Elastic properties of the lungs and chest. Loop flow - volume

PHYSIOLOGY OF RESPIRATION

Breathing is one of the most important physiological functions. This is gas exchange between the external environment and the body, in which oxygen is consumed, carbon dioxide is released and the necessary energy is generated. It includes external (pulmonary) respiration, transport of gases by the blood and gas exchange in tissues (tissue or internal respiration). External respiration, in turn, consists of 3 stages: ventilation - air exchange between the environment and the alveoli, diffusion of gases through the alveolar-capillary membrane and blood perfusion in the pulmonary capillaries.

Biochemical methods are used to study tissue respiration, for example, the determination of lactate in venous blood, electrochemical blood gas analyzers, and the polarography method.

The transport of gases in the blood can be assessed using oximeters (pulse oximeters). Normally, hemoglobin is 96-98% saturated with oxygen. To assess lung perfusion, isotopic methods are used (introduction of albumin labeled with a gamma-emitting isotope into a vein) and radiopaque techniques. Diffusion ability is determined by inhalation of a small concentration of carbon monoxide by the rate of its entry into the blood.

Due to the complexity of the appropriate equipment, the diffusion capacity of the lungs and the features of hemodynamics are rarely determined even in the largest specialized clinics, while the ventilation function of the lungs is easily accessible for examination by widely used devices and methods. It is primarily characterized by static, dynamic and derived lung volumes and respiratory rates.

1.1. Lung volumes and capacities

Under lung volumes understand the amount of air contained in the lungs in different phases of respiration. Allocate and lung capacity - the sum of several volumes. Static volumes are determined with calm breathing, and dynamic volumes with forced breathing. Derived volumes are usually calculated using formulas.

There are the following static volumes and capacities:

OEL (TLC) - total lung capacity - all the air in the lungs at the height of maximum inspiration;

VC (VC) - vital capacity of the lungs - the largest number air that can be exhaled after a maximum inhalation. VC, obtained during inspiration after a full exhalation, is somewhat larger, since there is no blocking of air in the smallest bronchi (the phenomenon of "air trap");

OOL (R.V.) - residual lung volume - air remaining in the lungs after maximum expiration;

BEFORE (VT) - tidal volume - the air that passes through the lungs with a calm inhalation and exhalation, on average - about 500 ml;

ROVD (vyd) (IRV, ERV) - inspiratory and expiratory reserve volumes - this is the air that can be additionally inhaled or exhaled after a calm inhalation or exhalation;

Evd(IC) - inspiratory capacity - sum BEFORE And ROVD;

FFU (FRC) - functional residual capacity - the air remaining in the lungs after a quiet exhalation, the sum OOL And RO vyd.

In a routine study OEL, OOL And FFU not available for measurement. They are determined using gas analyzers, studying the change in the composition of gas mixtures during breathing in a closed circuit (the content of helium, nitrogen, radioactive xenon), or with general plethysmography, when the subject is in a sealed cabin and pressure fluctuations are measured in it during his breathing.

The part of the air in the airways and alveoli that is not involved in gas exchange is called dead space (MP). Anatomical dead space - part of the air that does not reach the alveoli on inspiration, and does not go out into the atmosphere on exhalation, functional dead space - the air of non-perfused alveoli. Dead space and residual volume air is involved in warming and moistening the inhaled gas to provide necessary conditions for the life of the alveoli.

The amount of dead space is determined in the same way as the residual volumes. Fine MP is 140 ml in women and 150 ml in men, mainly due to anatomical dead space. Under the minute volume of breathing understand the amount of air passing through the lungs per minute, it is determined by the formula MOD \u003d BH x DO, Where BH- respiratory rate, normally 12 - 20, an average of 16 per minute. Having accepted BEFORE for 500 ml, we get the average MAUD- 8 l.

Considering the presence MP, then only a part of this air, which is called alveolar ventilation, is involved in gas exchange and is AB \u003d (DO - MP) x BH. about 70% MAUD. With deep breathing, the ratio AB/MOD increases, at superficial - decreases.

The amount of oxygen consumed in 1 minute ( IGO 2) is easily determined spirographically. Based on it, you can determine the value of the main exchange ( OO), knowing energy value oxygen, taking into account the respiratory coefficient. For this IPC multiply by 7.07 (the number of minutes in a day X average caloric equivalent of oxygen):

OO \u003d IPC x 7.07(kcal/day).

1.2. Forced breathing tests

In addition to static volumes, dynamic volumes are of great clinical importance, determined during forced (most rapid and complete) breathing, especially during exhalation, since inspiration is a more arbitrary act, and therefore less constant. Their use in clinical practice helps to clarify the level of bronchial obstruction and diagnosis early manifestations bronchopulmonary changes in the form of impaired patency of small bronchi.

A quick and complete expiration test is carried out from the position of maximum inspiration, i.e. FZhEL (FVC) - expiratory forced vital capacity. FZhEL less VC by 200 - 400 ml due to the decline at the end of the accelerated exhalation of a part of the small bronchioles (expiratory collapse). If there is their pathology, the phenomenon of "air capture" is observed, when FZhEL less VC 1 liter or more. At the same time, the speed of forced inspiration (test of inspiratory FZhEL) will be greater than exhalation.

Cases when FZhEL greater than or equal VC, should be considered as an incorrectly performed test. All indicators must be determined at least 3 times and taken highest value everyone. In addition, the forced expiratory volume in the first second is determined ( FEV1 = FEV 10), which is compared either with the proper value, or with VC or FZhEL.

Tiffno index \u003d (FEV / VC)x100%, normal 70-80%

It decreases with obstructive processes and may increase with "clean" restriction, when VC reduced, and the expiratory rate did not decrease. However, the defeat of only small bronchi often does not lead to a change FEV1 therefore, the Tiffno test cannot serve as an early sign of obstruction. When decreasing VC and preserved bronchial patency, this indicator may slightly increase, and with mixed obstructive-restrictive processes, its value loses its diagnostic value. Then calculate the ratio FEV1 not to the actual, but to the due VC.

When determining the Tiffno index, two separate studies are required - with calm breathing ( VC) and during forced exhalation, which reduces the accuracy of the result. More reliable can be considered the Gensler index, performed in one go:

Gensler index \u003d (FEV1 / FVC) x 100%, normal 85-90%

Note that FEV, FZhEL And VC taken directly from the system ATPS without recalculation.

For a more subtle and accurate characterization of respiratory apparatus disorders, the expiratory rate is determined at its various moments, as well as the peak expiratory volumetric velocity ( PIC vyd), or the highest rate for the entire expiration time.

Abroad, the forced expiratory volumes are also often determined in 0.5, 2 and 3 s, the time to reach the maximum expiratory rate, the half-expiratory time VC etc. Compared with the Tiffno and Gensler tests, instantaneous expiratory volumetric velocities are more informative ( ISO = FEV in the US system), measured at expiratory points 25, 50, 75 and 85% VC (MOS 25, MOS 50 etc.), characterizing the state of large, medium and small bronchi, respectively, and the average volumetric velocities in the areas of expiration 25 - 50, 50 - 75, 75 - 80% VC (SOS 25 _ 50 etc.).

In another, European, notation, the countdown is based on the proportion VC, remaining in the lungs, then these instantaneous expiratory velocities ( MEF) are denoted, respectively, MSV 75, MSV 50, MSV 25, MSV 25 _ 75 And PSV(peak expiratory flow).

Important information about the functional reserves of the external respiration apparatus is given by the test of maximum ventilation of the lungs ( MVL). Maximum ventilation is the volume of air passing through the lungs per minute of the most frequent and deep breathing.

Typically, the test is carried out for 10 - 15 s, and the result is given in 1 min. Fine MVL 8-20 times more MAUD and reaches 150 - 180 liters. A close correlation of changes has been established MVL And FEV1, so some authors restrict themselves to defining only FEV1.

Additional information can give the shape of the curve of maximum ventilation of the lungs, which is shifted upward with obstruction due to air entrapment (increased FFU and decrease RO vd).

