Vital capacity of the lungs and volume of pulmonary ventilation. The concept of human lung volume. Vital capacity of the lungs

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Common to all living cells is the process of breaking down organic molecules through a successive series of enzymatic reactions, resulting in the release of energy. Almost any process in which the oxidation of organic substances leads to the release of chemical energy is called breathing. If it requires oxygen, then breathing is calledaerobic, and if reactions occur in the absence of oxygen - anaerobic breathing. For all tissues of vertebrate animals and humans, the main source of energy is the processes of aerobic oxidation, which occur in the mitochondria of cells adapted to convert the energy of oxidation into the energy of reserve high-energy compounds such as ATP. The sequence of reactions by which the cells of the human body use the energy of the bonds of organic molecules is called internal, tissue or cellular breathing.

The respiration of higher animals and humans is understood as a set of processes that ensure the supply of oxygen to the internal environment of the body, its use for the oxidation of organic substances and the removal of carbon dioxide from the body.

The function of breathing in humans is realized by:

1) external, or pulmonary, respiration, which carries out gas exchange between the external and internal environment of the body (between air and blood);
2) blood circulation, which ensures the transport of gases to and from tissues;
3) blood as a specific gas transport medium;
4) internal, or tissue, respiration, which carries out the direct process of cellular oxidation;
5) means of neurohumoral regulation of breathing.

The result of the activity of the external respiration system is the enrichment of the blood with oxygen and the release of excess carbon dioxide.

Changes in the gas composition of blood in the lungs are ensured by three processes:

1) continuous ventilation of the alveoli to maintain the normal gas composition of the alveolar air;
2) diffusion of gases through the alveolar-capillary membrane in a volume sufficient to achieve equilibrium in the pressure of oxygen and carbon dioxide in the alveolar air and blood;
3) continuous blood flow in the capillaries of the lungs in accordance with the volume of their ventilation

Lung capacity

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Total capacity. The amount of air in the lungs after maximum inspiration is the total lung capacity, the value of which in an adult is 4100-6000 ml (Fig. 8.1).
It consists of the vital capacity of the lungs, which is the amount of air (3000-4800 ml) that comes out of the lungs during the deepest exhalation after the deepest inhalation, and
residual air (1100-1200 ml), which still remains in the lungs after maximum exhalation.

Total capacity = Vital capacity + Residual volume

Vital capacity makes up three lung volumes:

1) tidal volume , representing the volume (400-500 ml) of air inhaled and exhaled during each respiratory cycle;
2) reserve volumeinhalation (additional air), i.e. the volume (1900-3300 ml) of air that can be inhaled during a maximum inhalation after a normal inhalation;
3) expiratory reserve volume (reserve air), i.e. volume (700-1000 ml) that can be exhaled at maximum exhalation after normal exhalation.

Vital capacity = Inspiratory reserve volume + Tidal volume + Expiratory reserve volume

functional residual capacity. During quiet breathing, after exhalation, an expiratory reserve volume and residual volume remain in the lungs. The sum of these volumes is called functional residual capacity, as well as normal lung capacity, resting capacity, equilibrium capacity, buffer air.

functional residual capacity = Expiratory reserve volume + Residual volume

The main methods for studying breathing in humans include:

· Spirometry is a method for determining the vital capacity of the lungs (VC) and its constituent air volumes.

· Spirography is a method of graphically recording indicators of the function of the external part of the respiratory system.

· Pneumotachometry is a method for measuring the maximum speed of inhalation and exhalation during forced breathing.

· Pneumography is a method of recording respiratory movements of the chest.

· Peak fluorometry is a simple way of self-assessment and constant monitoring of bronchial patency. The device - peak flow meter allows you to measure the volume of air passing during exhalation per unit time (peak expiratory flow).

· Functional tests (Stange and Genche).

Spirometry

The functional state of the lungs depends on age, gender, physical development and a number of other factors. The most common characteristic of the condition of the lungs is the measurement of lung volumes, which indicate the development of the respiratory organs and the functional reserves of the respiratory system. The volume of air inhaled and exhaled can be measured using a spirometer.

Spirometry is the most important way to assess respiratory function. This method determines the vital capacity of the lungs, lung volumes, as well as the volumetric air flow rate. During spirometry, a person inhales and exhales as forcefully as possible. The most important data is provided by analysis of the expiratory maneuver - exhalation. Lung volumes and capacities are called static (basic) respiratory parameters. There are 4 primary pulmonary volumes and 4 capacities.

