Lung volumes table. Breath volumes

To assess the quality of lung function, it examines tidal volumes (using special devices - spirometers).

Tidal volume (VT) is the amount of air that a person inhales and exhales during quiet breathing in one cycle. Normal = 400-500 ml.

Minute respiration volume (MRV) is the volume of air passing through the lungs in 1 minute (MRV = DO x RR). Normal = 8-9 liters per minute; about 500 l per hour; 12000-13000 liters per day. With increasing physical activity, MOD increases.

Not all inhaled air participates in alveolar ventilation (gas exchange), because some of it does not reach the acini and remains in the respiratory tract, where there is no opportunity for diffusion. The volume of such airways is called “respiratory dead space”. Normally for an adult = 140-150 ml, i.e. 1/3 TO.

Inspiratory reserve volume (IRV) is the amount of air that a person can inhale during the strongest maximum inhalation after a quiet inhalation, i.e. over DO. Normal = 1500-3000 ml.

Expiratory reserve volume (ERV) is the amount of air that a person can additionally exhale after a quiet exhalation. Normal = 700-1000 ml.

Vital capacity of the lungs (VC) is the amount of air that a person can maximally exhale after the deepest inhalation (VC=DO+ROVd+ROVd = 3500-4500 ml).

Residual lung volume (RLV) is the amount of air remaining in the lungs after maximum exhalation. Normal = 100-1500 ml.

Total lung capacity (TLC) is the maximum amount of air that can be held in the lungs. TEL=VEL+TOL = 4500-6000 ml.

DIFFUSION OF GASES

Composition of inhaled air: oxygen - 21%, carbon dioxide - 0.03%.

Composition of exhaled air: oxygen - 17%, carbon dioxide - 4%.

The composition of the air contained in the alveoli: oxygen - 14%, carbon dioxide -5.6%.

As you exhale, the alveolar air is mixed with the air in the respiratory tract (in the “dead space”), which causes the indicated difference in air composition.

The transition of gases through the air-hematic barrier is due to the difference in concentrations on both sides of the membrane.

Partial pressure is that part of the pressure that falls on a given gas. At an atmospheric pressure of 760 mm Hg, the partial pressure of oxygen is 160 mm Hg. (i.e. 21% of 760), in the alveolar air the partial pressure of oxygen is 100 mm Hg, and carbon dioxide is 40 mm Hg.

Gas voltage is the partial pressure in a liquid. Oxygen tension in venous blood is 40 mm Hg. Due to the pressure gradient between alveolar air and blood - 60 mm Hg. (100 mm Hg and 40 mm Hg), oxygen diffuses into the blood, where it binds to hemoglobin, converting it into oxyhemoglobin. Blood containing a large amount of oxyhemoglobin is called arterial. 100 ml of arterial blood contains 20 ml of oxygen, 100 ml of venous blood contains 13-15 ml of oxygen. Also, along the pressure gradient, carbon dioxide enters the blood (since it is contained in large quantities in the tissues) and carbhemoglobin is formed. In addition, carbon dioxide reacts with water, forming carbonic acid (the reaction catalyst is the enzyme carbonic anhydrase, found in red blood cells), which breaks down into a hydrogen proton and bicarbonate ion. CO 2 tension in venous blood is 46 mm Hg; in alveolar air – 40 mm Hg. (pressure gradient = 6 mm Hg). Diffusion of CO 2 occurs from the blood into the external environment.

Breathing phases.

External respiration process is caused by changes in the volume of air in the lungs during the inhalation and exhalation phases of the respiratory cycle. With quiet breathing, the ratio of the duration of inhalation to exhalation in the respiratory cycle is on average 1:1.3. External breathing of a person is characterized by the frequency and depth of respiratory movements. Respiration rate a person is measured by the number of respiratory cycles within 1 minute and its value at rest in an adult varies from 12 to 20 per 1 minute. This indicator of external respiration increases with physical work, increasing ambient temperature, and also changes with age. For example, in newborns the respiratory rate is 60-70 per 1 min, and in people aged 25-30 years - an average of 16 per 1 min. Breathing depth determined by the volume of inhaled and exhaled air during one respiratory cycle. The product of the frequency of respiratory movements and their depth characterizes the basic value of external respiration - ventilation. A quantitative measure of pulmonary ventilation is the minute volume of breathing - this is the volume of air that a person inhales and exhales in 1 minute. The minute volume of a person's breathing at rest varies between 6-8 liters. During physical work, a person's minute breathing volume can increase 7-10 times.