1.3. Systems of physical conditions in which gas volumes can be located during spirography

When analyzing tidal volumes, it is necessary to take into account their dependence on changes in pressure, temperature and humidity. In the lungs, the air is in alveolar conditions, i.e. at t = 37 ° C, relative air humidity of 100% and a pressure approximately equal to atmospheric pressure. Under the same conditions, the proper values ​​\u200b\u200bare given in tables and formulas (less often - in standard ones). When air exits the lungs into the external environment or into the spirograph circuit, it quickly cools to room temperature, and excess moisture condenses, while the relative humidity remains 100% (for room temperature), and the pressure does not change. Such conditions are called atmospheric.

The measured oxygen consumption is usually reduced to standard conditions - 0 ° C, zero humidity, pressure 760 mm Hg. Art. These three systems of conditions are abbreviated as BTPS(alveolar conditions - Body temperature, Pressure, Saturated), ATPS(atmospheric - Ambient Temperature, Pressure, Saturated) and STPD(standard - Standard Temperature. Pressure, Dry). The values ​​obtained by spirography (under atmospheric conditions) lead to alveolar and standard conditions. For such recalculations, tables and nomograms have been developed in which, taking into account temperature, pressure and sometimes humidity, the corresponding coefficients are found (Table 1).

Table 1

Approximate conversion factors to BTPS and STRD (at atmospheric pressure 740 - 780 mmHg)

In mass studies, it is permissible to use a coefficient of 1.1 to convert to BTPS and 0.9 - to STRD. Volumes should not be recalculated if they are used in any formula based on the division of two indicators obtained in the same system of conditions (for example, the Tiffno index, Table 2).

table 2

The degree of violation of the ventilation function of the lungs according to N.N. Kanaev

1.4. Research standardization

To obtain stable results of the study, spirography is carried out under the same conditions, as close as possible to the main exchange. The data obtained are compared with the standards (proper values) calculated on the basis of the results of a survey of large groups healthy people, summarized in tables standardized by sex, age and height, or by formulas derived from tables. An indicator that differs from the tabular one by no more than 15–20% is considered normal.

When evaluating the results of a study of lung ventilation function, it is necessary to take into account the reproducibility and repeatability of indicators.

Reproducibility is the allowable fluctuation of the measured values ​​during repeated examination during the day. For VC it is +150 ml.

Repeatability - the limit of fluctuations when repeating the study several times during the year. For VC repeatability is +380 ml. For FEV1 fluctuations within +15% are allowed.

1.5. Lateral test

If it is necessary to detect unilateral lung damage, the lateral (spiroplanimetric) Bergan test, or the lateral position test, is used. To do this, a curve of calm breathing is recorded in the supine position with a raised head (place a high pillow), then the patient is asked to turn on his right side, pressing the outstretched right hand to the torso. Due to the displacement of air from the compressed lung, the curve rises horizontally. Next, the spirogram is recorded again in the prone position, and then in the same way, but in the position on the left side. Measure the rise of the curve above the initial level in millimeters when turning to the right and left side (hpr and hleft) and determine the function of the right and left lung according to the formula:

Normally, the function of the right lung is 55 - 57%, the left - 43 - 45%.

Rice. 1. Principles of lateral test analysis

2. METHODS FOR STUDYING THE RESPIRATORY FUNCTION

Spirometry is a method for measuring lung volumes, spirography is a graphical recording of their changes over time. The curve obtained by writing on paper, in the coordinates "volume - time", is called a spirogram. The rate of inhalation and exhalation can be measured indirectly from a spirogram or directly determined using pneumotachometry and pneumotachography.

Spirometry, spirography and pneumotachometry are the most commonly used methods for studying the ventilation function of the lungs. They are non-invasive, cheap, require relatively little time and with satisfactory accuracy allow to establish the presence, nature and severity of ventilation disorders.

There are open and closed type spirographs. The latter can be with or without compensation for the consumed oxygen. In open-type devices, atmospheric air is breathed without taking into account oxygen consumption, which simplifies the study and maintenance of devices. In closed-type spirographs, the subject breathes air from a sealed breathing circuit, which requires the mandatory use of a chemical carbon dioxide absorber, but allows determining the minute oxygen consumption. In this case, the curve of the spirogram gradually shifts due to a decrease in the volume of gas.

To increase the study time on closed-type spirographs, it is possible to gradually add oxygen to the respiratory system as it is consumed, and the main curve will be horizontal, and the amount of added gas is recorded as an additional line on the spirogram.

2.1. Method of spirographic research

Spirometry and spirographic studies in full and in a simplified version (with registration of only the main indicators) are carried out in conditions close to the main metabolism, usually in a sitting position, in the first half of the day, on an empty stomach or not earlier than 1 - 1.5 hours after eating . In the afternoon, a longer rest is needed.

The study of gas exchange indicators is carried out in the morning, in the supine position, 12-13 hours after eating. No pre-training required. The subject is explained the purpose of the study and the respiratory maneuvers that he has to perform.

Unlike ECG spirography has contraindications. It is not recommended to perform it in febrile and infectious patients, persons suffering from severe angina pectoris or highly unstable arterial hypertension, severe heart failure and other serious illnesses, patients with mental disorders who are unable to properly perform the study, and elderly people for whom standard values ​​have not been developed.

Connection to a spirometer or spirograph is made through a sterile mouthpiece (mouthpiece). A disinfected clamp is applied to the nose. Connection to open-type devices is carried out without taking into account the phase of breathing, and to closed-type devices - at the level of calm exhalation.

Respiratory volumes are determined using the formula:

Where LV- line length, S- sensitivity of the device, equal to 25 mm/l.

At a tape speed of 50 mm / min, one minute corresponds to a segment of 5 cm, and 600 mm / min - 1 cm = 1 sec (to determine FEV1. Convenient to use special calculation rulers, marked on such a scale. To determine the proper indicators of respiration and basal metabolism, tables and nomograms are included in the device kit. Taking into account the measurement error (not less than 50 ml), all obtained values ​​​​of lung volumes should be rounded up to the correct numbers (up to 0.05 l).

A complete spirographic study begins with registration BH, BEFORE And software 2 at rest, not less than 3 - 5 minutes (until steady state). During registration BH, BEFORE And software 2 the subject is offered to breathe calmly, without fixing attention on breathing. Then, after a short break (1 - 2 minutes) with disconnection from the apparatus of a closed type, register VC, FEV 1 or forced expiratory curve ( FZhEL) And MVL. Each of these indicators is recorded at least 3 times until the maximum values ​​are obtained.

During registration VC It is recommended to take the deepest breath and the most complete calm exhalation. Carry out a two-stage test VC when, against the background of calm breathing, they are asked to take only one deep breath, and after a while - only the maximum exhalation. The distance between the tops of these teeth somewhat (by 100 - 200 ml) exceeds the one-time VC. To assess the correctness of the respiratory maneuver, it is necessary to pay attention to the shape of the curve vertices VC. When a truly maximum inhalation and exhalation is reached, the curves are somewhat rounded at the upper and lower points (inspiratory and expiratory apnea).

During registration FEV, And FZhEL it is necessary to inhale as deeply as possible and after a short pause (1 - 2 s) exhale as quickly and as completely as possible, when registering MVL- breathe as often as possible and at the same time as deeply as possible.

Before registering MVL it is useful to demonstrate the pattern of breathing by performing this breathing maneuver with several forced breaths. Registration time MVL- no more than 10 - 15 s. Duration of intervals between individual measurements VC, FEV,, FZhEL And MVL without disconnection from the open-type apparatus and with disconnection from the closed-type apparatus, if the subject easily copes with the necessary breathing maneuvers, does not exceed 1 min.

When fatigue and shortness of breath occur, which is most often observed after a short but tiring registration MVL, the intervals between individual measurements are increased to 2 - 3 or more minutes. When recording indicators of pulmonary ventilation at rest ( BH, BEFORE), software 2 And VC The spirograph paper moves at a speed of 50 mm/min. FZhEL And MVL– 600 - 1200 mm/min.