Vital capacity of the lungs

The vital capacity of the lungs is the maximum amount of air that can be exhaled after a maximum inhalation. During the study, the actual vital capacity is determined, which is compared with the expected vital capacity (VC) and calculated using formula (1). In an adult of average height, the BEL is 3-5 liters. In men, its value is approximately 15% greater than in women. Schoolchildren aged 11-12 years have a VAL of about 2 liters; children under 4 years old - 1 liter; newborns - 150 ml.

VIT=DO+ROVD+ROVD, (1)

Where vital capacity is the vital capacity of the lungs; DO - respiratory volume; ROVD - inspiratory reserve volume; ROvyd - expiratory reserve volume.

JEL (l) = 2.5 Chrost (m). (2)

Tidal volume

Tidal volume (TV), or depth of breathing, is the volume of inhaled and

air exhaled at rest. In adults, DO = 400-500 ml, in children 11-12 years old - about 200 ml, in newborns - 20-30 ml.

Expiratory reserve volume

Expiratory reserve volume (ERV) is the maximum volume that can be exhaled with effort after a quiet exhalation. ROvyd = 800-1500 ml.

Inspiratory reserve volume

Inspiratory reserve volume (IRV) is the maximum volume of air that can be additionally inhaled after a quiet inhalation. Inspiratory reserve volume can be determined in two ways: calculated or measured with a spirometer. To calculate, it is necessary to subtract the sum of the respiratory and expiratory reserve volumes from the vital capacity value. To determine the inspiratory reserve volume using a spirometer, you need to fill the spirometer with 4 to 6 liters of air and, after a quiet inhalation from the atmosphere, take a maximum breath from the spirometer. The difference between the initial volume of air in the spirometer and the volume remaining in the spirometer after a deep inspiration corresponds to the inspiratory reserve volume. ROVD =1500-2000 ml.

Residual volume

Residual volume (VR) is the volume of air remaining in the lungs even after maximum exhalation. Measured only by indirect methods. The principle of one of them is that a foreign gas such as helium is injected into the lungs (dilution method) and the volume of the lungs is calculated by changing its concentration. The residual volume is 25-30% of the vital capacity. Take OO=500-1000 ml.

Total lung capacity

Total lung capacity (TLC) is the amount of air in the lungs after maximum inspiration. TEL = 4500-7000 ml. Calculated using formula (3)

OEL=VEL+OO. (3)

Functional residual capacity of the lungs

Functional residual lung capacity (FRC) is the amount of air remaining in the lungs after a quiet exhalation.

Calculated using formula (4)

FOEL=ROVD. (4)

Input capacitance

Inlet capacity (IUC) is the maximum volume of air that can be inhaled after a quiet exhalation. Calculated using formula (5)

EVD=DO+ROVD. (5)

In addition to static indicators that characterize the degree of physical development of the respiratory apparatus, there are additional dynamic indicators that provide information about the effectiveness of lung ventilation and the functional state of the respiratory tract.

Forced vital capacity

Forced vital capacity (FVC) is the amount of air that can be exhaled during a forced exhalation after a maximum inhalation. Normally, the difference between VC and FVC is 100-300 ml. An increase in this difference to 1500 ml or more indicates resistance to air flow due to narrowing of the lumen of the small bronchi. FVC = 3000-7000 ml.

Anatomical dead space

Anatomical dead space (ADS) - the volume in which gas exchange does not occur (nasopharynx, trachea, large bronchi) - cannot be directly determined. DMP = 150 ml.

Breathing rate

Respiratory rate (RR) is the number of respiratory cycles in one minute. BH = 16-18 bpm/min.

Minute breathing volume

Minute respiration volume (MVR) is the amount of air ventilated in the lungs in 1 minute.

MOD = TO + BH. MOD = 8-12 l.

Alveolar ventilation

Alveolar ventilation (AV) is the volume of exhaled air entering the alveoli. AB = 66 - 80% of mod. AB = 0.8 l/min.

Breathing reserve

Breathing reserve (RR) is an indicator characterizing the possibilities of increasing ventilation. Normally, RD is 85% of maximum pulmonary ventilation (MVV). MVL = 70-100 l/min.

Total lung capacity is the maximum volume of air in the lungs at the height of maximum inspiration. TLC consists of the vital capacity of the lungs and residual volume.