Rice. 10.5. Volumes and capacities of air in the human lungs and the curve (spirogram) of changes in air volume in the lungs during quiet breathing, deep inhalation and exhalation. FRC - functional residual capacity.

Pulmonary air volumes. IN respiratory physiology a unified nomenclature of pulmonary volumes in humans has been adopted, which fill the lungs during quiet and deep breathing during the inhalation and exhalation phases of the respiratory cycle (Fig. 10.5). The lung volume that is inhaled or exhaled by a person during quiet breathing is called tidal volume. Its value during quiet breathing averages 500 ml. The maximum amount of air that a person can inhale above the tidal volume is called inspiratory reserve volume(average 3000 ml). The maximum amount of air that a person can exhale after a quiet exhalation is called the expiratory reserve volume (on average 1100 ml). Finally, the amount of air that remains in the lungs after maximum exhalation is called the residual volume, its value is approximately 1200 ml.

The sum of two or more pulmonary volumes is called pulmonary capacity. Air volume in human lungs it is characterized by inspiratory lung capacity, vital lung capacity and functional residual lung capacity. Inspiratory capacity (3500 ml) is the sum of tidal volume and inspiratory reserve volume. Vital capacity of the lungs(4600 ml) includes tidal volume and inspiratory and expiratory reserve volumes. Functional residual lung capacity(1600 ml) is the sum of expiratory reserve volume and residual lung volume. Sum vital capacity of the lungs And residual volume is called the total lung capacity, the average value of which in humans is 5700 ml.

When inhaling, the human lungs due to contraction of the diaphragm and external intercostal muscles, they begin to increase their volume from the level, and its value during quiet breathing is tidal volume, and with deep breathing - reaches different values reserve volume inhale. When exhaling, the volume of the lungs returns to the original level of functional function. residual capacity passively, due to elastic traction of the lungs. If air begins to enter the volume of exhaled air functional residual capacity, which occurs during deep breathing, as well as when coughing or sneezing, then exhalation is carried out by contracting the muscles of the abdominal wall. In this case, the value of intrapleural pressure, as a rule, becomes higher than atmospheric pressure, which determines the highest speed of air flow in the respiratory tract.

2. Spirography technique .

The study is carried out in the morning on an empty stomach. Before the study, the patient is recommended to remain calm for 30 minutes, and also stop taking bronchodilators no later than 12 hours before the start of the study.

The spirographic curve and pulmonary ventilation indicators are shown in Fig. 2.

Static indicators(determined during quiet breathing).

The main variables used to display observed indicators of external respiration and to construct construct indicators are: volume of respiratory gas flow, V (l) and time t ©. The relationships between these variables can be presented in the form of graphs or charts. All of them are spirograms.

A graph of the volume of flow of a mixture of respiratory gases versus time is called a spirogram: volume flow - time.

The graph of the relationship between the volumetric flow rate of a mixture of respiratory gases and the flow volume is called a spirogram: volumetric velocity flow - volume flow.

Measure tidal volume(DO) - the average volume of air that the patient inhales and exhales during normal breathing at rest. Normally it is 500-800 ml. The part of sediments that takes part in gas exchange is called alveolar volume(AO) and on average equals 2/3 of the DO value. The remainder (1/3 of the DO value) is volume of functional dead space(FMP).

After a calm exhalation, the patient exhales as deeply as possible - measured expiratory reserve volume(ROvyd), which is normally 1000-1500 ml.

After a calm inhalation, the deepest possible breath is taken - measured inspiratory reserve volume(Rovd). When analyzing static indicators, it is calculated inspiratory capacity(Evd) - the sum of DO and Rovd, which characterizes the ability of lung tissue to stretch, as well as vital capacity(VC) - the maximum volume that can be inhaled after the deepest exhalation (the sum of DO, RO VD and Rovyd normally ranges from 3000 to 5000 ml).

After normal quiet breathing, a breathing maneuver is performed: the deepest possible breath is taken, and then the deepest, sharpest and longest (at least 6 s) exhalation is taken. This is how it is determined forced vital capacity(FVC) - the volume of air that can be exhaled during forced exhalation after maximum inspiration (normally 70-80% VC).

As the final stage of the study, recording is carried out maximum ventilation(MVL) - the maximum volume of air that can be ventilated by the lungs in 1 min. MVL characterizes the functional capacity of the external respiration apparatus and is normally 50-180 liters. A decrease in MVL is observed with a decrease in pulmonary volumes due to restrictive (limiting) and obstructive disorders of pulmonary ventilation.

When analyzing the spirographic curve obtained in the maneuver with forced exhalation, measure certain speed indicators (Fig. 3):

1) forced expiratory volume in the first second (FEV 1) - the volume of air that is exhaled in the first second with the fastest possible exhalation; it is measured in ml and calculated as a percentage of FVC; healthy people exhale at least 70% of FVC in the first second;

2) sample or Tiffno index- ratio of FEV 1 (ml)/VC (ml), multiplied by 100%; normally is at least 70-75%;

3) maximum volumetric air velocity at the expiratory level of 75% FVC (MOV 75) remaining in the lungs;

4) maximum volumetric air velocity at the expiratory level of 50% FVC (MOV 50) remaining in the lungs;

5) maximum volumetric air velocity at the expiratory level of 25% FVC (MOV 25) remaining in the lungs;

6) average forced expiratory volumetric flow rate, calculated in the measurement interval from 25 to 75% FVC (SES 25-75).

Symbols on the diagram.
Indicators of maximum forced expiration:
25 ÷ 75% FEV- volumetric flow rate in the average forced expiratory interval (between 25% and 75%
vital capacity of the lungs),
FEV1- flow volume during the first second of forced exhalation.

Rice. 3. Spirographic curve obtained in the forced expiratory maneuver. Calculation of FEV 1 and SOS 25-75 indicators

Calculation of speed indicators is of great importance in identifying signs of bronchial obstruction. A decrease in the Tiffno index and FEV 1 is a characteristic sign of diseases that are accompanied by a decrease in bronchial patency - bronchial asthma, chronic obstructive pulmonary disease, bronchiectasis, etc. MOS indicators are of the greatest value in diagnosing the initial manifestations of bronchial obstruction. SOS 25-75 reflects the state of patency of small bronchi and bronchioles. The latter indicator is more informative than FEV 1 for identifying early obstructive disorders.
Due to the fact that in Ukraine, Europe and the USA there is some difference in the designation of lung volumes, capacities and speed indicators that characterize pulmonary ventilation, we present the designations of these indicators in Russian and English (Table 1).

Table 1. Name of pulmonary ventilation indicators in Russian and English

Name of the indicator in Russian	Accepted abbreviation	Indicator name in English	Accepted abbreviation
Vital capacity of the lungs	vital capacity	Vital capacity	V.C.
Tidal volume	TO	Tidal volume	TV
Inspiratory reserve volume	Rovd	Inspiratory reserve volume	IRV
Expiratory reserve volume	Rovyd	Expiratory reserve volume	ERV
Maximum ventilation	MVL	Maximum voluntary ventilation	M.W.
Forced vital capacity	FVC	Forced vital capacity	FVC
Forced expiratory volume in the first second	FEV1	Forced expiratory volume 1 sec	FEV1
Tiffno index	IT, or FEV 1/VC%		FEV1% = FEV1/VC%
Maximum flow rate at the moment of exhalation 25% FVC remaining in the lungs	MOS 25	Maximum expiratory flow 25% FVC	MEF25
Forced expiratory flow 75% FVC	FEF75
Maximum flow rate at the moment of exhalation of 50% FVC remaining in the lungs	MOS 50	Maximum expiratory flow 50% FVC	MEF50
Forced expiratory flow 50% FVC	FEF50
Maximum flow rate at the moment of exhalation 75% FVC remaining in the lungs	MOS 75	Maximum expiratory flow 75% FVC	MEF75
Forced expiratory flow 25% FVC	FEF25
Average expiratory volumetric flow rate in the range from 25% to 75% FVC	SOS 25-75	Maximum expiratory flow 25-75% FVC	MEF25-75
Forced expiratory flow 25-75% FVC	FEF25-75

Table 2. Name and correspondence of pulmonary ventilation indicators in different countries

Ukraine	Europe	USA
mos 25	MEF25	FEF75
mos 50	MEF50	FEF50
mos 75	MEF75	FEF25
SOS 25-75	MEF25-75	FEF25-75

All indicators of pulmonary ventilation are variable. They depend on gender, age, weight, height, body position, the state of the patient’s nervous system and other factors. Therefore, for a correct assessment of the functional state of pulmonary ventilation, the absolute value of one or another indicator is insufficient. It is necessary to compare the obtained absolute indicators with the corresponding values ​​in a healthy person of the same age, height, weight and gender - the so-called proper indicators. This comparison is expressed as a percentage relative to the proper indicator. Deviations exceeding 15-20% of the expected value are considered pathological.

5. SPIROGRAPHY WITH REGISTRATION OF THE FLOW-VOLUME LOOP

Spirography with registration of the flow-volume loop - a modern method for studying pulmonary ventilation, which consists of determining the volumetric speed of air flow in the inhalation tract and graphically displaying it in the form of a flow-volume loop during quiet breathing of the patient and when he performs certain breathing maneuvers. Abroad this method is called spirometry.

Purpose The study is to diagnose the type and degree of pulmonary ventilation disorders based on the analysis of quantitative and qualitative changes in spirographic indicators.
Indications and contraindications for the use of the method are similar to those for classical spirography.

Methodology. The study is carried out in the first half of the day, regardless of food intake. The patient is asked to close both nasal passages with a special clamp, take an individual sterilized mouthpiece into his mouth and tightly clasp his lips around it. The patient, in a sitting position, breathes through the tube along an open circuit, experiencing virtually no breathing resistance
The procedure for performing breathing maneuvers with recording the flow-volume curve of forced breathing is identical to that performed when recording FVC during classical spirography. The patient should be explained that in a test with forced breathing one should exhale into the device as if one were to extinguish the candles on a birthday cake. After a certain period of quiet breathing, the patient takes a maximally deep breath, as a result of which an elliptical curve is recorded (AEB curve). Then the patient makes the fastest and most intense forced exhalation. In this case, a curve of a characteristic shape is recorded, which in healthy people resembles a triangle (Fig. 4).

Rice. 4. Normal loop (curve) of the relationship between the volumetric flow rate and air volume during breathing maneuvers. Inhalation begins at point A, exhalation begins at point B. POSV is recorded at point C. The maximum expiratory flow in the middle of the FVC corresponds to point D, the maximum inspiratory flow to point E

Spirogram: volumetric flow rate - volume of forced inhalation/exhalation flow.

The maximum expiratory volumetric air flow rate is displayed by the initial part of the curve (point C, where peak expiratory flow rate- POS EXP) - After this, the volumetric flow rate decreases (point D, where MOC 50 is recorded), and the curve returns to its original position (point A). In this case, the flow-volume curve describes the relationship between the volumetric air flow rate and the pulmonary volume (lung capacity) during respiratory movements.
Data on speeds and volumes of air flow are processed by a personal computer thanks to adapted software. The flow-volume curve is displayed on the monitor screen and can be printed on paper, saved on magnetic media or in the memory of a personal computer.
Modern devices work with spirography sensors in an open system with subsequent integration of the air flow signal to obtain synchronous values ​​of lung volumes. The computer-calculated research results are printed together with the flow-volume curve on paper in absolute values ​​and as a percentage of the required values. In this case, FVC (air volume) is plotted on the abscissa axis, and air flow, measured in liters per second (l/s), is plotted on the ordinate axis (Fig. 5).

Rice. 5. Forced breathing flow-volume curve and pulmonary ventilation indicators in a healthy person

Rice. 6 Scheme of the FVC spirogram and the corresponding forced expiratory curve in “flow-volume” coordinates: V - volume axis; V" - flow axis

The flow-volume loop is the first derivative of the classical spirogram. Although the flow-volume curve contains essentially the same information as the classic spirogram, the visualization of the relationship between flow and volume allows deeper insight into the functional characteristics of both the upper and lower airways (Fig. 6). Calculation of highly informative indicators MOS 25, MOS 50, MOS 75 using a classical spirogram has a number of technical difficulties when performing graphic images. Therefore, its results are not highly accurate. In this regard, it is better to determine the indicated indicators using the flow-volume curve.
Assessment of changes in speed spirographic indicators is carried out according to the degree of their deviation from the proper value. As a rule, the value of the flow indicator is taken as the lower limit of the norm, which is 60% of the proper level.

MICRO MEDICAL LTD (UNITED KINGDOM)

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Spirometer-spirograph SpiroS-100 ALTONIKA, LLC (RUSSIA)

Spirometer SPIRO-SPECTRUM NEURO-SOFT (RUSSIA)

Vital capacity of the lungs is an important parameter that reflects the health of the human respiratory system. The greater the lung capacity, the better and faster all tissues of the body are saturated with oxygen.

Lung volume can be measured at home using a balloon, simple steps and simple calculations. Proper breathing, special exercises and a healthy lifestyle will help increase your overall lung capacity.

Vital capacity (VC) is an indicator used to assess the condition of the human respiratory system. Lung capacity is the amount of air a person can exhale after taking a deep breath.

Vital vital capacity consists of a combination of 3 indicators:

• • tidal volume - volume during quiet breathing;
  • functional residual volume - a volume that consists of residual volume (air that cannot be exhaled) and expiratory reserve volume;
  • reserve inhalation volume - a breath of air that a person can take after taking a deep breath.

A decrease in vital capacity can affect the health of the respiratory system and lead to pathological changes in the body.

Pulmonary or respiratory failure is a disease in which a small volume of breathing capacity leads to incomplete saturation of the blood with oxygen and an increased content of carbon dioxide in the body. Normalization of the blood gas composition in this case occurs due to the intensive work of the circulatory system.

There are several ways to measure vital lung capacity: measurement with a spirometer or spirograph and an inflatable round ball (at home).

A spirometer is a special device for determining vital capacity. You can find it from doctors in clinics, hospitals, and sports centers.

To find out the vital capacity of the lungs at home, you will need a round balloon, thread, ruler, pencil and a sheet of paper. The accuracy of such a measurement will be “approximate”; for greater accuracy, repeat the measurements 2-3 times.

Procedure for measuring vital capacity at home:

1. Relax and take a few leisurely breaths.
2. Take a balloon, take a full breath and inflate it with one maximum exhalation.
3. Tie a ball and measure its diameter with a ruler.
4. Perform calculations using the formula: V = 4/3*π*R 3, where π is the number Pi equal to 3.14, R is the radius (1/2 diameter).

The resulting number is the lung capacity in milliliters.

Lung capacity standards

The normal vital capacity of the lungs in men, women and children is calculated using empirical formulas for calculating the proper vital capacity (VC), which depend on the person’s gender, height and age:

• GEL husband = 0.052* height (cm) – 0.029* age (years) – 3.2;
• JEL for women = 0.049* height (cm) – 0.019* age (years) – 3.76;
• JEL m 4 - 17 years = 4.53 * height (cm) -3.9 for height 100 - 164 cm;
• JEL m 4 – 17 years = 10* height (cm) -12.85 for height 165 cm and above;
• JEL d 4 -17 years = 3.75 * height (cm) -3.15 for height 100 - 175 cm.

On average, vital capacity in an adult is 3500 ml, and deviations of real indicators from tabulated data do not exceed 15%. Exceeding the norm by more than 15% means excellent condition of the respiratory system. A visit to a specialist for consultation and examination is inevitable if the actual vital capacity is significantly less than the table value.

Athletes have a significantly larger lung capacity than the average person. In smokers, vital capacity may decrease over time.

How to increase vital capacity?

Lung capacity increases when playing sports and performing specially designed simple exercises. Aerobic sports are ideal for this purpose: race walking, running, swimming, cycling, skiing, skating, mountaineering, rowing. The vital volume of the lungs in professional swimmers reaches 6200 ml.

You can increase your breathing volume without prolonged and exhausting physical exercise. It is necessary to monitor proper breathing in everyday life. Here are some tips:

1. Breathe with your diaphragm. Chest breathing limits the amount of oxygen entering the lungs.
2. Make even and full exhalations.
3. Hold your breath while washing your face. When washing, the “diving” reflex is triggered and the body begins to prepare to plunge into the water.
4. Arrange “minutes of rest.” At this time, you need to take a comfortable position and relax. Inhale and exhale slowly with delays for a count, at a comfortable rhythm.
5. Regularly carry out wet cleaning of premises. Large amounts of dust are bad for the lungs.
6. Refrain from visiting smoky places. Passive smoking negatively affects the respiratory system.

Breathing exercises can improve blood circulation and metabolism in the body, which promotes natural weight loss.

Yoga is another way to quickly increase your breathing volume. Hatha yoga includes a whole section devoted to breathing and exercises aimed at its development - pranayama. Pranayama teaches not only proper breathing, but also control over emotions, mental management and new ways of perceiving the world around us through breathing.

Caution: if dizziness occurs during breathing exercises, you should immediately return to your normal breathing rhythm.

An assessment of the functional state of the external respiration system is carried out in order to determine its participation in the energy, heat, and water metabolism of the body, i.e., in the physical and chemical components of thermoregulation to maintain, mainly, gas and heat homeostasis. There are qualitative (rhythm) and quantitative (frequency, depth, minute volume of breathing, etc.) indicators of breathing.

There are four primary pulmonary volumes:

TO– tidal volume of gas inhaled or exhaled during each cycle at rest, (400–500 ml);

District Department of Internal Affairs– inspiratory reserve volume. The maximum amount of air that

which can be inhaled additionally after a normal inhalation, (1,900 – 3,000 ml);

ROvyd– expiratory reserve volume. The maximum amount of air

which can be exhaled after a normal exhalation, (700–1,000 ml);

OO– residual volume. The amount of gas remaining in the lungs after

maximum exhalation. The volume of residual air is 1,100–2,000 ml.

In addition, there are also four lung capacities, each of which includes two or more primary volumes:

OEL– total lung capacity. The amount of gas in the lungs at the end of max.

small breath. Under normal conditions it consists of 50% ROVD + 11% DO + 15%

ROvyd + 24% OO. This value in adults is 4,200–6,000 ml;

vital capacity– vital capacity of the lungs. The largest volume of gas that

You can exhale after maximal inhalation. Represents the amount:

DO+ROVD+ROVD. In adults, vital capacity is 3,300–4,800 ml;

EV– inhalation capacity. Maximum air that can be inhaled after

calm exhalation; consists of DO + ROVD. Normally, EB is about 75%

Vital life, and ROvyd – 25% Vital;

FOE– functional residual capacity. The amount of gas remaining in the lungs after a quiet exhalation is equal to the sum of PO + OO.

It should be taken into account that ROvyd is a very variable value, changing significantly even in the same person.

One of the main indicators of pulmonary ventilation is the minute volume of breathing (MVR), which is the volume of air inhaled or exhaled in 1 minute. MOD = DO*RR (respiratory rate).

JEL– proper vital capacity of the lungs.

The pulmonary ventilation coefficient (PCV) is calculated using the formula:

KLV = DO/ROvyd + OO.

Breathing reserve (RR)– an indicator characterizing the possibility of human

century to increase pulmonary ventilation, i.e. the ability to increase intensive

breathing rate from calm to maximum:

RD=Max VL – MOD, where Max VL – maximum ventilation, l.

Methods for studying external respiration

Various methods are used to assess the ventilation function of the lungs and the condition of the respiratory tract.

Pneumography– registration of chest movements during breathing movements. It is carried out by transforming changes in linear movements of the chest into a mechanical or electrical signal. A pneumogram allows you to estimate the number of respiratory movements per unit of time,

however, the method does not allow assessing lung volumes and capacities.

Spirometry– registration of primary lung volumes – DO, RO, ROM and vital capacity of the lungs. Various designs of spirometers are used - water, air (A, B. C).

Spirography. There are various spirographs (Metatest-1), which allow you to graphically reflect the volume of air passing through the lungs - during quiet breathing (RT), maximum expiration (MER), as well as during voluntary hyperventilation. Spirography allows you to evaluate the minute volume of respiration, tidal volume, inspiratory reserve volume, expiratory reserve volume, and vital capacity of the lungs.

Indicators of pulmonary ventilation largely depend on the constitution, physical training, height, body weight, gender and age of a person, so the data obtained must be compared with the so-called proper values. The proper values ​​are calculated using special nomograms and formulas, which are based on the determination of the proper basal metabolism. Many functional research methods have been reduced to a certain standard scope over time.

Lung volume measurement

Tidal volume

Tidal volume (TV) is the volume of air inhaled and exhaled during normal breathing, equal to an average of 500 ml (with fluctuations from 300 to 900 ml). Of this, about 150 ml is the volume of air in the functional dead space (FSD) in the larynx, trachea, and bronchi, which does not take part in gas exchange. The functional role of HFMP is that it mixes with the inhaled air, moisturizing and warming it.

Expiratory reserve volume

The expiratory reserve volume is the volume of air equal to 1500-2000 ml that a person can exhale if, after a normal exhalation, he exhales maximally.

Inspiratory reserve volume

The inspiratory reserve volume is the volume of air that a person can inhale if, after a normal inhalation, he takes a maximum breath. Equal to 1500 - 2000 ml.

Vital capacity of the lungs

Vital capacity of the lungs (VC) is equal to the sum of the reserve volumes of inhalation and exhalation and tidal volume (on average 3700 ml) and is the volume of air that a person is able to exhale during the deepest exhalation after a maximum inhalation.

Residual volume

Residual volume (VR) is the volume of air that remains in the lungs after maximum exhalation. Equal to 1000 - 1500 ml.

Total lung capacity

Total (maximum) lung capacity (TLC) is the sum of respiratory, reserve (inhalation and exhalation) and residual volumes and is 5000 - 6000 ml.

A study of tidal volumes is necessary to assess compensation for respiratory failure by increasing the depth of breathing (inhalation and exhalation).

Spirography of the lungs

Lung spirography allows you to obtain the most reliable data. In addition to measuring lung volumes, using a spirograph you can obtain a number of additional indicators (tidal and minute ventilation volumes, etc.). The data is recorded in the form of a spirogram, from which one can judge the norm and pathology.

Pulmonary ventilation intensity study

Minute breathing volume

The minute volume of breathing is determined by multiplying the tidal volume by the respiratory frequency, on average it is 5000 ml. More accurately determined using spirography.

Maximum ventilation

Maximum ventilation of the lungs ("breathing limit") is the amount of air that can be ventilated by the lungs at maximum tension of the respiratory system. Determined by spirometry with maximum deep breathing with a frequency of about 50 per minute, normally 80 - 200 ml.

Breathing reserve

The respiratory reserve reflects the functionality of the human respiratory system. In a healthy person it is equal to 85% of the maximum ventilation of the lungs, and with respiratory failure it decreases to 60 - 55% and below.

All these tests make it possible to study the state of pulmonary ventilation, its reserves, the need for which may arise when performing heavy physical work or in case of respiratory disease.

Study of the mechanics of the respiratory act

This method allows you to determine the ratio of inhalation and exhalation, respiratory effort in different phases of breathing.

EFZHEL

Expiratory forced vital capacity (EFVC) is examined according to Votchal - Tiffno. It is measured in the same way as when determining vital capacity, but with the fastest, forced exhalation. In healthy individuals, it is 8-11% less than vital capacity, mainly due to an increase in resistance to air flow in the small bronchi. In a number of diseases accompanied by an increase in resistance in the small bronchi, for example, broncho-obstructive syndromes, pulmonary emphysema, EFVC changes.

IFZHEL

Inspiratory forced vital capacity (IFVC) is determined with the fastest possible forced inspiration. It does not change with emphysema, but decreases with airway obstruction.

Pneumotachometry

Pneumotachometry

Pneumotachometry evaluates the change in “peak” air flow velocities during forced inhalation and exhalation. It allows you to assess the state of bronchial obstruction. ###Pneumotachography

Pneumotachography is carried out using a pneumotachograph, which records the movement of an air stream.

Tests to detect obvious or hidden respiratory failure

Based on the determination of oxygen consumption and oxygen deficiency using spirography and ergospirography. This method can determine oxygen consumption and oxygen deficiency in a patient when he performs a certain physical activity and at rest.