Loop flow - volume

An important diagnostic value is the analysis of the volume-flow loop of maximum forced expiration and inspiration. This loop is formed as a result of overlaying the flow velocity graph along the vertical axis, and the lung volume value along the horizontal axis. This loop is built by modern computer spirographs in automatic mode (Fig. 2). On this loop, the main indicators of the spirogram are highlighted.

Rice. 2. Loop flow - volume

According to the shape of the loop and changes in its parameters, it is possible to distinguish the norm and the main types of respiratory failure: obstructive, restrictive and mixed.

Normal spirogram. In a healthy person, the conclusion of the study of respiratory function usually indicates that there are no disorders. The table lists the indicators of the function respiratory system and their normal values. Most of the values ​​of the indicators are expressed as a percentage of the so-called "proper" values. These are values ​​characteristic of a healthy person, male or female, age, weight and height. Conventionally, this can be considered "normal" values.

Rice. 3. Loop flow - volume is normal.

The normal flow-expiratory volume loop (Figure 3) has a fast peak top speed exhalation ( pic) and a gradual decline in the flow to zero, and it has a linear section - MOS50vyd. The inspiratory loop on the negative part of the flow axis is quite deep, convex, and often symmetrical. MOS50vd > MOS50vyd.

Table 3

The main indicators of spirography:

Fine FEV1, FZhEL, FEV1/FVC exceed 80% of standard indicators. If these indicators are less than 70% of the norm, this is a sign of pathology (Table 3).

The range from 80% to 70% due is interpreted individually. In older age groups, such indicators may be normal, in young and middle-aged people they may indicate initial signs obstruction. In such cases, it is necessary to deepen the examination, conduct a test with β2-adrenergic receptor agonists.

Spirography is a method of graphic recording of changes in lung volumes during various breathing exercises.

Spirography is one of the oldest, simplest and most common methods for studying the respiratory function of the patient under study.

A modern medical spirograph is a portable device that allows you to evaluate the following indicators of human respiratory function:

• lung volumes and capacities (the capacity includes several volumes);
• indicators of pulmonary ventilation;
• oxygen consumption by the body;
• ventilation efficiency.

Lung volumes and capacities

Rice. Lung volumes, capacities and stages of respiration.

Tidal volume(DO) - the volume of inhaled / exhaled air in a calm position.

Inspiratory reserve volume(RVD) - the maximum volume of air that the patient can additionally inhale after a quiet breath.

expiratory reserve volume(ROvyd) - the same for exhalation.

Residual lung volume(OOL) - the volume of air remaining in the lungs after maximum exhalation (OOL does not allow the lung to subside, contributing to a more uniform mixing of air in the lungs).

Inspiratory capacity(Evd = TO + Rvd) - the total volume of inhaled air and maximum inspiration, characterizes the ability of lung tissues to stretch (Evd always decreases with restrictive syndrome).

Vital capacity of the lungs(VC = TO + RVD + ROvyd) - the maximum volume of air exhaled after maximum inspiration (the main indicator of the ventilation function of the lungs).

Functional residual capacity(FOE = ROvyd + OOL) - the volume of air that remains in the lungs at the level of calm exhalation (normally FOE = 0.5 OEL).

Total lung capacity(TEL = VC + TOL) - the maximum volume of air held by the lungs at the height of maximum inspiration (a decrease in TEL is the main sign of restrictive syndrome).

Pulmonary ventilation disorders, accompanied by changes in lung volumes and capacities, can be obstructive or restrictive character.

For restrictive syndrome a decrease in TRL with a proportional decrease in all its constituent volumes is characteristic.

For obstructive syndrome difficult exhalation is characteristic, due to the fact that the lumen of the airways during exhalation is less than during inhalation, thus, conditions are formed for expiratory narrowing of the small bronchi (up to their collapse) - a characteristic situation for emphysema. The obstructive syndrome is characterized by a decrease in ERR, an increase in TRL, FFU, while TRL may either remain unchanged (increase in RUR is compensated by a decrease in ERV and VC) or increase (increase in RUR with an increase in the ratios of TOL/TFU and FFU/TFU).

Indicators of pulmonary ventilation

Pulmonary ventilation measures the volume of air entering and leaving the lungs per unit of time.

Number of breaths(RR) during quiet breathing.

Minute breathing volume(MOD = DO · RR) - displays the value of total ventilation per minute during quiet breathing (normally in adults, RR = 10..20/min, DO = 0.3..0.8 l, on average, MOD = 6. .8 l / min), this is a purely individual characteristic that characterizes the breathing pattern (pattern) of a particular organism.

Minute alveolar ventilation(MAV) - the amount of air that the body exchanges in the alveoli during quiet breathing for 1 minute.

forced vital capacity(FVC) - one of the main tests in spirography, similar to the VC test, with the difference that the exhalation is done as quickly as possible.

The forced expiratory volume in 1 second of the FVC maneuver (FEV 1) is one of the main indicators in the study of pulmonary ventilation function (it decreases with any violations), reflects the expiratory rate at the beginning and middle phase, and practically does not depend on the rate at the end of forced expiratory.

Tiffno index(FEV 1 / VC),% - in obstructive syndrome it decreases due to a decrease in FEV 1 (slow expiratory flow), while VC drops slightly; with a restrictive syndrome, it does not change (FEV 1 and VC decrease proportionally) or increases (relatively faster exhalation due to the small amount of air available in the lungs).

In practice, an SOS indicator of 25-75 is often used, which displays the average expiratory volumetric flow rate at the level of inspiration in the range of 25-75% FVC ( middle part forced expiration). This indicator more objectively reflects the patency of the bronchial tree, to a lesser extent depending on the voluntary effort of the subject.

Maximum ventilation(MVL) - the maximum volume of air ventilated by the lungs in 1 min.

The data of spirographic studies are compared with tabular values ​​that take into account the sex, age and height of the patient under study.

Types of violations of the ventilation function of the lungs according to the main indicators:

Violation of bronchial patency, assessment of its severity and predominant levels of damage is carried out using bronchodilation test, which is the initial stage in the program of making a functional diagnosis in pathologies respiratory tract obstructive nature. At the next stage, under the action of bronchodilators, the degree of reversibility of obstructive changes is determined.

Also, with the help of a bronchodilator test, a distinction is made between reversible and irreversible destructive changes ( bronchial asthma and COPD).

The most common method for measuring the reversibility of changes is to evaluate the ratio of the absolute increase in FEV 1 (ml), expressed in%, to the original (using salbutamol, the bronchodilatory response is measured after 15 minutes):

FEV 1 (%) \u003d (FEV 1 dilat - FEV 1 ref) / FEV 1 ref 100%

When FEV 1 ≥15% bronchodilatory response is considered positive (reversible bronchial obstruction).

Peakflowmetry

Determination of peak expiratory flow rate (PSV) is carried out using, which was invented by the English physician V. M. Wright in 1958.

Currently, the peak flow meter is a compact device that is simple to use. The main task of the patient is to learn how to dose his exhalation effort (depending on age and height).

The first measurement is taken by the patient himself after morning sleep before taking medication, the second - in the evening, before bedtime, after taking medicines. The best measured value from three attempts is entered by the patient in the chart.

Bronchial obstruction reversibility test:

• measure the initial value of PSV1;
• inhalation of salbutamol 400 mcg (beta2-agonist short action);
• measure again (15 minutes after taking the drug) the value of PSV2;
• calculate the coefficient of bronchial obstruction (BO) according to the formula: BO = (PSV2-PSV1) / PSV1 100%

Criteria for the severity of bronchial obstruction:

• a significant degree of severity of BO more than 25%;
• moderate - 15-24%;
• insignificant - 10-14%;
• negative reaction - less than 10%.

