What kind of analysis fvd. FVD results decoding. Positive Ventolin test: what does it mean

“External respiration” is a general term that describes the process of moving air in the respiratory system, its distribution in the lungs and the transport of gases from the air to the blood and back.

Diagnosis of the function of external respiration (RF) is a method for studying the functions of lung ventilation by means of graphic fixation during various respiratory actions. Readings help to understand some aspects of lung function.

Why is it necessary to study the functions of external respiration

Any deviation in the tissues and respiratory organs provokes a violation of the respiratory process, and any changes in the functions of the bronchi and lungs can be detected on the spirogram. If the pathology is not detected in time, then the disease can affect the chest (pump), lung tissue (gas exchange and oxygen saturation) or the respiratory tract (free movement of air).

During the study of the respiratory organs, not only the presence of respiratory dysfunction is revealed, but also a clear understanding appears which area of ​​the lungs has been damaged, how quickly the disease passes, what treatment methods are suitable in a particular case.

When examining the respiratory function, several indications are simultaneously recorded, which are based on gender, age, height, weight, genetics, lifestyle and existing chronic diseases. That is why the interpretation of these indicators should be carried out by the attending doctor.

Moreover, the results of the study of respiratory function help to determine the source of dyspnea and the extent of respiratory system disorders, choose the right treatment and determine the level of its effectiveness, detect reduced lung ventilation and determine the nature of its severity, calculate the reversibility of disorders when using bronchodilators, and also track the frequency of bronchopulmonary modifications. tree during the course of the disease.

Research types

Spirometry (spirometry) is based on the identification of the working state of the respiratory organs. Completely painless and fast process, therefore it is not contraindicated for children. It helps to make a conclusion about which area is affected, how much the functional indicators have decreased, and to what extent these deviations are dangerous.

Pneumotachometry - measurement of the patency of the respiratory tract. It is carried out using a special device that sets the speed of the air flow during inhalation and exhalation. It is mainly used to study diseases in a chronic form.

The study of respiratory effort - describes the deviation of the maximum speed of air entering the lungs with increased inhalation and exhalation, thereby helping to assess the position of bronchial patency.

Body plethysmography - studies of respiratory function by comparing the results of spirography and indicators of mechanical variations of the chest during the entire breathing cycle. Allows you to detect the real volume of the lungs, which is not displayed during spirometry.

The study of the diffusion capacity of the lungs - reveals an indicator of the ability of the lungs to transport oxygen into human blood. It is considered a significant diagnostic method, therefore it is included in the list of mandatory respiratory function studies for interstitial and disseminated lung ailments.

Spirometry test with bronchodilators - performed to assess the reversibility of the obstruction. Helps to distinguish between COPD and asthma and indicate the stage of development of the disease.

Indications and contraindications for the procedure

The study of the function of external respiration has the following indications:

• complaints of changes in breathing, coughing and shortness of breath;
• asthma, COPD;
• pathology of the lungs, which was discovered during another diagnosis;
• a large amount of carbon dioxide and a small amount of oxygen in the blood;
• preoperative or invasive examination of the respiratory system;
• screening study of people who smoke, employees of hazardous factories and people who have respiratory allergies.

Like any form of research, FVD also has a number of contraindications, including bleeding in the bronchi or lungs, aortic aneurysm, tuberculosis, stroke or heart attack, pneumothorax, mental or mental disorders.

The process of studying the function of external respiration

First, the patient is explained the research method and the rules of the patient's behavior during the examination: how to breathe correctly, when to breathe with effort, when to hold your breath, and so on. If necessary, the patient is offered additional diagnostics that will help establish a more accurate diagnosis.

The study of FVD takes place in a sitting position. The patient closes his nose with a clamp and holds a disposable mouthpiece with his mouth, which is combined with the spirometer tube.

This is necessary so that the respiratory process passes only through the mouth, and the entire air flow is taken into account by the spirometer. After installing all the necessary devices, the diagnostic itself begins. As a rule, testing takes place several times and then the average value is taken to minimize the error.

