How to make fvd. Spirometry is a study of the function of external respiration. Study of external respiration functions

Normal gas exchange in the lungs is ensured by adequate perfusion

ventilation ratio. In turn, pulmonary ventilation depends on the condition of the lung tissue, chest and pleura (static characteristics), as well as on the patency of the airways (dynamic characteristics).

Static parameters of pulmonary ventilation include

the following indicators:

1. Tidal volume (VT) - the amount of air inhaled and exhaled during quiet breathing. Normally it is 500-800 ml.

2. Inspiratory reserve volume (IRV) is the volume of air that a person can inhale after a normal inhalation. Normally it corresponds to 1500-2000 ml.

3. Expiratory reserve volume (ERV) is the volume of air that a person can exhale after a normal exhalation. Normally, it usually corresponds to 1500-2000 ml.

4. Vital capacity of the lungs (VC) - the volume of air that a person can exhale after a maximum inhalation. Usually it is 300-5000 ml.

5. Residual lung volume (RLV) - the volume of air remaining in the lungs after maximum exhalation. Usually it corresponds to 1500 ml.

6. Inspiratory capacity (EIC) is the maximum volume of air that a person can inhale after a quiet exhalation. It includes the DO and ROVD.

7. Functional residual capacity (FRC) - the volume of air contained in the lungs at the height of maximum inspiration. It includes the amount of OOL and ROvyd.

8. Total lung capacity (TLC) - the volume of air contained in the lungs at the height of maximum inspiration. It includes the sum of the total and vital capacity.

Dynamic parameters include the following speed indicators:

1. Forced vital capacity (FVC) - the amount of air that a person can exhale at maximum speed after a maximum deep breath.

2. Forced expiratory volume in 1 second (FEV1) - the amount of air that a person can exhale in 1 second after taking a deep breath. Usually this indicator is expressed in % and it averages 75% of vital capacity.

3. Tiffno index (FEV1/FVC) is indicated in % and reflects both the degree of obstructive impairment of pulmonary ventilation (if less than 70%) and restrictive (if more than 70%).

4. Maximum volumetric flow rate (MVF) reflects the maximum volumetric flow rate of forced expiration averaged over the period of 25-75%.

5. Peak expiratory flow (PEF) is the maximum volumetric flow rate of forced expiration, usually determined on a peak flow meter.

6. Maximum pulmonary ventilation (MVV) - the amount of air that a person can inhale and exhale with maximum depth in 12 seconds. Expressed in l/min. Typically, the MVL averages 150 l/min.

The study of static and dynamic indicators is usually carried out using the following methods: spirography, spirometry, pneumotachometry, peak flowmetry.

In pathology, there are two main types of pulmonary ventilation disorders: restrictive and obstructive.

The restrictive type is associated with disturbances in the respiratory excursion of the lungs, which is observed in diseases of the lungs, pleura, chest and respiratory muscles. The main indicators for the restrictive type of ventilation impairment include vital capacity, which also allows you to monitor the dynamics of restrictive pulmonary disease and the effectiveness of treatment; OEL, FOE, DO, ROVD. In pathology, these indicators decrease.

The obstructive type of pulmonary ventilation disorder is associated with a violation of the passage of air flow through the respiratory tract. This may be due to a narrowing of the airways and an increase in aerodynamic resistance, due to the accumulation of secretions during bronchitis and bronchiolitis, swelling of the bronchial mucosa, spasm of the smooth muscles of the small bronchi (bronchial asthma), early expiratory collapse of the small bronchi with emphysema, laryngeal stenosis.

Main indicators reflecting the obstructive type of ventilation impairment: FEV1; Tiffno index, maximum expiratory volumetric flow rate at 25%, 50% and 75%; FVC and peak expiratory flow rate decrease in pathology.

FVD is a function of external respiration. Thanks to the FVD examination, the doctor can find out whether the patient’s lungs are healthy.

FVD with salbutamol: examination features, preparation, technique.

To understand whether there are any abnormalities in the functioning of the respiratory system or not, a test with Salbutamol is used. Salbutamol is a drug that dilates the bronchi.

Preparation

The details of the preparation are told by the doctor himself, based on the patient’s case. But despite this, there are main aspects of preparation:

The FVD session can begin only after the patient sits in a free, relaxed position, in a well-ventilated room with a normal temperature (not exceeding +20 degrees Celsius).
The patient should rest for about thirty minutes before the examination.
The day before the examination you should not smoke or drink alcohol. Also, you should not wear clothes that compress the chest and prevent normal breathing.

If you follow all the rules in preparing for a physical examination, the examination results are guaranteed to be reliable.

Technique

In order to conduct a physical function test, you need a device called a spirometer. The doctor who prepared the spirometer puts a mouthpiece on it and measures the readings. In addition, performing a FVD examination includes placing a clamp on the patient's nose and inserting a tube into the patient's mouth.

Sequence of examination

The patient needs to stand or sit.
A clamp is installed to prevent air from entering the patient's nose.
A special tube is inserted into the patient's mouth.

Once the patient is ready for the examination, the doctor must give the patient instructions that he must follow. The patient is recommended to take a strong breath, and then a long and equally strong exhalation.

You can see how the spirometer works in the video at the link.

FVD: research methods

The study of external respiration functions (ERF) contains the following techniques:

spirography— determines changes in indicators in air volumes;
peak flowmetry- determines the speed at which a person exhales.

A little about our breathing

Respiration is a physiological process that ensures normal metabolism by receiving oxygen from the environment and releasing carbon dioxide into the environment.

In case of disturbances in the functioning of the respiratory organs, studies of the ventilation function of the lungs are carried out.

FVC (forced vital capacity of the lungs)- this is the amount of air exhaled with intensification after a strong inhalation.
Vital capacity (vital capacity of the lungs)- this is the largest volume of air exhaled after an intense inhalation.

Study of external respiration functions

Since in recent days there has been an increase in bronchological diseases, a study of respiratory function becomes necessary. To identify any pulmonary diseases or disturbances in the functioning of the pulmonary system, a pulmonary function test is used.

Indications and contraindications

The examination cannot be carried out in the following cases:

heart failure;
acute infectious diseases;
high blood pressure;
severe angina.

Also, the study is contraindicated for children and people with mental disabilities who will not be able to follow the doctor’s instructions.

Indications for the study:

asthma;
bronchitis;
silicosis;
pneumonia and others.

Blood gas studies

Blood is mobile connective tissue.

A blood gas study examines a patient's arterial blood.

Blood for research is taken from the brachial, radial or femoral artery.

The components of blood that maintain the body's hydrogen level in a normal state are called pH. Normal: 7.30 - 7.49.

Exceeding the normal threshold can result in severe illness or even death. A decrease indicates that the patient has developed pathological processes.

Many important processes, such as biosynthesis, stimulation of cell fermentation, muscle and nerve transmission, depend on the state of the human blood.

Changes in blood gas composition may be metabolic or respiratory. The respiratory one depends on the normal level of carbon dioxide, and the metabolic one depends on the reaction of changes in the content of sodium bicarbonate in the blood fluid.

FVD study: spirography, provocation test with methancholine, body plethysmography

Spirography is a procedure that helps identify any diseases of the respiratory system in the early stages

With the help of spirography, you can find out if there are any disturbances in the functioning of the respiratory system.

Based on air volume indicators, the respiratory function is determined.

The examination is carried out using a spirometer. To study FVD using spirography, a clamp is placed on the patient's nose to prevent air from entering the nose, and a special tube is placed in the mouth.

The patient needs to exhale into the tube of the device.

The spirometer contains electronic sensors that record the volume and speed of air exhaled.

A study of the function of the respiratory system using spirography can be seen below:

Provocative test with methancholine

It often happens that the doctor cannot say for sure whether the patient has asthma or not. In order to accurately find out the presence or absence of asthma, you need to use a provocative test with methancholine.

This type of spirometry reveals readiness for bronchospasm, hyperactivity and asthma. Only through this type of spirometry can we say for sure whether a person has asthma or not.

With this test you can find out the presence of any bronchial asthma.

Bodyplethysmography

Body plethysmography is similar in many ways to conventional spirometry, but body plethysmography can provide more information. It determines all lung volumes.

The main aspects of undergoing body plethysmography:

The patient needs to sit in a special booth, which is equipped with a pneumotapograph.
During body plethysmography, the patient needs to breathe through a tube and follow all the doctor’s instructions.
Any vibrations of the chest during body plethysmography are recorded.
After this, you can immediately receive the results of the examination.

You can learn more about body plethysmography from the educational video

Study of the diffusion features of the lungs

The diffusion test evaluates the lungs' ability to deliver gas to red blood cells. This test requires expensive equipment and highly qualified doctors.

Aspects of preparation for the study of respiratory function: spirometry and body plethysmography

The day before the FVD, you should not smoke, eat heavily, or take bronchodilator medications.

What is spirometry and how is it performed?

Spirometry is used to determine lung parameters. A spirometric study identifies respiratory diseases and determines the severity of the pathology.

Preparing for spirometry

To ensure accurate spirometry results, you must:

The day before the test, do not take medications that affect respiratory processes.
Before starting the session, do not drink strong tea or coffee. Do not use tobacco.
The day before the procedure, do not wear clothing that restricts breathing.
Before starting the session, you need to rest for about thirty minutes.

Sequence of spirometry

The patient needs to sit or lie down.
The doctor needs to apply a clamp to the patient's nose.
And then insert the tube into your mouth.
After the doctor’s command, the patient needs to take a strong breath, and then exhale strong and long.

Indications for spirometry

If the respiratory system malfunctions, lung function decreases. Spirometry helps identify diseases.

Indications:

allergy;
poor gas exchange;
respiratory diseases;
physical condition assessment;
readiness for surgical intervention;
detection of chronic obstructive pulmonary disease (COPD).

Spirometry norm indicators. Table.

What is FVD research? Does it hurt?

A respiratory function test is a check of the condition of the lungs and identification of diseases of the respiratory system. FVD research helps to identify diseases in the initial stages and diagnose their treatment.

FVD examination can be carried out in three ways:

spirography;
peak flowmetry;
pneumotachometry.

Is it painful to get tested?

An FVD study does not hurt at all. All the patient needs to do is inhale and exhale into the tube at the doctor’s command.

FVD research in Moscow

The study of respiratory function makes it possible to identify lung diseases in the initial stages and diagnose their treatment. Since FVD research contains many different methods, prices will vary depending on the method, the equipment used, and the medications used.

The most inexpensive type of diagnostics is pneumotachography. On average, the procedure can cost about 500 rubles.

A study of respiratory function using spirography costs an average of 800 rubles. Below is a list of clinics in Moscow where you can undergo spirography:

Spirometry - study of respiratory function

Spirometry is a procedure that detects various diseases of the respiratory system in the early stages. In some cases, spirometry may be prescribed to teach proper breathing.

Indications for spirometry

chronic cough or shortness of breath;
allergy;
violation of gas exchange;
respiratory diseases;
physical condition assessment;
preparation for surgical intervention;
detection of chronic obstructive pulmonary disease.

Aspects of preparation for spirometry.

In order to obtain accurate spirometry results, you must:

the day before the examination, do not take medications that have any effect on the respiratory processes and respiratory organs;
three to five hours before the examination you should not drink strong tea and coffee;
three to five hours before the test, do not smoke;
the day before the examination, do not wear clothes that interfere with breathing and compress the chest.

Algorithm for spirometry

the patient must stand or take a sitting position;
a clip is placed on the patient’s nose;
a special tube is inserted into the patient’s mouth;
as directed by the doctor, the patient should take a deep breath, and then exhale forcefully and for a long time.

Post Views: 4,938

Human breathing is an important component that provides a person with not just normal functioning, but life itself. As a result, doctors pay a lot of attention to normal breathing, which leads to the need for regular examinations. This is especially important if you have problems with the respiratory organs.

In this case, respiratory function is always prescribed - a special examination of the function of external respiration. To determine deviations, a test with Salbutamol, a bronchodilator drug from the group of selective β2-adrenergic receptor agonists, is used. The results of the examination before and after taking Salbutamol are carefully studied, on the basis of which various diseases of the respiratory system can be identified.

FVD examination is the main direction of instrumental diagnostics in identifying diseases of a pulmonary nature. The examination method includes such examination methods as:

Breathing is a necessary life process for humans, allowing the body to receive the amount of oxygen that cells need for normal functioning. With a lack of oxygen, cells begin to break down, leading to disruptions in the functioning of internal organs. This often occurs as a result of bronchospasm. The cause can be determined by an examination of the respiratory function.

In most cases, spirometry is used to determine abnormalities in breathing, which allows:

The presented examination is carried out during physical activity or before and after inhalations with bronchodilators. The benefits of FVD using Salbutamol will be discussed further.

Indications and contraindications for examination

The doctor begins to talk about performing a respiratory tract test when he sees a patient at risk of developing a pulmonary disease - often the patient himself complains of breathing problems. The following indications are distinguished for examination:

Additionally, an examination of the respiratory function is carried out in the following cases:

before hiring a job where there are harmful working conditions;
before surgery with the need to use intubation anesthesia;
during screening to detect changes.

We must not forget about contraindications to performing FVD, which include:

FVD examination is not carried out for young children and elderly people over 75 years of age.

Preparation

Now we should talk in more detail about the preparation, conduct and results of the pulmonary examination in question.

The doctor tells you more about the preparation, guided by the individuality of the case and the patient himself - it is important to determine the exact prohibitions in a specific suspicion or disease. The main features of preparation include the following points:

It is important to take into account and comply with all the given restrictions and features in preparation, then the obtained indicators will be as reliable as possible. Otherwise, provided that the results reveal any pathology, the FVD must be repeated.

Conducting FVD

After preparation, the actual examination begins. In this case, the patient sits in a chair in a straight position, placing his hands on the armrests. The specialist prepares a spirometer device that measures the parameters necessary for diagnosis - he puts a disposable mouthpiece on it. After which a nose clip is put on the patient’s nose, and the specialist requires the following to be done:

The presented actions are performed several times, after which the results are studied by a specialist and a verdict is made.

About the norms of indicators

To determine pathology and other disorders in the pulmonary system, basic indicators are used. Based on them, other components are also determined through appropriate calculations. In the results obtained, the patient often encounters more than 20 values, each of which determines one or another respiratory factor. Now only the main values should be given, if they are deviated, the doctor makes a conclusion about developing disorders.

The given indicators are only basic, allowing you to determine the presence of problems with the respiratory system. You can understand the nature of the problem only after studying and comparing all the values and individual factors.

It should only be noted that the reliability of the results obtained is determined in the absence of errors between the indicators of three repetitions. An error is allowed, but not more than 5%, and this is only 100 ml. In other cases, you will have to take the test again.

Test with Salbutamol

A test using Salbutamol is carried out to identify an obstructive type of respiratory failure - the presence of bronchospasm. Salbutamol is a special bronchodilator drug that makes it possible to determine the degree of reversibility of changes and the severity of diseases.

The examination is carried out twice. First, the patient exhales into the device before applying Salbutamol. After recording the indicators, the patient is allowed to take 2-3 breaths with the inhaler, into which the drug for testing was previously filled. After 15-30 minutes, the FVD procedure is repeated again, the indicators of which are also recorded. Next, the doctor determines whether the test is positive or not.

A positive test is diagnosed when the forced expiratory volume in 1 second (FEV1) is increased by 12%, which in quantitative terms is 200 ml. The FEV1 indicator may be higher, but it means that the identified obstruction is reversible and after taking it in the form of inhalation with Salbutamol, bronchial patency improves significantly - this makes it possible to restore the respiratory system.

If the test with Salbutamol is negative, this means that bronchial obstruction is not reversible, and the bronchi do not respond in any way to the use of a bronchodilator drug in treatment.

This is important: before examining FVD with Salbutamol, the use of other bronchodilators is prohibited for 6 hours.

Spirometry or spirography with Salbutamol

Spirometry is a standard test of lung function and volume to help identify possible causes of gas exchange. Spirography is a graphical examination of lung volume and exhaled air flow rate by recording indicators over time.

But neither spirometry nor spirography provide an accurate and more reliable result. Often, hidden bronchospasms remain undetected when using standard examination methods.

Another thing is the use of the bronchodilator Salbutamol. In the case of spirometry, the drug allows you to determine hidden breathing disorders. Spirometry using Salbutamol gives a more accurate picture of respiratory functionality and allows you to identify even hidden bronchospasm.

Such use is necessary when the patient complains of characteristic difficulty breathing, but standard examination methods have not revealed any abnormalities.

Patient Maria, 54 years old. She has a full build, went to the doctor with breathing problems - she periodically develops a convulsive type of inhalation. As a result of such breathing difficulties, headaches and increased blood pressure appeared. A standard spirometry examination revealed no breathing problems.

However, after using Salbutamol, doctors discovered hidden bronchospasms. The cause was established later - displacement of the diaphragm due to an increased amount of fat on the internal organs of the abdominal cavity. A weight loss diet and bronchodilator medications are recommended.

If you have breathing problems, do not delay visiting your doctor. An examination of respiratory function will be carried out as soon as possible, which will determine the cause of dysfunction of the respiratory system and prescribe appropriate treatment.

All studies of external respiration function existing in the world can be done here at IntegraMedservice quickly and professionally.

If you need an assessment or examination of respiratory function - spirography, body plethysmography, assessment of the diffusion capacity of the lungs, feel free to contact us
If you need spirography for a planned operation, we will quickly do it and give a detailed conclusion.
Need spirometry at home? Nothing could be easier! We conduct spirometry at home, both as a separate study and as part of a consultation with a pulmonologist at home
We perform spirography for children
if necessary, we can immediately give .

Spirometric study

Spirography is an informative, non-invasive, painless study of pulmonary function. Using this method, it is possible to determine whether there are changes in the speed of air passage through the bronchi, the nature of this disorder, how the air passes through the bronchi and the forced vital capacity of the lungs.

Why is Spirometry and spirography needed?

allows you to accurately diagnose broncho-obstructive lung diseases: with bronchial obstruction, bronchiolitis.
suspect restrictive lung diseases.
Spirometry is often necessary for anesthesiologists before elective surgery under general anesthesia.
Spirometry is performed for both children and adult patients. For children, it is carried out provided that the child complies with the commands of the doctor conducting the study.

How is spirometry performed?

When performing spirometry in our medical center

The pulmonologist will ask you to make three attempts to maximally inhale and exhale into a special device (spirograph) through a disposable mouthpiece-tube.
all obtained results are stored and processed by the device.
Having received the result, the doctor immediately gives a written conclusion.
Especially for children, when conducting physical exercise, we use an animation program built into the computer. It’s easier and more fun for a child to go through a boring, but necessary, doctor’s visit.

Spirometry with a bronchodilator (bronchodilator)

This is carrying out the above-described spirometry after inhaling, using a certain maneuver, a bronchodilator drug (ventolin, salbutamol, berodual). According to all the rules, it must be carried out, since hidden bronchospasm can be missed. In addition, the test allows you to determine whether bronchodilators can help you, and which ones.

The total duration of full spirometry with a bronchodilator takes 20 minutes.

Bronchoprovocation test with methacholine

This is a study of physical activity with inhalation of the drug methacholine. This type of spirometry allows us to identify hyperreactivity and readiness for bronchospasm in patients with a controversial diagnosis of bronchial asthma, the “cough” version of bronchial asthma and physical exertion asthma. In other words, it allows you to detect any bronchial asthma. In these conditions, routine spirometry is normal, but the bronchodilator test is negative. And only an expert test with methacholine can correctly diagnose whether you have asthma or not.

Rules for preparing for the study of respiratory function: spirometry, body plethysmography

Breath tests are not recommended if:
pain in the heart, angina pectoris
after eye, chest or abdominal surgery
recent pneumothorax
with individual sensitivity to drugs

Some tips:

do not take bronchodilators (discuss the period of non-use with your pulmonologist)
do not overeat - a full stomach will interfere with the correct maneuvers
do not smoke or exercise at least 6-8 hours before the test

Do you want to do spirography of external respiration function?
Why do we make FVD better?
Where should you do: spirometry, body plethysmography, methacholine test?

IntegraMedservice medical center has a license for functional diagnostics and pulmonology
in the pulmonology department of our medical center we will carry out all the necessary breathing tests at the highest professional level
We employ pulmonologists and specialists in the study of external respiration function only from the Research Institute of Pulmonology
we know how to work with children
we can perform spirometry at home
you immediately get the result and, if you want, a consultation with a pulmonologist
the opinions of our specialists are authoritative in medical circles

Assessment of external respiratory function (RPF) in medicine is a very important tool for drawing conclusions about the state of the respiratory system. FVD can be assessed using different methods, the most common and more accurate of which is spirometry. Currently, spirometry is carried out using modern computer technology, which increases the reliability of the data obtained several times.

Show all

Spirometry

Spirometry is a method for assessing external respiratory function (ERF) by determining the volumes of inhaled and exhaled air and the speed of movement of air masses during breathing. It is a very informative research method.

Spirometry should only be performed on the recommendation of a competent medical specialist.

Indications

To assess the function of external respiration, the following indications exist:

diagnosis of diseases of the respiratory system (bronchial asthma, chronic obstructive pulmonary disease, chronic bronchitis, alveolitis, etc.);
assessment of the impact of any disease on the function of the lungs and airways;
screening (mass examination) of people who have risk factors for the development of pulmonary pathology (smoking, interaction with harmful substances due to profession, hereditary predisposition);
preoperative assessment of the risk of breathing problems during surgery;
analysis of the effectiveness of treatment of pulmonary pathology;
assessment of pulmonary function when determining disability.

Spirometry is an important method for diagnosing respiratory diseases

Contraindications

Spirometry is a safe procedure. It has no absolute contraindications, but forced (deep) exhalation, which is used to assess respiratory function, should be performed with caution:

patients with developed pneumothorax (presence of air in the pleural cavity) and within 2 weeks after its resolution;
in the first 2 weeks after the development of myocardial infarction or surgical interventions;
with severe hemoptysis (blood discharge when coughing);
for severe bronchial asthma.

Spirometry is contraindicated in children under 5 years of age. If it is necessary to assess respiratory function in a child under 5 years of age, a method called bronchophonography (BFG) is used.

Research methodology

To study the respiratory function, the patient needs to breathe for some time into the tube of a device called a spirograph. This tube (mouthpiece) is disposable and is changed after each patient. If the mouthpiece is reusable, then after each patient it is disinfected in order to prevent the transmission of infection from one person to another.

Spirometric testing can be carried out during quiet and forced (deep) breathing. The forced breathing test is carried out as follows: after a deep breath, the person is asked to exhale as much as possible into the tube of the device.

To obtain reliable data, the study is carried out at least 3 times. After receiving spirometry readings, a healthcare professional should check whether the results are reliable. If in three attempts the parameters of the respiratory function differ significantly, this indicates the unreliability of the data. In this case, additional recording of the spirogram is required.

All examinations are performed with a nose clip to prevent nasal breathing. If there is no clamp, the physician should ask the patient to pinch their nose with their fingers.

Preparing for the study

To obtain reliable survey results, you must follow some simple rules.

Do not smoke for 1 hour before the test.
Do not drink alcohol at least 4 hours before spirometry.
Avoid heavy physical activity 30 minutes before the test.
Do not eat 3 hours before the test.
The patient's clothing should be loose and not interfere with deep breathing.
If the patient wears removable dentures, they should not be removed before the examination. Prostheses should be removed only on the recommendation of a doctor if they interfere with spirometry.

Spirometry indicators

To assess physical activity, there are the following main indicators.

Vital capacity of the lungs (VC). This parameter shows the amount of air that a person can maximally inhale or exhale.
Forced vital capacity (FVC). This is the maximum volume of air that a person is able to exhale after a maximum inhalation. FVC can decrease in many pathologies, but increases only in one - acromegaly (excess growth hormone). With this disease, all other lung volumes remain normal. The reasons for a decrease in FVC may be:
- lung pathology (removal of part of the lung, atelectasis (collapsed lung), fibrosis, heart failure, etc.);
- pathology of the pleura (pleurisy, pleural tumors, etc.);
- reduction in chest size;
- pathology of the respiratory muscles.

Forced expiratory volume in the first second (FEV1) is the portion of FVC that is recorded during the first second of forced expiration. FEV1 decreases in restrictive and obstructive diseases of the bronchopulmonary system. Restrictive disorders are conditions that are accompanied by a decrease in the volume of lung tissue. Obstructive disorders are conditions that reduce the patency of the airways. To distinguish between these types of violations, it is necessary to know the values of the Tiffno index.
Tiffno index (FEV1/FVC). With obstructive disorders, this indicator is always reduced, with restrictive disorders it is either normal or even increased.

Decoding the results

If a patient has an increase or normal values of FVC, but a decrease in FEV1 and the Tiffno index, then they speak of obstructive disorders. If FVC and FEV1 are reduced, and the Tiffno index is normal or increased, then this indicates restrictive disorders. And if all indicators are reduced (FVC, FEV1, Tiffno index), then conclusions are made about mixed type FV violations.

Options for conclusions based on spirometry results are presented in the table.

Variant of violations	FVC	FEV1	Tiffno index
Obstructive disorders	norm/	↓	↓
Restrictive violations	↓	↓	norm/
Mixed violations	↓	↓	↓

It should be noted that parameters indicating pulmonary restriction may deceive the physician. Often, restrictive disorders are recorded where they do not actually exist (false-positive result). To accurately diagnose pulmonary restriction, a method called body plethysmography is used.

The degree of obstructive disorders is determined by the values of FEV1 and Tiffno index. The algorithm for establishing the degree of bronchial obstruction is presented in the table.

Bronchodilation test

If an obstructive type of respiratory function disorder is detected in a patient, it is necessary to additionally conduct a test with a bronchodilator to determine the reversibility of obstruction (impaired patency) of the bronchi.

A bronchodilator test involves inhaling a bronchodilator (a substance that dilates the bronchi) after spirometry has been performed. Then, after a certain time (the exact time depends on the bronchodilator used), spirometry is performed again and the results of the first and second studies are compared. Obstruction is reversible if the increase in FEV1 in the second study is 12% or more. If this indicator is lower, then a conclusion is made about irreversible obstruction. Reversible bronchial obstruction is most often observed in bronchial asthma, irreversible - in chronic obstructive pulmonary disease (COPD).

Bronchophonography (BFG) is used for children under 5 years of age. It does not consist of recording tidal volumes, but of recording breathing sounds. BFG is based on the analysis of respiratory sounds in different sound ranges: low frequency (200 – 1200 Hz), mid frequency (1200 – 5000 Hz), high frequency (5000 – 12600 Hz). For each range, the acoustic component of work of breathing (ACWP) is calculated. It represents a final characteristic proportional to the physical work of the lungs spent on the act of breathing. ACRD is expressed in microjoules (µJ). The most indicative is the high-frequency range, since significant changes in ACRD, indicating the presence of bronchial obstruction, are detected precisely in it. This method is carried out only with quiet breathing. Carrying out FG during deep breathing makes the examination results unreliable. It should be noted that BPG is a new diagnostic method, so its use in the clinic is limited.

Conclusion

Thus, spirometry is an important method for diagnosing diseases of the respiratory system, monitoring their treatment and determining the prognosis for the life and health of the patient.

In some cases, after implementing this method, additional procedures must be carried out. Therefore, the doctor may prescribe, for example, bronchodilator testing.

Other methods are not as widely used. The reason for this is that their use is still poorly understood in practice.