Vital capacity is the maximum volume of air that can be exhaled after maximum inhalation. Vital capacity includes tidal volume, inspiratory reserve volume, and expiratory reserve volume. Individual fluctuations in vital capacity are significant. On average for men it is about 5 liters. for women - about 4 liters. To assess the actual value of vital capacity, the so-called proper indicators of vital capacity, calculated using formulas, are used. The value of vital capacity can be influenced by:

• muscle weakness caused by drugs, brain tumors, increased intracranial pressure, damage to afferent nerve fibers due to polio or due to myasthenia gravis,
• reduction in the volume of the chest cavity due to the presence of a tumor (for example, neurofibroma), kyphoscoliosis, pericardial or pleural effusions, pneumothorax, lung cancer with infiltration of lung tissue;
• reduction in the volume of the abdominal cavity with subsequent limitation of excursions of the diaphragm due to intra-abdominal tumors and significant filling of the stomach.

During pregnancy, there is no decrease in vital capacity; although the pregnant uterus raises the diaphragm, at the same time the lower part of the chest expands, and the volume of vital capacity even increases. in the abdominal or thoracic cavity, associated with surgery or any disease process, significantly reduces vital capacity. So. with upper laparotomies, the vital capacity decreases to 25-30%. and for lower ones - up to 50% of the original data. After transthoracic vital capacity can often be 10-15% of the original. Abdominal bandaging, especially tight, significantly reduces vital capacity, so elastic bandaging is recommended. A change in posture also plays a role: vital vital capacity will be slightly higher in a sitting position than in a standing or lying position, which is associated with the position of the intra-abdominal organs and the blood supply to the lungs. Significant decreases in vital capacity (from 10 to 18%) were found with different surgical positions of unanesthetized individuals on the operating table. It should be assumed that in anesthetized patients these disturbances in pulmonary ventilation will be even more profound due to a decrease in reflex coordination.

Residual volume

This volume of air remaining in the lungs after the maximum possible exhalation is called residual volume. In healthy men it is about 1500 ml, in women it is 1300 ml. The residual volume is determined either by washing out all the nitrogen in the lungs under conditions of breathing with pure oxygen, or by uniformly distributing helium during breathing in a closed system with the absorption of carbon dioxide and continuous replenishment of the volume of absorbed oxygen. An increase in residual volume indicates a deterioration in alveolar ventilation, which is usually observed in patients with emphysema and bronchial asthma.

Minimum lung volume

When the pleural cavity is opened, the lung collapses, that is, it shrinks to a minimum volume. The air displaced during this process is called collapse air. Its volume, depending on the rigidity of the lung tissue and the respiratory phase in which the pleural cavity was opened, ranges from 300-900 ml.

Dead space volume. There are anatomical, physiological and anesthetic dead space.

Anatomical dead space- the capacity of the respiratory passages from the nostrils or lips to the entrance to the alveoli. On average, its volume is 150 ml. It depends on gender, height, weight and age. It is assumed that there is 2 ml of dead space volume per kg of weight. The size of the dead space increases with inhalation and decreases with exhalation. As breathing deepens, the volume of dead space also increases, which can reach 500-900 ml. This is due to a significant expansion of the lumen of the bronchial tree and trachea. The volume of anatomical dead space, compared with the depth of inspiration, characterizes the effectiveness of alveolar ventilation. To do this, the volume of harmful space is subtracted from the inhalation volume, and the resulting figure is multiplied by the number of breaths per minute. The found indicator is called minute alveolar ventilation (MAV). In cases of frequent shallow breathing, despite a high minute volume of ventilation, the MAV may be insignificant. A decrease in MAV to 3-4 liters per minute is accompanied by a significant disruption of alveolar gas exchange.

Physiological dead space- the volume of gas that did not have the opportunity to normally participate in alveolar gas exchange. This includes gas located in the anatomical dead space, part of the gas that was in the alveoli, but did not take part in gas exchange. The latter occurs:

• if the ventilated alveoli do not have capillary blood flow (these are the so-called non-perfused or non-perfused alveoli);
• if more air enters the perfused alveoli than is necessary in relation to the volume of blood flow (overstretched alveoli).

In both cases, the nature of the disorders is defined by the term “violation of the ventilation/blood flow ratio.” Under these conditions, the size of the physiological harmful volume will be greater than the anatomical one. Under normal conditions, due to the good correlation between the ventilation/blood flow ratio, both of these dead volumes are equal.