The duration of the FVD study is always different, since it depends on the methodology, but on average it takes no more than 30 minutes. If a test with bronchodilators is needed, then the diagnosis period may increase and require a second examination. Preliminary data (without doctor's comment) will be ready almost immediately.

Study preparation

Before the study of the respiratory function, special preparation is not required, however, it is still worth excluding any physical and nervous stress, physiotherapy; stop eating 2 hours and smoking 4 hours before the diagnosis; empty the intestines and bladder; refrain from taking bronchodilators (ventolin, berodual, atrovent, etc.) and caffeine-containing drugs (including and) 8 hours before the examination; exclude inhalation (except mandatory!); wash off lipstick; loosen the tie, unbutton the collar.

Be sure to take a doctor's referral for diagnosis with you, and if such an examination has already been carried out before, then the results of the previous study.

The patient must know the exact weight and height. Before starting the procedure, you need to be in a sitting position for 15 minutes, so the patient should arrive a little in advance. You need to wear loose clothing that does not restrict the activity of the chest during increased breathing. It is also strictly forbidden to take aminophylline or other similar drugs on the eve of the examination, after taking these drugs, at least a day must pass.

Assessment of the function of external respiration (RF) is the simplest test that characterizes the functionality and reserves of the respiratory system. A research method that allows you to evaluate the function of external respiration is called spirometry. This technique is currently widely used in medicine as a valuable way to diagnose ventilation disorders, their nature, degree and level, which depend on the nature of the curve (spirogram) obtained during the study.

Evaluation of the function of external respiration does not allow to make a final diagnosis. However, spirometry greatly facilitates the task of making a diagnosis, differential diagnosis of various diseases, etc. Spirometry allows you to:

• identify the nature of ventilation disorders that led to certain symptoms (shortness of breath, cough);
• assess the severity of chronic obstructive pulmonary disease (COPD), bronchial asthma;
• carry out with the help of certain tests differential diagnosis between bronchial asthma and COPD;
• to monitor ventilation disorders and evaluate their dynamics, the effectiveness of treatment, assess the prognosis of the disease;
• assess the risk of surgery in patients with ventilation disorders;
• identify the presence of contraindications to certain physical activities in patients with ventilation disorders;
• to check for the presence of ventilation disorders in patients at risk (smokers, professional contact with dust and irritating chemicals, etc.) who do not present any complaints at the moment (screening).

The examination is carried out after a half-hour rest (for example, in bed or in a comfortable chair). The room must be well ventilated.

The survey does not require complex preparation. The day before spirometry, it is necessary to exclude smoking, drinking alcohol, wearing tight clothing. You can not overeat before the study, you should not eat less than a few hours before spirometry. It is advisable to exclude the use of short-acting bronchodilators 4-5 hours before the study. If this is not possible, it is necessary to inform the medical staff conducting the analysis of the time of the last inhalation.

During the study, an assessment of respiratory volumes is carried out. Briefing on how to properly perform breathing maneuvers is given by the nurse immediately before the study.

Contraindications

The technique has no clear contraindications, except for a general severe condition or impaired consciousness that does not allow spirometry. Since it is necessary to make certain, sometimes significant efforts, to implement a forced respiratory maneuver, spirometry should not be performed in the first few weeks after myocardial infarction and operations on the chest and abdominal cavity, ophthalmic surgical interventions. The determination of the function of external respiration should also be delayed in case of pneumothorax, pulmonary hemorrhage.

If you suspect that the person being examined has tuberculosis, it is necessary to comply with all safety standards.

According to the results of the study, a computer program automatically creates a graph - a spirogram.

The conclusion on the received spirogramma can look like this:

• norm;
• obstructive disorders;
• restrictive violations;
• mixed ventilation disorders.

