessed October 2017
What is the peak flow meter and how does it work?
What is the peak flow meter and how does it work?

A peak flow meter is a small handheld device that is best suited to be used in children 5 years of age or older. It is used to measure the "peak expiratory flow (PEF)" of your child. PEF is a measurement of how fast your child can blow air out of their lungs after they take a full breath. When they blow into the mouthpiece the small marker will move, and where it ends up is the peak flow reading. The highest reading from three attempts should be recorded as their peak flow reading. If your child's asthma is well controlled, their airways are open, so they are able to blow air out of the lungs quickly, which will give a high peak flow reading. However, if your children's asthma is not controlled, the airways will narrow and they will not be able to blow air out so fast, which will give a lower peak flow reading.

References:

Asthma.org.uk. All_about_asthma/controlling_your_asthma/resources_to_help_you/peak_flow_diary. Accessed Oct 2017.
What is personal best peak flow reading?
What is personal best peak flow reading?

Your children's personal best peak flow reading is the highest reading that they can achieve when their asthma is well controlled. Well controlled means that they are feeling good and having no symptoms. To determine personal best peak flow, record the highest peak flow reading from three attempts that are performed twice a day for 2 weeks. Personal best peak flow is the highest reading achieved over this two week period. Remember that keeping track of your child’s peak flow reading is an important step in managing their asthma symptoms and preventing asthma flare-ups. All this information is recorded in a diary used by your healthcare professional.

What is a peak flow meter?

References:

Webmd.com. Asthma/guide/peak-flow-meter. Accessed October 2017.

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DISCLAIMER:
Information on this website is informational only and should not replace the advice of a physician.

FOOTNOTES:
[1] aaaai.org. Conditions-and-treatments/library/at-a-glance/peak-flow-meter. Accessed October 2017.

[2] Asthma.org.uk. All_about_asthma/controlling_your_asthma/resources_to_help_you/peak_flow_diary. Accessed Oct 2017.

[3] Webmd.com. Asthma/guide/peak-flow-meter. Accessed October 2017.