Goals and rules of peak flowmetry in bronchial asthma, PSV norms

Bronchial asthma is a common chronic respiratory system disease that requires constant medical supervision. This is the only way to track the dynamics of the disease, prevent complications and provide timely assistance to patients in case of an attack.

But in everyday life, a person busy at work and in the family does not always manage to visit a doctor regularly. With the help of peak flowmetry in bronchial asthma, the patient can independently monitor his condition and, if necessary, immediately adjust the dose of the drugs taken, preventing an exacerbation.

What is peak flowmetry

Peak flowmetry is a popular and affordable diagnostic method that allows you to quickly determine PSV in bronchial asthma – the peak expiratory flow rate. According to this indicator, it is assessed how well the respiratory organs function, whether there is a spasm of the respiratory tract.

In addition, this technique is used to monitor the effectiveness of the prescribed treatment. To carry out the procedure and make the necessary measurements, you will need a special device – a peak flow meter. For clarity, peak flowmetry can be compared with measuring blood pressure in hypertension or measuring blood glucose in diabetes.

Device and types of peak flow meters

It is not difficult to understand the device and the principle of operation of the device for measuring the breathing rate, no special skills are required for this.

Most often, the peak flow meter is a plastic tube with a scale into which the patient must exhale sharply. Three zones are highlighted on the scale in different colors:

  • green;
  • yellow;
  • red.

However, there are also electronic models where indicators are displayed digitally. They also differ in manufacturer, cost and design. But at the same time, fluctuations in values ​​for different devices can reach 15%. For this reason, it is recommended to purchase and use a personal peak flow meter only.

The main criterion by which peak flow meters differ is the age category. For children, since they are shorter and have less weight, devices of a different type are produced than for adults. There are also universal devices with replaceable mouthpieces that are suitable for both adults and children.

It will not be difficult to navigate in the readings of the scale and independently determine how stable the state of the asthmatic is. This is especially important if a child suffers from bronchial asthma, and regular measurements of PSV need to be carried out for him.

Role of peak flowmetry in the diagnosis and treatment of bronchial asthma

For bronchial asthma, spasms of the bronchi and bronchioles are characteristic, which makes it difficult for air to enter the lungs and disrupts the normal oxygenation of the patient’s body. As a result, respiratory failure develops, which leads to a sharp deterioration in the patient’s well-being.

Peak expiratory flow rate, or PSV, is a measure that changes with the width of the lumen in the bronchi. The larger it is, the easier it is for air to pass through the respiratory tract and reach the lungs, which means that the patient’s condition is more stable. Therefore, the peak flowmetry procedure in AD is of great importance.

The main goals of peak flowmetry are:

  • Diagnostics of the stage of the disease and control of the effectiveness of the treatment.
  • Evaluation of bronchial hyperreactivity, an increase in the inflammatory process, which makes it possible to establish the degree of disruption of their work.
  • Determination of the patient’s predisposition to the development of bronchial asthma.
  • Identification of the causes of the disease. Peak flowmetry is first performed in a hospital or at the patient’s home, and then at the workplace. If a decrease in PSV and narrowing of the bronchi are detected at the workplace, then the person suffers from occupational asthma (the development of the disease often provokes the inhalation of dusty or contaminated air for a long time).
  • Elucidation of the factors that gave rise to the development of the disease and can cause an attack of bronchospasm. With the help of peak flowmetry, it is possible to establish the response of the patient’s bronchi to various stimuli – pollen, household dust, chemicals, etc.
  • Drawing up an optimal therapy regimen. By measuring PSV, it is found out to which medications the patient responds best.
  • Identification of the features of the dynamics of the disease at different times of the day, in different climatic conditions.

Thanks to peak flowmetry, it is possible not only to diagnose bronchial asthma and assess its severity, but also to prevent the development of bronchospasm, as well as find out which drugs are preferable to treat it.

Indications for research

The main indications for peak flowmetry in case of suspicion of bronchial asthma or already diagnosed are:

  1. Differentiation of pathologies of the respiratory tract, accompanied by spasm of the bronchi.
  2. Condition monitoring in case of exacerbation of bronchial asthma.

Peak flowmetry rules

There are certain rules for conducting peak flowmetry in bronchial asthma. It is recommended that you familiarize yourself with them and strictly follow them in order to get a reliable result.

Doctors usually give patients a reminder for consultation so that they can correctly perform peak expiratory flow measurements at home on their own, without the help of a healthcare professional.

The main nuances of the correct procedure are as follows:

  • For home use, you need to purchase an individual peak flow meter. Passing it on to other patients or taking it from others is strongly discouraged.
  • At least two procedures are carried out per day, preferably in the morning, after waking up, and in the evening, before bedtime.
  • Peak flowmetry can be done more often, this is a completely harmless and painless procedure.
  • The procedure consists in a sharp three-fold exhalation into the device tube. In this case, you really need to exhale sharply, between exhalations you should pause for two to three minutes.

If the readings of the device change abruptly and indicate pronounced disorders in the functioning of the respiratory system, you should consult a doctor as soon as possible for additional advice. Most likely, it is required to adjust the regimen of taking medications.

Remember! Measuring the expiratory flow rate is not a compulsory procedure, and it depends only on the patient whether he will perform it regularly or not. But it should be understood that with such an unpredictable disease as bronchial asthma, peak flowmetry and its results are the only opportunity to independently identify the deterioration of the condition and make adjustments to the therapy in time.

The main stages of the procedure:

  1. Take the device out of the packaging, disinfect the tube, or simply wipe it if the device is individual.
  2. It is convenient to sit or stand, hold the device parallel to the floor and make sure that the slider remains completely motionless at the beginning of the scale.
  3. Clasp the tube with your lips and exhale sharply. The tongue should not block the entrance to the tube. During one procedure, three exhalations are made at small intervals.
  4. Clean the device with water and dish detergent, dry.
  5. Enter the results obtained in a special diary; every patient should have it.
  6. Compare new results with previous ones and consult a doctor if necessary.

The procedure is carried out, as mentioned above, twice a day. No preparation is required for its implementation. It is enough just to sit quietly for a few minutes, relax and calm down.

Childhood research

In case of bronchial asthma in children, PEF measurements should be taken by parents or other adults caring for a sick child. At the time of the procedure, the child should not be hungry or sleepy.

The baby is encouraged to blow into the tube as if he were blowing out the candles on the cake. Before measuring the peak expiratory flow rate, it is recommended to remove tight clothes from the child and persuade him to sit quietly for half an hour.

PSV norms, zoning and indicators

Peak flowmetry indices for bronchial asthma are different for each patient, since all people have different respiratory activity. The rate in patients varies greatly depending on age, height, gender and other individual characteristics.

There are generally accepted standards, but these are only indicative indicators.

To determine what is the rate of PSV in a particular patient, he must be examined for 21 days during the period of remission, when his condition is stable and there are no significant respiratory dysfunctions. Then a three-color graph is drawn up that will display the minimum and maximum values. It is according to this schedule that in the future the patient will be guided whether everything is in order or whether it is necessary to consult a doctor:

  • The green zone is the optimal indicator for the patient, which means that he is feeling well.
  • Yellow zone – means a slight deterioration in the patient’s condition, in which it is necessary to adjust the dosage of the drugs taken.
  • A slider in the red zone – a critical condition, the patient needs urgent hospitalization.

The established general normal indicators, according to which the decoding of the measurement results by the peak flow meter, is as follows:

  • PSV above 90% of the norm calculated for the patient individually is a stable condition that does not require treatment adjustments and doctor’s consultation.
  • PSV ranges from 80% to 89% – there is no need to change the treatment regimen yet, but the patient must carefully monitor his condition.
  • The PSV indicator ranges from 50% to 79% of the norm – an urgent need to correct the ongoing therapy.
  • PSV is below 50% of the established norm – the patient needs to be urgently hospitalized, his condition is critical.

How to calculate the daily variation in PSV values


To set the maximum PSV value for the green zone in bronchial asthma during a three-week examination of the patient, the highest indicator is multiplied by 0.8.

The highest result is multiplied by 0.5 to obtain the digital equivalent of the peak rate for the yellow zone, which indicates moderate deterioration. Everything that will be below the results of the yellow zone refers to the red, that is, to the critical.

For convenience, you can download tables of average norms for men, women and children on the Internet, print them and make a memo. For women and children, the numbers will be lower than for men, which is quite natural, since their respiratory activity is naturally also lower.

Peak flow diary


Usually, when buying a peak flow meter, the patient immediately receives a diary, where he will enter all the PSV data after morning and evening measurements. The diary provides a peak flow chart for 4 weeks.

Normally, the digital indicators should be approximately the same, and if you connect the points with which the PSV indicators are marked in the graph, you should get an almost flat line. In a patient with asthma, the graph looks like a curve with teeth of different sizes.


Peak flowmetry is a modern and affordable way for each patient to independently monitor their condition at home.

Using this procedure, you can minimize the risk of exacerbations, as well as track the dynamics of the disease and evaluate the effectiveness of the therapy. The main thing is to use the device correctly, do all the calculations correctly and do not forget to enter them into the diary.

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