What verdict the doctor of functional diagnostics will make depends on the compliance / non-compliance of the indicators obtained during the study with normal values. The parameters of the respiratory function, their normal range, the values ​​of the indicators according to the degrees of ventilation disorders are presented in the table ^

All data are presented as a percentage of the norm (with the exception of the modified Tiffno index, which is an absolute value that is the same for all categories of citizens), determined depending on gender, age, weight and height. The most important is the percentage compliance with the normative indicators, and not their absolute values.

Despite the fact that in any study the program automatically calculates each of these indicators, the first 3 are the most informative: FVC, FEV 1 and the modified Tiffno index. Depending on the ratio of these indicators, the type of ventilation violations is determined.

FVC is the largest volume of air that can be inhaled after a maximum exhalation or exhaled after a maximum inhalation. FEV1 is the portion of FVC determined in the first second of a respiratory maneuver.

Determination of the type of violations

With a decrease in only FVC, restrictive violations are determined, i.e., violations that limit the maximum mobility of the lungs during breathing. Both pulmonary diseases (sclerotic processes in the lung parenchyma of various etiologies, atelectasis, accumulation of gas or fluid in the pleural cavities, etc.) and pathology of the chest (Bekhterev's disease, scoliosis), leading to restriction of its mobility, can lead to restrictive ventilation disorders.

With a decrease in FEV1 below normal values ​​and the ratio of FEV1 / FVC< 70% определяют обструктивные нарушения - патологические состояния, приводящие к сужению просвета дыхательных путей (бронхиальная астма, ХОБЛ, сдавление бронха опухолью или увеличенным лимфатическим узлом, облитерирующий бронхиолит и др.).

With a joint decrease in FVC and FEV1, a mixed type of ventilation disorders is determined. The Tiffno index may correspond to normal values.

According to the results of spirometry, it is impossible to give an unambiguous conclusion. The interpretation of the results obtained should be carried out by a specialist, necessarily correlating them with the clinical picture of the disease.

Pharmacological tests

In some cases, the clinical picture of the disease does not allow to unambiguously determine what the patient has: COPD or bronchial asthma. Both of these diseases are characterized by the presence of bronchial obstruction, but the narrowing of the bronchi in bronchial asthma is reversible (except for advanced cases in patients who have not received treatment for a long time), and in COPD it is only partially reversible. The reversibility test with a bronchodilator is based on this principle.

The study of respiratory function is carried out before and after inhalation of 400 mcg of salbutamol (Salomola, Ventolina). An increase in FEV1 by 12% from the initial values ​​(about 200 ml in absolute terms) indicates a good reversibility of the narrowing of the lumen of the bronchial tree and testifies in favor of bronchial asthma. An increase of less than 12% is more characteristic of COPD.

The test with inhaled glucocorticosteroids (IGCS), prescribed as a trial therapy for an average of 1.5-2 months, has become less widespread. An assessment of the function of external respiration is carried out before the appointment of IGCS and after. An increase in FEV1 by 12% compared with baseline indicates the reversibility of bronchial constriction and a greater likelihood of bronchial asthma in a patient.

With a combination of complaints characteristic of bronchial asthma, with normal spirometry, tests are performed to detect bronchial hyperreactivity (provocative tests). During their implementation, the initial values ​​of FEV1 are determined, then inhalation of substances that provoke bronchospasm (metacholine, histamine) or an exercise test is performed. A decrease in FEV1 by 20% from baseline indicates in favor of bronchial asthma.

The world community notes a steady increase in bronchopulmonary diseases, including obstructive variants. Official statistics show an almost double increase in cases of bronchial asthma and chronic obstructive pulmonary disease (COPD). According to unofficial data, there are much more cases of pathology - many do not rush for medical help, preferring to fight the pathology on their own. Examination of respiratory function (RF) is the easiest way to identify these diseases.