Assessment of bronchial hyperreactivity

Bronchial hyperreactivity can be determined using peak flowmetry. A sign of hyperreactivity is the presence of a "morning dip", when the morning PSV value is 20% or more lower than that measured in the evening. They talk about bronchial hyperreactivity even in the case of one "morning dip" per week. Fluctuations between morning and evening PSV (%) are called the daily variability index (DIV) or daily bronchial lability (SLB):

WIS \u003d (PSV evening - PSV morning) / 0.5 (PSV morning + PSV night) 100%

Assessment of the severity of the disease

Fluctuations in PSV are the most important parameter to assess the severity of the course of the disease. For this, weekly PSV values ​​are taken, their maximum and minimum values ​​are determined:

K \u003d (PSV max - PSV min) / PSV max 100%

Predicting Asthma Exacerbations

The beginning of the development of bronchospasm is recorded on the PSV graph as a drop in values ​​relative to the best or as the appearance of "morning dips". This drop in PSV often occurs a few days before the onset of bronchospasm. In such cases, it is possible to prevent the onset of an attack by strengthening drug therapy in advance.

Determination of factors influencing the development of bronchospasm

On the daily PSV charts, measured values ​​​​are marked every 2 hours. On the time axis, the moments of the onset of potential factors provoking bronchospasm are recorded. By changing the graph, it is determined whether it is associated with bronchospasm.

Evaluation of the effectiveness of treatment

With the right treatment, the value of PSV rises to the best, "morning dips" disappear.

The method of measuring PSV is well suited for optimizing the treatment of patients with bronchial asthma and self-monitoring of patients. The attending physician builds a treatment plan based on acceptable indicators of changes in PSV:

• green zone (PSV indicators lie within 80-100% of the due);
• yellow zone (60-80%) - drug treatment needs correction;
• red zone (less than 60%) - the patient requires emergency medical care.

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As mentioned above, the methods of classical spirography, as well as computer processing of the flow-volume curve, make it possible to get an idea of ​​​​the changes in only five of the eight lung volumes and capacities (TO, RO vd, ROvyd, VCL, Evd, or, respectively, VT, IRV, ERV, VC and 1C), which makes it possible to evaluate the advantage and non-opportunity of the degree of obstructive disorders of pulmonary ventilation. Restrictive disorders can only be reliably diagnosed if UN are not combined with a violation of bronchial patency, i.e. in the absence of smg secret disorders of pulmonary ventilation. However, in the practice of a doctor more often BCQF0 there are just such mixed violations(for example, in chronic but structural bronchitis or bronchial asthma, complicated by emphysema and pneumo-lerosis, etc.). In these cases, the mechanisms of impaired pulmonary ventilation can only be identified by analyzing the structure of the RFE.

To solve this problem, you need to use additional methods determine the functional residual capacity (FRC, or FRC) and calculate BYE so whether residual lung volume (ROL, or RV) and total lung capacity (TLC, or TLC). Since FRC is the amount of air remaining in the lungs after maximum exhalation, it is measured only indirect methods(gas analysis or using whole body plethysmography).

The principle of gas analysis methods is that the inert gas helium is either injected into the lungs (dilution method), or the nitrogen contained in the alveolar air is washed out, forcing the patient to breathe pure oxygen. In both cases, the PON is calculated from the final gas concentration (R.F. Schmidt, G. Thews).

Helium breeding method. Helium is known to be inert and harmless For the body with a gas that practically does not pass through the alveolar-capillary membrane and does not participate in gas exchange.

The dilution method is based on measuring the helium concentration in the closed container of the spirometer before and after mixing the gas with the lung volume (Fig. 2.38). A covered spirometer with a known volume (V c ") is filled with a gas mixture consisting of oxygen and helium. At the same time, the volume occupied by helium (V U1) and its initial concentration (Fnej) are also known (Fig. 2.38, a). After a quiet exhalation, the patient begins to breathe from the spirometer, and helium is evenly distributed between the volume of the lungs (FOE, or FRC) and the volume of the spirometer (V c "; Fig. 2.38, b). After a few minutes, which concentration of helium in the general system (“spirometer-lungs”) decreases (Рн e2) -

The FRC calculation is based on the law of conservation of matter: the total amount of helium is equal to the product of its volume (V) and concentration (¥ts k), should be the same at baseline and after mixing with lung volume (FFU, or FR*)

VcpxF lll . l \u003d (V CII + FOE)xF l

."(by combining the volume of the spirograph (V c ") and the concentration of helium before and after the study (cor-K1 and" pio, Fuej and Fhc2)> you can calculate the desired lung volume (FOE, or FRC):

After that, the residual lung volume (ROL, or RV) and the total lung capacity (REL, or TLC) are calculated:

OOL \u003d FOE - RO vyd;

OEL \u003d VC + OOL.

Nitrogen washout method. In this method, the spirometer is filled with oxygen. The patient breathes into the closed circuit of the irometer for several minutes, while measuring the volume of exhaled air (gas), the initial content c length! in the lungs and its final content in the spirometer. The FRC is calculated using an equation similar to that of the helium dilution method.

The accuracy of both methods of determining the FRC (FRC) depends on the change in the lawn in the lungs, which in healthy people occurs within a few minutes. However, in some diseases accompanied by severe uneven ventilation (for example, with obstructive pulmonary pathology), balancing the concentration of gases takes long time. In these cases, the measurement of FRC (FRC) by the methods described may be inaccurate. These shortcomings are devoid of the more technically complex method of whole body plethysmography.

Whole body plethysmography. Whole body plethysmography is one of the most informative and sophisticated examination methods used in pulmopolo! nor to determine lung volumes, trachobrochial resistance, elastic properties of lung tissue and chest, as well as to evaluate some other parameters of pulmonary ventilation.

The integral plethysmograph is a hermetically sealed chamber with a volume of M 800 l, in which the patient is freely placed (Fig. 2.39 and 2.40). The subject breathes through a neumotachographic tube connected to a hose that is open to the atmosphere. The hose has a damper that allows you to automatically shut off the air flow at the right time. Special barometric sensors measure the pressure in the O "kam) chamber and in the oral cavity (P, ut). The latter, with the hose flap closed, is equal to the intra-alveolar pressure. The pneumotachograph allows you to determine the air flow (V).

The principle of operation of the integral plethysmograph is based on the law of Boiai-Moriyshta according to which, at a constant temperature, the difference between the pressure (P) and the volume of the gas (V) remains constant:

P, x V, \u003d P 2 x V 2,

where Pi is the initial gas pressure,

Vj - initial volume of gas,

R> - pressure after changing the volume of gas,

V 2 - volume after changing the gas pressure.

The patient inside the plethysmograph chamber inhales and dude pip exhales, after which (at the FRC level, or FRC) the hose flap is closed, and about* and the blown one makes an attempt to “inhale” and “exhale” (the “breathing” maneuver; Fig. 240) With such a “breathing” maneuver, the viutrial alveolar pressure changes, and the pressure in the closed chamber of the plethysmograph changes inversely proportional to it. When trying to "inhale" with a closed damper, the volume of the chest increases, which leads, on the one hand, to a decrease in intra-alveolar pressure, and on the other hand, to a corresponding increase in pressure in the plethysmograph chamber (P K am) - On the contrary, when trying to "exhale" alveolar pressure increases, and chest volume and pressure in the chamber decrease.

BASIC INDICATORS

VENTILATION CAPACITY OF THE LUNGS

Informative are the indicators that are calculated according to the spirogram in the "volume-time" coordinates, in the process of spontaneous breathing, performing calm and forced breathing maneuvers.

Calm Forced

breath. breathing maneuver. maneuver

BEFORE – tidal volume- the volume of air inhaled or exhaled during each respiratory cycle during quiet breathing, normally about 500 ml.

ROVD – inspiratory reserve volume- the maximum volume that can be inhaled after a quiet breath

ROvyd – expiratory reserve volume- the maximum volume that can be exhaled after a quiet exhalation

OOL – residual lung volume- the volume of air remaining in the lungs after maximum exhalation is the most valuable in diagnosis. The value of OOL and the ratio of OOL / OOL are considered the most important criteria for assessing the elasticity of the lungs and the state of bronchial patency. The OOL increases with emphysema, deterioration of bronchial patency. It decreases with restrictive processes in the lungs.

YELLOW – lung capacity The maximum volume of air that can be exhaled after a maximum inhalation.

