How many readings should you take when you are measuring a patients peak expiratory flow rate quizlet?

A peak flow meter is a small device that helps you check how well your asthma is controlled. Peak flow meters are most helpful if you have moderate to severe persistent asthma.

Measuring your peak flow can tell you and your health care provider how well you blow air out of your lungs. If your airways are narrowed and blocked due to asthma, your peak flow values drop.

You can check your peak flow at home. Here are the basic steps:

  • Move the marker to the bottom of the numbered scale.
  • Stand up straight.
  • Take a deep breath. Fill your lungs all the way.
  • Hold your breath while you place the mouthpiece in your mouth, between your teeth. Close your lips around it. Do not put your tongue against or inside the hole.
  • Blow out as hard and fast as you can in a single blow. Your first burst of air is the most important. So blowing for a longer time will not affect your result.
  • Write down the number you get. But, if you coughed or did not do the steps right, do not write down the number. Instead, do the steps over again.
  • Move the marker back to the bottom and repeat all these steps 2 more times. The highest of the 3 numbers is your peak flow number. Write it down in your log chart.

Many children under age 5 cannot use a peak flow meter very well. But some are able to. Start using peak flow meters before age 5 to get your child used to them.

To find your personal best peak flow number, take your peak flow each day for 2 to 3 weeks. Your asthma should be under control during this time. To find your personal best, take your peak flow as close to the following times of day as you can:

  • Between noon and 2 p.m. each day
  • Each time after you take your quick-relief medicine to relieve symptoms
  • Any other time your provider tells you to

These times for taking your peak flow are only for finding your personal best.

Write down the number you get for each peak flow reading. The highest peak flow number you had during the 2 to 3 weeks is your personal best.

Ask your provider to help you fill out an asthma action plan. This plan should tell you when to call the provider for help and when to use medicines if your peak flow drops to a certain level.

Your personal best can change over time. Ask your provider when you should check for a new personal best.

Once you know your personal best, make taking your peak flow a habit. Take your peak flow:

  • Every morning when you wake up, before you take medicine. Make this part of your daily morning routine.
  • When you are having asthma symptoms or an attack.
  • After you take medicine for an attack. This can tell you how bad your asthma attack is and if your medicine is working.
  • Any other time your provider tells you to.

Check to see which zone your peak flow number is in. Do what your provider told you to do when you are in that zone. This information should be in your action plan. If you use more than one peak flow meter (such as one at home and another one at school or work), be sure that all of them are the same brand.

Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter

Boulet LP, Godbout K. Diagnosis of asthma in adults. In: Burks AW, Holgate ST, O'Hehir RE, et al, eds. Middleton's Allergy: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 51.

Chassay CM. Pulmonary function testing. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 81.

National Asthma Education and Prevention Program website. How to use a peak flow meter. How to use a metered-dose inhaler. www.nhlbi.nih.gov/health/public/lung/asthma/asthma_tipsheets.pdf. Updated March 2013. Accessed April 22, 2022.

National Heart, Lung and Blood Institute. Asthma Management Guidelines: Focused Updates 2020. www.nhlbi.nih.gov/health-topics/asthma-management-guidelines-2020-updates. Updated February 4, 2021. Accessed January 8, 2022.

Viswanathan RK, Busse WW. Management of asthma in adolescents and adults. In: Burks AW, Holgate ST, O'Hehir RE, et al, eds. Middleton's Allergy: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 52.

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Pulmonary Asthma

What is peak flow measurement?

Peak flow measurement is a quick test to measure air flowing out of the lungs. The measurement is also called the peak expiratory flow rate (PEFR) or the peak expiratory flow (PEF). Peak flow measurement is mostly done by people who have asthma.

Peak flow measurement can show the amount and rate of air that can be forcefully breathed out of the lungs. The measurement should be started after a full lung inhalation.

During the test, you blow forcefully into the mouthpiece of a device. A peak flow meter (PFM) is used most often. This is a small handheld device made of plastic. A PFM is small and light enough to be used almost anywhere. It’s important to use the same PFM on a regular basis. The readings can vary between brands and types of meters. In some cases, the test is done in a healthcare provider's office or a hospital with a spirometer. This device has a handheld mouth piece that’s attached by cord to a larger electronic machine.

An important part of peak flow measurement is noting peak flow zones. Peak flow zones are areas of measurement on a peak flow meter. The goal of the peak flow zones is to show early symptoms of uncontrolled asthma. Peak flow zones are set differently for each person. Your healthcare provider will help determine your peak flow zones. The 3 peak flow zones are noted by color and include:

  • Green . This means “go.” The green zone is 80% to 100% of your highest peak flow reading, or personal best. This is the zone you should be in every day. When your measurements are in this zone, air is moving well through the large airways in your lungs. It means that you can do your usual activities and go to sleep without trouble.

  • Yellow. This means “caution” or “slow down.” The yellow zone is 50% to 80% of your personal best. Measurements in this zone are a sign that your large airways are starting to narrow. You may start to have mild symptoms, such as coughing, feeling tired, feeling short of breath, or feeling like your chest is tightening. These symptoms may keep you from your usual activities or from sleeping well.

  • Red. This means “stop.” The red zone is less than 50% of your personal best. Readings in this zone mean you have severe narrowing of your large airways. This is a medical emergency. You should get help right away. You may be coughing, very short of breath, wheezing while breathing in and out, or having retractions (the muscles between the ribs are working hard to help you breathe). You may also have trouble walking and talking.

Why might I need peak flow measurement?

