Closed chest trauma: clinical guidelines

List of Abbreviations

BP – blood pressure

RTA – road traffic accident

DHM – Moscow Healthcare Department

DIC – disseminated intravascular coagulation

CCT – closed chest trauma

IMV – invasive mechanical ventilation

SCT – spiral computed tomography

MRI – magnetic resonance imaging

ICU – intensive care unit

ARF – acute respiratory failure

ARDS – acute respiratory distress syndrome

ALI – acute lung injury

TBS – tracheobronchoscopy

US – ultrasound examination

RR – respiratory rate

TBI – traumatic brain injury

HR – heart rate

EGD – esophagogastroduodenoscopy

ECG – electrocardiogram

AAST – American Association for the Surgery of Trauma

AIS – Abbreviated Injury Scale

ATLS – Advanced Trauma Life Support

ISS – Injury Severity Score

OIS – Organ Injury Scale

SpO2 – oxygen saturation of hemoglobin

eFAST – Extended Focused Abdominal Sonography for Trauma

Terms and Definitions

Auscultation (from Lat. auscultatio – listening) is a physical method of medical diagnosis consisting of listening to sounds produced by the functioning of internal organs, as well as listening to peristaltic sounds in the intestine

"Safe triangle" is an area bounded anteriorly by the lateral border of the pectoralis major muscle, posteriorly by the anterior border of the latissimus dorsi muscle, and inferiorly by a horizontal line at the nipple level

Hemothorax is the accumulation of blood in the pleural cavity due to injury to the chest wall and/or intrathoracic organs and vessels, causing partial or total collapse of the lung.

Coagulated hemothorax is an accumulation of blood clots in the pleural cavity

Instrumental diagnostics – diagnostics involving the use of various devices, apparatus, and instruments to examine a patient

Catatrauma – trauma sustained from a fall from a significant height (exceeding 3 human heights)

Quality of medical care – a set of characteristics reflecting the timeliness of medical care delivery, the appropriateness of the chosen preventive, diagnostic, treatment, and rehabilitation methods, and the degree to which the planned outcome is achieved

Crepitation – a characteristic crunchy (crackling) sound heard upon palpation or auscultation

Criteria for evaluating the quality of medical care – indicators used to characterize both positive and negative aspects of medical activity, its individual stages, sections, and directions, and used to assess the quality of care provided to patients with a specific disease or condition (or a group of diseases/conditions)

Laboratory diagnostics – a set of methods aimed at analyzing test material using various specialized equipment

Mechanism of injury – the direct cause of damage to the body: traffic accident, fall, catatrauma, blunt force impact, sharp force injury, burn, etc.

Injury complications – pathological processes caused by trauma but possessing their own etiopathogenetic and clinical characteristics

Palpation is a physical examination method in which the physician feels various parts of the patient's body using fingers and palms to obtain information about their condition

Paradoxical pulse – weakening of the pulse during inspiration

Paradoxical respiration – in cases of pathological chest wall mobility, a segment of the chest wall (costal window, flail chest) moves paradoxically, i.e., in the direction opposite to the rest of the chest (outward during expiration and inward during inspiration)

Percussion (from Lat. percussio – tapping) is a physical examination method based on tapping specific body areas and analyzing the resulting sounds

Pneumothorax – accumulation of air in the pleural cavity resulting from damage to the bronchial tree and/or lung tissue, causing partial or total collapse of the lung.

Polytrauma – multiple severe injuries (multiple, combined, complex) accompanied by shock and impairment of vital body functions, requiring immediate resuscitation and multidisciplinary specialized surgical care

Sequelae of injuries – pathological processes resulting from trauma and causally related to it

Subcutaneous emphysema – accumulation of air beneath the skin

Pneumomediastinum – accumulation of air in the mediastinum

Ruvillois-Gregoire test – if the blood obtained from the pleural cavity clots, bleeding is ongoing; if the blood does not clot, bleeding has stopped

Sepsis – a pathological process based on the body's response in the form of generalized (systemic) inflammation to an infection of various origins (bacterial, viral, fungal), leading to acute organ dysfunction and failure

Syndrome is a set of symptoms sharing a common etiology and pathogenesis.

Hamman's sign – a crunchy or clicking sound heard upon auscultation over the precordial area, synchronized with heartbeats

Condition – changes in the body arising from the impact of pathogenic and/or physiological factors and requiring medical care

Trauma – an injury defined as a violation of the anatomical integrity or physiological functions of human body organs and tissues resulting from external exposure (mechanical, thermal, chemical, etc.). The terms "trauma" and "injury" are synonyms.

The historical origin of the term "trauma" from the Ancient Greek τραῦμα (wound) defines physical injury to the human body. At the modern stage, the term "trauma" includes two components: 1) anatomical and morphological – damage to tissues and organs, which determines the severity of the trauma; 2) functional – resulting from the impairment or loss of organ or system function combined with the body's adaptive response, which determines the severity of the victim's condition

Isolated trauma – injury to a single internal organ within a single anatomical region or a single functional segment of the musculoskeletal system

Multiple trauma – simultaneous injury to several organs within a single anatomical region or two or more functional segments of the musculoskeletal system

Open injury – an injury accompanied by a breach in the integrity of the skin or mucous membranes

Closed injury – an injury without a breach in the integrity of the skin or mucous membranes

Polysystem (combined) trauma – simultaneous injury to two or more anatomical regions of the body or functional segments of the musculoskeletal system caused by a single traumatic agent

Traumatic morbidity – the total number of injuries occurring in a specific population group over a given period. Traumatic morbidity is part of the overall morbidity of the population

Pediatric traumatic morbidity – the total number of injuries occurring in children of various age groups. This indicator is calculated per a specific number (usually 1,000) of children in the population

Injury severity – the degree of morphological damage to body organs and tissues that determines their functional impairment and the prognosis of the injury outcome

Chest trauma – damage to the tissues, organs, and anatomical structures of the chest resulting from external mechanical, thermal, electrical, chemical, or other exposures

Beck's triad – hypotension, muffled heart sounds, distended neck veins

Level of evidence – reflects the degree of certainty that the discovered effect of a medical intervention is true

Contusion – damage to soft tissues caused by a traumatic agent, not accompanied by the formation of wounds

Surgical intervention – an invasive procedure that can be used for diagnostic purposes and/or as a method of treating diseases

Surgical treatment – a method of treating diseases by dividing and joining tissues during a surgical operation

Chylothorax (traumatic) – accumulation of chyle in the pleural cavity resulting from a tear or rupture of the thoracic duct or major lymphatic trunks of the thoracic cavity draining into it

Shock – a state of tissue and organ hypoperfusion followed by cellular and organ dysfunction up to the patient's death

Septic shock – the most severe course of sepsis, characterized by prominent circulatory, cellular, and metabolic disorders

Obstructive shock – characterized by a decrease in cardiac output due to a physical obstruction to blood flow and occurs in tension pneumothorax, abdominal compartment syndrome, pulmonary embolism, acute pulmonary hypertension, etc.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Closed chest injury (CCI) – damage to the tissues, organs, and anatomical structures of the chest resulting from external mechanical, thermal, electrical, chemical, or other exposures without a breach in skin integrity.

Isolated and multiple chest injuries are distinguished. An injury is termed isolated when there is a single lesion. An injury is termed multiple when there are several lesions within the anatomical region of the chest. Simultaneous injury to the chest and other anatomical regions of the body (head, neck, face, abdomen, pelvis, spine, extremities) is defined as combined chest trauma. Complex injuries result from exposure to multiple etiologically heterogeneous traumatic factors (mechanical, thermal, chemical, radiation).

Within the framework of these clinical guidelines, the following will be considered:

Chest wall contusion – superficial injury to the chest wall without a breach in skin integrity. Clinically, superficial chest injuries also include breast contusion, sprains and strain of the rib and sternal ligamentous apparatus, and subcutaneous injuries of the muscles and tendons of the anterior and posterior chest walls

Rib fracture – disruption of the integrity of the bone or cartilaginous part of a rib.

Multiple rib fractures – disruption of the integrity of the bone or cartilaginous parts of two or more ribs.

Flail chest fractures (segmental, stovepipe chest, flail chest, paradoxical chest movement) are fractures in which segments of several ribs remain unconnected to the bony cage of the thorax ("rib window" or "flail segment") and paradoxically participate in the respiratory movements of the chest: they are drawn inward during inspiration and bulge outward during expiration.

Sternal fracture – disruption of the integrity of the sternal bone tissue.

Pneumothorax (traumatic) – accumulation of air in the pleural cavity due to traumatic injury to the bronchial tree and/or lung tissue, causing partial or total collapse of the lung.

Hemothorax (traumatic) – accumulation of blood in the pleural cavity due to traumatic injury to the chest wall and/or thoracic organs and vessels, causing partial or total collapse of the lung.

Hemopneumothorax – accumulation of blood and air in the pleural cavity.

Pneumomediastinum – accumulation of air in the mediastinum.