Under anesthesia, a violation of this correlation is common, since the reflex mechanism of maintaining the adequacy of ventilation and the adequacy of perfusion of the alveoli under anesthesia is impaired, especially after changing the position of the patient on the operating table. This circumstance requires that the volume of MAV during the period of anesthesia be higher than the preoperative one by 0.5-1 l, despite the decrease in metabolism.

Anesthetic dead space is the volume of gas located between the breathing circuit in circulating systems or the inhalation valve in open systems and the point where the patient is connected to the apparatus. In cases of using endotracheal tubes, this volume is less than the anatomical one or equal to it; with mask anesthesia, the anesthetic harmful volume is significantly greater than the anatomical one, which can have a negative effect in individuals with a shallow inspiratory depth during anesthesia with spontaneous breathing and is especially important during anesthesia in children. However, it is completely unacceptable to reduce the volume of anatomical dead space by using endotracheal tubes of a narrower diameter in relation to the tracheal lumen. In this case, the breathing resistance of the endotracheal tube increases sharply, leading to an increase in residual volume, disruption of alveolar gas exchange and can cause blockage of alveolar blood flow.

Physiological significance of dead space

The semantic meaning of the term “dead space” or “harmful space” is conditional. In this space, during each respiratory cycle, the air conditioning process occurs: cleaning from dust, microorganisms, humidification and warming. The degree of air purification from microorganisms is almost perfect: in the peripheral zone of the lung only in 30% of cases single staphylococci and streptococci are found. Bronchial secretion has a bactericidal effect.

Thus, “harmful” space is useful. However, when the inspiratory depth is sharply reduced, the volume of dead space can interfere with the adequacy of alveolar ventilation.

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 lower.

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.

The amount of pulmonary ventilation is determined by tidal volume (depth of breathing) and breathing frequency. There are a number of volume indicators that characterize the condition of the lungs (Fig. 1.1). Normal values ​​are given for an adult weighing 70 kg.

1. Tidal volume (VT) - the volume of inhaled and exhaled air during quiet breathing. The normal value is 0.5-0.6 l.

2. Inspiratory reserve volume (IRV) - the volume that can additionally arrive after a quiet inhalation, i.e. difference between normal and maximum ventilation. Normal values: about 2.5 l (about 2/3 vital capacity).

3. Expiratory reserve volume (ERV) - the volume that can be additionally exhaled after a quiet exhalation, i.e. difference between normal and maximum exhalation. Normal values ​​are 1.5 l (about 1/3 vital capacity).

4. Residual volume (VR) - the volume remaining in the lungs after maximum exhalation.

Vital capacity (VC) is the amount of air that can be exhaled with a maximum exhalation made after a maximum inhalation. Thus, it is a measure of the largest possible respiratory excursion. Vital capacity is an indicator of the mobility of the lungs and chest. Even with the body’s highest oxygen needs, the depth of breathing does not reach its maximum value. The value of vital capacity depends on age, gender, body size and position, and degree of fitness. Normal vital value: 3.5-5.5 l.

Figure 1.1. Static lung volumes of an adult

5. Inspiratory reserve (IR) - the maximum amount of air that can enter the lungs after a quiet exhalation.

6. Total lung capacity (TLC) or maximum lung capacity - the amount of air contained in the lungs at the height of maximum inspiration. It consists of vital capacity and residual volume and is calculated as the sum of vital capacity and OO. The normal value is about 6 liters. Studying the structure of TLC is crucial in elucidating ways to increase or decrease vital capacity, which can have significant practical significance. An increase in vital capacity can be assessed positively only if the vital capacity does not change or increases, but less than vital capacity, which occurs when vital capacity increases due to a decrease in VC. If, simultaneously with an increase in VC, an even greater increase in TLC occurs, then this cannot be considered a positive factor. When VC is below 70% TLC, the function of external respiration is deeply impaired. Usually, in pathological conditions, TLC and vital capacity change in the same way, with the exception of obstructive pulmonary emphysema, when vital capacity, as a rule, decreases, VT increases, and TLC may remain normal or be higher than normal.

7. Functional residual capacity (FRC) - the amount of air that remains in the lungs after a quiet exhalation. Normal values ​​for adults are from 3 to 3.5 liters.

FFU = OO + ROvyd.