Analysis of respiratory function

This is especially important for people of working age - bronchopulmonary diseases in the absence of adequate treatment often become the cause of patients' disability. In clinical practice, broncho-obstructive syndrome is often combined with other pathologies - arterial hypertension, coronary insufficiency, arrhythmias of various origins, endocrine disorders. Examination of respiratory function (RF) is the simplest and most reliable way to detect bronchopulmonary pathologies in the early stages.

Indications for the appointment of an examination

Despite the fact that the FVD study is carried out quickly and does not harm health, it has clear indications and some limitations. Today, the following methods for studying the function of external respiration are used - spirometry and pneumotachography. Patients are referred for examination in the following cases:

• suspicion of diseases of the bronchopulmonary sphere (asthma, pneumonia) - a prolonged cough that is not treatable, pain, shortness of breath, sputum with an unpleasant odor;
• assessment of the impact of the current disease on the lungs;
• preventive examinations of people at risk - long-term smokers, workers in hazardous industries;
• ongoing monitoring of the course of lung disease, incl. evaluation of the effectiveness of the treatment;
• disability examination;
• preparation of the patient for operations on the lungs or bronchi;
• selection of the optimal bronchodilator for the treatment of the underlying disease;
• in sports to determine how well an athlete tolerates current physical activity.

The ease of such an examination and its low cost allow each person to regularly undergo it.

Examination of the function of external respiration on a spirograph

Self-control, carried out at least once a year, is especially indicated for experienced smokers and workers in hazardous industries. After 40-50 years, such an examination is recommended for everyone.

When is the study of respiratory function not prescribed?

Regardless of the specific methodology, such a study has certain limitations, and is not prescribed in the following cases:

• severe airway obstruction;
• acute myocardial infarction, and within three months after it;
• acute violation of cerebral circulation of any type;
• aortic aneurysm;
• acute respiratory tract infections (RT) and 2 weeks after them;
• pregnancy;
• hypertensive crisis;
• epilepsy.

How to properly prepare for the examination?

Preparation for spirometry does not require compliance with complex conditions. A day before the examination, alcohol, strong tea and coffee are excluded, it is recommended to limit smoking if possible. If a person takes drugs that affect the functioning of the bronchopulmonary system, this should be notified in advance to your doctor. The last meal should be 2 hours before the study. The rest of the preparation for the study of the function of external respiration begins directly in the medical institution.

Before carrying out the necessary tests, the patient should be in a calm environment for half an hour, with the exception of active physical exercises. Clothing should be loose enough, not restricting movement and chest. In the presence of bronchial asthma, the inhaler should be with you, as well as a clean handkerchief. As can be seen, the method of preparation for the study of the function of external respiration allows you to correctly fulfill all the conditions even for patients in serious condition.

How is the research going?

Before the study of the function of external respiration, the patient is in the supine position for less than 15 minutes. During this time, breathing returns to normal, after which the study itself begins. It can be carried out by two methods - spirography and pneumotachography.

The first method is a graphical recording of changes occurring in a person's lungs when performing various respiratory maneuvers. Pneumotachography allows you to fix the volumetric air flow rate during quiet breathing and during physical activity. The currently used spirometric equipment allows for the simultaneous recording of pneumotachometric and spirographic indicators (maximum lung ventilation and functional test indicators) in a patient, which simplifies and speeds up the examination. In some cases, spirometry with a bronchodilator is indicated - this study helps to accurately determine the presence of pathology and prevent its development.

Modern spirograph

Spirometry FVD is performed in the patient's sitting position, the hands are located on special armrests. A disposable mouthpiece is put on the device, which the patient takes into his mouth, a nose clip is put on. The doctor asks the person to take a normal or slightly deeper breath, and then calmly release all the air through the mouthpiece. Thus, the tidal volume is determined - the amount of air inhaled by a person in everyday situations every day.

In the future, the expiratory reserve volume is fixed - when exhaling with maximum effort. Next, the patient must inhale as fully as possible - they receive indicators of the vital capacity of the lungs and the reserve inspiratory volume. As a rule, the function of external respiration requires several “approaches”, which provides extremely accurate indicators. In the future, the doctor evaluates the resulting graphs and forms a conclusion.