Peak flow measurement using a peak flow meter is useful for people with asthma. During an asthma flare-up, the large airways in the lungs slowly begin to narrow. This slows the speed of air moving through the lungs. A peak flow meter can help show the narrowing of the airways well before an asthma attack happens. A peak flow meter can help you determine:

  • When to get emergency medical care

  • How well an asthma treatment plan is working

  • When to stop or add medicine as directed by your healthcare provider

  • What triggers an asthma attack, such as exercise

A peak flow meter can help you manage asthma. It can give you and your healthcare provider information about how open the airways are in your lungs. The PFM can detect small changes in the large airways before you start to wheeze. Using a PFM every day will let you know when your peak flows are starting to drop. This allows you to make early changes in your medicine or routine to help keep asthma symptoms from getting worse. The PFM can also identify the reading at which you need to call your healthcare provider or go to the emergency room.

Your healthcare provider may not advise you use a PFM unless your asthma is moderate or severe and you are managing it with medicine. PFM can also be used to assess other lung problems, such as:

  • Emphysema. This is a chronic lung condition that affects the smallest air sacks in the lungs (alveoli).

  • Chronic bronchitis. This is long-term inflammation of the bronchi. It creates excess mucous and a chronic cough.

What are the risks of peak flow measurement?

All procedures have some risks. The risks of this procedure may include:

  • Having to take in deep breaths may make you feel dizzy or short of breath

  • It may trigger coughing or wheezing

Certain factors may interfere with the accuracy of peak flow measurement, such as:

  • Not breathing in deeply enough to start the test

  • Not breathing out forcefully enough to show your true level of dysfunction

  • Coughing during the test

  • Poor seal around the mouthpiece while performing the procedure

  • A dirty meter

  • Blocking the mouthpiece with your tongue

  • Use of medicines that open the airways (bronchodilators)

  • Use of a different type or brand of peak flow meter, as measurements may vary among brands and types of meters

How do I get ready for peak flow measurement?

Your healthcare provider will explain the procedure to you. Ask him or her any questions you have. You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully. Ask questions if anything is not clear.

Tell your healthcare provider if you take any medicines. This includes prescriptions, over-the-counter medicines, vitamins, and herbal supplements.

Make sure to:

  • Not eat a heavy meal before the procedure, if instructed by your healthcare provider

  • Follow any other instructions your healthcare provider gives you

Before starting daily peak flow meter measuring, your healthcare provider may have you follow a detailed schedule over 2 to 3 weeks. This is done to find your “personal best” peak flow measurement. This value will be used as a baseline for your daily measurements.

What happens during peak flow measurement?

Peak flow measurement is done 1 or more times daily at the same time of day, or whenever you are having early signs of an asthma attack. Or you should use it when directed by your healthcare provider. Use the peak flow meter (PFM) before taking asthma medicine. Your healthcare provider may advise other times when using a PFM is useful.

In most cases, peak flow measurement follows this process:

  1. Before each use, make sure the sliding pointer on the peak flow meter is reset to the 0 mark.

  2. Hold the PFM by the handle.

  3. Stand up straight.

  4. Remove chewing gum, candy, or food from your mouth.

  5. Take a deep breath and put the mouthpiece in your mouth. Seal your lips and teeth tightly around the mouthpiece.

  6. Blow out as hard and as fast as you can. A “fast blast” is better than a “slow blow.”

  7. Note the number where the sliding pointer has stopped on the scale.

  8. Reset the pointer to 0.

  9. Repeat this 3 times. The 3 readings should be close together. If not, adjust your technique.

  10. If you cough during a measurement, repeat the measurement.

  11. Record only the highest of the 3 readings on a graph or in a notebook. Do not average the numbers together. The highest number is called your peak flow or personal best.

  12. Use the peak flow meter once a day, or as directed by your healthcare provider. Measure peak flows about the same time each day. A good time might be when you first wake up, or at bedtime.

  13. Clean and care for your meter as instructed.

  14. If you use a new peak flow meter, you will need to find your new personal best value on the new meter.

  15. Your healthcare provider may give you other instructions as needed.

What happens after peak flow measurement?

Note which peak flow zone your measurement falls into. Follow the instructions below:

  • Green . This means “go.” You should continue to follow your asthma plan as directed by your healthcare provider.

  • Yellow. This means “caution” or “slow down.” You should tell your healthcare provider at this time. He or she may tell you to increase or change your medicines. He or she may give you other instructions to help keep your symptoms from getting worse.

  • Red. This means “stop.” This is a medical emergency. You should get help right away. Take your rescue medicine and call your healthcare provider or go to an emergency room.

Your healthcare provider may give you more instructions about what to do for each peak flow zone.

How many readings should you take when you are measuring a patient's peak expiratory flow rate?

The 3 readings should be close together. If not, adjust your technique. If you cough during a measurement, repeat the measurement. Record only the highest of the 3 readings on a graph or in a notebook.

How many readings should you take when you are measuring a patient's peak expiratory flow rate quizlet?

How do you calculate the peak expiratory flow rate from the three readings? Use the highest reading as the peak expiratory flow rate.

How often should you measure peak flow?

Measure your peak flow at least once a day, usually in the morning before you take your asthma medicines. You might have to check it more often if you are having more episodes than usual, or if your reading is below 80 percent of your personal best.

What should my reading be on a peak flow meter?

Peak expiratory flow (PEF) is measured in litres per minute. Normal adult peak flow scores range between around 400 and 700 litres per minute, although scores in older women can be lower and still be normal.