Shows fvd. What is the external respiration function and why is it determined? What disorders of the respiratory system and lungs does the examination show?
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 using 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.
Spirometry is the most important way to assess pulmonary function.
Spirography– a method of graphically recording lung volume during breathing, one of the main methods for diagnosing respiratory diseases.
Allows you to evaluate:
functional state of the lungs and bronchi (in particular the vital capacity of the lungs) –
airway patency
detect obstruction (bronchial spasm)
degree of severity of pathological changes.
Indications for spirometry:
Symptoms: shortness of breath, stridor, orthopnea, cough, sputum production, chest pain;
Objective examination data: weakened breathing, difficulty exhaling, cyanosis, chest deformation;
Abnormalities in laboratory tests: hypoxemia, hypercapnia, polycythemia, changes in chest x-rays.
2. Identifying people at risk of pulmonary diseases:
Smokers;
Persons whose work or service involves exposure to harmful substances.
3. Preoperative risk assessment.
4. Assessing the prognosis of the disease.
5. Assess your health status before participating in programs that require excessive physical effort.
6. Evaluation of therapeutic interventions and monitoring the effectiveness of treatment of acute and chronic lung diseases.
7. Supervision of persons working with harmful agents.
8. Military medical and medical labor examination.
Contraindications for spirometry:
1. Conditions requiring emergency care.
2. The presence of an acute (contagious) period of infectious diseases.
3. Conditions accompanied by disorientation and inappropriate behavior of the patient.
4. Changes in the area of the ENT organs, maxillofacial area, chest, preventing the test or its adequate assessment.
6. Young children.
TOabsolute contraindications Spirometric studies include:
Moderate or severe hemoptysis of unknown etiology;
Established or suspected pneumonia and tuberculosis;
Recent or existing pneumothorax on the day of examination;
Recent surgical intervention.
Fresh acute myocardial infarction, hypertensive crisis or stroke;
Methodology for studying the function of external respiration.
The study should be carried out after half an hour's rest lying in bed or sitting in a chair with armrests in a well-ventilated room at a temperature of 18-20C.
Before the study begins, the patient must sit for 5-10 minutes.
Age, height and gender must be recorded. Take into account the race of the person being studied and make appropriate adjustments if necessary.
The patient should avoid smoking for 24 hours before the test, drinking alcohol, wearing clothes that compress the chest, eating large meals 2-3 hours before the test, and using short-acting bronchodilators at least 4 hours before the test. If the patient cannot be without a bronchodilator for health reasons, the dose and time of taking the latter should be reflected in the study protocol.
Although the most informative part of the spirographic study is the dynamic (speed) characteristics of the respiratory act, this method is also used to study the static characteristics of breathing (total lung capacity and its structure).
Total lung capacity (TLC) corresponds to the volume of air that the lungs can accommodate when expanding from full collapse to the position of maximum inspiration. There are four volumes and four containers that make up the structure of the OEL.
Lung volumes:
- inspiratory reserve volume (IRV)- The maximum volume of air that can be inhaled after a quiet breath. The norm is 1500-2000ml.
- tidal volume (TO)– the volume of air inhaled and exhaled during each respiratory cycle. On the graph it is represented by a curve between the levels of quiet exhalation and quiet inhalation; norm is from 300 to 900 ml.
- expiratory reserve volume (ERV)- This is the maximum volume of air that can be exhaled after a quiet exhalation. The norm is 1500-2000ml.
- residual lung volume (RLV,RV) is the volume of gas remaining in the lungs after maximum exhalation. OOL=FOE-ROvyd. The residual volume is 1000-1500 ml.
Pulmonary capacities:
- inspiratory capacity (Evd)=DO+ROvd;
- vital capacity of the lungs (VC,V.C.) - this is the maximum amount of air that can be exhaled after taking the deepest breath possible. VIT=ROVD+DO+ROVD;
- total lung capacity (TLC,TLC) =VEL+OOL. TEL is the amount of air in the lungs after maximum inspiration. The norm is 5000-6000ml. (Residual volume cannot be determined using spirometry alone; it requires additional lung volume measurements.)
- functional residual capacity (FRC) is the amount of gas in the lungs after a quiet exhalation.
In addition to the listed characteristics, the following indicators are also used to evaluate spirometry:
- minute volume of respiration (MOV)- this is the amount of air ventilated by the lungs in 1 minute. It is calculated as the product of DO and RR (breathing frequency). The average is 5000ml.
- forced vital capacity (FVC, FVC)- the amount of air that can be exhaled during a forced exhalation after a deep maximum inspiration.
- forced expiratory volume in 1 second of the FVC maneuver (FEV1, FEV1). This is one of the main indicators characterizing lung ventilation. FEV1 reflects mainly the speed of expiration in the initial and middle parts and does not depend on the speed at the end of forced expiration.
- maximum ventilation (MVL)- this is the maximum amount of air that can be ventilated by the lungs within 1 minute. Normally it is 80-200 l/min.
- respiratory reserve (RR)– an indicator characterizing the patient’s ability to increase pulmonary ventilation. RD=MVL-MOD. Normally, RD=85-90%MVL.
- index (test) Tiffno (TT)– the ratio FEV1/VC or FEV1/FVC, expressed as a percentage, is usually calculated. Normal is 70-89%.
- MOS 25 (FEF25%)– instantaneous volumetric air velocity at the expiratory level is 25% of FVC.
- MOS 50 (FEF50%)– instantaneous volumetric air velocity at the expiratory level of 50% of FVC.
- MOS 75 (FEF75%)– instantaneous volumetric air velocity at the expiratory level is 75% of FVC.
- SOS 25-75– forced expiratory volumetric rate, averaged over a certain measurement period – from 25% to 75% FVC. The indicator primarily reflects the condition of the small airways, is more informative than FEV1 in identifying early obstructive disorders, and does not depend on effort.
- POS (PEF)– peak (maximum) volumetric expiratory flow rate when performing the FVC test.
- MOS50%vd (MIF50%)– maximum volumetric inspiratory flow rate at 50% of the vital capacity of the lungs.
- MIP (mm.in.st.)– Maximum inspiratory pressure (achieved at the lowest pulmonary volume (RV) when the length-tension relationship in the diaphragm is optimized).
- MEP (mm.in.st.)– maximum expiratory pressure (Patients with neuromuscular diseases are often unable to achieve maximum pressure values, which suggests restrictive pulmonary pathology).
Analysis and evaluation of spirometric study results
Interpretation or interpretation of spirometric test data comes down to analyzing the absolute values of FEV1, FVC and their ratio (FEV1/FVC), comparing these data with expected (normal) values and studying the shape of the graphs. Data obtained after three attempts can be considered reliable if they do not differ from each other by more than 5% (this corresponds to approximately 100 ml).
Based on the spirogram, we can conclude that the patient has one of two variants of pulmonary ventilation dysfunction: obstructive, the pathogenesis of which is associated with airway obstructions, or restrictive (restrictive), which occurs when there are obstacles to the normal expansion of the lungs during inspiration.
In the obstructive variant, bronchial obstruction may be caused by a combination of spasm of the smooth muscles of the bronchi (bronchospasm), edematous-inflammatory changes in the bronchial tree (swelling and hypertrophy of the mucous membrane, hyper- and discrinia, accumulation of pathological contents in the lumen of the bronchi, inflammatory infiltration of the bronchial wall), expiratory collapse of small bronchi, pulmonary emphysema, tracheobronchial dyskinesia. Since nonspecific lung diseases (COPD, bronchial asthma, bronchiectasis) are characterized by bronchial genesis, the obstructive variant of ventilation disorders is most common in them.
As a result of processes that limit the maximum excursions of the lungs and reduce the level of maximum inspiration, a restrictive variant of ventilation disorders develops. These are diffuse pneumosclerosis, atelectasis, cysts and tumors, the presence of gas or liquid in the pleural cavity, massive pleural adhesions, deformation or stiffness of the chest (kyphoscoliosis, ankylosing spondylitis), morbid obesity, absence of a lung (due to surgical removal).
A mixed type of impairment of the ventilation capacity of the lungs is relatively common.
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.
Diagnostics
High precision equipment
Modern research methods
Pulmonary function test
Prices for Pulmonary Function Testing
The study of external respiration is carried out using three methods: Spirography, Bodyplethysmography, Diffusion capacity of the lungs.
Spirography– basic examination of external respiration function. As a result of the study, they get an idea of the presence or absence of bronchial obstruction. The latter arise as a result of inflammatory processes, bronchospasm and other reasons. Spirography allows you to determine how pronounced changes in bronchial patency are, at what level the bronchial tree is affected, and how pronounced the pathological process is. Such data is necessary for the diagnosis of bronchial asthma, chronic obstructive pulmonary disease and some other pathological processes. Spirography is performed to select therapy, control treatment, select for sanatorium treatment, and determine temporary and permanent disability.
In order to determine how reversible the pathological process is, functional tests are used to select treatment. In this case, a spirogram is recorded, then the patient inhales (inhales) a medicine that dilates the bronchi. After this, the spirogram is recorded again. Comparison of data before the use of the drug and obtained after its use allows us to draw a conclusion about the reversibility of the pathological process.
Spirography is often performed on healthy people. This is necessary when carrying out professional selection, for planning and performing training sessions that require stress on the respiratory system, confirming the fact of health, etc.
Spirography allows you to obtain valuable information about the state of the respiratory system. Often, spirography data needs to be confirmed by other methods, or to clarify the nature of the changes, to identify or refute the assumption that lung tissue is involved in the pathological process, to detail the state of metabolism in the lungs, etc. In all these and other cases, body plethysmography is resorted to and carried out study of the diffusion capacity of the lungs.
Body plethysmography – if necessary, is performed after a basic study - spirography. The method accurately determines the parameters of external respiration, which cannot be obtained by spirography alone. These parameters include the determination of all lung volumes, capacities, including total lung capacity.
A study of the diffusion capacity of the lungs is performed after spirography and body plethysmography to diagnose pulmonary emphysema (increased airiness of the lung tissue) or fibrosis (thickening of the lung tissue due to various diseases - bronchopulmonary, rheumatic, etc.). In the lungs, gases are exchanged between the internal and external environment of the body. The entry of oxygen into the blood and the removal of carbon dioxide is carried out by diffusion - the penetration of gases through the walls of capillaries and alveoli. A conclusion about how efficiently gas exchange occurs can be made from the results of a study of the diffusion capacity of the lungs.
Why should it be done in our clinic?
Often, the results of spirography require clarification or detail. The Federal Scientific and Clinical Center of the Federal Medical and Biological Agency of Russia has special devices. These devices allow, if necessary, to carry out additional research and clarify the results of spirography.
The spirographs that our clinic has are modern and allow us to quickly obtain many parameters to assess the condition of the external respiration system.
All studies of external respiration function are performed on a multifunctional expert-class installation Master Screen Body Erich-Jäger (Germany).
Indications
Spirography is performed to establish the fact of health; establishing and clarifying the diagnosis (bronchitis, pneumonia, bronchial asthma, chronic obstructive pulmonary disease); preparation for surgery; selection of treatment and monitoring of treatment; assessing the patient's condition; clarifying the causes and predicting the timing of temporary disability and in many other cases.
Contraindications
Early (up to 24 hours) postoperative period. Contraindications are determined by the attending physician.
Methodology
The subject performs various breathing maneuvers (calm breathing, deep inhalation and exhalation), following the instructions of the nurse. All maneuvers must be performed carefully, with the required degree of inhalation and exhalation.
Preparation
The attending physician may discontinue or limit the intake of certain medications (inhaled, tablet, injected). Before the study (at least 2 hours before) stop smoking. Spirography is best performed before breakfast, or 2 to 3 hours after a light breakfast. It is advisable to be at rest before the study.
Breathing is the basic property of any living being. As a result of breathing movements, the body is saturated with oxygen and gets rid of carbon dioxide, which is formed during metabolism (metabolism). There are two stages in breathing:
- external (gas exchange between the environment and the lungs);
- internal or tissue (the process of transfer of gases by red blood cells and the use of oxygen by body cells).
One of the directions for diagnosing specific and nonspecific (chronic bronchitis, asthma, emphysema) pulmonary diseases is the study of external respiration function.
What is FVD
FVD in official medicine is a whole complex of studies of the condition of the lungs and bronchi. The main methods are spirography, bodyplethysmography, pneumotachometry, peak flowmetry.
How is FVD research carried out?
Pulmonologists prescribe a respiratory function test to calculate lung volume, work speed and identify pathology of the respiratory system for the purpose of diagnosis, monitoring the development of the disease and the effectiveness of treatment. Ecologists, biologists and doctors study the characteristics of people's external respiration for a comparative analysis of the influence of environmental conditions on the body. IFVD is necessary to determine a person’s suitability for work in special conditions, for example, under water, or to determine the degree of loss of temporary ability to work.
Indications for FVD
The main indications are diseases of the respiratory system:
- bronchial asthma, bronchitis;
- infectious and inflammatory processes in the lungs, alveolitis;
- silicosis, pneumoconiosis and other respiratory pathologies.
Silicosis is an occupational disease that develops from regular contact with dust containing silicon dioxide. Pneumoconiosis develops in miners when they inhale coal dust.
Who is contraindicated for IFVD?
- in acute infectious or febrile conditions;
- children under 4 years of age, since at this age they can rarely adequately understand the instructions of doctors;
- with persistent angina, heart attack, recent stroke, uncontrolled hypertension;
- after a recent operation;
- heart failure, causing a sharp nonspecific breathing disorder during exercise or at rest;
- aortic aneurysm;
- for mental illness.
Classical spirography is more difficult to determine hidden bronchospasm. Therefore, to identify an obstructive type of respiratory pathology, a test is performed using Salbutamol, Ventolin or Berodual (this is called a bronchodilator test). The study is carried out before and after inhalation of the bronchodilator. The presence of a difference in spirometry readings makes it possible to assume a hidden spasm of the bronchial vessels and to identify disorders in the initial stages of the development of the pathological process.
If a test with Salbutamol shows negative results, this means that the bronchi do not respond to bronchodilators, the test and the obstruction has become irreversible.
Before spirography with the bronchodilator Salbutamol, 6 hours before the examination, you cannot use other drugs of similar action. This can deceive a specialist during FVD, which will lead to incorrect interpretation of the results and ineffective treatment of the disease.
FVD testing with a bronchodilator is safe and can be performed on children. Contraindications are basically the same as for conventional spirometry. The bronchodilator should not cause an allergic attack.
Vital capacity of the lungs
Vital capacity (vital capacity of the lungs) shows how much air can enter the lungs after the deepest breath. If this indicator is below normal, it means that the respiratory surface of the pulmonary vesicles - the alveoli - is decreasing.
FVC – functional vital capacity of the lungs, maximum amount of air, exhale after maximum inhalation. Characterizes the extensibility of the lung tissue and bronchi. Indicators should be less than vital capacity, since part of the air during such an exhalation remains in the lungs. If FVC is less than VC per liter or more, pathology of small bronchial vessels is suspected. Due to the rapid collapse of the bronchi, the air does not have time to leave the lungs.
Indicators
Basic indicators in a healthy person:
| Tidal volume | With one inhalation and exhalation it is equal to | 0.3-0.8 l | |
| Inspiratory reserve volume | Maximum inspiratory volume after normal inspiration | 1.2-2 l | |
| Expiratory reserve volume | Maximum expiratory volume after normal exhalation | 1-1.5l | |
| Vital capacity of the lungs | Maximum expiratory volume after the same inhalation | 3-4-5 l | |
| Residual volume | Amount of air after maximum inspiration | 1-1.5l | |
| Total capacity | Consists of VC and RLV (residual lung volume) | 4-6.5l | |
| Minute breathing volume | 4-10 l | ||
| Maximum ventilation | Amount of air at maximum breathing depth | From 50 to 150 l/min | |
Forced expiratory volume
FEV1 - determination of air volume in 1 second during forced exhalation. Indicators decrease with chronic bronchitis, bronchial asthma - obstructive disorders in which it is difficult for air to escape from the bronchial tree.
Tiffno index
Shows the percentage ratio of FEV1 to FVC parameters. Normally, U is from 75 to 85%. The Tiffno index value decreases due to FEV1 with age or obstruction. This indicator becomes higher than normal when the elasticity of the lung tissue changes.
Minute ventilation rate
MVL shows the average amplitude of maximum respiratory movements multiplied by their number in 1 minute. Normally, this figure is from 250 liters.
Pneumotachometry
A simple, accessible and informative method for diagnosing the functional state of the pulmonary system and airway patency. The essence of the study is to measure the speed of air passage through the respiratory tract during inhalation and exhalation using a pneumotachometer. The device is equipped with a special tube with a replaceable mouthpiece.
Indications
Prescribed for bronchial asthma, atopic bronchitis, pneumosclerosis and chronic obstructive pathology, to select the most optimal therapy.
Contraindications
Pneumotachometry is prohibited for the following indications:
- recent stroke, heart attack;
- high blood pressure;
- acute inflammatory processes in the respiratory organs;
- aneurysms, respiratory failure, epilepsy;
- pregnancy.
Preparing for the study
The patient needs:
- stop drinking alcohol and cigarettes on the eve of the study;
- give up heavy physical activity during the day, try not to get into stressful situations;
- stop taking bronchodilators 4-5 hours before;
- prepare loose clothing that will not restrict breathing movements;
- on the day of pneumotachometry, refuse breakfast.
To more accurately determine the state of the respiratory system, anthropometric measurements are taken before the study.
Where is pneumotachometry performed?
The procedure is carried out in a hospital or clinic office. The patient, sitting on the couch, holds his nose with a special clamp and is given a device tube with a sterile mouthpiece. The patient is asked to make several calm breathing movements, then several maximum inhalations and exhalations. The doctor records, then deciphers the device readings and determines treatment tactics.
Indicators
Normal research parameters for pneumotachometry:
With chronic impairment, speed indicators decrease. This means that there is a narrowing of the distal, small bronchi.
Peak flowmetry
An examination method that determines the rate of exhalation and the degree of narrowing of the branches of the bronchial tree. This test is prescribed to patients to perform at home.
Indications
Prescribed to patients with chronic respiratory pathologies, bronchial asthma, bronchitis with difficulty breathing, and attacks of suffocation. The test is carried out in the morning and evening for a time determined by the doctor. During peak flowmetry, peak expiratory flow (PEF) is recorded - the highest air speed in the respiratory tract at maximum exhalation. Using this test, you can predict, monitor the dynamics of the disease, adjust treatment, and monitor medication intake.
Thanks to peak flowmetry, it is possible to determine the relationship between bronchospasm and signs of the disease, select more effective inhalers, and prevent the onset of attacks.
Types of peak flow meters
Peak flow meters are available in two versions - for hospitals and home use. Household appliances are small, compact, easily fit into pockets or handbags, and last at least two years. They are graduated in the form of color zones - green, red, yellow. There are models for different age categories of patients, or universal ones. Children differ from adults in the scale of divisions. For children, the scale is from 35 to 350 l/min. For adult devices, the scale is 50-850 l/min.
Technique for using the device
Using the device is quite simple - you just need to wrap your lips around the mouthpiece and blow harder. The test should be performed in a standing position, in the morning and in the evening, with a difference of 10 or 12 hours, on an empty stomach, half an hour after the end of active physical work or exercise.
results
The green part of the scale (from 80 to 100%) indicates normal functioning of the respiratory system and proper treatment.
The yellow scale (from 50% to 80%) requires careful attention to your health and the need to consult a doctor for advice.
The red scale (less than 50%) indicates that the patient’s condition is dangerous, treatment does not produce positive results, and an urgent examination or hospitalization is needed.
Peak flow diary
Keeping a diary is mandatory, because based on these results, the doctor can monitor the course of the disease, replace medications with more effective ones, and give appropriate recommendations.
Bodyplethysmography
A research technique that allows you to fully examine the functioning of the respiratory system, more accurately establish a diagnosis, and qualitatively select therapeutic treatment. The device, body plethysmograph, is a camera for a person, a pneumotapograph, a computer, on the display of which the researcher reads data - residual volume, total and functional residual capacity of the lungs.
Using pneumotachometry, peak flowmetry, and spirographic research methods, effective diagnosis of pulmonary diseases is achieved, treatment is prescribed and adjusted, and prognoses are made for the development of the disease and recovery of patients.
Studying the function of external respiration allows you to respond in a timely manner to changes in health status, prevent complications and maintain the health and vitality of patients.