Study with bronchodilators

Spirometry with prior administration of bronchodilators is necessary when it is difficult to make an accurate diagnosis, as well as to assess the degree of effectiveness of a particular drug. Initially, the study takes place in a regular manner, without exposure to the drug. After fixing all the necessary indicators, the patient is given the selected drug, and fixing the respiratory function is repeated.

Pulmonary function testing can be done before and after bronchodilator inhalation

When using products based on salbutamol, measurements are repeated at intervals of 15 minutes. If a drug based on ipratropium bromide is used, the interval between measurements is about half an hour. In some cases, measurements are preceded by physical activity, but the first data recording is always carried out at rest. Since most complex disorders of the respiratory function cannot be determined only by external signs, all the data obtained are entered into a special computer, where they are processed by special software. The study of the functions of external respiration with bronchodilators helps to identify dangerous pathologies at the earliest stages.

Before the study, it is strictly forbidden to take any drugs containing stimulants. They affect not only the cardiovascular, but also the pulmonary system, which can lead to data distortion and incorrect diagnosis.

Interpretation of results

Spirographic curve

The study of the function of external respiration, the norm of which differs depending on the age and gender of the patient, allows diagnosing the main diseases of the bronchopulmonary system with sufficient accuracy. One of the most dangerous disorders is airway obstruction. This will be evidenced by a decrease in expiratory force and vital capacity of the lungs. Obstruction may indicate the presence of bronchial asthma, acute bronchitis with an asthmatic component, as well as chronic obstructive bronchitis. The doctor gives the transcript to the patient in his hands after analysis and diagnosis.

Function of external respiration (PFR)- This is a study that is carried out using a special device - a spirometer. A functional research method that allows you to evaluate the respiratory function is called spirometry. Spirometry allows you to determine the functionality of the respiratory system - the speed of air movement during inhalation and exhalation, the volume of inhaled and exhaled air and diagnose the nature and degree of ventilation disorders. FVD is the main method for diagnosing bronchopulmonary diseases.

INDICATIONS FOR FVD

• Diagnosis of diseases of the respiratory system (chronic bronchitis, bronchial asthma, chronic obstructive pulmonary disease, alveolitis, etc.);
• Examination of people with risk factors for the development of broncho-pulmonary pathology (smoking, the presence of occupational hazards, hereditary predisposition);
• Preoperative risk assessment for possible breathing problems during surgery;
• Repeated procedure allows you to assess the dynamics of the disease and the effectiveness of the treatment;
• Expert assessment of the function of external respiration in determining the ability to work or disability group;
• In sports, to determine the athlete's tolerance for physical activity.

RESULTS

• The functional state of the lungs and bronchi, including the vital capacity of the lungs;
• Identify bronchospasm (obstruction);
• Assess airway patency;
• Identify the nature of ventilation disorders that cause certain symptoms (shortness of breath, cough);
• Assess the severity of diseases (chronic obstructive pulmonary disease, bronchial asthma);
• Carry out differential diagnostics between bronchial asthma and COPD using drug tests.

CONTRAINDICATIONS

Since during the procedure it is necessary to make a powerful and prolonged exhalation, which is accompanied by a significant tension of the main and auxiliary respiratory muscles, a load on the bone-ligamentous apparatus of the chest, an increase in intrathoracic, intra-abdominal and intracranial pressure, there are a number of contraindications:

• Severe angina pectoris, myocardial infarction in the acute period and within 3 months after it;
• High blood pressure numbers, recent acute cerebrovascular accident;
• Congestive heart failure, accompanied by shortness of breath at rest and with little exertion;
• Surgical treatment of the eyes, organs of the chest and abdominal cavity and within 3 months after it;
• Changes in the area of ​​ENT organs, maxillofacial region, chest, preventing the test or its adequate assessment;
• Acute respiratory tract infections and 2 weeks after them;
• Hemoptysis of unknown etiology;
• Pneumonia and tuberculosis, pneumothorax;
• aortic aneurysm;
• Pregnancy;
• Epilepsy;
• Children under 4 - 5 years old who cannot correctly follow the commands of the nurse;
• Mental disorders that do not allow you to correctly follow instructions.

