Asthma advice: Peak flow meter technique


Introduce yourself with your name and role, and confirm the patient’s name and date of birth. Obtain consent and wash your hands.

In explanation stations, it is very important to follow exactly what the station instruction sheet says. Some stations may ask you to take a brief history and/or examination, and then proceed to explanation or demonstration. Even if it is not written in the instructions, it is often useful to establish a very brief history on the patient’s understanding of their condition. Use the instructions as a framework to decide how to approach this station.


Establish the patient’s understanding of their condition and why they need to use a peak flow meter. Then proceed to fill any gaps in their knowledge. This should be summarised using only a few sentences.

This is a good time to establish the patient’s ICE (ideas, concerns and expectations). Expectations are most important; if you know what the patient hopes to gain from the consultation you can tailor your approach.

Purpose of a peak flow meter

Explain the purpose of a peak flow meter and peak expiratory flow rate (PEFR). PEFR is defined as the highest flow rate out of the mouth during a rapid forced expiration (i.e. a person’s maximum speed of expiration). This makes it ideal for monitoring obstructive diseases such as asthma. The greater the patency of the airway, the greater the rate of airflow. In an asthma attack, the PEFR can also be used to grade the severity of their attack.

Be careful to avoid jargon when explaining to the patient. Minimally, you just need to say to the patient that “it is a breathing exercise that allows us to see how well controlled your asthma is.”

Correct peak flow meter technique

Explain and demonstrate correct peak flow meter technique. There are various ways to approach this part. The ‘tell, show, do’ approach works well. This involves talking to the patient through the steps (listed below), moving to you demonstrating the correct technique to the patient and then finally asking the patient to perform the correct technique.

The correct technique will now be described below.

It is crucial that you explain as you talk through the steps. However, this can sometimes lead to confusion. Hence, it can be helpful to say “please interrupt me at any point if any of this isn’t making sense or you don’t understand something.”

Preparing the peak flow meter

Obtain the peak flow meter and mouthpiece. The mouthpiece will fit onto the end of one side. Once again, ensure that you are sitting or standing upright. This is very important, as a deep breath will be required. The red dial should be set to zero every time that you use (breathe into) the device.

Peak flow meter with a mouthpiece inserted.

A peak flow meter with a mouthpiece inserted.

Using the peak flow meter

Keep hands on either side, being careful not to obstruct the red dial. Make sure that the peak flow meter is exactly horizontal, parallel to the floor. This is to avoid any confounding effects of gravity. Take in as deep a breath as possible, then secure a tight seal around the mouthpiece of the peak flow meter with your tongue below the mouthpiece, and breathe out as hard and as fast as possible. The red dial will move up from 0 to a value given on the side of the meter, giving the PEFR (measured in L/min). Reset and repeat three times, taking the best (highest) reading out of the three.

How to hold the peak flow meter.

Ensure that the peak flow meter is horizontal.

Ending the demonstration

Once you have finished demonstrating and explaining, check for understanding and ask the patient to demonstrate the process back to you.

Remember to remove your mouthpiece and place it in the bin, then provide the patient with a fresh mouthpiece to use.

Peak flow diary

The best PEFR reading needs to be taken every day, once in the morning and once in the night. This value then needs to be recorded in a peak flow diary or something similar. This is required for the healthcare team to see the trend of the patient's asthma (getting better, worse, staying the same). The diary should be examined alongside the patient's medication use and the symptoms. In doing so, one can see if the patient has had any exacerbations of their asthma or any shortness of breath during a period when they have been exposed to a potential asthma trigger.

In an examination setting, it is possible that you will be asked to inform the patient on how to record their PEFR values as well as how to fill in the other information provided on the sheet/diary. Take a good look at the sheet first and then talk to the patient about it – most of what will be on the sheet is listed above or self-explanatory.

There are 3 main influences on PEFR: gender, age and height.

Normal values for peak expiratory flow - EU scale

Normal values for PEFR. By Mikael Häggström, used with permission.


Summarise broadly what you have spoken about today with the patient, clarify if there is anything the patient does not understand and whether they have any further questions.

Wash your hands and remember to offer leaflets that provide more information about asthma, inhalers and peak flow at the end of the consultation.


The importance of communication in this station cannot be overstated. Examiners use it to differentiate good from exceptional candidates. A good candidate will be able to remember the necessary instructions, however a great candidate will be able to fluently communicate these in a simple, memorable way. Listed below are some of the most effective techniques:

Explicit categorisation

Organising the discussion into different categories to help structure the consultation. For example: “There are three things I’d like to discuss with you. Firstly I’d like to speak to you about what exactly asthma is, secondly, I will show you how to use the correct technique for your inhaler to help you breathe easier and finally I will explain how best to monitor your asthma using something we call a peak flow meter.”


Transition statements can help you to move from one topic to another. For example: “We have talked and demonstrated how to use your inhaler correctly, now I’d like to show you how to use a peak flow meter to help us monitor how well controlled your asthma is.”

Avoid medical jargon

Ensure you use language that the patient will be able to understand. If you must use a medical term, be sure to explain what it means.

Interactive markscheme

When assessing each other, click on each list item as you go along. Doing so will turn the list item green. Make careful note of any steps missed at the end.
We recommend completing any examination or procedure in under 10 minutes, but you can adjust the timer to suit your needs.

  1. Introduction: “Hello, I’m SimpleOSCE and I am a medical student, could I confirm your full name and DOB? I’ve been asked to talk to you about your asthma, specifically how to use your inhaler and then how to record how well you’re doing with your asthma. Are you happy to proceed?”
  2. Wash hands.
  3. Check patient’s current knowledge and understanding of asthma.
  4. Fill in any gaps in their knowledge in a simple manner.
  5. Ask patient if they have ever done a peak flow measurement before and explain the purpose behind it.
  6. Obtain the equipment (peak flow meter, two mouthpieces) and proceed to talking the patient through the correct technique.
  7. Explain and/or demonstrate the following (7-13):

  8. Insert mouthpiece.
  9. Stand upright with shoulders back.
  10. Ensure red dial is set to zero at the start and after each use.
  11. Keep hands on either side, so not to obstruct the red dial.
  12. Peak flow meter must be held exactly horizontal, parallel to the floor.
  13. Take in a deep breath, then form a tight seal around the mouthpiece and breathe out as hard and as fast as possible, making a note of the reading.
  14. Repeat 3 times, taking the best (highest) reading.
  15. Check that the patient has understood steps 7-13 and/or request a demonstration.
  16. Talk through a peak flow diary sheet.
  17. Answer any questions the patient may have.
  18. Wash your hands and offer leaflets that provide more information on asthma, inhaler and PEFR at the end of the consultation.
  19. Communication mark 1: Good patient manner.
  20. Communication mark 2: Clear explanations with minimal jargon.
  21. Communication mark 3: Good communication technique (e.g. categorisation and signposting).
Overall: 0/20