YEL=DO+ROVD+ROVID

The most important informative indicator of the function of external respiration. Depends on gender, height, age, body weight, physical condition of the body. A decrease in VC occurs with a decrease in the amount of functioning lung tissue (pneumosclerosis, fibrosis, atelectasis, pneumonia, edema, etc.), with insufficient expansion of the lungs due to extrapulmonary causes (kyphoscoliosis, pleurisy, pathology of the chest and respiratory muscles). A moderate decrease in VC is also observed in bronchial obstruction.

OYOL – total lung capacity- the maximum amount of air that the lungs can hold at the height of a deep breath.

OOL=YEL+OOL

A decrease in ROL is the main reliable criterion for restrictive ventilation disorders. An increase in TOL is observed in obstructive pathology, pulmonary emphysema.

Allocate the same:

FOYO – functional residual capacity The volume of air remaining in the lungs after a quiet exhalation.

FOYO=OOL+ROvyd is the main volume in which the processes of intra-alveolar mixing of gases take place.

Yovd – inspiratory capacity- the maximum amount of air that can be inhaled after a quiet exhalation. Yovd \u003d TO + Rovd.

In practical medicine, the main problem is the definition of OOL and OOL, which requires the use of expensive body plethysmographs.

Determination of indicators of bronchial patency is based on the determination of the volumetric velocity of air movement, is carried out according to the curve of forced exhalation.

forced vital capacity–FJOL is the volume of air that can be exhaled with the fastest and most complete exhalation after a maximum inhalation. Basically, it is 100-300 ml less YELLOW. With obstructive processes, this difference increases to 1.5 liters or more.

Forced expiratory volume in 1 second maneuver FJOL - FEV1- one of the main indicators of the ventilation function of the lungs.

It decreases with any violations: with obstructive ones due to slowing down of forced expiration, and with restrictive ones - due to a decrease in all lung volumes.

Tiffno index – FEV1/VC ratio, expressed in %- a very sensitive index, decreases with obstructive syndrome, does not change with restrictive syndrome or even increases due to a proportional decrease in FEV1 and VC.

At present, it is widely FORCED EXPIRATION PNEUMOTHAPHOGRAPHY

The patient sequentially performs 2 breathing maneuvers:

2) forced expiration (FZHOL expiration).

In the coordinates "flow-volume" a curve is written, which is called - flow-volume curve. It resembles the shape of a triangle, the base of which is FJOL, the hypotenuse has a slightly curved shape.

For convenience, in modern spirographs, the curve is presented with a rotation of 90 degrees: the flow is plotted along the vertical (ordinate axis), and the volume is plotted horizontally (abscissa). Exhalation is reflected from above, inhalation from below.

In addition to FVC, FEV1 and the Tiffno index, other forced expiratory parameters are calculated automatically using computer devices.

pic – peak volumetric velocity- the maximum flow achieved during exhalation does not depend on the applied effort

ISO – instantaneous volumetric velocities, speeds at the moment of exhalation of a certain proportion of FVC (usually 25, 50 and 75% of FVC), are subject to instrumental error, depend on the expiratory effort and VC.

There are 2 ways to designate the fraction of FVC at which MOS is calculated:

1) that part of the FZhOL is indicated, which already exhaled– America, Russia – MOS25=MEF 25=FEF 75

2) that part of the FZhOL is indicated, which still needs to be exhaled– Europe – MOS75= MEF 75=FEF 25

In practice, MOCs have not proven to be as reliable and important as previously thought. It was believed that the level of bronchial obstruction can also be determined from the curve of forced expiration (MOS25 reflects the level of patency of large, MOS50 - medium, MOS75 - patency of small bronchi). At present, the determination of the level of obstruction according to the FVC curve has been abandoned.

But in the diagnosis of obstructive disorders, the assessment of speed indicators takes place: for example, with early obstructive disorders, an isolated decrease in MOC50.75 is noted with other normal indicators. As the obstruction worsens, there is a decrease below the norm of POS and MOS25.

SOS25-75 – average volumetric velocity exhalation at the level of 25-75% FVC - a decrease in this indicator in the absence of changes in the VC indicates the initial manifestations of bronchial obstruction.

BREATHING MANEUVERS TECHNIQUE

1st lung capacity test (VC) - options for its implementation are possible depending on the brand of the device -

the patient must draw as much air into the lungs as possible, tightly clasp the mouthpiece with his lips and then comfortably exhale all the air to the end (not forced!)

2nd forced vital capacity test (FVC) -

the patient should take as much air into the lungs as possible, tightly clasp the mouthpiece with his lips and exhale the air as sharply, strongly and to the end, then immediately take a full breath (closing the flow-volume loop).

An important condition is a sufficient duration of expiration (at least 6 seconds) and maintaining the maximum expiratory effort until the end of exhalation.

The quality of the maneuvers depends on the level of training of the operator and on the active cooperation of the patient.

Each test is repeated several times (at least 3 times), the differences in attempts should not exceed 5%, for each of the attempts the researcher exercises visual control on the screen. The device builds and processes an envelope curve that reflects the best result.

To obtain reliable results of the study, it is extremely important to observe the correct technique for performing the patient's breathing maneuvers. The researcher must carefully read the instructions for the device, where the features of the device model are necessarily specified.

Before the study, the patient is instructed in detail and, in some cases, clearly demonstrates the upcoming procedure.

The most common mistakes in performing breathing maneuvers are: insufficiently tight grip of the mouthpiece by the patient with air leakage, incomplete inspiration, untimely early start of forced expiration, lack of proper willpower and insufficient exhalation duration, premature inspiration, coughing during the breathing maneuver.

The doctor of functional diagnostics is responsible for the quality of the study.

CRITERIA FOR CORRECT PERFORMANCE

BREATHING MANEUVERS

1.TPOS– time to reach POS in the norm< 0,1 сек

OPOS- the volume at which the POS is reached in the norm < 20% FJOL

Normally, POS is achieved in less than 0.1 sec when the first 20% of FVC is exhaled. An increase in these indicators is observed with the late development of maximum effort, the peak of the triangle is shifted along the volume axis. Exclusion for stenosis of the extrathoracic airways.

2. Tvyd (FET)– exhalation time is normal 2.5 – 4 sec

Increase to 5 - 7 seconds with severe bronchial obstruction,

Reduction to 2 sec with severe restriction.

A common maneuver error is the patient “squeezing out” an exhalation, then a curve with a long tail is recorded.

3. Comparison of ZHOLVD and FZHOL.

In healthy people > FZHOL per 100-150 ml, with violations of bronchial conduction, the difference can reach 300-500 ml.

Maneuver errors: - YELLOW< ФЖЁЛ (неправильно выполненное

measurement of VC),

YELLOW > FYOL more than 500 ml

4. Speed ​​Cascade: POS > MOS25 > MOS50 > MOS75

MOST COMMON MANEUVERING ERRORS

Late development of maximum effort by the patient and its insufficient value: small steepness, rounded top, peak shift

>

Expiratory interruption, sharp drop to Waveform distortion

zero with involuntary closure due to fluctuations in voice

“Squeezing” by the test subjects at the end of exhalation of air from the lungs within the residual volume: the curve has a long flattened “tail”

ASSESSMENT OF SPIROMETRY AND

FORMATION OF THE CONCLUSION

Steps for evaluating spirometry data:

1. Expression of indicators as a percentage of due values

2. Determination of the fact of the presence of a pathological deviation of indicators from the norm

3. Assessment of the degree of change in indicators in gradations

4. Final analysis, conclusion formation.

To resolve the issue of the nature and degree of the patient's ventilation disorders, it is first necessary to evaluate the changes in each individual indicator by comparing its value with the proper values, the limits of the norm and the gradations of deviation from it.

The interpretation of all spirographic indicators is based on the calculation of the deviation of the actual values ​​from the due ones.

due value- the value of the corresponding indicator in a healthy person of the same weight, height, age, sex and race as the subject. There are many different formulas for the proper values ​​of the parameters of the respiratory system.

In our country, the consolidated system of due values ​​of spirometry indicators for adults, developed in 1984 by R.F. Clement et al., has become widespread. at the All-Russian Research Institute of Pulmonology of the Ministry of Health of the USSR (now the State Scientific Center for Pulmonology of the Ministry of Health of the Russian Federation). Later, in 1994, R.F. Klement and N.A. Zilber developed a similar system for persons under 18 years of age.