By definition, FRC is the volume of gas that remains in the lungs during a quiet exhalation and can be a measure of the area of ​​gas exchange. It is formed as a result of the balance between the oppositely directed elastic forces of the lungs and chest. The physiological significance of FRC is the partial renewal of the alveolar volume of air during inspiration (ventilated volume) and indicates the volume of alveolar air constantly present in the lungs. An increase in FRC may be physiologically appropriate, since this increases the respiratory surface of the lungs. In addition, the expansion of the lumen of the airways reduces the resistance to air flow and increases the area of ​​​​diffusion of gases in the respiratory tract below the 16th division order. It must be taken into account that simultaneously with an increase in FRC, the diffusion path of gases slightly increases, the inspiratory capacity (ventilated volume) decreases, and the ability to increase DO and, accordingly, to increase maximum ventilation of the lungs is limited. An increase or decrease in FRC is determined by a corresponding change in the ratio of two oppositely directed forces - the elastic traction of the lung, which tends to reduce its volume, and the elastic force of the chest tissue. Assessing the relationship between these two forces largely determines the mechanics of breathing.

The clinical significance of FRC is great. It decreases by 20% a few minutes after the start of anesthesia. This decrease is likely due to elevation of the diaphragm due to increased intra-abdominal pressure in the supine position, increased central blood volume, and loss of respiratory muscle tone. A decrease in FRC is associated with the development of atelectasis, closure of small airways, a decrease in lung compliance, an increase in the alveolar-arterial difference in O2 as a result of perfusion of atelectasis areas of the lungs, and a decrease in the ventilation-perfusion ratio. Obstructive ventilation disorders lead to an increase in FRC, restrictive disorders lead to a decrease in FRC.

From a physiological and clinical point of view, the closure volume (CV) and closure capacity (EC) are of great importance. Lung closure volume (CV) is the pulmonary volume, part of the vital capacity, at which the small airways (bronchioles) close during exhalation, quiet or forced. Closing capacity (EC) is the sum of OC and residual volume (VR):

EZ = OZ + OO.

Closure of bronchioles is observed more often in the dorsobasal pulmonary segments, in which external tissue pressure as a result of the action of gravity on the lungs exceeds the endobronchial pressure created by the FRC air. Since in healthy adults the closing capacity (EC) is less than the FRC (FRC = PO ext. + + OO), the small airways do not close at average expiratory pressure.

Factors leading to a decrease in FRC:

Lying position on your back;

Obesity;

Operations on the upper abdomen;

Thoracic operations.

Factors that lead to an increase in EZ:

Smoking;

Previous chronic obstructive pulmonary diseases (COPD);

Heart failure;

Age (EF = FRC at 65 years in a standing position and at 54 years in a supine position).

In the work of an anesthesiologist, among other disorders of pulmonary function, postoperative pulmonary restriction is quite common. During and after surgery performed under general anesthesia, especially after upper leg and thoracotomy, there is a significant decrease in lung function, which is usually described as an acute restriction (contraction) of all lung volumes. The degree of such restriction of lung volumes is associated mainly with the following factors:

Reducing the inspiratory reserve volume by 10% of the initial value;

Decrease in vital capacity by approximately 50-75%;

Reducing FRC by 35%.

A decrease in static lung volumes is caused mainly by:

Pain followed by shallow breathing;

Suppressing cough;

Dorsobasal postoperative atelectasis;

Increased intra-abdominal pressure due to various reasons;

Residual effects of drugs and muscle relaxants;

After surgery, patients often breathe shallowly and do not cough, since for an effective cough they must have at least three tidal volumes (normal value 8 ml/kg body weight). In this case, there is a danger of retention of bronchial mucus with the subsequent development of atelectasis and secondary pneumonia. The pathophysiological significance of a decrease in FRC is to reduce the difference between FRC and closing capacity. When the closure capacity exceeds the FRC level, the small airways close at the end of a quiet exhalation. Periodic closure of the alveoli quickly leads to increased intrapulmonary right-to-left shunting and decreased oxygenation. Therefore, it is necessary to maintain the FRC above the EZ, keeping the gas exchange zone open. In this regard, adequate postoperative anesthesia and respiratory therapy are a priority. When planning treatment in the postoperative period, it is necessary to take into account that more than 30% of patients after surgery develop respiratory failure if vital capacity is less than 50% of the normal value (1.75-2 l in adults). Postoperative restriction of pulmonary functions returns to normal only after 2-3 weeks.