PREPARATION FOR THE PROCEDURE

• The study is carried out on an empty stomach or 2 hours after eating;
• It is necessary not to smoke for 4 hours, not to drink strong tea or coffee, not to drink alcohol;
• 30 minutes before the study, exclude active physical exercises, sit in a calm atmosphere;
• Clothing should be comfortable and loose so as not to hamper the movements of the chest;
• When taking medications that affect lung function, it is necessary to agree with the attending physician on the possibility of their cancellation;
• In the absence of recommendations, stop short-acting bronchodilators 4 hours before the study;
• If the patient uses an inhaler, you should take it with you, have a handkerchief with you.

METHODOLOGY

The examination is carried out in a sitting position in a chair. The patient takes a disposable mouthpiece connected to the device into his mouth. A special clip is put on the nose so that breathing occurs through the mouth, and the spirometer would take into account the entire volume of air.

Then the research itself begins. After several cycles of calm breathing, the patient is asked to take the deepest possible breath and the most sharp, powerful and complete exhalation. To obtain reliable results, the described procedure is repeated several times and the average value is calculated to minimize the error.

After spirometry, a salbutamol test can be performed to assess the degree of bronchial obstruction. The patient inhales a fixed dose of the drug, which expands the lumen of the bronchi, and then repeat the study after 15 minutes. The test allows you to distinguish obstructive bronchitis from bronchial asthma and clarify the severity of obstruction.

The test is considered positive when the forced expiratory volume increases in 1 second. This means that the initially identified bronchial obstruction is reversible. This is observed in bronchial asthma. A negative test indicates irreversible bronchial obstruction. This is observed in obstructive bronchitis.

ADVERSE EVENTS

In some cases, the study is accompanied by slight fatigue and dizziness, passing within 1-3 minutes. More serious adverse events are unlikely. In the case of a test with salbutamol, palpitations and slight trembling in the limbs may appear.

Patients with diseases of the respiratory system are often prescribed a study of the function of external respiration (RF). Despite the fact that this type of diagnosis is quite simple, affordable, and therefore common, few people know what it is and for what purpose it is carried out.

What is FVD, and why measure it

Breathing is a vital process for a person of any age. During the respiratory process, the body is saturated with oxygen and releases carbon dioxide formed during metabolism. Therefore, impaired respiratory function can lead to a number of health problems.

External respiration is a medical term that includes a description of the processes of air circulation through the respiratory system, its distribution, the transfer of gases from the inhaled air to the blood and vice versa.

The study of respiratory function, in turn, allows you to calculate the volume of the lungs, assess the speed of their work, identify dysfunctions, diagnose diseases of the respiratory system and determine effective methods of treatment. Therefore, doctors use FVD for various purposes:

1. For diagnostics. In this case, the state of health, the impact of the disease on the functionality of the lungs and its prognosis are assessed. Also, the risk of developing pathology is determined (in smokers, people working in harmful conditions, etc.).
2. For dynamic monitoring of the development of the disease and evaluation of the effectiveness of therapy.
3. To issue an expert opinion, which is required when assessing suitability for work in special conditions and determining temporary disability.

Also, the diagnosis of the function of external respiration is carried out as part of epidemiological studies and in order to carry out a comparative analysis of people's health in different living conditions.

Indications and limitations for diagnosis

The reason for the study of lung function and the assessment of respiratory function are many diseases of the respiratory system. Carrying out such a diagnosis is prescribed for:

• chronic bronchitis;
• asthma;
• infectious inflammatory process in the lungs;
• chronic obstructive pulmonary disease;
• silicosis (occupational disease resulting from regular inhalation of dust with a high content of silicon dioxide);
• idiopathic fibrosing alveolitis and other pathologies.