The imported spirometry equipment is based on the standards of the European Coal and Steel Community, approved by the European Respiratory Society. Similar standards have been developed by the American Thoracic Society.

At the first stage of processing spirometry data, the values ​​of the indicators are expressed in% of their due values. Next, they are compared with the existing defined border of the norm.

Pathological changes in spirometric indicators are unilateral: in case of lung diseases, all indicators only decrease. Thus, it is determined the fact of having pathological changes indicators.

The next stage is assessment of the degree of change in indicators.

Deviations from the norm are usually placed in a system of three gradations: “moderate”, “significant” and “abrupt” changes.

There are various tables, one of the most common is:

indicators of external respiration (L.L. Shik, N.N. Kanaev, 1980)

Limits of the norm and gradations of deviations from the norm

indicators of the ventilation function of the lungs (according to R.F. Clement)

The system of three gradations of deviation from the norm is popular in the clinic, but, according to pulmonologists, it poorly reflects the entire range of pathological changes.

In modern domestic spirometry programs there are 10 gradations of severity of changes in indicators in the form of the following verbal characteristics:

The use of 10 gradations to assess the severity of changes in spirometry indicators does not interfere with the assessment in three categories: gradations 4, 5 and 6 are moderate, 7 and 8 are significant, 9 and 10 are sharp.

Thus, the actual values ​​of indicators are compared with their due values, and the degree of their deviation from the norm is determined. Further analysis of the results and drawing up a conclusion is carried out on the basis of a comparison of changes in the entire set of indicators.

When formulating a conclusion, according to spirometry data, it is determined type of ventilation violations:

- restrictive (restrictive)- connected:

1) - with a decrease in the functioning lung parenchyma (pneumosclerosis, pneumofibrosis, atelectasis, pneumonia, abscess, tumors, surgical removal of lung tissue, pulmonary edema), loss of elastic properties of the lungs (emphysema),

2) - with insufficient expansion of the lungs (deformity of the chest, pleural adhesions, effusion pleurisy, limitation of movement of the diaphragm, muscle weakness)

It is characterized by a decrease in VC with relatively smaller changes in speed indicators, Tiffno is normal or exceeds the norm.

- obstructive- associated with a violation of the passage of air through the bronchi, characterized by a decrease in speed indicators (FEV1, POS, MOS, SOS25-75), normal VC and a decrease in Tiffno.

- mixed- observed with a combined decrease in speed indicators and VC.

Evaluation of the type of flow-volume curve

As already mentioned, normally, the flow-volume curve resembles the shape of a triangle, the base of which is FVC, the hypotenuse has a slightly curved shape.

In lung pathology, the shape and size of the flow-volume loop changes:

With a moderately pronounced obstruction, the hypotenuse of the triangle bends, the base practically does not change,

With severe obstruction - the hypotenuse bends significantly, the base of the triangle decreases (reduction of VC),

With restrictive changes, the height and base of the triangle are reduced.

Formulation of the conclusion:

In a standard spirographic report, the research physician must clearly answer three main questions:

1. whether the examined person has a violation of the ventilation function of the lungs (impaired pulmonary ventilation),

2. what type of ventilation violations are most appropriate,

3. what is the severity of pulmonary ventilation disorders.

Example: Significant violations of pulmonary ventilation of the lungs of obstructive type (II stage)

As is known, VC decreases both with restriction and obstruction. The main features of the difference between these syndromes are OOL and OOL.

With restriction, the TOL and TOL decrease, and with obstruction, on the contrary, the TOL and TOL increase. Determination of TOL and TTL is associated with technical difficulties, expensive equipment is required. And, since the data of the FVC test do not give an idea of ​​the magnitude of the FVC and the RCA, it is unlawful to draw a conclusion about the type of ventilation disorders using a single FVC test, especially when determining the restrictive type and the mixed one.

Therefore, in view of the above, it is possible to assess the value of VC and indicators characterizing the patency of the respiratory tract, that is, the degree of bronchial obstruction.

On this issue, there is still inconsistency in the conclusions of various clinics in Russia.

The main objective generally accepted criterion for bronchial obstruction is a decrease in the integral indicator of FEV1 to a level that is less than 80% of the proper values.

Based on this indicator, the severity of COPD is also determined:

Promising is monitoring of the current state of bronchial patency in patients with COPD is a long-term measurement of FEV1 in dynamics. Normally, there is an annual drop in FEV1 within 30 ml per year, in patients with COPD - more than 50 ml per year.

PEAKFLOWMETRY

Self-assessment of the current state of bronchial patency at home is carried out using peak flowmetry- measurement of the maximum, peak forced expiratory flow rate (PSEF) using a peak flowmeter. The method is simple and accessible to patients. It is recommended for patients with bronchial asthma and COPD.

Self-measurement of PSEF in a hospital or at home allows you to:

Diagnose obstructive airway disorders

Establish control over the severity of obstruction in dynamics,

Determine the factors that increase bronchial obstruction,

Evaluate the effectiveness of the therapy, choose the dose of the drug,

Adjust the therapeutic complex during long-term therapy.

The peak flow meter is a portable instrument. It has a digital scale on the body showing the peak forced expiratory flow in l / s or l / min and a removable mouthpiece (mouthpiece).

The patient constantly carries the specified device with him and independently takes measurements at least 2 times a day (morning and evening), sometimes every 3-4 hours, and additionally when respiratory discomfort occurs.

When measuring, the patient should:

Place the instrument pointer at the beginning of the digital scale,

Hold the peak flow meter in such a way that your fingers do not touch the scale, while it is better to stand up or sit straight,

Take the deepest possible breath and squeeze the mouthpiece tightly with your lips,

Exhale as strongly and quickly as possible (for example, blow out the flame of a candle),

View the result on the scale of the device, put the device pointer at the beginning of the scale again and repeat the measurement two more times,

Record the highest of the three indicators in a special self-observation diary, where the measurement time is indicated.

The measurement accuracy depends on the efforts of the patient.

To get the most complete information you need to know about bronchial patency due value of the patient's PEF according to sex, height and age. The predicted indicator can be found by the nomogram (a table of standard PSEF values) developed for each peak flow meter model. Nomograms of different devices have significant differences. Patient's personal best PEF may be higher or lower than the standard value. You can determine the best indicator for a two-week period of good health and the absence of symptoms of the disease, against the background of effective treatment. PEFV should be measured daily in the morning after waking up and 10-12 hours later in the evening.

The use of a short-acting bronchodilator with single measurements of PSEF allows the doctor to assess the reversibility of obstruction in the bronchial tree at the time of examining the patient.

Indicators of home peak flowmetry:

PSEF morning, obtained immediately after waking up and taking medications in l / s or l / min and in% of the proper value,

PSFV evening, after taking medications in l / s or l / min and in% of the proper value,

Average PSEF values ​​(morning + evening) / 2, in% of the due value or the best personal indicator,

Mean daily variability - the spread between the maximum and minimum values, the spread between morning and evening measurements is especially important; if the difference in indicators in the morning and in the evening is 20% or more, then such a person high degree likelihood of a diagnosis of asthma.

Index of daily variability of PSEF, which is determined by the formula: (Quackenboss J ., 1991)

(PSVFmax - PSFVmin) x 100

? (PSVFmax - PSFVmin)

It is possible to represent the recorded peak flow measurements both in the form of a graphic and in the form of a simple digital record. The indicators are analyzed by the doctor at the next visit of the patient.

Evaluation of the severity of obstructive disorders according to peak flowmetry:

In national and international guidelines for the diagnosis and treatment of respiratory diseases occurring with obstructive disorders, in the classifications of the severity of the course of the disease, FEV1 and PSEF occupy an important place.

To obtain reliable information using a peak flow meter, a doctor needs not only to teach the patient the correct technique of peak flow metering, evaluate the data obtained, but also periodically monitor his knowledge and skills.

FUNCTIONAL SPIROMETRIC TESTS

For additional diagnostic information, functional spirometric tests of 2 types are used:

Bronchodilators (bronchodilators)

Bronchoconstrictor (provocative).

