Features of the structure and development of the respiratory system in children. Respiratory organs in a child

Newborns take their first breath immediately after birth, often with their first cry. Sometimes there is some delay in the first breath due to labor pathology (asphyxia, intracranial birth injury) or as a result of reduced excitability of the respiratory center due to a sufficient supply of oxygen in the newborn’s blood. In the latter case, a short-term cessation of breathing occurs - apnea. If the physiological holding of breath is not prolonged and does not lead to asphyxia, then it usually does not have a negative effect on the further development of the child. Subsequently, more or less rhythmic but shallow breathing is established.

In some newborns, especially premature babies, due to shallow breathing and a weak first cry, the lungs do not fully expand, which leads to the formation of atelectasis, more often in the posterior lower parts of the lungs. Often these atelectasis are the beginning of the development of pneumonia.

The depth of breathing in children in the first months of life is significantly less than in older children.

Absolute respiration volume(the amount of air inhaled) gradually increases with age.

Due to shallow breathing in newborns and the lack of elastic tissue in the respiratory tract, the excretory ability of the bronchi is impaired, as a result of which secondary atelectasis is often observed. These atelectasis are more often observed in premature infants due to functional impairment respiratory center and all nervous system.

The respiratory rate in newborns, according to various authors, ranges from 40 to 60 per minute; With age, breathing becomes less frequent. According to the observations of A.F. Tour, the frequency of inhalation in children of different ages is as follows:

In children early age the ratio of breathing rate to pulse rate is 1:3.5 or 1:4.

The volume of a respiratory act multiplied by the respiratory rate per minute is called minute breathing volume. Its value varies depending on the age of the child: in a newborn it is 600-700 ml per minute, in the first year of life it is about 1700-1800 ml, in adults it is 6000-8000 ml per minute.

Due to the high respiratory rate in young children, the minute volume of breathing (per 1 kg of weight) is greater than in an adult. For children under 3 years of age it is 200 ml, and for an adult it is 100 ml.

Study external respiration is of great importance in determining the degree respiratory failure. These studies are carried out using various functional tests(Stange, Hench, spirometry, etc.).

In young children, for obvious reasons, external respiration is examined by counting breaths, pneumography, and clinical observations of the rhythm, frequency, and pattern of breathing.

The type of breathing in a newborn and infant is diaphragmatic or abdominal, which is explained by the high position of the diaphragm, the significant size of the abdominal cavity, and the horizontal arrangement of the ribs. From 2-3 years of age, the type of breathing becomes mixed (thoracic breathing) with a predominance of one or another type of breathing.

After 3-5 years, chest breathing gradually begins to predominate, which is associated with the development of the muscles of the shoulder girdle and a more oblique arrangement of the ribs.

Gender differences in the type of breathing are revealed at the age of 7-14 years: in boys, abdominal breathing is gradually established, in girls - breast type breathing.

To cover all exchange needs, the child needs more oxygen than an adult, which in children is achieved by rapid breathing. This requires the correct functioning of external respiration, pulmonary and internal tissue respiration, i.e., for normal gas exchange to occur between blood and tissues.

External respiration in children is disrupted due to the poor composition of the external air (for example, due to insufficient ventilation of rooms where children are). The condition of the respiratory apparatus also affects the child’s breathing: for example, breathing quickly becomes impaired even with slight swelling of the alveolar epithelium, so oxygen deficiency can occur more easily in young children than in older children. It is known that the air exhaled by a child contains less carbon dioxide and more oxygen than the air exhaled by an adult.

The respiratory coefficient (the ratio between the volume of carbon dioxide released and the volume of oxygen absorbed) in a newborn is 0.7, and in an adult - 0.89, which is explained by the significant oxygen consumption of the newborn.

Easily occurring oxygen deficiency - hypoxemia and hypoxia - worsens the child’s condition not only with pneumonia, but also with catarrh of the respiratory tract, bronchitis, and rhinitis.

Breathing is regulated by the respiratory center, which is constantly influenced by the cerebral cortex. The activity of the respiratory center is characterized by automaticity and rhythm; it distinguishes two sections - inspiratory and expiratory (N. A. Mislavsky).

Stimulations from extero- and interoreceptors travel along centripetal pathways to the respiratory center, where processes of excitation or inhibition occur. The role of impulses coming from the lungs is very large. The excitation that occurs during inhalation is transmitted through the vagus nerve to the respiratory center, causing its inhibition, as a result of which impulses are not sent to the respiratory muscles, they relax, and the exhalation phase begins. Afferent endings vagus nerve in the collapsed lung they are not excited, and inhibitory impulses do not enter the respiratory center. The latter is excited again, which causes a new breath, etc.

The function of the respiratory center is influenced by the composition of the alveolar air, the composition of the blood, the content of oxygen, carbon dioxide, and metabolic products in it. The entire mechanism of external respiration is in close connection with the circulatory, digestive, and hematopoietic systems.

It is known that an increased content of carbon dioxide causes deepening of breathing, and a lack of oxygen causes increased breathing.

Under the influence of various emotional moments, the depth and frequency of breathing changes. Many works by domestic scientists have established that the regulation of breathing in children is carried out mainly by the neuroreflex pathway. Thus, the regulatory role of the central nervous system ensures the integrity of the child’s body, its connection with the environment, as well as the dependence of breathing on the function of blood circulation, digestion, metabolism, etc.

Features of the respiratory system in young children

The respiratory organs of young children anatomically and functionally differ not only from those of adults, but even of older children. This is explained by the fact that in young children the process of anatomical and histological development has not yet been fully completed. This naturally affects the frequency and nature of respiratory damage in children of this age.

Nose the child is relatively small, short, the bridge of the nose is poorly developed, the nasal openings and nasal passages are narrow, the lower nasal passage is almost absent and is formed only by 4-5 years. With the growth of facial bones and teething, the width of the nasal passages increases. The choanae are narrow, resemble transverse slits, and reach full development by the end of early childhood. The nasal mucosa is delicate, lined with columnar ciliated epithelium, rich in blood vessels and lymphatic vessels. The slightest swelling makes breathing and sucking very difficult. Rhinitis in an infant is certainly combined with pharyngitis; the process is sometimes localized in the larynx, trachea and bronchi.

The cavernous tissue of the submucosal layer is very weakly expressed and develops sufficiently only by the age of 8-9 years, which, apparently, can explain the rather rare nosebleeds in young children.

Accessory cavities There are practically no noses in young children, since they are very poorly developed (4-5 times less than in children of high school age). Frontal sinuses and maxillary cavities develop by 2 years, but they reach final development much later, and therefore diseases of these sinuses in young children are extremely rare.

Eustachian tube short, wide, its direction is more horizontal than that of an adult. This can explain the significant frequency of otitis in young children, especially with a pathological condition of the nasopharynx.

Nasopharynx and pharynx. The pharynx of a young child is short and has a more vertical direction. Both pharyngeal tonsils do not protrude into the pharynx cavity.

By the end of the first year, and in children suffering from exudative or lymphatic diathesis, the tonsils become noticeable much earlier even with a routine examination of the pharynx.

Tonsils in children at an early age they also have structural features: the vessels and crypts in them are poorly expressed, as a result of which sore throats are rarely observed.

With age, lymphoid tissue grows and reaches its maximum between 5 and 10 years. However, even in the early childhood There are quite frequent catarrhal conditions of the nasopharynx with swelling and redness of the tonsils.

With the growth of certain tonsils, various painful conditions are observed: with enlargement and inflammation of the nasopharyngeal tonsil, adenoids develop, and nasal breathing is impaired. The child begins to breathe through his mouth, his speech becomes nasal, and sometimes his hearing decreases.

Larynx occupies the middle part of the neck anterior to the esophagus and in a child has a funnel-shaped shape with a narrow lumen, with pliable and delicate cartilage. The most vigorous growth of the larynx is observed in the first year of life and at puberty.

A child's larynx is small; up to 3 years of age, it is the same length in boys and girls. The false vocal cords and mucous membrane in young children are delicate and very rich in blood vessels. The true vocal cords are shorter than those of older children.

Especially enhanced growth observed in the first year of life and in puberty. The mucous membrane of the larynx is covered with columnar ciliated epithelium, and on the true vocal cords the epithelium is multilayered, flat, without signs of keratinization, unlike in adults. The mucous membrane is rich in acinar-type glands.

The indicated anatomical physiological characteristics The larynx explains the difficulty in breathing that is quite often observed even with mild inflammatory processes of the larynx, reaching the point of laryngeal stenosis, known as “false croup”.

Trachea. In children in the first half of life, the trachea has a funnel shape, a narrow lumen, and is located 2-3 vertebrae higher than in adults.

The mucous membrane of the trachea is tender, rich in blood vessels and relatively dry due to the insufficient development of the mucosal glands. The cartilage of the trachea is soft, easily compressed and can become dislodged.

All these anatomical and physiological features of the trachea contribute to the more frequent occurrence of inflammatory processes and the onset of stenotic phenomena.

The trachea is divided into two main bronchi - right and left. The right bronchus is, as it were, a continuation of the trachea, which explains the more frequent entry of foreign bodies into it. The left bronchus deviates from the trachea at an angle and is longer than the right one.

Bronchi. In newborns and young children, the bronchi are narrow, poor in muscle and elastic fibers, their mucous membrane is rich in blood vessels, due to which inflammatory processes occur more quickly, and the lumen of the bronchi narrows faster than in older children. In the postnatal period, differentiation of the structures of the bronchial walls, most intensely expressed in the system muscular type bronchi (V.I. Puzik). The age structure of the bronchial tree plays a major role in the pathology of this organ.

The greatest increase in the size of the bronchi (sagittal and frontal) occurs during the first year of life; the left bronchus lags behind the right.

Lungs. The main functional unit of the lungs is the acinus, consisting of a group of alveoli and bronchioles (1st, 2nd and 3rd order), within which the main function of the lungs is carried out - gas exchange.

In young children, the lungs are more full-blooded and less airy. Interstitial, interstitial lung tissue more developed than in older children, more abundantly supplied with blood vessels.

A child's lungs are looser, richer in lymphatic vessels and smooth muscle fibers. These structural features the child's lungs suggest that they have a greater ability to contract and more rapidly resorption of intra-alveolar exudate.

Child's lungs infancy are poor in elastic tissue, especially in the circumference of the alveoli and in the walls of the capillaries, which can explain their tendency to form atelectasis, develop emphysema, and a protective compensatory reaction of the lungs to infection during pneumonia.

The weight of the lungs of a newborn child is, according to Gundobin, 1/34 - 1/54 of the weight of his body; by the age of 12, it increases 10 times compared to the weight of the lungs of newborn children. The right lung is usually larger than the left.

Lung growth occurs with the age of the child, mainly due to an increase in the volume of the alveoli (from 0.05 mm in newborns to 0.12 mm by the end of early childhood and 0.17 mm in adolescence).

At the same time, there is an increase in the capacity of the alveoli and a growth of elastic elements around the alveoli and capillaries, and the replacement of the connective tissue layer with elastic tissue.

Pulmonary fissures in young children are weakly expressed and represent shallow grooves on the surfaces of the lungs.

Due to the proximity of the root of the lungs, a group of lymph nodes seems to protrude into the main fissures on both sides and is the source of interlobar pleurisy.

The processes of growth and differentiation of the functional elements of the lung - in the lobule, acini and intralobular bronchi - end by the age of 7 years of a child’s life (A. I. Strukov, V. I. Puzik).

Behind last years An important contribution to pediatrics is the developed doctrine of segmental structure of the lungs(A.I. Strukov and I.M. Kodolova).

The authors showed that by the time a child is born, all segments and the corresponding bronchi have already been formed, just like in adults. However, this similarity is only external and in the postnatal period differentiation of the lung parenchyma and growth of subsegmental bronchi continues.

Each segment has independent innervation, an artery and a vein. There are 10 segments on the right: in upper lobe-3, in the middle - 2, in the lower - 5. On the left there are 9 (less often 10) segments: in the upper lobe - 3, in the uvula of the middle lobe - 2, in the lower - 4 segments. Each segment consists of 2 sub-segments and only segments VI and X consist of 3 sub-segments.

Rice. 1. Scheme of the segmental structure of the lungs according to the nomenclature of the International Congress of Otolaryngologists in 1949 in London.

1st segment s. apicale(1); 2nd segment s. posterius(2); 3rd segment s. anterius (3); 4th segment s. Iateral (4); 5th segment s. mediale (5); 6th segment s. apicale superius (6); 7th segment s. (basale) mediale (not visible on the diagram); 8th segment s. (basale) anterius (8); 9th segment s. (basale) Iateral (9); 10th segment s. (basale) posterius (10).

Currently, the generally accepted nomenclature of segments and bronchi is the nomenclature adopted in 1945 at the International Congress of Anatomists in Paris and in 1949 at the International Congress of Otolaryngologists in London.

Based on this, simple diagrams of the segmental structure of the lungs have been created [F. Kovach and Z. Zhebek, 1958, Boyden (Boyden, 1945), etc.] (Fig. 1).

Lung root(hilus). Consists of large bronchi, nerves, vessels, huge amount lymph nodes.

Lymph nodes in the lungs are divided into the following groups (according to A.F. Tour): 1) tracheal; 2) bifurcation; 3) bronchopulmonary; 4) lymph nodes of large vessels. All lymph nodes are connected by lymphatic tracts to the lungs, as well as to the mediastinal and supraclavicular lymph nodes.

The root of the right lung is located slightly higher (at the level of the V-VI thoracic vertebrae), the left one is located lower (at the level of the VI-VII vertebrae). As a rule, the root of the left lung as a whole and its individual elements (pulmonary artery, vein, bronchi) are somewhat behind in their development from the corresponding formations of the right side.

Pleura. In newborns and young children, the pleura is thin and easily displaced. The pleural cavity, as in adults, is formed by two layers of the pleura - visceral and parietal, as well as two visceral layers in the interlobar spaces. The pleural cavity in children of this age is easily distensible due to the weak attachment of the parietal layers of the pleura to the chest. The accumulation of fluid in the pleura in young children as a result of inflammatory processes in the lungs easily causes displacement of the mediastinal organs, since they are surrounded by loose tissue, which often entails significant circulatory disorders.

Mediastinum. In children it is relatively larger than in adults, more elastic and pliable. The mediastinum is limited posteriorly by the vertebral bodies, below by the diaphragm, on the sides by the layers of the pleura enveloping the lungs, and in front by the manubrium and body of the sternum. In the upper part of the mediastinum there is the thymus gland, trachea, large bronchi, lymph nodes, nerve trunks (n. recurrens, n. phrenicus), veins, and ascending aortic arch. The lower part of the mediastinum contains the heart, blood vessels, and nerves. In the posterior mediastinum there are n. vagus, n. sympaticus and part of the esophagus.

Rib cage. Structure and form chest in children can vary significantly depending on the age of the child. The chest of a newborn is relatively shorter in the longitudinal direction, its anteroposterior diameter is almost equal to the transverse one. The shape of the chest is conical, or almost cylindrical, the epigastric angle is very obtuse due to the fact that the ribs in young children are located almost horizontally and perpendicular to the spine (Fig. 2).

The chest is constantly in a state of inhalation, which cannot but affect the physiology and pathology of breathing. This also explains the diaphragmatic nature of breathing in young children.

With age, the anterior part of the chest, sternum, and trachea descend together with the diaphragm, the ribs take on a more inclined position, as a result of which the chest cavity increases and the epigastric angle becomes more acute. The chest gradually moves from the inspiratory position to the expiratory position, which is one of the prerequisites for the development of thoracic breathing.

Diaphragm. In children, the diaphragm is high. When it contracts, the dome flattens and thus the vertical size increases chest cavity. That's why pathological changes in the abdominal cavity (tumors, enlarged liver, spleen, intestinal flatulence and other conditions accompanied by difficulty moving the diaphragm) reduce ventilation to a certain extent.

Specified Features anatomical structure respiratory organs cause changes in respiratory physiology in young children.

All of the indicated anatomical and physiological features of breathing in children put the child at a disadvantage compared to adults, which to some extent explains the significant frequency respiratory diseases in young children, as well as their more severe course.

The formation of the respiratory system in a child begins at 3-4 weeks of intrauterine existence. By 6 weeks embryonic development the child develops ramifications respiratory organs second order. At the same time, the formation of the lungs begins. By the 12th week of the intrauterine period, areas of lung tissue appear in the fetus. Anatomical and physiological features - AFO of the respiratory organs in children undergo changes as the baby grows. The correct development of the nervous system, which is involved in the breathing process, is crucial.

Upper respiratory tract

In newborn babies, the skull bones are not sufficiently developed, due to which the nasal passages and the entire nasopharynx are small and narrow. The mucous membrane of the nasopharynx is delicate and riddled with blood vessels. It is more vulnerable than that of an adult. Nasal appendages are most often absent; they begin to develop only by 3-4 years.

As the baby grows, the nasopharynx also increases in size. By the age of 8, the baby develops a lower nasal passage. In children, the paranasal sinuses are located differently than in adults, due to which the infection can quickly spread into the cranial cavity.

In children, a strong proliferation of lymphoid tissue is observed in the nasopharynx. It reaches its peak by the age of 4, and from the age of 14 it begins to reverse development. Tonsils are a kind of filters, protecting the body from the penetration of microbes. But if a child is often sick for a long time, then the lymphoid tissue itself becomes a source of infection.

Children get sick often respiratory diseases, which is due to the structure of the respiratory organs and insufficient development of the immune system.

Larynx

In small children, the larynx is narrow and funnel-shaped. Only later does it become cylindrical. The cartilages are soft, the glottis is narrowed and the vocal cords themselves are short. By age 12, boys' vocal cords become longer than girls'. This is what causes the change in voice timbre in boys.

Trachea

The structure of the trachea also differs in children. During the first year of life, it is narrow and funnel-shaped. By age 15 top part trachea reaches 4 cervical vertebra. By this time, the length of the trachea doubles, it is 7 cm. In children, it is very soft, so when the nasopharynx is inflamed, it is often compressed, which manifests itself as stenosis.

Bronchi

The right bronchus is like a continuation of the trachea, and the left one moves to the side at an angle. That is why in case of accidental hit foreign objects into the nasopharynx, they often end up in the right bronchus.

Children are susceptible to bronchitis. Any cold can result in inflammation of the bronchi, severe cough, high temperature and a violation of the general condition of the baby.

Lungs

Children's lungs undergo changes as they grow older. The mass and size of these respiratory organs increase, and differentiation in their structure also occurs. In children, there is little elastic tissue in the lungs, but the intermediate tissue is well developed and contains a large number of vessels and capillaries.

The lung tissue is full-blooded and contains less air than in adults. By the age of 7, the formation of the acini ends, and until the age of 12, the growth of the formed tissue simply continues. By the age of 15, the alveoli increase 3 times.

Also, with age, the mass of the lung tissue in children increases, and more elastic elements appear in it. Compared to the neonatal period, the mass of the respiratory organ increases by approximately 8 times by the age of 7 years.

The amount of blood that flows through the capillaries of the lungs is higher than in adults, which improves gas exchange in the lung tissue.

Rib cage

The formation of the chest in children occurs as they grow and ends only closer to 18 years. According to the age of the child, the volume of the chest increases.

In infants, the sternum is cylindrical in shape, while in adults the chest is oval in shape. Children's ribs are located in a special way; due to their structure, a child can painlessly transition from diaphragmatic to chest breathing.

Peculiarities of breathing in a child

Children have an increased respiratory rate, with respiratory movements becoming more frequent the more smaller child. From the age of 8, boys breathe more often than girls, but starting from adolescence, girls begin to breathe more often and this state of affairs continues throughout the entire period.

To assess the condition of the lungs in children, it is necessary to consider the following parameters:

• Overall volume breathing movements.
• The volume of air inhaled per minute.
• Vital capacity of the respiratory organs.

The depth of breathing in children increases as they grow older. The relative volume of breathing in children is twice as high as in adults. Vital capacity increases after physical activity or sports exercises. The more exercise stress, the more noticeable is the change in breathing pattern.

In a calm state, the child uses only part of the vital capacity of the lungs.

Vital capacity increases as the diameter of the chest increases. The amount of air that the lungs can ventilate in a minute is called the respiratory limit. This value also increases as the child grows older.

Huge value for assessment pulmonary function has gas exchange. The carbon dioxide content in the exhaled air of schoolchildren is 3.7%, while in adults this value is 4.1%.

Methods for studying the respiratory system of children

To assess the condition of the child’s respiratory organs, the doctor collects an anamnesis. The little patient’s medical record is carefully studied and complaints are clarified. Next, the doctor examines the patient, listens to the lower respiratory tract with a stethoscope and taps them with his fingers, paying attention to the type of sound produced. Then the examination takes place according to the following algorithm:

• The mother is asked how the pregnancy progressed and whether there were any complications during childbirth. In addition, it is important what the baby was sick with shortly before the appearance of problems with the respiratory tract.
• They examine the baby, paying attention to the nature of breathing, the type of cough and the presence of nasal discharge. Look at the color skin, their cyanosis indicates oxygen deficiency. An important symptom is shortness of breath; its occurrence indicates a number of pathologies.
• The doctor asks the parents if the child experiences short-term pauses in breathing during sleep. If this condition is typical, then this may indicate problems of a neurological nature.
• X-rays are prescribed to clarify the diagnosis if pneumonia or other lung pathologies are suspected. X-rays can be performed even on young children, if there are indications for this procedure. To reduce the level of radiation exposure, it is recommended that children be examined using digital devices.
• Examination using a bronchoscope. It is carried out for bronchitis and suspicion of a foreign body entering the bronchi. Using a bronchoscope, the foreign body is removed from the respiratory organs.
• Computed tomography is performed if there is a suspicion of oncological diseases. This method, although expensive, is the most accurate.

For young children, bronchoscopy is performed under general anesthesia. This eliminates respiratory injuries during the examination.

The anatomical and physiological characteristics of the respiratory system in children differ from the respiratory system in adults. Children's respiratory organs continue to grow until approximately 18 years of age. Their size, vital capacity and weight increase.

The characteristics of the chest determine in infants the shallow nature of breathing, its high frequency, arrhythmia, and incorrect alternation of pauses between inhalation and exhalation. At the same time, the depth of breathing (absolute capacity), that is, the amount of air that is inhaled, is significantly less in a newborn than in subsequent periods of childhood and in adults. With age, the respiratory capacity increases. The child's breathing rate is higher the lower it is.

In young children, the need for oxygen is greater (increased metabolism), therefore the shallow nature of breathing is compensated by its frequency. A newborn child appears to be in a state of constant shortness of breath (physiological shortness of breath of newborns).

Accelerated breathing in a child often occurs when he screams, cries, during physical stress, bronchitis, or pneumonia. Minute breathing capacity is the capacity of the respiratory act multiplied by the frequency. It indicates the degree of oxygen saturation of the lungs. Its absolute value in a child is less than in an adult.

Determination of vital capacity is possible in children from 5-6 years old using a spirometer. Define maximum amount air that is exhaled into the spirometer tube after maximum inspiration. Vital capacity increases with age and also increases as a result of training.

The relative minute breathing capacity (per 1 kg of body weight) as a result of accelerated breathing in children is much greater than in an adult; from birth to 3 years - 200 ml, at 11 years - 180 ml, for an adult - 100 ml.

The type of breathing in a newborn and a child in the first year of life is diaphragmatic, or abdominal; from the age of 2, breathing is mixed - diaphragmatic-thoracic, and from 8-10 years old in boys it is abdominal, in girls it is thoracic. The breathing rhythm in young children is unstable, the pauses between inhalation and exhalation are uneven. This is due to the incomplete development of the respiratory center and increased excitability of the vagal receptors. Breathing is regulated by the respiratory center, which receives reflex stimuli from the branches of the vagus nerve.

Gas exchange in the lungs of an infant is more vigorous than in older children and adults. It consists of three phases: 1) external respiration - exchange through the alveoli of the lungs between atmospheric air (air external environment) and pulmonary air; 2) pulmonary respiration - exchange between the air of the lungs and the blood (associated with the diffusion of gases); 3) tissue (internal) respiration - gas exchange between blood and tissues.

The correct development of the child's chest, lungs, and respiratory muscles depends on the conditions in which he grows. To strengthen it and normal development respiratory organs, to prevent respiratory diseases, it is necessary for the child to remain on the fresh air. Particularly useful are outdoor games, sports, physical exercises, outdoor activities, and regular ventilation of rooms where children are.

You should diligently ventilate the room during cleaning and explain to parents the importance of this event.

Basic vital important function respiratory organs are providing tissues with oxygen and removing carbon dioxide.

The respiratory organs consist of air-conducting (respiratory) tracts and paired respiratory organs - the lungs. The respiratory tract is divided into upper (from the opening of the nose to the vocal cords) and lower (larynx, trachea, lobar and segmental bronchi, including intrapulmonary branches of the bronchi). By the time the child is born, their morphological structure is still imperfect, which is also associated with the functional characteristics of breathing.

Intensive growth and differentiation of the respiratory organs continues during the first months and years of life. The formation of the respiratory organs ends on average by the age of 7, and only their sizes subsequently increase.

Anatomical and physiological features. All airways in a child are significantly smaller and have narrower openings than in an adult.

The features of their morphological structure in children of the first years of life are the following:

1) thin, delicate, easily wounded dry mucous membrane with insufficient development of glands, reduced production of secretory immunoglobulin A (SIg A) and surfactant deficiency;

2) rich vascularization of the submucosal layer, represented predominantly by loose fiber and containing few elastic and connective tissue elements;

3) softness and pliability of the cartilaginous frame of the lower respiratory tract, the absence of elastic tissue in them and the lungs.

This reduces the barrier function of the mucous membrane, facilitates easier penetration of the infectious agent into the bloodstream, and also creates the preconditions for narrowing of the airways due to rapidly occurring swelling or compression of the pliable breathing tubes from the outside (thymus gland, abnormally located vessels, enlarged tracheobronchial lymph nodes).

Nose and nasopharyngeal space. In young children, the nose and nasopharyngeal space are small, the nasal cavity is low and narrow due to insufficient development of the facial skeleton. The shells are thick, the nasal passages are narrow, the lower one is formed only by 4 years. Even slight hyperemia and swelling of the mucous membrane during a runny nose makes the nasal passages obstructed, causes shortness of breath, and makes breastfeeding difficult. Cavernous tissue develops by the age of 8-9 years, so nosebleeds in young children are rare and are caused by pathological conditions. During puberty they are observed more often.

Paranasal (paranasal) sinuses. By the birth of the child, only the maxillary (maxillary) sinuses are formed; The frontal and ethmoid are open protrusions of the mucous membrane, taking shape in the form of cavities only after 2 years; the main sinus is absent. All paranasal sinuses develop completely by the age of 12-15, however, sinusitis can also develop in children in the first two years of life.
Nasolacrimal duct. It is short, its valves are underdeveloped, the outlet is located close to the corner of the eyelids, which facilitates the spread of infection from the nose to the conjunctival sac.

Pharynx.
In young children, the pharynx is relatively wide, tonsils at birth they are clearly visible, but do not protrude due to well-developed arches. Their crypts and vessels are poorly developed, which to some extent explains rare diseases sore throat in the first year of life. By the end of the first year, the lymphoid tissue of the tonsils, including the nasopharyngeal (adenoids), often hyperplasias, especially in children with diathesis. Their barrier function at this age is low, like that of lymph nodes. The overgrown lymphoid tissue is populated by viruses and microorganisms, and foci of infection are formed - adenoiditis and chronic tonsillitis. In this case, frequent sore throats and acute respiratory viral infections are observed, nasal breathing is often disrupted, the facial skeleton changes and an “adenoid face” is formed.

Epiglottis.
Closely related to the root of the tongue. In newborns it is relatively short and wide. The incorrect position and softness of its cartilage can cause a functional narrowing of the entrance to the larynx and the appearance of noisy (stridor) breathing.

Larynx. In children, the larynx is higher than in adults, it descends with age, and is very mobile. Its position is not constant even in the same patient. It has a funnel-shaped shape with a distinct narrowing in the area of ​​the subglottic space, limited by the rigid cricoid cartilage. The diameter of the larynx in this place in a newborn is only 4 mm and increases slowly (6-7 mm at 5-7 years, 1 cm by 14 years), its expansion is impossible. Narrow clearance, the abundance of nerve receptors in the subglottic space, easily occurring swelling of the submucosal layer can cause severe breathing problems even with minor manifestations of respiratory infection (croup syndrome).

The thyroid cartilages form a blunt, rounded angle in young children, which becomes sharper in boys after 3 years of age. From the age of 10, the characteristic male larynx is formed. The true vocal cords of children are shorter than those of adults, which explains the pitch and timbre of a child's voice.

Trachea.
In children in the first months of life, the trachea is often funnel-shaped; at older ages, cylindrical and conical shapes predominate. Its upper end is located in newborns much higher than in adults (at the level of the IV and VI cervical vertebrae, respectively), and gradually descends, like the level of the tracheal bifurcation (from the III thoracic vertebra in a newborn to V-VI at 12-14 years). The tracheal framework consists of 14-16 cartilaginous half-rings connected posteriorly by a fibrous membrane (instead of an elastic end plate in adults). The membrane contains many muscle fibers, the contraction or relaxation of which changes the lumen of the organ.

The child’s trachea is very mobile, which, along with the changing lumen and softness of the cartilage, sometimes leads to a slit-like collapse during exhalation (collapse) and is the cause of expiratory shortness of breath or rough snoring breathing (congenital stridor). Symptoms of stridor usually disappear by age 2 as the cartilage becomes denser.

Bronchial tree.
By the time of birth, the bronchial tree is formed. As the child grows, the number of branches and their distribution in lung tissue don't change. The size of the bronchi increases rapidly in the first year of life and during puberty. They are also based on cartilaginous semirings, in early childhood without a closing elastic plate, connected by a fibrous membrane containing muscle fibers. The cartilage of the bronchi is very elastic, soft, springy and easily displaced. Right main bronchus It is usually an almost direct continuation of the trachea, therefore it is in it that foreign bodies are most often found.

The bronchi, like the trachea, are lined with multirow cylindrical epithelium, the ciliated apparatus of which is formed after the birth of the child. Hyperemia and swelling of the bronchial mucosa, its inflammatory swelling significantly narrow the lumen of the bronchi, up to their complete obstruction. Thus, with an increase in the thickness of the submucosal layer and mucous membrane by 1 mm, the total area of ​​the bronchial lumen of a newborn decreases by 75% (in an adult - by 19%). Active bronchial motility is insufficient due to poor development of muscles and ciliated epithelium.

Incomplete myelination of the vagus nerve and underdevelopment of the respiratory muscles contribute to weakness cough impulse at small child; Infected mucus accumulating in the bronchial tree clogs the lumens of the small bronchi, promotes atelectasis and infection of the lung tissue. Thus, the main functional feature of the bronchial tree of a small child is the insufficient performance of the drainage and cleansing function.

Lungs.
In children, as in adults, the lungs have a segmental structure. The segments are separated from each other by narrow grooves and layers of connective tissue (lobular lung). The main structural unit is the acini, but its terminal bronchioles end not in a cluster of alveoli, as in an adult, but in a sac (sacculus). New alveoli are gradually formed from the “lace” edges of the latter, the number of which in a newborn is 3 times less than in an adult. The diameter of each alveoli also increases (0.05 mm in a newborn, 0.12 mm at 4-5 years, 0.17 mm at 15 years). At the same time, the vital capacity of the lungs increases.

The interstitial tissue in a child's lung is loose, rich in blood vessels, fiber, and contains very little connective tissue and elastic fibers. In this regard, the lungs of a child in the first years of life are more full-blooded and less airy than those of an adult. Underdevelopment of the elastic framework of the lungs contributes to both the occurrence of emphysema and atelectasis of the lung tissue. Atelectasis occurs especially often in the posterior regions of the lungs, where hypoventilation and blood stagnation are constantly observed due to the forced horizontal position of a small child (mainly on the back).

The tendency to atelectasis is enhanced by a deficiency of surfactant, a film that regulates alveolar surface tension and is produced by alveolar macrophages. It is this deficiency that leads to insufficient expansion of the lungs in premature infants after birth (physiological atelectasis), and also underlies the respiratory distress syndrome, clinically manifested by severe respiratory failure.
Pleural cavity. In a child, it is easily extensible due to weak attachment of the parietal layers. The visceral pleura, especially in newborns, is relatively thick, loose, folded, contains villi and outgrowths, most pronounced in the sinuses and interlobar grooves. In these areas there are conditions for faster emergence of infectious foci.

Root of the lung.
Consists of large bronchi, vessels and lymph nodes (tracheobronchial, bifurcation, bronchopulmonary and around large vessels). Their structure and function are similar to peripheral lymph nodes. They easily respond to the introduction of infection - a picture of both nonspecific and specific (tuberculous) bronchoadenitis is created. The root of the lung is integral part mediastinum.

The latter is characterized by easy displacement and is often the site of development of inflammatory foci, from where the infectious process spreads to the bronchi and lungs. The mediastinum also contains the spectacle gland (thymus), which is large at birth and normally gradually decreases during the first two years of life. Enlarged thymus can cause compression of the trachea and large vessels, impair breathing and blood circulation.

Diaphragm.
Due to the characteristics of the chest, the diaphragm plays a large role in the breathing mechanism of a small child, ensuring the depth of inspiration. The weakness of its contractions partly explains the extremely shallow breathing of the newborn. Any processes that impede the movement of the diaphragm (formation of a gas bubble in the stomach, flatulence, intestinal paresis, enlargement of parenchymal organs, intoxication, etc.) reduce ventilation of the lungs (restrictive respiratory failure).

The main functional physiological features of the respiratory organs are the following:

1) the depth of breathing, the absolute and relative volumes of one respiratory act in a child are significantly less than in an adult. With age, these figures gradually increase. When screaming, the volume of breathing increases 2-5 times. The absolute value of the minute volume of respiration is less than that of an adult, and the relative value (per 1 kg of body weight) is much greater;

2) the respiratory rate increases, the younger the child. It compensates for the small volume of each respiratory act and provides oxygen to the child’s body. Rhythm instability and short (3-5 min) pauses in breathing (apnea) in newborns and premature infants are associated with incomplete differentiation of the respiratory center and its hypoxia. Oxygen inhalation usually eliminates respiratory arrhythmia in these children;

3) gas exchange in children is carried out more vigorously than in adults, due to the rich vascularization of the lungs, blood flow speed, and high diffusion capacity. At the same time, the function of external respiration in a small child is disrupted very quickly due to insufficient excursion of the lungs and straightening of the alveoli.

Swelling of the epithelium of the alveoli or interstitium of the lungs, exclusion of even a small area of ​​lung tissue from the act of breathing (atelectasis, congestion in the posterior parts of the lungs, focal pneumonia, restrictive changes) reduce pulmonary ventilation, cause hypoxemia and the accumulation of carbon dioxide in the blood, i.e. the development of respiratory failure, as well as respiratory acidosis. Tissue respiration occurs in a child at higher energy costs than in adults, and is easily disrupted with the formation metabolic acidosis due to the instability of enzyme systems characteristic of early childhood.

Research methodology.
Assessing respiratory health involves questioning (usually the mother) and objective methods- inspection and counting the number of respiratory movements, palpation, percussion, auscultation, as well as laboratory and instrumental studies.

Questioning. The mother is asked how the perinatal period and childbirth proceeded, what the child was sick with, including shortly before the present illness, what symptoms were observed at the onset of the illness. Pay special attention to nasal discharge and difficulty in nasal breathing, the nature of cough (periodic, paroxysmal, barking, etc.) and breathing (hoarse, whistling, audible at a distance, etc.), as well as contacts with patients with respiratory or other acute or chronic infection.

Visual inspection. Examination of the face, neck, chest, and limbs provides more information the younger the child. Pay attention to the child’s scream, voice and cough. The examination helps to identify, first of all, signs of hypoxemia and respiratory failure - cyanosis and shortness of breath.
Cyanosis can be pronounced in certain areas (nasolabial triangle, fingers) and be widespread. With advanced microcirculation disorders, a rough cyanotic (marble) pattern on the skin is observed. Cyanosis may appear during crying, swaddling, feeding, or be constant.

Expansion of the superficial capillary network in the area of ​​the VII cervical vertebra (Frank's symptom) may indicate an enlargement of the tracheobronchial lymph nodes. Expressed vasculature sometimes appears on the skin of the chest additional symptom hypertension in the pulmonary artery system.
Dyspnea is often accompanied by the participation of accessory muscles and retraction of the compliant areas of the chest.
Inspiratory dyspnea with difficult, sonorous, sometimes whistling inhalation is observed with croup syndrome and any obstruction of the upper respiratory tract.

Expiratory shortness of breath with difficulty and prolongation of exhalation is characteristic of obstructive bronchitis, bronchial asthma, bronchiolitis, viral respiratory syncytial infection, and significant enlargement of tracheobronchial lymph nodes.

Mixed shortness of breath is observed with pneumonia, pleurisy, circulatory disorders, restrictive respiratory failure (severe flatulence, ascites). Puffing shortness of breath of a mixed nature is observed in severe rickets.

Swelling and tension of the wings of the nose indicate difficulty breathing and are the equivalent of shortness of breath in newborns and children in the first months of life.

It is also necessary to pay attention to nasal discharge and its nature. Bloody, especially unilateral, discharge can be observed with a foreign body in the nasal passages or nasal diphtheria. Pink foam coming from the nose and mouth is one of the symptoms acute pneumonia in newborns.

The child's voice allows us to judge the condition of the upper respiratory tract. A hoarse, low-pitched voice or complete aphonia is characteristic of laryngitis and croup syndrome. A rough, low voice is characteristic of hypothyroidism. The voice acquires a nasal, nasal tone in cases of chronic runny nose, adenoids, paresis of the velum palatine (due to birth trauma, polio, diphtheria), tumors and abscesses of the pharynx, birth defects development of the upper jaw.
The cry of a healthy full-term baby is loud, sonorous, promotes the straightening of lung tissue and the disappearance of atelectasis. A premature and weakened baby has a weak cry. Crying after feeding, before defecation, during urination requires, accordingly, the exclusion of hypo-galactia, fissures anus, phimosis, vulvitis and urethritis. A periodic loud cry is often observed with otitis, meningitis, abdominal pain, a monotonous, inexpressive “brain” cry - with organic damage to the central nervous system.

Cough- very valuable diagnostic sign. To artificially induce a cough, you can press on the cartilage of the trachea, the root of the tongue, or irritate the pharynx. A barking, rough cough that gradually loses sonority is characteristic of croup syndrome. A paroxysmal, prolonged cough consisting of successive cough shocks, accompanied by a loud, difficult inhalation (reprise) and ending with vomiting, is observed with whooping cough.

Bitonal cough is characteristic of enlarged tracheobronchial and bifurcation intrathoracic lymph nodes. A short, painful cough with a groaning exhalation often occurs with pleuropneumonia; dry, painful - with pharyngitis, tracheitis, pleurisy; wet - for bronchitis, bronchiolitis. It must be remembered that swelling of the mucous membrane of the nasopharynx, enlarged adenoids, and excessive mucus formation can cause a persistent cough, especially when changing position and without affecting the underlying respiratory tract.

Counting the number of respiratory movements should be carried out at the beginning of the examination in a state of rest (or sleep), since the child easily experiences tachypnea under any influence, including emotional. Brady pnea is rare in children (with meningitis and other brain lesions, uremia). In cases of severe intoxication, the breathing of a “hunted animal” is sometimes observed - frequent and deep. The count is made within a minute, better in sleeping children and by breathing sounds, through a phonendoscope brought to the nose. In older children, counting is done with a hand placed on the chest and stomach at the same time (on the costal arch), since children tend to have abdominal or mixed types breathing. The respiratory rate of a newborn child is 40-60 per minute, a one-year-old child is 30-35, 5-6 years old is 20-25, 10 years old is 1R-20, an adult is 15-16 per minute.

Palpation.
Palpation reveals deformities of the chest (congenital, associated with rickets or other bone formation defects). In addition, the thickness of the skin fold is determined symmetrically on both sides of the chest and the bulging or retraction of the intercostal spaces, the lag of one half of the chest during breathing. Swelling of the tissue, a thicker fold on one side, and bulging of the intercostal spaces are characteristic of exudative pleurisy. Recession of the intercostal spaces can be observed with atelectasis and adhesive processes in the cavity of the pleura and pericardium.

Percussion.
In children, percussion has a number of features:

1) the position of the child’s body should ensure maximum symmetry of both halves of the chest. Therefore, the back is percussed with the child standing or sitting with legs crossed or extended, the lateral surfaces of the chest - in a standing or sitting position with the hands on the back of the head or extended forward, and the chest - lying down;

2) percussion should be quiet - finger on finger or direct, since the chest of a child resonates much more than that of an adult;

3) the pessimeter finger is located perpendicular to the ribs, which creates conditions for a more uniform formation of percussion tone.

The percussion tone in a healthy child of the first years of life is usually high, clear, with a slightly boxy tint. When screaming, it can change - from distinct tympanitis at maximum inspiration and shortening during exhalation.

Any stable change in the nature of the percussion tone should alert the doctor. With bronchitis, bronchiolitis, asthmatic syndrome and asthma, and often bronchopneumonia with small foci of compaction of lung tissue and vicarious emphysema, a box or high-pitched tympanic sound may occur. With pneumonia, especially prolonged and chronic ones, a “variegated” sound is possible - alternating areas of shortening of the tone and percussion tympanic sound. Significant local or total shortening of tone indicates massive (lobar, segmental) pneumonia or pleurisy. Enlargement of the tracheobronchial lymph nodes is detected by direct percussion along the spinous processes of the vertebrae, starting from the lower thoracic regions.

Shortening of the sound below the second thoracic vertebra indicates possible bronchoadenitis (Coranyi de la Campa symptom).

The boundaries of the lungs are determined along the same lines as in adults, on average 1 cm higher due to the higher position of the diaphragm (in infants and preschool children). The mobility of the pulmonary edge is determined when the child breathes freely.

Auscultation. Features of the technique: 1) strictly symmetrical position of both halves of the chest, similar to that during percussion; 2) the use of a special children's stethoscope - with long tubes and a small diameter, since the membrane can distort the sound.

The normal respiratory sounds heard depend on age: up to 6 months in a healthy child, breathing is weakened vesicular due to its superficial nature; at the age of 6 months - 7 years, puerid (children's) breathing is heard, with a more distinct inhalation and a relatively louder and longer exhalation. In school-age children and adolescents, breathing is the same as in adults - vesicular (the ratio of the duration of inhalation and exhalation is 3:1). When a child is crying, auscultation is no less valuable than at rest. When screaming, the depth of inspiration increases, bronchophony is well defined, increasing over areas of compaction of the lung tissue, and various wheezing sounds are heard.

Pathological breathing sounds include the following types of breathing:

1) bronchial (the ratio of the duration of inhalation and exhalation is 1:1), observed during infiltration of the lung tissue and above the area pressed with liquid or lung air, while an extended exhalation indicates bronchospasm;

2) weakened vesicular in children over a year old with pleurisy, tuberculous infiltration of lung tissue, painful inhalation (with a rib fracture, myositis, appendicitis, peritonitis), severe bronchial obstruction, foreign body;

3) amphoric, heard over bullous (with destructive pneumonia) and other cavities in the lungs.

Wheezing is heard during various pathological processes in the bronchi and lungs, most often at the depth of inspiration. Dry wheezing of a conductive nature (rough, sonorous, whistling) is heard during laryngitis, pharyngitis, tracheitis, asthmatic bronchitis, a foreign body, an attack of bronchial asthma. In the latter case, they can be heard at a distance. Moist rales - large and medium bubble - indicate damage to the bronchi; small, voiced ones are formed in the bronchioles, crepitants - in the alveoli.

The prevalence and stability of auscultation of wheezes are of diagnostic importance: small and crepitating wheezes detected locally over a long period of time are more likely to indicate a pneumonic focus. Diffuse, intermittent, variable-caliber moist rales are more typical of bronchitis or bronchiolitis.

Bronchoadenitis is characterized by D'Espina's symptom - clear auscultation of whispered speech over the spinous processes below the first thoracic vertebra. Pleural friction noise is detected in pleurisy and is characterized in children by instability and a transient nature.
The oropharynx is the last place to be examined in a child. The patient’s head and hands are securely fixed by the mother or a nurse; first, the mucous membrane of the cheeks, gums, teeth, tongue, hard and soft palate are examined using a spatula. Then use a spatula to press down on the root of the tongue and examine the palatine tonsils, arches, back wall throats. In young children, the epiglottis can often be examined. The main signs of damage to the oropharynx, having diagnostic value, see Digestive and abdominal organs.
Laboratory and instrumental research.

The following studies are of greatest diagnostic importance:
1) x-ray;
2) bronchological;
3) determination of gas composition, blood pH, acid-base balance;
4) external respiration functions;
5) analysis of bronchial secretions.

The features of instrumental and laboratory research in pediatric practice are the following:
1) technical difficulties of bronchological examination associated with the small size of the airways;
2) use general anesthesia, especially in young children, for bronchoscopy and bronchography;
3) mandatory participation in the bronchological examination of specialists - pediatrician, pediatric bronchopulmonologist, anesthesiologist;
4) the impossibility of using the most common spirographic determination of external respiration function in children under 5-6 years of age and the use of pneumography and general plethysmography in this group of patients;
5) difficulties in conducting gas analytical studies in newborns and children under 3 years of age due to rapid breathing and a negative attitude towards the methods used.

There are several stages in the development of the respiratory system:

Stage 1 – before the 16th week of intrauterine development, the formation of bronchial glands occurs.

From the 16th week - the recanalization stage - cellular elements begin to produce mucus and fluid and, as a result, the cells are completely displaced, the bronchi acquire lumen, and the lungs become hollow.

Stage 3 - alveolar - begins from 22 - 24 weeks and continues until the birth of the child. During this period, the formation of the acini, alveoli, and the synthesis of surfactant occurs.

By the time of birth, there are about 70 million alveoli in the fetal lungs. From 22-24 weeks, differentiation of alveolocytes, the cells lining the inner surface of the alveoli, begins.

There are 2 types of alveolocytes: type 1 (95%), type 2 – 5%.

Surfactant is a substance that prevents the alveoli from collapsing due to changes in surface tension.

It lines the alveoli from the inside thin layer, during inspiration, the volume of the alveoli increases, increases surface tension, which leads to breathing resistance.

During exhalation, the volume of the alveoli decreases (more than 20-50 times), surfactant prevents their collapse. Since 2 enzymes are involved in the production of surfactant, which are activated at different stages of gestation (at the latest from 35-36 weeks), it is clear that the shorter the child’s gestational age, the more pronounced the surfactant deficiency and the higher the likelihood of developing bronchopulmonary pathology.

Surfactant deficiency also develops in mothers with preeclampsia, during complicated pregnancy, and during cesarean section. The immaturity of the surfactant system is manifested by the development of respiratory distress syndrome.

Surfactant deficiency leads to collapse of the alveoli and the formation of atelectasis, as a result of which the function of gas exchange is disrupted, the pressure in the pulmonary circulation increases, which leads to the persistence of fetal circulation and the functioning of the patent ductus arteriosus and oval window.

As a result, hypoxia and acidosis develop, vascular permeability increases and the liquid part of the blood with proteins sweats into the alveoli. Proteins are deposited on the wall of the alveoli in the form of half rings - hyaline membranes. This leads to impaired diffusion of gases and the development of severe respiratory failure, which is manifested by shortness of breath, cyanosis, tachycardia, and the participation of auxiliary muscles in the act of breathing.

The clinical picture develops within 3 hours from the moment of birth and changes increase within 2-3 days.

AFO of the respiratory organs

By the time a child is born, the respiratory system reaches morphological maturity and can perform the function of breathing.
In a newborn, the respiratory tract is filled with a liquid that has low viscosity and a small amount of protein, which ensures its rapid absorption after the birth of the child through the lymphatic and blood vessels. In the early neonatal period, the child adapts to extrauterine existence.
After 1 inhalation, a short inspiratory pause occurs, lasting 1-2 seconds, after which exhalation occurs, accompanied by a loud cry of the child. In this case, the first respiratory movement in a newborn is carried out according to the type of gasping (inspiratory “flash”) - this is deep breath with difficulty breathing. Such breathing persists in healthy full-term infants until the first 3 hours of life. U healthy newborn With the child's first exhalation, most of the alveoli expand, and at the same time, vasodilation occurs. Complete expansion of the alveoli occurs within the first 2-4 days after birth.
The mechanism of the first breath. The main trigger point is hypoxia, which occurs as a result of clamping of the umbilical cord. After ligation of the umbilical cord, oxygen tension in the blood drops, carbon dioxide pressure increases and pH decreases. In addition, temperature has a great influence on a newborn baby. environment, which is lower than in the womb. Contraction of the diaphragm creates negative pressure in the chest cavity, which allows air to enter the airways more easily.

A newborn baby has well-expressed protective reflexes - coughing and sneezing. Already in the first days after the birth of a child, the Hering-Breuer reflex functions, which, at threshold stretching of the pulmonary alveoli, leads to the transition of inhalation to exhalation. In an adult, this reflex occurs only with very strong stretching of the lungs.

Anatomically, the upper, middle and lower respiratory tract are distinguished. The nose is relatively small at the time of birth, the nasal passages are narrow, the lower nasal passage and the nasal concha, which are formed by the age of 4, are absent. Submucosal tissue is poorly developed (matures by 8-9 years), cavernous or cavernous tissue is underdeveloped up to 2 years (as a result, young children do not experience nosebleeds). The nasal mucosa is delicate, relatively dry, and rich in blood vessels. Due to the narrowness of the nasal passages and the abundant blood supply to their mucous membrane, even minor inflammation causes difficulty breathing through the nose in young children. Breathing through the mouth is impossible in children in the first six months of life, since the large tongue pushes the epiglottis backward. The exit from the nose - the choanae - is especially narrow in young children, which is often the cause of long-term disruption of nasal breathing in them.

The paranasal sinuses in young children are very poorly developed or completely absent. As they increase in size facial bones(upper jaw) and teeth erupt, the length and width of the nasal passages and the volume of the paranasal sinuses increase. These features explain the rarity of diseases such as sinusitis, frontal sinusitis, ethmoiditis in early childhood. A wide nasolacrimal duct with underdeveloped valves contributes to the transfer of inflammation from the nose to the mucous membrane of the eyes.

The pharynx is narrow and small. The lymphopharyngeal ring (Waldeyer-Pirogov) is poorly developed. It consists of 6 tonsils:

• 2 palatines (between the anterior and posterior palatines)

  2 tubes (near the Eustachian tubes)

  1 throat (in the upper part of the nasopharynx)

  1 lingual (in the area of ​​the root of the tongue).

The palatine tonsils are not visible in newborns; by the end of the 1st year of life they begin to protrude from behind the palatine arches. By the age of 4-10 years, the tonsils are well developed and their hypertrophy can easily occur. During puberty, the tonsils begin to undergo reverse development. The Eustachian tubes in young children are wide, short, straight, located horizontally and at horizontal position child, the pathological process from the nasopharynx easily spreads to the middle ear, causing the development of otitis media. With age they become narrow, long, and tortuous.

The larynx has a funnel shape. The glottis is narrow and located high (at the level of the 4th cervical vertebra, and in adults - at the level of the 7th cervical vertebra). Elastic tissue is poorly developed. The larynx is relatively longer and narrower than in adults; its cartilages are very pliable. With age, the larynx acquires a cylindrical shape, becomes wide and descends 1-2 vertebrae lower. The false vocal cords and mucous membrane are delicate, rich in blood and lymphatic vessels, elastic tissue is poorly developed. The glottis in children is narrow. Young children's vocal cords are shorter than those of older children, which is why they have a high-pitched voice. From the age of 12, boys' vocal cords become longer than girls'.

The bifurcation of the trachea lies higher than in an adult. The cartilaginous frame of the trachea is soft and easily narrows the lumen. Elastic tissue is poorly developed, the mucous membrane of the trachea is tender and richly supplied with blood vessels. The growth of the trachea occurs in parallel with the growth of the body, most intensively in the 1st year of life and during puberty.

The bronchi are richly supplied with blood, muscle and elastic fibers in young children are underdeveloped, and the lumen of the bronchi is narrow. Their mucous membrane is richly vascularized.
The right bronchus is like a continuation of the trachea; it is shorter and wider than the left. This explains the frequent entry of a foreign body into the right main bronchus.
The bronchial tree is poorly developed.
There are bronchi of the 1st order - main, 2nd order - lobar (3 on the right, 2 on the left), 3rd order - segmental (10 on the right, 9 on the left). The bronchi are narrow, their cartilage is soft. Muscle and elastic fibers in children of the 1st year of life are not yet sufficiently developed, the blood supply is good. The bronchial mucosa is lined with ciliated epithelium, which provides mucociliary clearance, which plays a major role in protecting the lungs from various pathogens from the upper respiratory tract and has an immune function (secretory immunoglobulin A). The tenderness of the bronchial mucosa and the narrowness of their lumen explain the frequent occurrence of bronchiolitis in young children with complete or partial obstruction, pulmonary atelectasis.

Lung tissue is less airy, elastic tissue is underdeveloped. In the right lung there are 3 lobes, in the left 2. Then the lobar bronchi are divided into segmental ones. A segment is an independently functioning unit of the lung, with its apex directed towards the root of the lung, and has an independent artery and nerve. Each segment has independent ventilation, a terminal artery and intersegmental septa made of elastic connective tissue. The segmental structure of the lungs is already well expressed in newborns. There are 10 segments in the right lung, and 9 in the left lung. The upper left and right lobes are divided into three segments - 1st, 2nd and 3rd, middle right lobe- into two segments - 4th and 5th. In the left light medium The lobe corresponds to the lingual lobe, also consisting of two segments - the 4th and 5th. The lower lobe of the right lung is divided into five segments - 6, 7, 8, 9 and 10th, the left lung - into four segments - 6, 7, 8 and 9th. The acini are underdeveloped, the alveoli begin to form from 4 to 6 weeks of life and their number quickly increases within 1 year, increasing up to 8 years.

The oxygen requirement in children is much higher than in adults. Thus, in children of the 1st year of life, the need for oxygen per 1 kg of body weight is about 8 ml/min, in adults - 4.5 ml/min. The shallow nature of breathing in children is compensated by a high breathing frequency, the participation of most of the lungs in breathing

In the fetus and newborn, hemoglobin F predominates, which has an increased affinity for oxygen, and therefore the dissociation curve of oxyhemoglobin is shifted to the left and up. Meanwhile, in a newborn, like in a fetus, red blood cells contain extremely little 2,3-diphosphoglycerate (2,3-DPG), which also causes less saturation of hemoglobin with oxygen than in an adult. At the same time, in the fetus and newborn, oxygen is more easily transferred to the tissues.

In healthy children, depending on age, different breathing patterns are determined:

a) vesicular - exhalation is one third of inhalation.

b) puerile breathing - enhanced vesicular

c) hard breathing - exhalation is more than half of the inhalation or equal to it.

d) bronchial breathing - exhalation is longer than inhalation.

It is also necessary to note the sonority of breathing (normal, increased, weakened). In children of the first 6 months. breathing is weakened. After 6 months up to 6 years of age, breathing is puerile, and from 6 years of age - vesicular or intensely vesicular (one third of inhalation and two thirds of exhalation are heard), it is heard evenly over the entire surface.

Respiratory rate (RR)

	Frequency per minute
Premature
Newborn

Stange test - holding your breath while inhaling (6-16 years old - from 16 to 35 seconds).

Gench's test - holding your breath while exhaling (N - 21-39 seconds).