Contraindications for FVD include:

• age less than 4 years - if the child is not able to correctly understand and follow the instructions of the health worker;
• development in the body of acute infections and febrile conditions;
• severe angina pectoris and myocardial infarction;
• stable increase in blood pressure;
• a stroke suffered shortly before the proposed study;
• congestive heart failure, which is accompanied by respiratory failure even with low exertion and at rest.

Important. Also, this type of diagnosis is not carried out in patients suffering from deviations in mental or mental activity that do not allow them to adequately respond to requests from medical staff.

Spirometry

Currently, there are various methods for studying the function of external respiration. One of the most common is spirometry.

For studies of this kind, a dry or water spirometer is used - a device consisting of two components. The spirometer sensor records the volume of air inhaled and the rate at which the subject inhales and exhales it. A microprocessor processes information.

Spirometry allows you to evaluate:

• the functionality of the organs involved in breathing (including the vital capacity of the lungs);
• airway patency;
• the complexity of changes in the respiratory system, their type.

In addition, with its help, bronchospasms are detected and determine whether changes in the respiratory system are reversible.

Examination process

During the diagnostic study, the patient is asked to inhale as deeply as possible, and then exhale into the spirometer. Initially, measurements are taken in a calm state, and then with forced breathing. The process is repeated several times with short breaks. When evaluating the result, the highest indicator is taken into account.

To determine the reversibility of the process of narrowing of the bronchi, spirometry is performed with a bronchodilator - a drug that expands this respiratory organ.

Study preparation

All studies are carried out, as a rule, in the morning on an empty stomach, or two hours after a small breakfast.

In order for the spirometry readings to be the most accurate, the patient must prepare for it in advance. As part of the preparation, doctors recommend:

• give up smoking for a day;
• do not drink strong tea, coffee and alcoholic beverages;
• half an hour before the examination, exclude active physical activity.

In some cases, medications that affect the functioning of the respiratory system are also canceled.

During the diagnosis, the patient must wear loose clothing that does not interfere with breathing with full breasts.

Deciphering the results

The average rate of breathing for a healthy person is:

• volume (DO) - from 0.5 to 0.8 liters;
• frequency (FR) - 10-20 times / min;
• minute volume (MOD) - 6-8 liters;
• expiratory reserve volume (ERV) - 1-1.5 l;
• vital capacity of the lungs (VC) - from 3 to 5 liters;
• forced VC (FVC) - 79-80%;
• forced exit volume for 1 sec. (FEV1) - from 70% FVC.

In addition to these indicators, the instantaneous expiratory volume velocity (MOS) is also determined. It is traced at different% filling of the lungs.

Important! Indicators of the volume and speed of breathing depend on the gender of the patient, his age, weight and physical condition (training). A small variability is also allowed in each individual category of the examined (no more than 15% of the norm).

Significant deviations from normal readings allow the doctor to determine which pathologies are taking place in the patient's respiratory system. So, if the VC indicator is 55% of the norm, and FEV1 is 90%, then this indicates the development of restrictive disorders characteristic of pneumonia, alveolitis.

Evidence of chronic obstructive pulmonary disease, in turn, is considered a slight decrease in VC (up to 70%) against the background of a sharp decrease in FVR1 (up to 47%). Other respiratory disorders also have characteristic indicators.

Bodyplethysmography

In terms of its functionality, this test is similar to spirometry, but it provides detailed and complete information about the state of the human respiratory system.

Body plethysmography helps to assess not only the patency of the bronchi, but also the volume of the lungs, as well as to recognize air traps that indicate emphysema.

Such a diagnosis is carried out using a body plethysmograph - an apparatus consisting of a body camera (in which the subject is placed) with a pneumotograph and a computer. On the monitor of the latter, the data of the study are displayed.