Bronchodilatory test (bronchodilator) is used for:

Determining the reversibility of bronchial obstruction and the role of bronchospasm in its genesis,

Differential diagnosis between bronchial asthma (reversible obstruction) and COPD (predominantly irreversible obstruction),

Diagnosis of latent bronchospasm,

Individual selection of the most effective medicine and its dosage.

The test is carried out on a clean background with the abolition of short-acting?2-sympathomimetics - in 6 hours, long-acting - in 12 hours, prolonged theophyllines - in 24 hours.

Commonly used selective beta-agonist - berotek. The patient performs 2 inhalations of Berotek with an interval of 30 seconds. The correct inhalation technique is observed: the patient should slightly throw his head back, raise his chin, exhale deeply calmly, tightly clasp the mouthpiece of the inhaler with his lips and, pressing the inhaler, take a deep slow breath through the mouth, followed by holding the breath for at least 10 seconds at the height of inspiration. Spirography is carried out before and 15 minutes after inhalation administration of the drug.

Sample rating:

Quite common is the method of calculating the increase in FEV1, expressed in% of the original value.

FEV1, % RI = x 100%

FEV1 ISH, ML

The most correct method of calculation is considered in relation to the proper value:

FEV1, % SHOULD = FEV1 DILAT, ML – FEV1 ISH, ML x 100%

FEV1 SHOULD, ML

The main criterion for a positive test is increase in FEV1 > 12 % :

A positive test indicates reversible obstruction,

A positive test with initially normal values ​​indicates latent obstruction,

A decrease in indicators, that is, a paradoxical reaction to berotek, does not have an unambiguous interpretation.

Although the evaluation of the sample is based on the change in FEV1, it is necessary to pay attention to the change in other indicators in the aggregate.

Limits of normal changes in the flow-volume curve after Berotek inhalation

Adults - data of E.A. Melnikova, N.A. Zilber (1990)

Children - data of T.M. Potapova, B.M. Gutkina (1989)

Bronchoconstrictor (provocative) tests.

Performed only in patients with normal ventilation function of the lungs (FEV1 > 80%).

As irritants use: pharmacological preparations(acetylcholine, methacholine), cold air, exercise.

Reveal nonspecific airway hyperresponsiveness. A positive test is considered with a decrease in FEV1 by 20% from the original, it indicates an increase in bronchial tone in response to stimuli that do not cause such a reaction in healthy people.

Exercise-induced bronchoconstriction is defined as exercise asthma. A dosed physical load on a VEM or treadmill is used.

Concluding the review of the spirography method, clinicians should be warned against overestimating the possibilities of this study.

A spirometric study of the flow-volume-time relationship during forced breathing maneuvers reveals only changes in the mechanical properties of the ventilator. It is a screening among the methods for studying the respiratory system. Its capabilities should not be overestimated. For a correct assessment of the forms of changes in the anatomical and physiological properties of the ventilation apparatus (obstruction or restriction), it is necessary to study the AOL.

As practice shows, clinicians tend to treat spirography as an accurate and highly informative research method. Common mistake the attending physician is the automatic transfer of the degree of violation of ventilation to the entire state of the respiratory function.

At the same time, the very name "examination of the function of external respiration", which is commonly used in wide practice to call the spirographic study, which is still the most widespread, should once again remind of the great responsibility that is entrusted to the doctor who conducts it.

Respiratory insufficiency is a broader, fundamental concept that occurs in the pathology of all links in the exchange of gases between the atmosphere and the body.

The conclusion about the degree of respiratory failure in a patient cannot be made only on the basis of the results of a study of lung ventilation, parameters of forced exhalation. For example, in patients with impaired gas diffusion and severe respiratory failure, there may be normal performance breathing mechanics.

The most important criterion for respiratory failure is shortness of breath (or decreased physical activity) and diffuse cyanosis (manifestation of hypoxemia), which are determined clinically.

The final conclusion about the degree of respiratory failure should be made by the attending physician, using the full range of clinical data along with the results of a study of the mechanical properties of the ventilator.

ADDITIONAL RESEARCH METHODS

Study of the structure of the total lung capacity– produced by convection methods (helium dilution method, nitrogen flushing) or barometric method using general plethysmography.

The body plethysmograph is a hermetic stationary cabin, a closed system with a constant volume. A change in the volume of gas or the patient's body in it leads to a change in pressure. Body plethysmography which provides more in-depth information about emphysema and its severity.

Bronchial resistance study– can be performed using body plethysmography or the method of short-term interruption of the air flow and pulse oscillometry.

There are special attachments to pneumotachographs for the flow interruption method, this method is simpler and cheaper than body plethysmography.

Study of the diffusion capacity of the lungs is carried out using carbon monoxide CO using complex and expensive equipment.

The amount of test gas (CO) passing into the blood from the lungs per unit time is determined; it reflects diffusion very conditionally. In foreign literature, the term is more often used transfer factor(transfer factor, DL).

Determination of ventilation indicators and gas composition of alveolar air produced using gas analyzers.

Ergospirometric study- a method for studying ventilation and gas exchange under conditions of dosed physical activity. The ventilation-perfusion relationship is assessed for a number of parameters.

Pulmonary circulation is examined radiologically, with the help of MRI-tomography, radioisotope methods. Echocardiography is the most common non-invasive method for assessing pulmonary artery pressure.

Analysis of blood gases and acid-base status is intended for the final assessment of the effectiveness of lung function. This is the determination of the content of O2 and CO2 in the blood.

PULSE OXYMETRY

Blood saturation is the percentage of saturation of arterial blood with oxygen. It is measured non-invasively pulse oximetry based on the principle of spectrophotometry. A special optical sensor is superimposed on the finger or auricle. The device captures the differences in the absorption spectra at two wavelengths (for reduced and oxidized hemoglobin), while the SaO 2 values ​​​​and pulse rates are displayed on the screen.

Normal saturation of arterial blood is 95 - 98%.

SaO 2< 95 % - гипоксемия.

The study must be carried out in a warm room, the patient's cold fingers should be warmed by rubbing.

Pulse oximetry is an easy and affordable method for diagnosing the effectiveness of the respiratory system as a whole, assessing the presence of respiratory failure. Recommended for wide application in patients with a pulmonological profile in functional diagnostics rooms in parallel with spirometry.

REFERENCES:

1. Klement R.F., Zilber N.A. "Functional and diagnostic studies in pulmonology". Guidelines. St. Petersburg, 1993. St. Petersburg medical institute named after academician I.P. Pavlov, Aeromed Medical and Technical Center
2. "Spirometry. A unified methodology for conducting and evaluating a functional study of the mechanical properties of a human ventilation apparatus. Toolkit for doctors. St. Petersburg, 1999. State Research Center for Pulmonology, Ministry of Health of the Russian Federation
3. federal program"Chronic obstructive pulmonary disease". Ministry of Health of the Russian Federation All-Russian Scientific Society of Pulmonologists (Chairman - Academician of the Russian Academy of Medical Sciences A.G. Chuchalin). Moscow, 1999
4. S.A. Sobchenko, V.V. Bondarchuk, G.M. Laskin. "Study of the function of external respiration in the practice of a general practitioner and pulmonologist". St. Petersburg, 2002. St. Petersburg medical Academy postgraduate education
5. Baranov V.L., Kurenkova I.G., Kazantsev V.A., Kharitonov M.A. "Research on the function of external respiration". "Elbi-SPb". St. Petersburg, 2002. St. Petersburg Military Medical Academy, Department of Postgraduate Therapy for Doctors
6. Z.V.Vorobyova. "Fundamentals of pathophysiology and functional diagnostics of the respiratory system". Moscow, 2002. Institute for Advanced Studies of FU "Medbioekstrem" under the Ministry of Health of the Russian Federation
7. A.A. Belov, N.A. Lakshina. "Assessment of respiratory function". Methodological approaches and diagnostic value. Moscow, 2006. Moscow Medical Academy. I.M. Sechenov
8. M.F. Yakushev, A.A. Wiesel, L.V. Khabibullina. "Methods for studying the function of external respiration in the clinical practice of a doctor." Department of Phthisiopulmonology, Kazan State medical university. Lecture.
9. Federal target program"Development of the pulmonological service of Russia for 2002-2007"
10. www. website

c) moderately pronounced changes in the restrictive type

7.100. Give a conclusion on the results of the study of the ventilation function of the lungs: VC - 74% D; FEV1 - 32% D; FEV/VC - 39%; POS - 39% D; MOS25 - 30%D; MOS50 - 17% D; MOS75 - 13% D;
SOS 25-75 - 17% D

a) moderately pronounced restriction

b) pronounced generalized obstruction. Moderate decrease in VC

c) moderately pronounced generalized obstruction, Moderate decrease in VC.

