What is peak flowmetry and indications for its implementation?

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My son, like many allergy sufferers, is at risk of developing bronchial asthma, so he was introduced to the unpronounceable peak flow meter at the age of 4.

Peak flowmetry, along with the measurement of exhaled nitric oxide, is considered the main method of asthma control, according to the scientific committee of GINA (Global Strategy for the Treatment and Prevention of Asthma).

The international GINA program has been operating since 1993, and involves leading asthma experts from around the world.

Indications for peak flowmetry

• Diagnosis of bronchial asthma when it is not possible to perform external respiration.
• Assessment of asthma severity over the course of the disease.
• In cases where it is necessary to distinguish bronchial asthma from chronic obstructive pulmonary disease (COPD).
• Control of bronchial asthma.
• Prognosis of exacerbation of the disease.
• Determine the feasibility of changing the treatment strategy.
• Assess the patient's response to new medications.
• Prevent addiction to medications.

Peak flow meter - what is it and how to use it for allergies and bronchial asthma?

Breathing pathologies lead to severe disorders throughout the body. This occurs due to a lack of oxygen and excess carbon dioxide. Serious respiratory dysfunction is observed in chronic diseases of the lungs and bronchi. In addition, other pathologies can lead to hypoxia. Among them are laryngospasm, enlargement of the tonsils of the 2nd and 3rd degree with tonsillitis, entry of a foreign body into the respiratory tract, etc.

To distinguish between diseases, various research methods are used. One of them is peak flowmetry. This diagnostic procedure is performed if bronchial asthma, chronic obstructive pulmonary disease, or emphysema are suspected. People suffering from these pathologies know firsthand about such a device as a peak flow meter. What it is and how to use it should be explained by your doctor. Treatment tactics depend on the indicators of this device.

Peak flow meter - what is it?

As is known, the main method for determining respiratory functions is spirometry. However, the device needed for this study is quite expensive and is only available in the clinic. So that patients could measure their breathing parameters at home, a more convenient device was invented - a peak flow meter. Every patient suffering from bronchial asthma and COPD knows what it is. After all, such diseases are pathologies that require constant monitoring of the condition. This is especially true for patients with an established diagnosis of moderate and severe severity. Thanks to peak flowmetry, the stage of the disease can be determined. After all, the severity level is set based on an indicator such as peak expiratory flow (PEF). A peak flow meter is a portable device that every patient has. It can be used to measure PEF both during attacks and at rest. Thanks to the peak flow meter, the disease is controlled. If there are changes in the readings of this device, you should consult a doctor to adjust the treatment.

Operating principle of a peak flow meter

The action of the peak flow meter is based on the movement of the needle when pressure is applied to it by the air flow. The device has a scale from 0 to 1000. It is used to determine how much air the patient can exhale in 1 minute. In this way, the vital capacity of the lungs can be approximately calculated. A mouthpiece is attached to the device. It is into this that the patient exhales. In addition to the numbers, the device has colored markings. They are necessary to assess the state of respiratory function.

Despite the fact that the principle of operation of the peak flow meter is quite simple, in some cases errors are noted when using it. More often this applies to pediatric patients, who need to be explained exactly how to exhale. To make it clear to the child, he is told to blow as if extinguishing the candles on a cake. Regardless of the patient’s age, all patients suffering from bronchial asthma must attend special classes organized at the clinic. Thanks to them, people learn about the correct lifestyle, types of medications and indications for their use. Why a peak flow meter is needed, what it is and how to use it is also explained here. Patients are also informed about the target values ​​of this device and pronounced deviations from the norm.

Types of peak flow meters: differences

A peak flow meter is an instrument for measuring expiratory flow that was created in the 1950s by Professor Wright. This device had the same mechanism of action as the modern device, but was larger in size. In 1975, the device was improved. The peak flow meter was called a “mini-right” device, it was small in size and could be used at home.

Currently, there are several types of devices produced by various medical companies. However, they differ from the “mini-right” only slightly. The Omron peak flow meter is considered quite popular. This company also produces other medical devices. Among them are a tonometer, a phonendoscope, inhalers, etc. Omron peak flow meters have proven themselves in the market due to their ease of use and good quality.

In addition to the usual devices, the mechanism of which is based on air pressure, this company also produces electronic devices. They are convenient for patients who cannot independently regulate their breathing (children, elderly people).

The Philips peak flow meter is not inferior in quality. It is slightly different in shape (rectangular) and also has a stand. Thanks to this, the device does not need to be held during the study.

How to use a peak flow meter yourself?

This device must be used as follows:

1. Remove the peak flow meter from the packaging.
2. Make sure that the pointer arrow is on o.
3. Take a maximum breath as deeply as possible.
4. Cover the mouthpiece with your lips, while lightly holding it with your teeth. The tongue should not touch the device.
5. Exhale once with maximum force.
6. Remove the mouthpiece from your mouth.
7. Note the PSV indicator.

This procedure should be repeated 3 times in a row. After this, the indicators should be recorded in a special diary, which is kept by patients suffering from bronchial asthma. The average peak expiratory flow rate is noted. If the PEF value is low (less than 60%), inhalation of a fast-acting drug should be done. The electronic peak flow meter differs in that the value of the peak expiratory flow rate is calculated automatically and displayed on the screen. As when using a mechanical device, the study must be repeated 3 times and the average PEF value must be noted.

What do the colored stripes on a peak flow meter mean?

Regardless of the manufacturer, all peak flow meters have colored markings. They are located on the side of the directional arrow. Thanks to them, you can judge the degree of bronchial obstruction. If the PEF is within the green range (80-100%), this means that the disease is treatable and controllable. Indicators in this zone indicate the stage of remission and correspond to the volume of exhaled air equal to 320-400 ml. If the PEF is 60-80% of the norm, then on the device this value is within the yellow range. Such a result means that the disease is in the acute stage. In this case, clinical manifestations such as cough, shortness of breath when walking, and sleep disturbances may be observed. The yellow zone is a warning that the treatment should be reconsidered. Indicators that are within the red color are considered critical. In this case, PEF is less than 60% of the norm. Such a result is a reason to urgently seek medical help.

Normal indicators for peak flowmetry

The peak flow meter targets should correspond to the green zone. If the volume of exhaled air is more than 320 ml, then the spread of PEF indicators does not exceed 20% per day. This result is observed in patients with controlled bronchial asthma and chronic obstructive pulmonary disease. PEF indicators correspond to the forced expiratory volume during spirometry. The norm for both indicators in healthy people is 100%. With physical activity and respiratory diseases, it may decrease slightly. If a patient is diagnosed with COPD or bronchial asthma, then a PEF of 80% is the norm for exhalation. The peak flow meter records this indicator 3 times. Slight fluctuations in daily peak expiratory flow mean that airway obstruction is not severe. In this case, no treatment adjustment is required.

Peak flowmetry indicators for pathologies of the respiratory system

In case of severe respiratory dysfunction, peak flow metry readings are below 80%. That is, after exhalation, the pointer arrow is in the yellow or red zone. Such changes are observed only in chronic pathologies of the respiratory system. The most common cause is bronchial obstruction. In some cases, a decrease in PEF may be observed with restrictive disorders. Similar changes occur in severe inflammatory diseases of the lung tissue (large focal pneumonia, tuberculosis). Unlike chronic obstructive pathologies, these disorders are reversible.

Differential diagnosis between COPD and bronchial asthma

Chronic bronchial obstruction occurs in COPD and bronchial asthma. Both diseases are accompanied by a decrease in PEF. Therefore, peak flowmetry does not always allow one to distinguish between these pathologies. However, there is a difference between these diseases. In bronchial asthma, the PEF value fluctuates more often. If there are no asthma attacks, then the peak expiratory flow rate may be normal. During an exacerbation, PEF decreases sharply and is restored immediately after taking bronchodilators. COPD is characterized by a progressive course and no connection with exposure to allergens. After taking medications, PEF does not change as much as in asthma.

How often should you use a peak flow meter?

Regular peak flow testing helps prevent the development of attacks. For reliability, it is recommended to measure PEF at least 2 times a day - in the morning and in the evening. The frequency of the study depends on the severity of the disease. It is advisable to use a peak flow meter with replaceable mouthpieces. This will help avoid infection of the oral mucosa.

Peak flow meter

A peak flow meter is a device invented in 1957 in England that measures the speed of exhalation.

Types of peak flow meters

• Mechanical (Omron, Philips, Personal Best);
• Electronic (eMini Wright).

Advantages of mechanical peak flow meters

• The price is lower;
• Easy to use;
• Rarely break;
• No batteries needed.

Advantages of electronic peak flow meters

• Measure more accurately;
• You can set individual indicators;
• You can save, view and compare results;
• There is additional functionality;
• Compact.

Which peak flow meter to choose

According to their purpose, peak flow meters are divided into two groups

1. For children - from 35 to 350 l/min (height up to 135 cm).
2. For adults - from 60 to 800 l/min (height above 135 cm).

It is better to choose a peak flow meter that has colored sliders or zones designated by color. The mouthpiece of the device can be round or oval with a protective cap. Round mouthpieces are better for children.

We have a mechanical peak flow meter from OMRON, which we use only to control the bronchi during flowering. It seems to me that for daily use, an electronic device would be better suited.

Peak Flow Meter Care

The peak flow meter is an individual device, so after use it must be wiped with an alcohol wipe or left for 10 minutes in a disinfectant solution (see the article How to clean inhalers) or use replaceable mouthpieces.

2. Peak flow meter

The device for measuring peak expiratory flow looks like a cylinder or rounded parallelepiped with a mouthpiece and a graduated scale. The shape and design, by and large, do not matter at all: it is enough for the peak flow meter to be convenient and practical, and, if used by children, also attractive, bright, and “friendly”.

The peak flow meter belongs to medical devices for personal use and is intended for independent daily functional monitoring (with a total duration of quantum satis, i.e. as long as needed), and the lower age limit for users starts from 4-5 years.

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Algorithm for performing peak flowmetry

• The starting position for the test is standing;
• measurements should be carried out in the morning and evening, twice a day;
• It is better to do the test on an empty stomach in the morning, in the evening 2 hours after eating (consult your doctor);
• keep the peak flow meter in a horizontal position;
• before the test, set the device indicator to 0 (or below the minimum number);
• take as deep a breath as possible;
• tightly wrap your lips around the mouthpiece (tip);
• exhale as strongly and sharply as possible through the peak flow meter (as if blowing out a candle from a distance);
• write down the result;
• repeat the measurements 2 more times, not forgetting to set the indicator to zero;
• select the maximum (highest) result and record it in your peak flow diary.

1.General information

In pulmonology, many techniques are practiced that allow one to assess the state of the respiratory organs in the simplest and shortest way: by measuring various characteristics of inhalation and exhalation. Such functional tests also include peak flowmetry, a method that has become widespread in recent years due to its combination of information content and simplicity.

Sometimes you can hear an apt aphorism: “The most difficult thing about peak flowmetry is its name.” Indeed, the term in Russian looks somewhat cumbersome, but in the original English it sounds quite natural; it is formed from the words “peak” (peak, maximum, highest point) and “flow” (flow, in this context - exhalation). Thus, peak flowmetry is an instrumental measurement of the maximum possible speed of exhaled air flow for a given patient.

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Peak flowmetry norms

According to GINA 2018

Peak flow meter zones are marked with colored markers, similar to a traffic light: green, yellow, red.

Green zone (80-100% of the norm) – everything is fine. Everything's under control. Normal lung condition.

Yellow zone (50 – 80% of normal) – attention. Warning of deterioration of condition. Analyze the diary indicators and be sure to consult a doctor - you need to find the reason for the deterioration of the condition.

Red zone (less than 50% of the norm) – danger! You must immediately consult a doctor or call an ambulance.

Interestingly, bronchial patency changes throughout the day. Fluctuations in patency in healthy children should not change by more than 15% of normal. 20% of the norm – in children with bronchial asthma in remission.

3.Indications

The largest group of patients for whom regular recording of peak expiratory flow is indicated are patients with bronchial asthma. However, peak flowmetry is advisable for any pulmonary diseases associated with reduced bronchial patency, their suspected or proven obstruction and a tendency to bronchospasm. The method makes it possible to objectify the assessment of the functional state of the airways “in numbers”, to monitor the therapeutic dynamics and effectiveness of treatment (for example, when prescribing a new drug, subjective sensations may not coincide with the actual effect). In addition, in some cases it is extremely important to identify the dependence of attacks on a specific situation and conditions, on the time of day and other factors, the influence of which may not be obvious. Finally, for many patients, peak flowmetry is a simple and visual way to assess the effectiveness of one’s own autogenic training skills and the ability to independently prevent (or stop) the development of an attack of respiratory failure.

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How to evaluate results

Test results will depend on age, gender, weight and height. You cannot expect the same results from a young athlete and an elderly couch potato.

The generally accepted table for assessing peak flowmetry data compares indicators only by height, which is not entirely correct. Therefore, do not chase the results according to the table; remember that the results depend on many factors.

For example, some children can inflate a balloon at 2 years old, while others find it difficult to cope with this task even at 7 years old. It is important to understand which numbers are optimal for your baby.

Table of approximate norms of peak flowmetry in children depending on height

Explanations for the table

First, you need to find out what exhalation parameters will be normal for your child. The norm is determined when the child is healthy and there are no exacerbations of the disease.

Let's say your child's expiratory rate (EF) is 200 l/min. This means that indicators of at least 160 l/min will be a green zone for him (up to 80% of his norm).

If the exhalation rate is in the range from 100 to 160 l/min. – this is the yellow zone (below 80% of normal).

Indicators are less than 100 l/min. (less than 50% of the norm) is the red zone. You need to see a doctor urgently.

4.Procedure

The key (and the only, if you look at it) obligation that the patient must accept and strictly observe is the regularity of measurements. Peak flowmetry is performed at least twice a day, usually in the morning and evening, at the same hours. The measuring indicator goes to zero. After two or three quiet breathing cycles, the patient draws into the lungs the maximum volume of air available to him, then exhales it through the mouthpiece, trying to do this as quickly as possible. Such “rapid exhalations” should be repeated two or three times. The highest of the measurements is taken as the desired peak expiratory flow (PEF). The unit of measurement is “liters per minute”, which is then converted using certain factors.

There is a close direct correlation between PEF and bronchial patency, due to the anatomy and physics of the respiratory tract. This is, in fact, what the method is based on. World pulmonology has accumulated a huge amount of statistical material that allows us to confidently and reliably judge what peak expiratory flow rate is normal for a person of a given age, gender and height; what are the permissible limits of this norm; what deviations should be considered pathological and dangerous.

The peak flow meter must be accompanied by instructions with all the necessary standards, tables and calculation formulas for constructing a graph (these instructions will be explained to the patient in the most detailed way by the doctor, who must ensure that the technique is fully understood and mastered). The results of regular measurements day after day reflect the dynamics of respiratory function; The graph usually highlights intuitive multi-colored zones - green, yellow and red - which allows even a non-specialist to assess the situation quite adequately and objectively.

Ultra-modern models of peak flow meters are high-tech microprocessor devices that provide a number of convenient options (for example, the ability to pair with a smartphone). It should be understood, however, that in this case these are market offers, and even the most expensive digital device does not change either the essence of the method or its effectiveness: a simple peak flow meter, if used correctly, can tell no less about the bronchi.