Peakflowmetry

A diagnostic method that allows you to determine the rate of inhalation / exhalation, and thereby assess the degree of narrowing of the airways.

The study is of particular importance for those who suffer from bronchial asthma, as well as patients with obstructive pulmonary disease in the chronic stage - it makes it possible to analyze the effectiveness of the chosen therapy.

Diagnostics is carried out using a special device - a peak flow meter. The first such apparatus in history was quite large and heavy, which greatly complicated the research. Modern peak flow meters are mechanical (in the form of a tube, on which divisions with colored markers are applied) and electronic (computer), which are distinguished by ease of use and compactness. At the same time, the methodology for conducting and evaluating the results is so simple that it can be carried out at home.

But, despite this, the device should be used only on the recommendation of the attending doctor, and even better under his control (you can set up the peak flow meter together with the doctor, and then use it yourself, recording the readings). This approach will allow you to correctly measure and interpret the indicators.

With a peak flowmeter:

• changes in bronchial patency at different times of the day are determined;
• the necessary treatment is planned, the correctness and effectiveness of previous appointments are assessed;
• periods of exacerbation of asthma are predicted.

In addition, factors are identified that increase the risk of exacerbation (in cases where seizures often occur in some places and do not occur at all in others).

How the study is conducted and the results are evaluated

Before starting regular measurements, the peak flow meter is adjusted to take into account the normal values ​​​​of peak expiratory force (PEF), which depends on the gender, age group and height of the patient. When setting also, according to special tables, the boundaries of the areas (normal, alarming and unsatisfactory) are calculated.

For example, the rate of PSV in a man of middle age and height (175 cm) is 627 l / min. The normal area (on the device it is marked in green) in this case is at least 80% of the norm, that is, 501.6 l / min.

The alarming (yellow color) includes indicators from 50 to 80% (in this case, from 313.5 to 501.6 l / min).

All values ​​that are below the limit of the alarm area will be marked as unsatisfactory (red).

Important. As an option for setting the peak flowmeter, the patient's spirometry indicators can be used (the best indicator of the study is taken as the basis).

Terms of use

To obtain the most complete picture, peak flowmetry is carried out twice a day - in the morning and in the evening. Special preparation for diagnosis is not required, but there are a number of rules that require strict adherence to:

• diagnosis is carried out before taking medications;
• before the start of the study, the slider-pointer is set to the beginning of the scale;
• during the measurement, the patient is standing or sitting (while the back is even);
• the device is held in a horizontal position with both hands (hands do not close the slider and holes);
• first inhale deeply and hold the breath for a short time, after which they exhale as quickly as possible.

Important. Each measurement is performed three times, with short breaks. The maximum indicator of the device is fixed and noted in an individual schedule, which the doctor subsequently gets acquainted with.

Additional Research

In addition to the main research methods, doctors often use additional tests to clarify the diagnosis or evaluate the effectiveness of treatment.

So, with spirometry, samples are prescribed with:

• salbutamol;
• physical activity;
• methacholine.

Salbutomol is a drug with a bronchodilator effect. A functional test with it is carried out after control studies and allows you to establish whether the narrowing in the bronchi is reversible or not. It also gives a more accurate picture of the state of the respiratory system and makes it possible to clarify the diagnosis. So, if FEV1 improves after taking a bronchodilator, this indicates asthma. If the test gives a negative result, this indicates chronic bronchitis.

Methacholine is a substance that provokes spasm (hence the name of the test - a provocative test) and allows you to determine asthma with 100% accuracy.

As for the load tests, in this case, the second study is carried out after exercise on a bicycle or running simulator and allows you to determine the asthma of physical effort with maximum accuracy.

As an additional study, a diffusion test is also often used. It allows you to evaluate the speed and quality of blood oxygen supply.

Reduced rates in this case indicate the development of a lung disease (and in a rather advanced form), or a possible thromboembolism of an artery in the lungs.