7.101. Give a conclusion on the results of the study of the ventilation function of the lungs: VC -100% D;
FEV1 -60% D; FEV1/VC -57%; POS -74%D; MOS25 -58%; MOS50 -55%D; MOS75 -42%D; SOS 25-
75 -62%D

a) pronounced generalized obstruction

b) moderately pronounced violations of lung ventilation by obstructive type

c) significant generalized obstruction

7.102. Give a conclusion on the results of the study of the ventilation function of the lungs: VC -63% D;
FEV1 -75% D: FEV1/VC -99%; POS -78%D; MOS25 -72%D; MOS50 -70%D; MOS75 -69%D; SOS 25-
75 -72%D

a) a moderate decrease in the ventilation function of the lungs according to the obstructive type

b) a moderate decrease in the ventilation function of the lungs according to the restrictive type

c) violation of the ventilation function of the lungs of a mixed type

Pathological changes in the respiratory system

7.103. Specify the main mechanisms that form airway obstruction:

a) bronchospasm and swelling of the bronchial mucosa

b) cicatricial deformity

c) congestion in the lungs
e) hyper- and dyscrinia

7.104. clinical sign respiratory failure I degree is:

b) shortness of breath with little physical exertion

c) shortness of breath at rest

7.105. The clinical sign of respiratory failure II degree is:

a) shortness of breath on exertion

c) shortness of breath at rest

7.106. Clinical sign of respiratory failure III degree is:

a) shortness of breath on exertion

b) shortness of breath with little physical exertion
c) shortness of breath at rest

7.107. Which of the following drugs is best used to determine
reversibility of obstruction in patients with chronic obstructive pulmonary disease:

a) salbutamol

b) berodual

c) atrovent

d) ephedrine

7.108. Coefficient: the ratio of residual lung volume to total lung capacity (ROL / TLC),
rises when:

a) pulmonary fibrosis

b) inflammation of the lungs

c) neoplasms of the lungs

d) emphysema

7.109. Restrictive respiratory failure can occur when:

a) pneumonia

b) massive exudative pleurisy

c) an asthma attack

7.110. Obstructive pulmonary ventilation disorders lead to: 1) violation of sputum rheology, 2)
decrease in surfactant, 3) spasm and swelling of the mucous bronchioles, 4) interstitial pulmonary edema, 5)
laryngospasm, 6) foreign bodies trachea and bronchi

a) all are correct

b) all are true except 2.4

c) all are correct except 1, 5, 6

d) only 5, 6 are correct

e) only 1 is correct

7.111. Vital capacity of the lungs (VC) decreases with:

a) pneumonia

b) pneumosclerosis

c) exudative pleurisy

d) acute bronchitis

7.112. The following indicators of the function of external respiration correspond to the norm:

a) vital capacity (VC) - 80% D

b) vital capacity of the lungs (VC) -92% D

c) forced expiratory volume in 1 sec. (FEV1) - 85% D

d) forced expiratory volume in 1 sec. (FEV1) - 60% D

7.113. The following indicators of the function of external respiration do not correspond to the norm:

a) Tiffno test (FEV1 / VC) - 75% D

b) Tiffno test (FEV1 / VC) - 60% D

c) total lung capacity (TLC) -120% D

d) total lung capacity (OEL) - 95% D

7.114. Indicators: Residual lung volume (RLV) and ROL/REL ratio increase with:

a) restrictive type of violation of the ventilation function of the lungs

b) with an obstructive type of violation of the ventilation function of the lungs

7.115. In the obstructive type of violations of the ventilation function of the lungs, the indicators decrease:

a) total lung capacity

b) forced expiratory volume in 1 s (FEV1)

c) residual lung volume (RLV)

d) Tiffno test (FEV 1/VC)

e) peak expiratory volume flow (PIC)

7.116. With a restrictive type of violation of the ventilation function of the lungs, the following
indicators:

a) the ratio of forced exhalation in 1 sec. (FEV1) to vital capacity (VC)

b) total lung capacity (TLC)

c) the average volumetric expiratory flow rate during inspiration from 25 to 75% FVC (SOS 25-75)

7.117. A sharp decrease in lung capacity (VC) is typical for:

a) chronic obstructive bronchitis

b) fibrosing alveolitis, kyphoscoliosis, pneumoconiosis

c) bronchial asthma

7.118. The main causes of arterial hypoxemia:

a) hypoventilation of the alveoli

b) uneven distribution of ventilation and blood flow in the lungs

c) pulmonary shunts

e) all of the above factors

7.119. Mucociliary transport is inhibited by:

a) smoking

b) traumatic brain injury

d) poisoning

e) all the mentioned factors

7.120. The following indicators allow the diagnosis of acute respiratory failure in
patient with chronic obstructive bronchitis:

a) decrease in FEV1 less than 40% D

b) decrease in PaO2 by 10-15 mm Hg. Art. and more, an increase in PaCO2

7.121. Predominantly on "β2" - adrenoreceptors of the lungs act:
a) ephedrine

b) isadrin (isoprotenol)

c) salbutamol (ventolin)

d) atrovent

e) fenoterol (berotec)

7.122. In violation of bronchial conduction, the residual volume of the lungs:

a) decreases

b) increases

c) does not change

7.123. The criterion for the completeness of remission of bronchial asthma is:

a) return to normal residual lung volume

b) normalization of the indicator of forced expiratory volume in 1 s. (FEV1)

c) normalization of the Tiffno test

7.124. How do the main static lung volumes change with age:

a) the vital capacity of the lungs (VC) decreases, the residual lung volume (RLV) is significantly
increases

b) the vital capacity of the lungs (VC) increases

c) residual lung volume (RLV) decreases

7.125. How will the residual volume of the lungs change with emphysema of the lungs and the streets of the elderly:

a) decrease

b) increase

7.126. Bronchial patency at the level of the proximal respiratory tract is reflected by the following indicators:

b) ROVD
c) FEV1

7.127. Bronchial patency at the level of the distal respiratory tract is reflected by the following indicators:
a) MOS25

d) MVL
e) ROvyd

7.128. What factors lead to a decrease in FEV1 in pulmonary emphysema?

a) bronchospasm

b) decreased elastic recoil of the lungs

c) edematous and inflammatory changes

a) test with bronchodilators

b) exercise test

c) hyperventilation test

d) OEL study

e) cold air test

7.130. For bronchodilator tests, there are the following indications:

a) severe pathology of the cardiovascular system

b) determination of the reversibility of obstructive disorders

c) diagnosis of early ("hidden") obstructive disorders

d) poor reproducibility of forced expiratory maneuvers

e) selection of individual effective drugs

7.131. Decrease in speed indicators - FEV1, POS, MOS25, MOS50, MOS75 - with normal VC
testifies:

a) about the restrictive variant of violations

b) about a mixed version of violations

c) about tracheobronchial dyskinesia

d) about the obstructive variant

7.132. A decrease in VC with relatively minor changes in speed indicators indicates:

a) for an obstructive variant of the violation

b) on the restrictive variant of violations

c) tracheobronchial dyskinesia

d) collapse of small bronchi

e) for a mixed variant of violations

7.133. Qualitative changes in spirogram in restrictive variant of dysfunction

a) fast breathing

b) shift of the MVL record in the direction of inhalation

c) shift of the MVL record in the direction of exhalation

d) small DO

e) low VC

7.134. Qualitative changes in spirogram in obstructive variant of dysfunction
external respiration are characterized by: