FVD on an empty stomach. Pulmonary function tests: Spirometry, provocative test with methacholine, body plethysmography. Is it possible to eat food before the study

So that "wonderful" moment came when my allergy mutated into something incredible. Now, when I enter a room where not only is there, but once there was (!) a cat, I start to suffocate. Breathing turns into wheezing, there is not enough air, it seems that consciousness is about to pass out and I will go to the forefathers. All antihistamine tablets known to me do not help or assist. But such a reaction only for cats.

The prospect of premature departure into the world is not the most rosy, I had to go to an allergist. In addition to a bunch of various samples, analyzes and a ton of pumped money, I was assigned a strange procedure called FVD (function of external respiration) or spirogram.

I was assigned FVD + bronchodilator.

Examination of respiratory function (RF) Examination of respiratory function is a set of diagnostic procedures and tests that are used to diagnose diseases of the lungs and bronchi. Gas exchange between outside air and blood occurs in the lung tissue.

I don’t know how the situation is with medicine in other cities, but to the shame of Voronezh, everything is really bad here. Or maybe I'm out of luck.

Having visited a free allergist and spending the whole day waiting in line, despite the appointment ticket, I only heard from the doctor a recommendation to visit her paid clinic and received a receipt for the payment of tests that must be done in the same clinic. And that's all. The appointment lasted 5 minutes.

Taught by bitter experience, I went to a personally chosen paid clinic, to a doctor with good reviews, I hope, not wound up through QComment.

Actually, therefore, the procedure for diagnosing the lungs was paid. The cost was 1150 rubles.

FVD - what is this procedure?

Her goal find out if the patient has bronchial asthma, chronic obstructive pulmonary disease or any other respiratory system deviations.

the study allows you to find out how much air can be inhaled and exhaled by the subject and at what speed he is able to do this.

If everything is clear with this, because you will have to breathe into a special machine, which can fix the volume of the lungs. But how are deviations detected, i.e. the research system itself remains a mystery to me. Too bad I'm not a doctor!

The results of spirometry change in a number of other diseases of the respiratory, cardiovascular, nervous systems and the musculoskeletal system, characterizing their effect on the breathing of the subject.

How to prepare for the procedure?

Naturally, the first thing I did was go online, read what kind of execution it was, whether it hurt, whether it was scary and what to be prepared for.

Everywhere the information is different: somewhere it is said that you need to do it on an empty stomach, or not eat for 4-5 hours, somewhere - do not drink coffee and do not smoke the day before.

Also, be sure to take fluorography.

About the procedure.

They say that you need to sit quietly for half an hour before the FVD, breathe in the air, calm down and warm your hands.

But I'm lucky! Having collected all the traffic jams on the way to the clinic and getting nervous, I still managed to make it on time. A fly went up to the third floor to the right office. She even came 10 minutes earlier than necessary. The door of the office was closed, there were no patients for the same procedure.

I waited half an hour, went downstairs to the reception, to find out who ate my doctor, maybe he was sucked in by a terrible apparatus? Or was he tired of working and he fucking decided that today is the best day to go on strike?

Well, hell knows. Why even write the time on coupons if no one is looking at them? And okay in free, but in paid! sorry for this cry of the soul

The receptionist said that the doctor who was running away from the clinic was not noticed. So, it's still there, just hiding somewhere. The answer satisfied me. I went back to the third floor. And what?! There is already a queue in front of the office! And, of course, no one looked at the time stamps!

The case took place in Diagnostic Plus, on Moskovsky Prospekt.

Finally it's my turn (an hour has passed)

I was asked about age, weight and height. And we started the procedure of spirometry.

The device is a small box with a hose that you need to blow into. Each patient is given an individual nozzle, which after use is lowered into a solution for disinfection.

So, a kind of clothespin is put on the nose, the tube is tightly wrapped around the lips and breaths are taken. That's the whole procedure.

Total has been done 6 approaches.

1. Inhale the air with a full chest and exhale calmly.

2. Inhale air and exhale as long as possible.

3. Inhale air and exhale as quickly as possible.

I have had FVD with bronchodilator- this means, as the doctor explained, the allergist wanted to identify the reaction of the lungs to the medicine: positive or negative.

I was given a balloon Salbutamol for two inhalations. (In general, you need 4, but I have a small weight). Then I was sent to the corridor to wait 20 minutes.

By the way, Salbutamol has a number of contraindications, which the doctor conducting the procedure did not say about!

Hypersensitivity, pregnancy (when used as a bronchodilator), breastfeeding, children's age (up to 2 years - for oral administration and for a metered-dose aerosol without a spacer, up to 4 years - for inhalation powder, up to 18 months - for inhalation solution). For intravenous administration as a tocolytic (optional): infections of the birth canal, intrauterine fetal death, fetal malformations, bleeding with placenta previa or placental abruption; threatened miscarriage (in the I-II trimester of pregnancy).

I endured the drug strangely - my head began to feel a little dizzy, and when I got up, I felt a tremor in my arms and legs. The lousy feeling stopped as soon as I stepped out into the fresh air.

Then there was a repetition of 3 of the above procedures.

They immediately gave me a conclusion - an A4 sheet with graphs on both sides.

The conclusion says that I have a negative test for Salbutamol. This means that there is no obstruction in the lungs, which, in fact, is good. If the result was positive, then this meant the likelihood of asthma or any other changes.

By the way, the diagnosis states that I have "bronchial obstruction" - the device recorded my forced "communication" with the cat three days ago.

FVD decoding.

A complete and thorough analysis of the schedules can only be done by a doctor. Good doctor.

But you can understand the approximate situation yourself: next to your indicators there will be a norm by which you can compare the data.

My allergist, after looking at the results, diagnosed me with bronchial asthma. But I recently visited a pulmonologist who did not say a word about any changes in the lungs.

I went to another allergist, who rejected this diagnosis, added some other tests and recommended to redo the FVD.

Well, and finally.

I was not even asked about the fluorogram! And when I myself reminded about it, the doctor said that she asks her only from the elderly. WTF?! Young people don't get sick, do they?! And it is unlikely that a disposable mouthpiece can save you from tuberculosis.

I rate the procedure itself five stars and recommend it. But I do not advise Voronezh residents to go through it in Diagnostics Plus.

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 function of external respiration (RF) needs an objective analysis in any pulmonological diseases. Evaluation of the parameters of respiratory activity is the basis for making an accurate diagnosis, forecasting and choosing a treatment regimen. Pulmonary function studies are also necessary when making a decision on the surgical treatment of a pathology of a different profile, when choosing drugs for anesthesia, to collect data in preparation for a medical and social examination, and also to evaluate the effectiveness of existing therapy.

Spirometry is a modern method for assessing respiratory function, which allows obtaining objective information about the functioning of the respiratory system. This is a painless non-invasive method based on the analysis of the parameters of the passage of air through the respiratory tract. In the course of spirometry, as well as through subsequent software calculations, the airflow rate, vital capacity of the lungs, and other indicators that reflect the degree of deviation from the norm are estimated. Spirometry can act as the main diagnostic method or serve as an addition to other diagnostic methods, for example, become a clarifying tool for confirming a suspected diagnosis after radiography.

2. What are the features of the spirometry test with a bronchodilator

Spirometry in modern pulmonology makes it possible not only to experimentally evaluate the explicit parameters of the respiratory function, but also to identify hidden deviations that reveal themselves under certain conditions. This is especially important for those diseases that cannot be diagnosed by standard spirometry.

Classical spirography provides valuable information and reflects a clear clinical picture in bronchial asthma, chronic bronchitis with bronchial obstruction, bronchiolitis, and restrictive pathology. However, latent bronchospasm may go unnoticed, which makes it difficult to diagnose with certain violations of the function of external respiration. In this regard, a test with a bronchodilator is always recommended in addition to the standard complex.

Such a study takes into account the parameters of breathing before and after inhalation inhalation of a drug that relieves a possible spasm. If the indicators differ significantly, it is highly likely that latent bronchospasm can be assumed. As a bronchodilator can be used:

• berodual;
• salbutamol;
• ventolin.

Such testing does not significantly increase the duration of the procedure, but it makes it possible to identify many violations in the early stages. In addition, spirometry with a bronchodilator shows which drug is most effective for a given patient in order to relieve spasm of the respiratory system.

3. Who is spirometry with a bronchodilator

The indications for conducting studies of the function of external respiration are quite wide and cover any disturbances in the functioning of the lungs and bronchi. Objective diagnostic data give the doctor a clearer idea of ​​the causes of certain subjective complaints of the patient, allow assessing the severity of the current condition and prescribing adequate treatment. If the patient describes the symptoms as more severe in certain situations, or if his perception of his own condition differs significantly from the objective results of spirometry, it is worth suggesting that there is a latent bronchospasm. In this case, the assessment of respiratory function must necessarily include a test after inhalation of a bronchodilator.

Diagnosis using a spirometer is completely safe, it can be carried out even for children if they are able to follow the doctor's commands and control their own breathing.

A contraindication to testing that includes a bronchodilator is intolerance to the drug used for inhalation. Other restrictions are the same as for conventional spirometry:

• pain in the heart, angina pectoris;
• postoperative period;
• pneumothorax;
• uncontrolled arterial hypertension;
• aortic aneurysm.

4. How is the spirometry procedure with a bronchodilator

Before undergoing diagnostics on a spirograph, you must refrain from smoking and coffee, as well as eating. Stressful situations and physical activity a day before the study are not recommended.

After coming to the pulmonologist, you need to sit quietly and warm up for some time. The doctor at this time describes the actions that you may be asked to perform during spirometry. For children, special animated computer programs have been developed that, in the form of a game, set a sequence of breathing maneuvers.

Each patient uses an individual disposable mouthpiece. Inhalation of a bronchodilator also meets the requirements of antisepsis.

The results of the study enter the memory of the spirograph, which then processes them. Special software allows you to obtain calculated parameters of the respiratory function, which will then form the basis for the development of an effective therapeutic regimen. As the course of treatment progresses, spirometry can be re-appointed by a pulmonologist in order to assess the response to ongoing therapy.

Inhalation and exhalation for a person is not just a physiological process. Remember how we breathe in different life circumstances.

Fear, anger, pain - breath is clamped and constrained. Happiness - for the manifestation of joy there are not enough emotions - we breathe deeply.

Another example with the question: how long will a person live without food, sleep, water? And without air? Probably, we should not continue talking about the importance of breathing in human life.

Breathing at a Glance

The ancient Indian teaching of yoga states: “A person’s life is the time periods between inhalation and exhalation, because these movements, which saturate all cells with air, ensure his very existence.”

A person who breathes half, also lives half. This, of course, is about unhealthy or improper breathing.

How can you breathe incorrectly, the reader will object, if everything happens without the participation of consciousness, so to speak "on the machine." The smart guy will continue - unconditioned reflexes control breathing.

The truth lies in the psychological trauma and all sorts of diseases that we accumulate throughout our lives. It is they who make the muscles clamped (overstrained) or, conversely, lazy. Therefore, over time, the optimal mode of the respiratory cycle is lost.

It seems to us that the ancient man did not think about the correctness of this process, nature itself did it for him.

The process of filling human organs with oxygen is divided into three components:

1. Clavicular (upper). Inhalation occurs due to the upper intercostal muscles and clavicles. Try it to make sure that this mechanical movement does not fully rotate the chest. Little oxygen enters, breathing becomes frequent, incomplete, dizziness occurs and the person begins to suffocate.
2. Medium or chest. With this type, the intercostal muscles and the ribs themselves are included. The chest expands as much as possible, allowing it to be completely filled with air. This type is typical under stressful circumstances or with mental stress. Remember the situation: you are excited, but if you take a deep breath, everything disappears somewhere. This is the result of proper breathing.
3. Abdominal diaphragmatic breathing. This type of breathing, from the point of view of anatomy, is the most optimal, but, of course, not quite comfortable and familiar. You can always use it when you need to relieve mental "strained". Relax the abdominal muscles, lower the diaphragm to a lower position, then return it back to its original position. Pay attention, there was a calm in the head, thoughts brightened up.

Important! By moving the diaphragm, you not only improve your breathing, but also massage the abdominal organs, improving metabolic processes and digestion of food. Due to the movement of the diaphragm, the blood supply to the digestive organs and venous outflow are activated.

This is how important it is for a person not only to breathe correctly, but also to have healthy organs that ensure this process. Constant monitoring of the condition of the larynx, trachea, bronchi, and lungs largely contributes to the solution of these problems.

Examination of the function of external respiration

FVD in medicine, what is it? To test the functions of external respiration, a whole arsenal of techniques and procedures is used, the main task of which is to objectively assess the condition of the lungs and bronchi, as well as to open the pathology at an early stage.

The gas exchange process that occurs in the tissues of the lungs, between blood and air from outside, penetrating the body, medicine calls external respiration.

Research methods that allow diagnosing various pathologies include:

1. Spirography.
2. Bodyplethysmography.
3. Study of the gas composition of exhaled air.

Important! The first four methods of analysis of respiratory function allow you to study in detail the forced, vital, minute, residual and total volume of the lungs, as well as the maximum and peak expiratory flow. While the gas composition of the air leaving the lungs is studied using a special medical gas analyzer.

In this regard, the reader may have a false impression that the examination of the respiratory function and spirometry are one and the same. We emphasize once again that the study of respiratory function is a whole range of tests, which includes spirometry.

Indications and contraindications

There are indications for complex testing of the functions of upper breathing.

These include:

1. Patients, including children, who manifest: bronchitis, pneumonia, emphysema of lung tissue, nonspecific lung diseases, tracheitis, rhinitis in various forms, laryngotracheitis, diaphragmatic damage.
2. Diagnosis and control and COPD (chronic obstructive pulmonary disease).
3. Examination of patients involved in hazardous areas of production (dust, varnishes, paints, fertilizers, mines, radiation).
4. Chronic cough, shortness of breath.
5. The study of upper breathing in preparation for surgical operations and invasive (taking living tissue) examinations of the lungs.
6. Examination of chronic smokers and people prone to allergies.
7. Professional athletes, in order to find out the maximum capacity of the lungs during increased physical exertion.

At the same time, there are restrictions that make it impossible to conduct a survey due to certain circumstances:

1. Aneurysm (protrusion of the wall) of the aorta.
2. Bleeding in the lungs or bronchi.
3. Tuberculosis in any form.
4. Pneumothorax is when a large amount of air or gas accumulates in the pleural region.
5. Not earlier than one month after undergoing surgery on the abdominal or thoracic cavity.
6. After a stroke and myocardial infarction, the study is possible only after 3 months.
7. Intellectual retardation or mental disorders.

Video from an expert:

How is the research done?

Despite the fact that the procedure for studying the respiratory function is a completely painless process, in order to obtain the most objective data, it is necessary to carefully approach its preparation.

1. FVD is done on an empty stomach and always in the morning.
2. Smokers should abstain from cigarettes four hours before the test.
3. On the day of the study, physical activity is prohibited.
4. Asthmatics exclude inhalation procedures.
5. The subject must not take any drugs that dilate the bronchi.
6. Do not drink coffee or other caffeinated tonic drinks.
7. Before the test, loosen clothing and its elements that restrict breathing (shirts, ties, trouser belts).
8. In addition, if necessary, follow the additional recommendations voiced by the doctor.

Research algorithm:

If there is a suspicion of an obstruction that disrupts the patency of the bronchial tree, a respiratory tract with a sample is performed.

What is this test and how is it done?

Spirometry in the classical version, gives the maximum, but incomplete idea of ​​the functional state of the lungs and bronchi. Thus, in asthma, a breath test on a machine without the use of bronchodilators, such as Ventolin, Berodual and Salbutamol, is not able to detect latent bronchospasm and it will go unnoticed.

Preliminary results are ready immediately, but their decoding and interpretation by the doctor is still to be done. This is necessary to determine the strategy and tactics of treating the disease, if any.

Deciphering the results of the FVD

After all the test events, the results are entered into the memory of the spirograph, where they are processed with the help of software and a graphic drawing is built - a spirogram.

The preliminary output compiled by the computer is expressed as follows:

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

After deciphering the indicators of the function of external respiration, their compliance or non-compliance with regulatory requirements, the doctor makes a final verdict regarding the patient's health status.

The studied indicators, the rate of respiratory function and possible deviations are presented in a generalized table:

Important! When deciphering and interpreting the results of respiratory function, the doctor pays special attention to the first three indicators, because it is FVC, FEV1 and the Tiffno index that are diagnostically informative. According to the ratio between them, the type of ventilation violations is determined.

Such an unpronounceable name was given to a survey method that allows you to measure the peak volumetric velocity during forced (maximum strength) expiration.

Simply put, this method allows you to determine the speed at which the patient exhales, applying maximum effort for this. This is how the narrowing of the airways is checked.

Peak flowmetry is especially needed by patients with asthma and COPD. It is she who is able to obtain objective data on the results of therapeutic measures.

A peak flow meter is an extremely simple device consisting of a tube with a graduated scale. How useful is it for individual use? The patient can independently take measurements and prescribe the dosage of the medications taken.

The device is so simple that even children can use it, not to mention adults. By the way, some models of these simple devices are produced especially for children.

How is peak flow measurement performed?

The testing algorithm is extremely simple:

How to interpret the data?

We remind the reader that peak flowmetry, as one of the methods for studying the respiratory function of the lungs, measures the peak expiratory flow rate (PEF). For a correct interpretation, it is necessary to determine for yourself three signal zones: green, yellow and red. They characterize a certain range of PSV, calculated according to the maximum personal results.

Let's give an example for a conditional patient, using a real technique:

1. Green Zone. In this range there are values ​​that indicate remission (weakening) of asthma. Anything above 80% PSV characterizes this condition. For example, a patient's personal record - PSV is 500 l / min. We make a calculation: 500 * 0.8 = 400 l / min. We get the lower border of the green zone.
2. yellow zone. It characterizes the beginning of the active process of bronchial asthma. Here, the lower limit will be 60% of PSV. The calculation method is identical: 500 * 0.6 = 300 l / min.
3. red zone. Indicators in this sector indicate an active exacerbation of asthma. As you understand, all values ​​below 60% of PSV are in this danger zone. In our "virtual" example, this is less than 300 l/min.

A non-invasive (without penetrating inside) method for measuring the amount of oxygen in the blood is called pulse oximetry. It is based on a computer spectrophotometric assessment of the amount of hemoglobin in the blood.

In medical practice, two types of pulse oximetry are used:

In terms of measurement accuracy, both methods are identical, but from a practical point of view, the second one is the most convenient.

Scope of pulse oximetry:

1. Vascular and plastic surgery. This method is used to saturate (saturate) oxygen and control the patient's pulse.
2. Anesthesiology and resuscitation. It is used during the movement of the patient to fix cyanosis (blue mucosa and skin).
3. Obstetrics. For fixing fetal oximetry.
4. Therapy. The method is extremely important for confirming the effectiveness of treatment and for fixing apnea (respiratory pathology that threatens to stop) and respiratory failure.
5. Pediatrics. It is used as a non-invasive tool for monitoring the condition of a sick child.

Pulse oximetry is prescribed for the following diseases:

• complicated course of COPD (chronic obstructive pulmonary disease);
• obesity;
• cor pulmonale (enlargement and expansion of the right parts of the heart);
• metabolic syndrome (complex of metabolic disorders);
• hypertension;
• hypothyroidism (disease of the endocrine system).

Indications:

• during oxygen therapy;
• insufficient activity of breathing;
• if hypoxia is suspected;
• after prolonged anesthesia;
• chronic hypoxemia;
• in the postoperative rehabilitation period;
• apnea or prerequisites for it.

Important! With blood normally saturated with hemoglobin, the rate is almost 98%. At a level approaching 90%, hypoxia is noted. The saturation rate should be about 95%.

Study of the gas composition of the blood

In humans, the gas composition of the blood, as a rule, is stable. Shifts of this indicator in one direction or another indicate pathologies in the body.

Indications for carrying out:

1. Confirmation of a pulmonary pathology in a patient, the presence of signs of an acid-base imbalance. This is manifested in the following diseases: COPD, diabetes mellitus, chronic renal failure.
2. Monitoring the state of health of the patient after carbon monoxide poisoning, with methemoglobinemia - a manifestation in the blood of an increased content of methemoglobin.
3. Control of the patient's condition, which is connected to forced ventilation of the lungs.
4. The data is needed by the anesthesiologist before performing surgical operations, especially on the lungs.
5. Determination of violations of the acid-base state.
6. Assessment of the biochemical composition of blood.

The reaction of the body to a change in the gas components of the blood

Acid-base balance pH:

• less than 7.5 - there was a supersaturation of the body with carbon dioxide;
• more than 7.5 - the amount of alkali in the body is exceeded.

Partial pressure level of oxygen PO 2: falling below the normal value< 80 мм рт. ст. – у пациента наблюдается развитие гипоксии (удушье), углекислотный дисбаланс.

Partial (partial) pressure level of carbon dioxide PCO2:

1. The result is below the normal value of 35 mmHg. Art. - the body feels a lack of carbon dioxide, hyperventilation is not carried out in full.
2. The indicator is above the norm 45 mm Hg. Art. - there is an excess of carbon dioxide in the body, the heart rate decreases, the patient is seized by an inexplicable anxious feeling.

Bicarbonate level HCO3:

1. Below normal< 24 ммоль/л – наблюдается обезвоживание, характеризующее заболевание почек.
2. The indicator is above the normal value> 26 mmol / l - this is observed with excessive ventilation (hyperventilation), metabolic alkalosis, an overdose of steroid substances.

The study of respiratory function in medicine is the most important tool for obtaining deep generalized data on the state of the work of the human respiratory organs, the impact of which on the entire process of his life and activity cannot be overestimated.

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.