Lung contusion – lung injury with alveolar hemorrhage, which typically occurs as a result of blunt chest trauma without rupture of the lung parenchyma.

Lung laceration – disruption of the integrity of the lung parenchymal tissue.

Ruptures of the thoracic trachea and major bronchi – disruption of the integrity of the thoracic tracheobronchial tree. Tracheal and bronchial ruptures are among the most severe types of chest trauma with a high mortality rate.

Injury to major thoracic blood vessels – injuries to the thoracic aorta and its branches (brachiocephalic trunk, left subclavian and carotid arteries), superior and intrathoracic segments of the inferior vena cava, anonymous (brachiocephalic), azygos, and subclavian veins, which in an acute situation manifest as profuse intrapleural hemorrhage, tension mediastinal hematoma, and/or cardiac tamponade.

Cardiac injury – damage to cardiac structures (myocardium, endocardium, epicardium, papillary muscles, chordae tendineae, fibrous skeleton, and valve leaflets) ranging from mild contusion to overt avulsion/rupture, manifested by cardiovascular dysfunctions ranging from moderate hemodynamic instability to cardiogenic shock and asystole.

Diaphragmatic injury – a tear (disruption of the integrity across the entire thickness of the diaphragm) in its muscular and/or tendinous parts without compromising the integrity of the chest or abdominal wall, with or without damage to abdominal and thoracic organs.

Injury to the thoracic duct – disruption of the integrity of the wall of the thoracic duct or its major branches and collaterals due to external factors.

Chylothorax (traumatic) – accumulation of chyle in the pleural space resulting from trauma (tearing or rupture) of the thoracic duct or major lymphatic trunks of the thoracic cavity draining into it.

Esophageal injury – disruption of the integrity of the thoracic esophageal wall due to external factors.

Thymic injury – damage to the thymus gland due to external factors.

Anatomical and physiological features of childhood [1, 2]

The chest skin in newborns and infants is exceptionally delicate. The epidermis and basement membrane are thin, and the dermis contains collagen fibers, the amount of which increases with age. Elastic fibers appear only after 6 years of age. Subcutaneous adipose tissue is well developed, especially in the anterior regions, while connective tissue septa are poorly developed. The superficial fascia of the chest in newborns is very thin, interfascial spaces are poorly defined and contain a minimal amount of loose connective tissue. Intercostal muscles in infants are poorly differentiated, muscle fibers are thin, closely apposed, and their bundles are separated by a thin layer of fibrous tissue. The intercostal neurovascular bundle lies closer to the lower margin of the inner surface of the rib. As the rib cage develops, the neurovascular bundle becomes increasingly covered by the rib and occupies the costal groove by 12–15 years of age. The endothoracic fascia is poorly developed in young children and fused with the parietal pleura. After 5 years of age, the attachment zones of the pleura and endothoracic fascia to the ribs are approximately the same as in adults. Like the entire respiratory system, the rib cage develops most intensively during the first 3 years of a child's life. Subsequently, growth slows down somewhat and accelerates again during puberty. A characteristic feature of the ribs in infants during the first year of life, particularly the lower ribs, is that the angles between the ribs and the spine approach right angles, and the intercostal spaces are relatively wide. The shape of the superior thoracic aperture is oval, elongated anteriorly, and becomes round only by 3–6 months. After the first year, the costochondral angles begin to smooth out, and the chest acquires its characteristic funnel-like shape. The formation of the rib cage is completed by 12–13 years of age. Ossification centers in the heads and tubercles of the upper ten pairs of ribs appear at 5–6 years of age, with fusion occurring by 18–20 years of age. In children under 2 years of age, the ribs consist of spongy bone, after which compact bone develops from the center, and ossification is completed only by 20 years of age. In children under 3–5 years of age, the rib periosteum is thick and loose, and the subperiosteal layer is well developed. The sternum forms and develops later than all other skeletal bones. The ossification center in the xiphoid process appears at 6–12 years of age. The sternal body has multiple paired ossification centers that fuse very slowly, a process that may be completed by 30 years of age. In infants during the first months of life, the trachea is funnel-shaped and positioned relatively higher, then gradually assumes a conical shape, and after 25 years of age – a cylindrical shape. The topographic anatomy of the bronchial tree in newborns and infants is also specific: the trachea in infants begins at the level of the IV cervical vertebra, and its bifurcation is projected onto the bodies of the II–III thoracic vessels (vertebrae), followed by gradual descent. Tracheal ligaments are not well defined, peritracheal tissue is loose with small fatty accumulations, making the organ easily mobile throughout its length. Unlike in adults, the cartilaginous part of the anterior wall, consisting of tracheal rings, is smaller than the posterior wall, which consists of the connecting membrane. The tracheal mucosa is lined with a very delicate single-layer epithelium and is rich in blood vessels and cellular elements. It swells rapidly during inflammatory processes, leading to asphyxia. In newborns, the number of mucous glands is small, which accounts for the relative dryness of the tracheal mucosa. As in adults, the right main bronchus is wider and diverges from the trachea at a more obtuse angle than the left, appearing as a direct continuation of the trachea. With age, the right main bronchus grows faster than the left. The most intensive growth in bronchial length occurs in the first 3 months of the child's life and during puberty. The bronchial mucosa is similar to that of the trachea. The development of individual lung lobes is uneven. The upper and middle lobes of the right lung are almost identical in size, while the lower lobe is larger than the combined size of the upper and middle lobes. In the left lung, both lobes are nearly identical in size. By approximately 2 years of age, the lobe size ratios become similar to those in adults. Interlobar fissures are poorly defined in infants, and frequently the middle lobe of the right lung almost merges with the upper lobe, which is not observed in adults. Lungs in children are more congested and less aerated due to a greater number of blood and lymphatic vessels. This explains the pronounced tendency of children to develop atelectasis, pneumonia, and hypostatic phenomena. In addition, there is poor development of reticular fibers and an almost complete absence of elastic fibers, which explains the greater susceptibility of lung tissue to lacerations. With age, it thickens and the fixation strength of the pleural layers to each other increases. The visceral pleura is densely fused with the lungs, forming septa that separate pulmonary lobules from one another. The mediastinum in newborns is relatively large, occupying half of the thoracic cavity; with age, it decreases and occupies one-third of the total volume. Mediastinal adipose tissue is virtually absent in early childhood. As the child grows older, mediastinal adipose tissue increases significantly and communicates with the tissue of the neck and retroperitoneal space. In the upper anterior mediastinum, newborns and infants have the thymus gland. By 3–5 years of age, fatty degeneration of the thymus tissue begins with a decrease in its size. The shape of the pericardium in newborns and infants is spherical, matching the rounded contours of the heart. Later, it acquires a conical configuration. The esophagus is surrounded by tissue that in the first years of a child's life is loose, with a minimal amount of adipose tissue. At this age, the esophagus is slightly compressed in the anteroposterior direction with a conical expansion toward the cardiac part of the stomach. The mucosa and submucosa of the esophagus are rich in blood vessels and cellular elements, while the muscle layers (circular and longitudinal) are poorly developed. By 2–3 years of age, distinct mucosal folds appear, the epithelial and muscular layers thicken noticeably (especially the circular layer), and tubular glands appear in the lower esophagus. A distinctive age-related feature of the diaphragm is the significant predominance of the muscular part over the tendinous part in children. In newborns and infants, the sternocostal and lumbocostal triangles, known respectively as Larrey's slit and Bochdalek's triangle, are usually well developed. In the majority of children, characteristic triangular defects are observed in the sternocostal region of the diaphragm, where the serous membranes of the abdominal and thoracic cavities are separated only by a thin layer of loose tissue and come into contact with each other, which is a predisposing factor for diaphragmatic hernias, including traumatic ones. Up to 3 years of age, children exhibit a diaphragmatic type of breathing.

Features of chest trauma in children

The chest in children is more compliant due to high bone elasticity and a large amount of cartilage tissue; internal organs are located closer to the surface of the chest wall because of lesser adipose tissue, which is why in severe trauma internal organs are quite frequently injured without bone fractures (unlike adults), explaining the high mortality rate [3-10]. The bony cage absorbs the entire force and transmits the shock wave to the internal organs. Due to the relatively small size of the chest, pediatric chest trauma is frequently polytrauma.

Bone tissue in children contains fewer minerals (calcium, phosphorus, copper, fluorine) than in adults, making bones more flexible and less prone to fractures. Due to flexibility and elasticity, as well as the presence of a thick and loose periosteum, rib fractures in children are typically subperiosteal.

Children are also more prone to developing hypoxia because they have a lower functional residual capacity to total lung capacity ratio and a higher tissue oxygen consumption rate. In infants and young children, the pleura is extremely thin, so unilateral tears can lead to bilateral pneumothorax. The mediastinum in children is more mobile, allowing a pneumothorax to rapidly progress to a tension pneumothorax and obstructive shock. Although this effect is similar to the hypovolcemic shock observed in adults, it is more pronounced in children and can cause dramatic changes in vital signs [5, 10]. Children with chest trauma have higher Injury Severity Scores in polytrauma [5]. The tissues of the larynx and trachea are very elastic, which is why small children almost never experience their rupture. At the same time, even minor external compression, including that due to mediastinal shift, causes stenotic phenomena. The right bronchus in children, as in adults, is wider, which explains the more frequent aspiration of foreign bodies into the lumen of the right bronchus.

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

There are four mechanisms of blunt chest trauma: direct blows to the chest, chest compression, acceleration/deceleration injuries, and blast wave injury [11]. In the vast majority of cases, children sustain chest trauma as a result of motor vehicle accidents (MVAs) and falls from height (catatrauma) [2-10]. In MVAs, children sustain chest trauma both as passengers—including from seatbelts—and as pedestrians. In children, closed chest injuries account for more than 90% [2-11].

The primary danger of chest injuries is related to impaired respiration and circulation [2-11]. Respiration can be impaired due to direct trauma to the lungs or airways and alteration of respiratory mechanics. Injuries that directly damage the lungs or airways include lung contusion and tracheobronchial injuries. Injuries that alter respiratory mechanics include hemothorax, pneumothorax, and flail chest. Trauma to the lungs, tracheobronchial tree, or, rarely, the esophagus, can facilitate the entry of air into the soft tissues of the chest and/or neck (subcutaneous emphysema) or mediastinum (pneumomediastinum).

Circulation can be impaired as a result of hemorrhage, impaired venous return, or direct cardiac trauma. Hemorrhage with the development of hemothorax can be massive and lead to a shock state resulting from blood loss. Decreased venous return impairs cardiac filling, resulting in hypotension. Decreased venous return can occur due to increased intrathoradic pressure in tension pneumothorax, or increased intrapericardial pressure in cardiac tamponade. Heart failure and/or cardiac conduction disturbances can occur due to blunt cardiac injury, which damages the myocardium or heart valves. Unlike adults, children have significant compensatory mechanisms: even massive blood loss (up to 40-50% of circulating blood volume) may have no overt clinical manifestations, making hypotension and hypoxia late clinical signs associated with mortality [5].

Acute respiratory failure (ARF) is a life-threatening condition associated with impaired oxygenation and/or carbon dioxide elimination. Primary acute respiratory failure in chest trauma is caused by a compromised chest wall cage, pneumothorax, hemothorax, or upper airway obstruction (aspiration syndrome, bronchospasm, bronchial injury, foreign body airway obstruction) [2-10].

The most important role in the pathogenesis of acute respiratory failure is played by increased pressure in the pleural cavity (regardless of its etiology)—pneumothorax, hemothorax, pneumomediastinum, mediastinal hematoma, or herniation of abdominal organs into the pleural cavity in diaphragmatic rupture. Throughout the entire respiratory cycle, pleural pressure is negative: from -2 to -5 cm $H_2O$ during expiration and from -25 to -30 cm $H_2O$ during inspiration [12]. This explains the tendency of air and/or blood to occupy the space with lower pressure in both penetrating and blunt injuries. In pneumothorax/hemothorax, this process is characterized by varying degrees of lung collapse, decreased vital capacity, and lowered partial pressure of oxygen in the blood. In tension pneumothorax/massive hemothorax, positive pressure in the pleural cavity throughout the entire respiratory cycle leads to lung collapse, mediastinal shift, and decreased venous return, which in turn leads to systemic hypotension, respiratory and cardiac impairment up to cardiac arrest.

Hypercapnic respiratory failure occurs due to hypoventilation, an increase in functional dead space, and increased carbon dioxide production. Hypoxic respiratory failure develops due to impaired alveolar diffusion capacity and pulmonary blood shunting. Secondary respiratory failure is associated with post-traumatic pathological conditions of the cardiopulmonary system: cardiogenic pulmonary edema, pulmonary embolism, acute respiratory distress syndrome, and severe pneumonia.

Acute respiratory distress syndrome (ARDS) is a diffuse inflammatory lung injury that causes hypoxic respiratory failure. The development of ARDS is caused by intrapulmonary blood shunting, leading to a ventilation-perfusion mismatch due to alveolar filling or collapse [13, 14]. ARDS is classified into 3 degrees of severity: mild, moderate, and severe, based on oxygenation impairments and clinical criteria. Mild severity corresponds to acute lung injury (ALI).

In ARDS, pulmonary or systemic inflammation leads to the release of cytokines and other inflammatory mediators. Cytokines activate alveolar macrophages and recruit neutrophils to the lungs, which in turn release leukotrienes, oxidants, platelet-activating factor, and proteases, contributing to tissue damage in the lungs and other organs. These substances damage the capillary endothelium and alveolar epithelium, disrupting the barrier between the capillaries and the air space. Fluid, protein, and cell breakdown products fill the air space and interstitium, causing surfactant destruction, alveolar collapse, ventilation-perfusion mismatch, and pulmonary hypertension [13, 14].

Acute cardiopulmonary failure. Chest trauma results in decreased cardiac performance due to a reduced circulating blood volume from hemorrhage, direct impact on the heart (cardiac contusion, hemopericardium), altered peripheral resistance of the pulmonary circulation (hemothorax, pneumothorax, intrapulmonary hematoma), or systemic circulation (neuroendocrine response to pain). The primary role in the development of acute heart failure in trauma is played by decreased venous return with impaired blood outflow from the pulmonary circulation, leading to increased pressure in the pulmonary veins and capillaries (passive pulmonary hypertension), and subsequently in the arterioles (active pulmonary hypertension). This creates conditions for fluid transudation with the development of interstitial and, subsequently, alveolar pulmonary edema [4-10].

Shock is a state of tissue and organ hypoperfusion resulting in cellular and organ dysfunction up to the patient's death. The danger of shock lies in the reduced blood supply to vital tissues [13, 14]. As soon as perfusion decreases and oxygen delivery becomes insufficient for aerobic metabolism, cells switch to anaerobic metabolism with increased carbon dioxide synthesis and elevated blood lactate levels. Cellular function declines, and if shock persists, irreversible damage and cell death occur. During shock, both the inflammatory and coagulation cascades are activated. In a state of tissue hypoxia, endothelial cells activate leukocytes, which begin to produce damaging factors (e.g., reactive oxygen species, proteolytic enzymes) as well as inflammatory mediators (cytokines, leukotrienes, tumor necrosis factor), which increase vascular wall permeability. Some of these mediators bind to cell surface receptors, leading to the production of additional cytokines and nitric oxide (NO), a potent vasodilator. The result of the activation of these cascades is disseminated intravascular coagulation (DIC) with the development of hypocoagulation. Arterial blood pressure is not always low in the early stages of shock (although hypotension ultimately occurs if shock is not resolved). Similarly, not all patients with "low" blood pressure are in shock. The degree and consequences of hypotension vary depending on the adequacy of physiological compensation. Shock, regardless of its etiology, manifests similarly in its final stage. There is a disruption of blood rheological properties, its sequestration in capillaries, hypovolemia with "low output" syndrome, and tissue ischemia with fatal metabolic disorders [15, 16]. In the pathogenesis of shock development in chest trauma, nociceptive impulses from extensive receptor fields of the parietal and visceral pleura play a significant role.

Sudden chest compression (e.g., being pinned against a wall by a car) causes traumatic asphyxia. Under conditions of reflex vocal cord spasm, intrathoracic pressure sharply increases, and blood outflow through the superior vena cava system from the upper half of the body to the right chambers of the heart is hindered. This leads to marked blood congestion in the venous network of the head, neck, and shoulder girdle, accompanied by the rupture of capillaries and small vessels and the formation of petechial hemorrhages in soft tissues, including the skin, mucous membranes, and subconjunctivally. In the first hours and days after trauma, traumatic asphyxia is accompanied by the development of a severe condition and acute respiratory failure.

Rib fractures. Direct and indirect mechanisms of rib fracture are distinguished. Rib fractures in children occur as a result of direct impacts to the chest area, falls from a height, or onto protruding objects [3-11, 17-19]. Rib fractures in young children are rare. The number of broken ribs depends both on the force of the impact and the area of the traumatic surface. In the indirect mechanism (in the form of severe chest compression), rib fractures occur on both sides of the applied force. Severe compression results in multiple bilateral fractures complicated by internal organ damage. The most frequent are fractures of the VII–X ribs in the lateral regions (up to 75% of all rib cases). This is due to the fact that the rib cage has its greatest width here. Fractures of the first 3 ribs characterize severe trauma with possible mediastinal injury, neurological, vascular, and extrathoracic injuries [4, 5]. Fractures of the first rib in children are associated with severe vascular injuries [4]. In fractures of the lower ribs (below the 8th), concurrent abdominal injuries are possible. In children, due to the age-related characteristics of the musculoskeletal system in mild trauma, fractures of the cortical plate of the rib on the convex surface (incomplete greenstick fracture) are most often diagnosed [3-10, 19].

Flail chest fractures. A pathologically mobile chest wall is an extremely rare injury in children due to the high elasticity of the rib cage [2-10, 17–19]. This injury reveals fractures of two or more ribs, including chondrocostal junctions, leading to disruption of the framework integrity. Paradoxical chest wall movement leads to incomplete expansion of the lung on the injured side. Notably, during inhalation, due to the indrawing of the flail segment, the intra-alveolar air pressure on the injured side is higher, and during exhalation, due to the bulging of the "rib flap", it is lower than in the lung on the healthy side. Consequently, during breathing, air is partially shuttled from the lung on the affected side to the lung on the healthy side, and vice versa during exhalation. This pendular movement of air in the lungs increases "dead space" and contributes to worsening hypoxia. Furthermore, the pressure gradient between the healthy and injured halves of the chest, which changes during the respiratory cycle, causes pendular shifting of the mediastinal organs (including the heart and large vessels), which also contributes to the development of cardiovascular disorders. The development of respiratory failure associated with pulmonary contusion and severe mediastinal injuries requires respiratory support. Life-threatening disorders of external respiration occur with fractures of 6 or more ribs on one side, when the vital capacity of the lungs on the affected side decreases by 30-40% [18].

Sternal fracture. A significant traumatic force is required for a sternal fracture to occur, as the cartilaginous part of the ribs acts as shock absorbers. Sternal fracture is a result of direct trauma in severe injuries, primarily motor vehicle collisions, falls from a height, or compression of the sternum by heavy objects [4, 5]. Less commonly, sternal trauma results from sudden hyperextension during forced extension or flexion of the torso. A sternal fracture with fragment displacement frequently leads to potential thoracic organ injuries, such as pleural and lung injury with the development of hemothorax or pneumothorax. Cardiac contusion is a fairly frequent concomitant injury in such fractures. Particularly common fracture locations are the junction of the sternal body and manubrium, as well as the attachment area of the fourth rib. Sternal fractures are uncommon in pediatric patients because their chest wall is highly elastic.

Pulmonary contusion occurs as a result of the kinetic energy transfer from the chest wall to the lung parenchyma. As a result of the contusion, alveolar ruptures with hemorrhages and interstitial edema occur in the lung tissue [2-10]. At the same time, inflammation and edema of the pulmonary parenchyma develop within the first 24–48 hours after trauma and gradually lead to ventilation/perfusion mismatch in the lungs, intrapulmonary blood shunting, increased lung water content, decreased lung compliance with the development of atelectasis and infiltration of the lung tissue. In addition, damage to the lung tissue releases a large amount of inflammatory mediators, which leads to a decrease in immune resistance, increasing the risk of pneumonia.

Pneumothorax in blunt chest trauma develops upon rupture of the lung parenchyma or tracheobronchial tree, when air can enter the pleural cavity [2-10]. In tension pneumothorax, air accumulates and compresses the lung, leading to mediastinal shift, compression of the contralateral lung, and increased intrathoracic pressure with a decrease in venous return and the development of shock.

Hemothorax in blunt chest trauma is a consequence of the rupture of the lung, an intercostal vessel, or the internal thoracic artery [2-10]. Bleeding into the pleural cavity can occur with almost any injury to the chest wall tissues or intrathoracic structures. Hemothorax is often accompanied by pneumothorax (hemopneumothorax). The volume of blood loss varies from minimal to massive. Massive hemothorax is defined as the rapid accumulation of blood in the pleural cavity with a mediastinal shift to the unaffected side and the development of shock. The blood loss volume in massive hemothorax generally exceeds 30% of the circulating blood volume.

Clotted hemothorax. Blood entering the pleural cavity is subjected to the movement of the diaphragm and lung, leading to blood defibrination with fibrin precipitation and clot formation. Within a few hours after cessation of bleeding, lysis of existing blood clots by pleural enzymes begins. However, when a large amount of blood has been poured out simultaneously, or due to post-traumatic dysfunction of the parietal pleura, high overall blood coagulation activity, or increased activity of coagulating factors in the pleural cavity contents resulting from thromboplastin influx from damaged tissues, clot lysis is insufficient. Fibrin and blood clots accumulated in the pleural cavity organize with subsequent adhesion to the pleural layers. By the seventh day, angioblastic and fibroblastic proliferation is observed, leading to the formation of massive fibrous layers both around the collapsed lung and on the layers of the altered parietal pleura. The outcomes of clotted hemothorax include complete spontaneous resorption within several weeks; progression to fibrothorax and the development of a 'frozen' lung; or infection with the occurrence of empyema thoracis. Clotted hemothorax forms within 1–2 days after the cessation of bleeding into the pleural cavity in blunt chest trauma. Late diagnosis and inadequate drainage contribute to the formation of clotted hemothorax.

Airway trauma (trachea, bronchi). The mechanism of this injury is usually associated with anteroposterior compression of the chest wall; the compression of the sternum against the spine leads to lateral displacement of the lungs and injury to the bronchi or trachea [2, 8, 10]. In addition, there may be direct trauma to the trachea or trauma from a rapid increase in intratracheal pressure with a closed glottis. Tracheobronchial tree ruptures are usually localized near the carina; they typically affect the cartilaginous part in the form of irregular or circumferential tears of the trachea. Injuries to the right main bronchus are more common. Such injuries can cause refractory respiratory failure or difficulties in maintaining adequate oxygenation in mechanically ventilated patients, and are almost always accompanied by pneumomediastinum and subcutaneous emphysema [4, 5, 8, 20–23]. Cases of pneumothorax with the typical lack of lung re-expansion and persistence of a significant air leak after chest tube insertion are also frequent. Incomplete ruptures may remain undiagnosed, causing strictures and stenosis when overlooked.

Major thoracic blood vessel trauma. Such injuries typically occur in high-speed motor vehicle accidents, pedestrian-vehicle collisions, or falls from a height [3-10, 21, 22]. The mechanism of injury consists of a sharp tissue shift and compression, especially of arterial trunks. Massive bleeding develops upon vessel rupture, which becomes the cause of death either directly at the scene or on the way to the hospital. Favorable outcomes are observed only if the rupture is sealed by an undamaged adventitia. Major vascular and cardiac injuries are rare and occur less frequently in children than in adults [4, 5, 8].

Aortic injury. The primary mechanism of aortic rupture in blunt chest trauma is high-energy trauma (motor vehicle collision, fall from a height) [4, 5, 8, 24–26]. As a rule, patients have injuries to the 1st and/or 2nd ribs [4, 5, 8]. Complete rupture causes rapid death as a result of blood loss. Partial rupture usually occurs in the area of the ligamentum arteriosum, while blood flow is preserved, usually due to the intact adventitial layer. Partial ruptures can lead to the formation of a mediastinal hematoma. Aortic trauma in children is a casuistic occurrence.

Cardiac injury. Any mechanism that transmits kinetic energy can cause cardiac injury [2-11]. The most common variant of blunt cardiac trauma is cardiac contusion—typically of the right ventricle due to its proximal location relative to the anterior chest wall. Valvular injuries usually involve the chordae tendineae and papillary muscles of the subvalvular apparatus; the aortic valve is injured more often than others. Myocardial ruptures are the most severe type of cardiac injury and can be the cause of sudden death or cardiac tamponade. Interventricular septal ruptures are less common. Valvular and interventricular septal ruptures can cause acute heart failure.

Cardiac contusion. Cardiac contusion is often a consequence of a sternal fracture, but it can also occur without injury to the bony skeleton of the chest. Mechanical impact on the chest causes hemorrhage into the myocardium, subepicardial space, or subendocardial space. The magnitude of myocardial hemorrhage depends on the degree of filling of the cardiac chambers with blood at the time of injury. The hydraulic effect during systole causes more severe cardiac injury than during diastole. Ruptures and maceration of muscle fibers, bleeding from damaged vessels, and the formation of tamponade are possible. Myocardial hemorrhage can result in compression of a coronary vessel and the development of myocardial infarction. The latter may also occur in the event of thrombus formation on the damaged intima of a coronary artery.

Cardiac tamponade in chest trauma develops when blood accumulates in the pericardium, leading to impaired cardiac filling, reduced cardiac output, and potentially leading to shock and death [4, 5, 8]. With rapid fluid accumulation, as occurs in traumatic hemorrhage, a blood volume of less than 150 ml can cause tamponade. Cardiac tamponade most frequently develops in penetrating cardiac wounds. Tamponade in blunt chest trauma is associated with a rupture of a cardiac chamber, which is usually fatal. Cardiac tamponade in children is a casuistry.

Diaphragmatic rupture. The mechanism of diaphragmatic rupture is associated with the pressure gradient between the pleural and abdominal cavities. Most commonly, diaphragmatic rupture occurs as a result of motor vehicle accidents and falls from a height [2, 4, 5, 8, 27–29]. An exceptional feature of thoracoabdominal injuries is damage to the diaphragm. Depending on the damaging factor, single or multiple ruptures may occur, ranging from pinpoint, small slit-like or oval tears to large defects with ragged edges. Prolapse of abdominal organs into the thoracic cavity is frequently observed. It is precisely the injury to the diaphragm that exacerbates the development of general pathogenetic mechanisms. Restriction of the activity of the damaged diaphragm leads to a significant decrease in gas exchange, impaired lymphatic drainage from the lungs, and disruption of venous blood inflow to the heart via the inferior vena cava. Extensive diaphragmatic ruptures lead to the herniation of abdominal organs into the thoracic cavity.

Injury to the thoracic lymphatic duct. Traumatic rupture of the thoracic duct is rare. It is more commonly described in cases of clavicular fractures, esophageal and spinal injuries [4, 5, 8, 30–32]. The anatomical features associated with the development of chylothorax originate from the cisterna chyli, which represents a confluence of lymphatic vessels located in the retroperitoneal space, to the right of the posteromedial aorta at the level of the renal arteries. The thoracic duct ascends from this level and enters the thorax through the aortic hiatus into the right hemithorax. The arch crosses into the left side of the thorax at the fourth and fifth thoracic levels and enters the neck anterior to the left subclavian artery, joining the venous system at the junction of the left subclavian vein and the left internal jugular vein. Knowledge of this anatomy should alert the physician in the event of thoracic duct injury during thoracic spine fractures or any concomitant upper abdominal or chest injuries affecting this region. Injury to the duct above the level of the fifth thoracic vertebra typically causes left-sided chylothorax, while injury below this level causes right-sided chylothorax.

Esophageal injury. The main causes of esophageal injuries from mechanical trauma in children include falls from height, motor vehicle accidents, and blunt force impact (barogenic trauma resulting from a sudden sharp increase in intraesophageal pressure exceeding 150 mm Hg). Sudden compression of the upper abdomen can lead to the expulsion of gastric contents into the esophagus, where linear tears may occur. The most frequent causes of esophageal injuries in children are foreign bodies (batteries) and chemical substances causing esophageal burns (not covered in these clinical guidelines).

Thymus injury. The thymus is located immediately posterior to the sternum in the anterior mediastinum. In adults aged 20–25 years, the functioning of the thymus ceases, and it gradually transforms into adipose tissue. Trauma to the thymus is extremely rare (casuistic). Most commonly, thymic injuries occur in high-energy trauma (motor vehicle accidents, falls from a height), although descriptions of thymus trauma in the literature are extremely rare [39].

1.3 Epidemiology of the Disease or Condition

Trauma is the leading cause of mortality and disability in children over one year of age worldwide [40]. In Russia, injuries and poisoning rank second in the structure of childhood mortality, and first among adolescents [41].

Chest trauma deserves special attention, although it accounts for less than 10% of traumatic injuries in children [2-10]. Despite its relative rarity, chest trauma in children represents one of the leading causes of death, especially in patients with concomitant abdominal or traumatic brain injuries [6]. According to the Center for Severe Mechanical Trauma of the Moscow Healthcare Department, chest trauma accounts for 80.6% of the polytrauma structure; among these, pneumothorax was diagnosed in 30% of children, and pneumohemothorax in 6%; in more than half of the observations (53.3%), the pneumothorax was small and did not require surgical treatment, in 33.3% of patients it was moderate, and in 13.3% large; in 26.6% of observations, pneumothorax was diagnosed bilaterally [42]. In the structure of chest trauma, pneumothorax ranks second in frequency, second only to lung contusion, and accounts for up to 37% of chest injuries in children. Speaking of pneumothorax with lung collapse greater than 50%, the frequency of such injuries is even lower—up to 3.5%. In 11% of observations, pneumothorax was combined with hemothorax. Despite the fairly high incidence of pneumothorax, only in 10% of cases did pneumothorax require drainage [42].

According to the Pediatric Report of the National Trauma Data Bank (USA), chest trauma accounted for 12.8% [5]. Thoracic trauma in children had high mortality rates of 7.7%. The most common cause of death in pediatric patients with chest trauma was central nervous system injuries, followed by hemorrhagic shock. Overall, the most common injuries were pulmonary contusions (53.3%), rib fractures (49.5%), and pneumothorax/hemothorax (37.1/13.3%). Other injuries were significantly less frequent: diaphragmatic injury (1.9%), tracheobronchial tree injury (2.9%), aortic injury (1.0%), and flail chest (0.9%) [5].

Tracheobronchial tree injuries in blunt chest trauma occur in children with a frequency of 0.5 to 3% [10]. Unfortunately, in more than 50% of cases, they result in mortality at the scene, given the severity of respiratory failure and concomitant injuries [10].

Thoracic aorta injuries occur in 1–7.4% of children with blunt chest trauma [4, 5, 8, 24–26], and cardiac injury occurs in 0.3–4.6% of children [4, 5, 8, 10]. These injuries have significant mortality within the first 6 hours after hospitalization: up to 30% for aortic injury and up to 40% for cardiac injury [8]. According to autopsy data, aortic ruptures are the cause of death in 2–5% of cases. 85% of victims die during transport. Of those admitted to the hospital, 30% die in the first 6 hours. Of those diagnosed and operated on, 90% survive. Aortic ruptures were more frequently noted in children older than 12 years, with concomitant trauma present in 60–80% of cases. In 90% of observations, the aortic rupture is localized in the isthmus region—the site of the ligamentum arteriosum attachment.

Diaphragmatic injury in blunt chest trauma is extremely rare, accounting for about 1–2%, and is generally combined with liver or spleen injury [4, 10, 27–29].

Chylothorax caused by traumatic chest injuries, including iatrogenic postoperative injuries, accounts for approximately 25% of all chylothorax cases (the main cause of chylothorax is neoplasms at 50%), with the remaining 25% due to other iatrogenic complications, primarily associated with central venous catheters [30]. Traumatic injuries of the duct can be caused by various reasons, but the most common mechanism of injury is sudden excessive spinal hyperextension with rupture of the duct just above the diaphragm [30–32]. Cases of vomiting or severe coughing fits leading to rupture of the lymphatic duct in the area of the right diaphragmatic attachment have also been reported. The first traumatic injury of the thoracic duct was described in 1875, and the first ligation of the thoracic duct was performed in 1948 [30].

Since the esophagus is a well-protected organ surrounded by other structures, its blunt trauma is very rare, accounting for less than 1% [4, 5, 8–10, 33–38]

Based on Ali Özdülger's 2024 review, mortality in isolated chest trauma is 5%, whereas when combined with traumatic brain injury and/or abdominal trauma, mortality reaches 25–40% [4].

1.4 Features of Coding the Disease or Condition

These clinical guidelines provide information on blunt chest trauma:

S20 Superficial injury of thorax

S22.2 Fracture of sternum

S22.3 Fracture of rib

S22.4 Multiple fractures of ribs

S22.5 Flail chest

S23.4 Sprains and strains of joints and ligaments of thorax

S25 Injury of blood vessels of thorax

S26 Injury of heart

S27 Injury of other and unspecified intrathoracic organs

S28.0 Crushed chest

S29 Other and unspecified injuries of thorax

1.5 Classification of the disease or condition

There are numerous classifications of chest trauma in domestic and foreign literature. First of all, chest injuries should be divided into closed (blunt), open, and penetrating, precisely because of the differing treatment strategies. The vast majority (up to 90%) of thoracic injuries in children are blunt. Penetrating chest injuries are rare in pediatric practice. Gunshot wounds occupy a special place due to the high kinetic energy of the damaging factor and the specific features of the wound healing process.

Traditionally, trauma is classified by the external cause of injury: motor vehicle accidents, drowning, poisoning, etc. Occupational, school, sports, street, and other injuries are also distinguished.

In practical work, systematization of chest injuries is rational as it determines the diagnosis structure and surgical tactics, and allows for the evaluation and comparison of treatment outcomes. Thus, the following should be distinguished:

By nature of injury:

• Closed (blunt)

• Open (wounds and injuries)

  • Penetrating

  • Non-penetrating

The criterion for classification is the integrity of the skin. A special form of closed chest injury is traumatic asphyxia, which occurs with brief, powerful compression of the chest in the anteroposterior direction and is caused by hypertension in the superior vena cava system.

By side of injury:

• Unilateral

• Bilateral

By localization of injuries:

With damage to the bony framework of the chest

With damage to the internal organs of the thoracic cavity

By number of injuries:

• Isolated

• Multiple

• Polytrauma (associated)

The classification of closed chest injuries by E.A. Wagner [43] (Table 1) is the most popular in Russia, including among pediatric surgeons.

Table 1 – Classification of chest injuries (E.A. Wagner, 1981)

Along with domestic classifications, the Organ Injury Scale (OIS) proposed by the AAST [44–46] is becoming increasingly widespread in our country. According to the working group for the development of these clinical guidelines, it allows for maximum standardization of injuries, which in clinical practice helps to correctly formulate the diagnosis and determines surgical tactics. It should also be taken into account that at the present stage, the AAST scale is used by the majority of radiologists to describe injuries based on MSCT data. To assess the severity of polytrauma, including thoracic trauma, most researchers use the ISS [47].

Thus, for an objective assessment of chest injuries, it is advisable to use the scales: ISS/AIS in correlation with OIS (AAST).

AIS (Abbreviated Injury Scale, https://www.aaam.org/abbreviated-injury-scale-ais). Injury severity in the AIS is ranked into 6 grades: 1. minor; 2. moderate; 3. serious (non-life-threatening); 4. severe (life-threatening, but with a high probability of survival); 5. critical (life-threatening, survival uncertain); 6. maximal (currently untreatable) [48].

OIS (Organ Injury Scale, https://www.aast.org/resources-detail/injury-scoring-scale) was developed by the American Association for the Surgery of Trauma (AAST). To date, more than 30 classifications have been created, including for virtually all thoracic organs. The advantages of this system include detailed injury description with standardized terminology, correlation with AIS, and, most importantly, the ability to determine indications for surgical treatment. Thus, grade 5 injuries require life-saving surgical treatment, grades 1–3 are managed conservatively, while for grade 4 injuries the probability of surgical treatment (thoracentesis, bronchial occlusion) is extremely high, although conservative management is also possible. The correlation of AIS with thoracic OIS allows the AAST classification to be used to assess the severity of associated injuries using the ISS scale.

ISS (Injury Severity Score) is based on assessing the severity of organ injury using the AIS scale. Each injury is assessed by body region (head and neck; face; chest, abdomen, extremities, and pelvic girdle) and general characteristics of the integumentary tissues (abrasions, contusions, lacerations, wounds, burns) (Table 2).

Table 2 – Injuries by anatomical body region

When assessing multiple injuries in a single region, the highest severity score is assigned. Injury severity is determined in points by summing the squares of the scores of the three most severely injured body regions (from 1 to 75 points). The ISS scale does not account for the patient's age. However, when assessing validity in children, the ISS showed satisfactory characteristics for the pediatric age group [49]. The correlation of the traditional trauma severity gradation in Russia (mild, moderate, and severe) with the point-based assessment using the AIS and ISS scales is presented in Table 3.

Table 3 – Assessment of injury severity

Superficial chest injuries and lung injuries are most common in pediatric surgery practice (Tables 4, 5) [1–8].

Table 4 – Chest wall injuries (OIS, AIS)

Table 5 – Lung injuries (OIS, AIS)

Pneumothorax is classified according to the volume of air in the pleural cavity and the degree of lung collapse:

• small (limited, partial) – lung collapsed by 1/3 of its volume

• moderate – lung collapsed by 1/2 of its volume

• large – lung collapsed by more than 1/2 of its volume

• total (tension) – lung completely collapsed, mediastinum shifted to the healthy side

Hemothorax is classified according to the volume of blood in the pleural cavity:

• small – blood accumulates in the sinuses or fills the pleural cavity below the scapular angle (level of 7th–8th ribs), up to 15% BCC

• moderate – blood reaches the middle of the scapula (level of 5th–6th ribs), up to 30% BCC

• large – blood reaches above the level of the 2nd rib,

• total (massive) – lung completely collapsed, mediastinum shifted to the healthy side, blood loss volume greater than 30% BCC

1.6 Clinical presentation of the disease or condition

In chest trauma, three main syndromes are distinguished: pain syndrome, blood loss syndrome, and acute respiratory failure syndrome. Clinical manifestations in severe chest injuries are associated with a number of morphological and functional changes in the patient's body, which primarily include: disorders of external respiration, circulatory impairment, and the development of pleuropulmonary shock [2-10].

Impairment of external respiration is associated with the development of pathological changes in thoracic tissues, severe chest pain that impairs chest excursion, and manifests as hypoxia—expressed by symptoms of cardiopulmonary failure and the development of acute respiratory distress syndrome. With the development of pneumothorax or hemothorax, the clinical manifestations of respiratory and circulatory impairment are further exacerbated.

Common manifestations of ARF include dyspnea, use of accessory muscles of respiration, tachypnea, tachycardia, diaphoresis, cyanosis, and altered mental status. Severe chest injuries (lung and/or cardiovascular trauma) accompanied by bleeding often lead to shock. Clinical symptoms of shock include hypotension, decreased level of consciousness, and oliguria.

From the anamnesis, it is necessary to determine the nature of the injury, the time elapsed since the accident, and identify characteristic complaints and their dynamics. Characteristic complaints include chest pain worsening with deep inspiration and coughing, respiratory disturbances (dyspnea, paradoxical breathing), hemoptysis, swallowing and phonation disorders, hypersalivation, loss of consciousness, mucosal cyanosis, and chest deformity.

On inspection, attention is paid to skin color (cyanosis of the fingers, lips, face, etc.), the presence of external injuries (ecchymoses, hematomas, petechial hemorrhages); changes in chest shape (asymmetry, retraction/bulging of intercostal spaces, ribs, sternum), lagging of the chest during respiration, and paradoxical breathing.

Palpation of the chest makes it possible to determine tenderness, subcutaneous emphysema, pathological mobility of the ribs and sternum, and bone fragment crepitus.

Percussion makes it possible to establish the presence of air and fluid in the pleural cavity, as well as widening and shifting of the mediastinum. It should be noted that pneumothorax is characterized by a hyperresonant (box-like) percussion sound and shifting of the mediastinum to the healthy side. Hemothorax, pulmonary contusions, and atelectasis are accompanied by dullness of the percussion note. Intermuscular hematomas are generally undetectable on percussion.

Auscultation makes it possible to detect lung and heart injuries. In pneumothorax, diminished or absent breath sounds are determined on the affected side. In pulmonary contusion, diminished or completely absent breathing is noted over the site of lung contusion, along with altered breath sound quality, rales, and pleural friction rub. Auscultation of the heart allows the detection of its injury through muffled heart sounds, tachycardia, arrhythmia, and the appearance of cardiac murmurs. The auscultation of bowel sounds in the pleural cavity is a sign of diaphragmatic injury.

When chest trauma is suspected, one must be very careful about the combination of symptoms such as tachycardia, hypotension, and auscultatory or percussive signs of pneumothorax. In this case, tension pneumothorax and the development of pleuropulmonary shock unrelated to hypovolemia may be present.

Traumatic asphyxia in the first hours and days after trauma is accompanied by the development of a severe condition and acute respiratory failure. The clinical presentation of traumatic asphyxia has characteristic features. The skin of the upper body is covered with pinpont hemorrhages, which merge in places. Subconjunctival hemorrhages are particularly pronounced (sometimes the sclerae are completely covered by hematoma). In areas of tight clothing fit (shirt collar, bra, etc.), skin hemorrhages are absent, leaving white spots. In cases where traumatic asphyxia is accompanied by multiple rib fractures, pulmonary parenchymal injuries, and contusions of the heart and lungs, the clinical course is significantly aggravated.

Rib fracture. Fractures are subdivided into single (1–2 ribs), multiple (>3 ribs), and flail. Clinically, there is pronounced chest pain (most severe at the fracture site), worsening with deep breathing and coughing; soft tissue swelling at the fracture site; tenderness upon palpation in the fracture area, frequently with crepitus and "step-off" deformity; shallow breathing; lagging of the chest in the respiratory cycle on the affected side; the "interrupted inspiration" symptom—interruption of an attempt to take a deep breath due to pain; the axial load symptom—when alternately compressing the chest in the sagittal and frontal planes, pain occurs at the bone fracture site rather than at the compression point. Fractures of the 1st and 2nd ribs require inspection and examination aimed at ruling out great vessel injuries. Rib fractures may be complicated by trauma to the lung parenchyma by the fractured rib, leading to hemoptysis, subcutaneous emphysema, pneumothorax, and hemothorax; or injury to intercostal vessels, liver, or spleen, leading to hemothorax, hemopericardium, and hemoperitoneum.

Pathological chest mobility (including flail chest). Pathological chest mobility occurs with multiple fractures of 3 or more adjacent ribs, resulting in a segment of the chest wall moving independently of the rest of the chest. Diagnosis of pathological chest mobility is made clinically by observing paradoxical movements of the chest wall segment during respiration. Nevertheless, such movement may be difficult to notice if the depth of inspiration is limited by pain. Paradoxical movements do not occur during mechanical ventilation. Upon palpation, crepitus can often be detected in the pathologically mobile segment. In flail fractures, the clinical picture and severity of the patient's condition are determined by the position and size of the "rib flap" as well as the amplitude of movement: the larger and more mobile the "flap," the more severe the patient's condition.

Sternal fracture. Sternal fracture is characterized by pain in the sternal region, which makes deep breathing difficult. Swelling and a "step-off" deformity are palpable and visible in the projection of the fracture. Tenderness and crepitus are also determined upon palpation.

Pulmonary contusion. The leading symptoms of pulmonary contusion are dyspnea, hypoxemia, hypercapnia, dullness on percussion, and diminished breath sounds on auscultation.

Cardiac contusion. In children, closed cardiac trauma typically occurs as part of polytrauma. Consequently, characteristic complaints are absent due to the patient's severe general condition. Based on physical examination, cardiac trauma can be suspected in the presence of bruises and ecchymoses on the anterior chest wall, anterior rib and sternal fractures, and pulse arrhythmia. Cardiac auscultation also frequently reveals an increased heart rate, sometimes a pericardial friction rub, pendulum rhythm, or gallop rhythm. Arterial hypotension is possible. Severe cardiac contusion is accompanied by tachycardia, arrhythmia, and arterial hypotension. Mild contusions manifest no symptoms during the first few hours after the injury. The clinical picture may include loss of consciousness at the time of injury, a severe general condition, and hemodynamic disturbances such as hypotension and decreased cardiac output resembling myocardial infarction. ECG findings include signs of myocardial ischemia with ST-segment depression, sinus tachycardia, delayed intraventricular conduction, and P-wave notching. Biochemical blood tests may show elevated cardiac isoenzymes, namely troponin I and creatine kinase MB. Extremely rarely, children may experience sudden death—cardiac arrest upon a blow to the chest. This is associated with a prolonged period of repolarization and the onset of cardiac fibrillation.

Cardiac tamponade. Beck's triad is considered the classic manifestation of cardiac tamponade: hypotension, muffled heart tones, and distended neck veins. Another manifestation of cardiac tamponade is a paradoxical pulse (weakening of the pulse during inspiration).

Hemothorax/pneumothorax. Main symptoms: chest pain on the affected side, difficulty breathing, a hyperresonant percussion note in pneumothorax, dullness of the percussion note in hemothorax; weakened or absent breath sounds upon auscultation. In small pneumothorax/hemothorax, complaints and physical symptoms may be absent. In large pneumothorax/hemothorax, there is lagging of the affected side during breathing or bulging of the chest on the affected side. In tension pneumothorax/massive hemothorax, there is a shift of the cardiac dullness borders toward the healthy side.

Clotted hemothorax. Symptoms of a clotted hemothorax are nonspecific and manifest as pain in the corresponding side of the chest, fever, tachycardia, and shortness of breath. Characteristic physical symptoms include dullness and weakened breath sounds on the affected side of the chest.

Pneumomediastinum. The main symptom is substernal chest pain. Objective examination reveals subcutaneous emphysema, usually in the jugular notch extending to the neck. Auscultation over the cardiac area reveals a crunching or clicking sound synchronized with heartbeats (Hamman's sign).

Airway trauma (trachea, bronchi). Injuries to the trachea and large bronchi manifest as respiratory failure and are almost always accompanied by the so-called "gas syndrome"—pneumomediastinum and subcutaneous emphysema of the neck, and the development of pneumothorax with the typical failure of the lung to expand and the persistence of substantial air leakage after pleural drainage tube insertion.

Aortic rupture. The clinical picture of aortic rupture may reveal a fracture of the 1st rib or sternum, paraplegia, elevated blood pressure in the upper extremities, and a decreased pulse in the lower extremities. A plain chest X-ray reveals widening of the mediastinal shadow, loss of the normal contour of the thoracic aorta, apical hemothorax, and deviation of the nasogastric tube. Additional methods must include computed tomography and aortography. Subclavian artery injuries can occur with fractures of the 1st rib, clavicle, or brachial plexus injuries. Patients with traumatic aortic rupture usually experience chest pain. Symptoms include a weak pulse, a harsh systolic murmur over the precordial area or the posterior interscapular space, as well as symptoms of impaired blood flow in the lower extremities, including decreased pulse volume or blood pressure in the lower extremities compared to the upper extremities.

Diaphragmatic injury. Diaphragmatic trauma typically occurs as part of polytrauma and may go undiagnosed in the early post-traumatic period. The clinical picture of diaphragmatic rupture is due to two groups of symptoms related to: a) impaired diaphragmatic movement and compression syndrome caused by abdominal organs displaced into the chest cavity, b) displacement of abdominal organs. The main symptoms are abdominal pain radiating to the shoulder and the auscultation of bowel sounds at the chest level. One or more of the following nonspecific symptoms may be present: shortness of breath, difficulty breathing, chest pain, shoulder joint pain, epigastric pain, a feeling of abdominal tightness, nausea and vomiting, dysphagia, and regurgitation. Percussion may reveal a shortened pulmonary sound on the affected side, high standing of the diaphragmatic dome, and mediastinal shift to the healthy side; chest auscultation may reveal weakened or absent breath sounds and audible small bowel peristaltic sounds. Clinical manifestations depend on the size and location of the injury. Most diaphragmatic ruptures are located on the left posterolateral side due to the protective effect of the liver. Small ruptures and those located in the right diaphragmatic dome are quite difficult to diagnose and are often detected years after the injury.

Esophageal trauma. Trauma to the thoracic esophagus may lead to the development of subcutaneous emphysema of the neck, pneumothorax, and/or pneumomediastinum. In 75% of patients, the diagnosis is established more than a day after the onset of the condition. Characteristic complaints in esophageal trauma include retrosternal pain, hypersalivation, and a hoarse or nasal voice. Physical examination focuses on the state of the soft tissues of the neck and chest wall, and the presence and extent of subcutaneous emphysema. During dynamic evaluation, important indicators are body temperature, respiratory rate, and heart rate. Depending on the type of esophageal injury, the clinical picture unfolds over a timeframe ranging from several minutes to a day. Esophageal wall contusion typically has no clinical manifestations. However, when the integrity of the esophageal wall is compromised, purulent complications begin to develop within 24 hours—cervical phlegmon, mediastinitis, pleural empyema, and purulent pericarditis. Rupture of the mediastinal pleura with the development of unilateral or bilateral pyopneumothorax is possible. As mediastinitis progresses, the victim's condition sharply deteriorates, leading to systemic inflammatory response syndrome, sepsis, infectious-toxic shock, and multiple organ failure. Without adequate treatment, the patient dies against the backdrop of progressive sepsis.

Thoracic duct injury. The main clinical manifestation of thoracic duct trauma is the development of chylothorax. Typically, hemothorax is diagnosed initially, and pleural drainage is performed. Dynamically, a milky-white fluid (chile) begins to discharge through the drainage tube. The diagnosis is confirmed by analyzing the pleural effusion. If this condition is not properly recognized and treated, it can lead to severe respiratory impairment, nutritional problems, and immune issues, which in turn affect the outcome of the disease.

Thymus trauma. Thymic ruptures can lead to the development of hemomediastinum with hemodynamic disturbances, which necessitates ruling out major vessel injuries and cardiac tamponade.

2. Diagnostics, medical indications and contraindications for diagnostic methods

The treatment and diagnostic algorithm for suspected chest trauma in children directly depends on the severity of the injury, which in turn determines the patient's clinical status. In severe trauma, including polytrauma, diagnostic measures are performed in parallel with resuscitation aimed at maintaining vital body functions [50, 51]. The basis of the diagnostic algorithm is determining the patient's stability based on hemodynamic status [50, 51]. The clinical presentation of tension pneumothorax upon admission is an indication for immediate pleural puncture followed by drainage without additional instrumental examinations. Extended FAST (eFAST) is performed in all patients with severe trauma. In the diagnosis of pneumothorax/hemothorax, thoracentesis with drainage is performed immediately. If the eFAST result is negative, a "stable" patient undergoes whole-body CT (WBCT). CT is the gold standard for diagnosing injuries in polytrauma in hemodynamically stable patients and has high specificity and sensitivity for detecting the entire spectrum of potential chest injuries. Immediate life-threatening conditions in blunt chest trauma include massive hemothorax, tension pneumothorax, flail chest, and cardiac tamponade. These conditions require immediate surgical intervention.

The primary diagnostic method for isolated mild chest trauma (without impairment of vital body functions) is chest radiography. If necessary, CT is performed to clarify the nature of the injuries. Radiography is less informative for diagnosing hemopneumothorax than computed tomography or even ultrasound. Radiography does not always detect a small pneumothorax. However, it should be noted that an undetected small pneumothorax on radiography that is discovered on CT does not affect the treatment strategy. When performing radiography in the supine position, the sensitivity of the method for detecting pneumothorax decreases.

Diagnostic criteria:

1. anamnestic data indicating chest trauma (mechanism, time of injury, etc.)

2. physical examination data characteristic of blunt chest trauma (see section 1.6)

3. laboratory test results

4. instrumental examination data

Comments: The length of stay in the emergency department for a "stable patient" with suspected blunt chest trauma and a moderate general condition should not exceed 2 hours

Comments: The first examination of the patient in the surgical department by a pediatric surgeon must be performed no later than 2 hours after hospitalization, with a record in the medical history. An important aspect of examining the patient in the department is assessing the severity of the condition in dynamics.

2.1 Complaints and Anamnesis

In blunt chest trauma, complaints directly depend on the severity of the injury and the patient's condition. With a small pneumothorax/hemothorax, complaints may be absent at the time of examination; in combined injuries, they may not be manifest; and in severe patients with impaired consciousness, they cannot be obtained.

In isolated chest trauma, patients complain of chest pain on the affected side and difficulty breathing. Dyspnea and the degree of respiratory failure can vary and depend on the severity of the injury, the degree of pneumothorax/hemothorax, and the presence of mediastinal shift.

Comments: The main causes of chest trauma in children are motor vehicle accidents and falls from a height. With a high-energy trauma mechanism, blunt chest trauma must be ruled out. The victim complains of pain at the site of injury, difficulty breathing, hemoptysis, tachypnea, and tachycardia. If the patient is conscious and breathing independently from the time of injury until arrival at the hospital, mild chest trauma can be suspected. Complaints of difficulty breathing, lack of air, and chest wall deformity should raise suspicion and increase vigilance regarding the chest area.

2.2 Physical Examination

Comments: The initial examination of a patient with chest trauma is performed in accordance with Advanced Trauma Life Support (ATLS) protocols, starting with an assessment of the child's airway patency [53,57].

The condition of the airway and neck in children should be thoroughly examined, as chest injuries can lead to airway obstruction. The neck should be inspected to rule out subcutaneous emphysema and check for carotid/jugular pulse. Next, examination of the chest wall may reveal paradoxical breathing, asymmetric movement typical of pneumothorax/hemothorax, and/or obvious signs of trauma (bruises, hematomas).

In chest trauma, the patient's general condition can range widely from minor impairment (moderate severity) to terminal and depends on the volume of the pneumothorax, the severity of respiratory failure, the degree of blood loss, and traumatic shock, which determines the severity of the chest trauma and the overall severity of injury in polytrauma. Symptoms of a severe condition include altered consciousness ranging from agitation to coma, respiratory failure, and cardiovascular impairment. Symptoms specific to chest trauma include signs of respiratory failure (pallor or cyanosis of the skin, tachypnea or bradypnea), jugular venous distension, soft tissue emphysema in the chest and neck area, bulging of one hemithorax, paradoxical respiratory movements, and external traumatic soft tissue injuries of the chest (abrasions, hematomas, wounds). Attention is paid to the patient's position, changes in chest shape, asymmetry, retraction or, conversely, bulging of the intercostal spaces, ribs, sternum, lag during breathing, and chest flailing.

Comments: Chest palpation detects soft tissue emphysema, pathological mobility of the ribs and sternum, and bone fragment crepitus. Tenderness on palpation, the presence of a step-off deformity, or rib flailing may indicate severe chest wall injury. Palpation of subcutaneous emphysema produces crackling or crunching sounds (crunching of snow). Subcutaneous emphysema may be localized within a small area or spread over a large part of the chest and/or neck area. The cause of subcutaneous emphysema in blunt chest trauma is damage to the tracheobronchial tree, upper respiratory tract, and/or esophagus.

Percussion makes it possible to establish the presence of air and fluid in the pleural cavity, as well as widening and displacement of the mediastinum and cardiac dullness. Pneumothorax is characterized by a hyperresonant (tympanic/box) sound, and tension pneumothorax by mediastinal shift to the healthy side. Large hemothorax manifests as a dull percussion sound with mediastinal shift to the healthy side. Medium and small hemothoraces, extrapleural and intermuscular hematomas are indistinguishable on percussion. Significant atelectasis is characterized by dulling of the pulmonary sound with mediastinal shift to the affected side. Mediastinal emphysema is characterized by a hyperresonant sound and the absence of cardiac dullness.

Auscultation of the lungs is performed over symmetrical lung fields. Auscultation makes it possible to detect lung injury by the weakening or absence of breath sounds, changes in their pitch, the appearance of rales, or pleural friction rub. Decreased breath sounds upon auscultation are a criterion for pneumothorax, hemothorax, or severe pulmonary contusion. Auscultation of the heart allows the detection of its injuries through muffled heart sounds, tachycardia, arrhythmia, and the appearance of heart murmurs. When air enters the mediastinum, a characteristic crunch synchronous with the heartbeat may be heard (Hamman's sign, or mediastinal crunch). Hamman's sign suggests the presence of pneumomediastinum and is often associated with injuries to the tracheobronchial tree or, less commonly, esophageal injuries. Hearing bowel sounds in the pleural cavity is a sign of diaphragmatic injury.

2.3 Laboratory Diagnostics

The scope and regimen of laboratory monitoring depend entirely on the severity of the chest trauma and the overall severity of polytrauma. A standard laboratory workup must be performed in all cases. Patients scheduled for surgical treatment undergo blood typing and Rh factor determination.

Comments: Potential changes (anemia, thrombocytopenia, decreased hematocrit) are important for assessing the degree of blood loss, including cases with multiple and associated injuries.

Comments: Urinalysis helps identify associated injuries and rule out urinary tract pathology.

Comments: A decrease in blood oxygen tension accompanied by acid-base disorders is the main symptom of respiratory failure. An elevated lactate level indicates the development of shock. The identified signs of hypovolemia and metabolic disorders require immediate correction. A drop in arterial oxygen tension to 50 mm Hg while breathing ambient air and to 100 mm Hg during pure oxygen inhalation is an important symptom of post-traumatic respiratory failure. Hypercapnia with a flail chest (PaCO2 greater than 50 mm Hg) indicates that the flail chest is functionally significant.

Comments: This allows for the assessment of organ dysfunction in patients with multiple and associated trauma, as well as the development of complications following respiratory failure.

Comments: Elevated troponins I and T in blunt chest trauma should be regarded as a sign of myocardial contusion. Measuring the activity of the CK-MB fraction has diagnostic value, though it is difficult to interpret in the presence of other injuries. Elevated levels of troponin T and I have higher specificity within 48 hours after trauma, but the interpretation of these parameters requires caution due to their insufficient sensitivity and prognostic value.

Comments: Assessment of APTT, fibrinogen, and INR levels allows for the diagnosis of hypocoagulation and disseminated intravascular coagulation (DIC). Hypocoagulation is a pathognomonic symptom of an extremely severe condition in polytrauma.

Comments: Prescribing correct antibiotic therapy is inseparable from comprehensive microbiological monitoring, the main function of which is to assess the etiological factors of infectious and inflammatory complications. In addition, implementing this monitoring helps address other important tasks: providing adequate antibiotic therapy for patients; assessing the rate of patient colonization and environmental contamination by various microorganisms, including those of epidemiological significance; identifying strains with priority spread in a specific medical organization; and evaluating the microbial landscape of the institution as a whole and its departments.

Comments: Chylothorax is an odorless exudate with a predominance of lymphocytes. Microscopy reveals chylomicrons. Chylothorax is also characterized by a high triglyceride content (>1.24 mmol/L / 110 mg/dL) and low cholesterol (<5.18 mmol/L / 200 mg/dL). The cholesterol-to-triglyceride ratio is less than 1.

2.4 Instrumental Diagnostics

The choice and sequence of instrumental diagnostic methods upon patient admission depend on the severity of the trauma and the patient's clinical condition.

Comments: The first group (unstable patients) includes patients in extremely critical condition with vital sign disturbances. Patients are admitted via the trauma resuscitation room. The core diagnostic tool is eFAST. If a large pneumothorax/hemothorax is detected, thoracentesis with pleural drainage must be performed immediately, followed by a decision on the necessity of emergency surgical treatment. The second group includes patients in severe condition but without vital sign disturbances (stable patients). Patients are admitted via the emergency trauma unit. The basis of the diagnostic algorithm is MSCT. Examination is performed concurrently with anti-shock measures. The third group includes patients in satisfactory/moderate condition. All clinical and instrumental examinations are performed in the admission department on a general queue basis.

Comments: Chest radiography allows for the identification of rib, sternum, and spine injuries, pneumothorax and hemothorax, as well as injuries to the lung, heart, and mediastinum. During radiography, the following should be assessed: the presence, volume, and nature of pneumothorax or hemothorax; mediastinal shift, border widening, and smoothing of the cardiac contours; the contours and level of the diaphragm; the presence of bone injuries (ribs, clavicles, scapulae, sternum, spine); changes in the lung tissue (atelectasis, hypoventilation, infiltration); the presence of mediastinal and soft tissue emphysema; and the presence and localization of foreign bodies. Targeted radiography should be avoided in favor of anteroposterior and lateral overview radiographs with mandatory inclusion of both hemithoraces from the diaphragmatic sinuses to the lung apices. Standard-penetration radiographs are required to diagnose lung injuries, extrapleural hematomas, and hemopneumothorax. However, normal radiographs do not rule out the presence of a lung contusion. Radiological signs of lung contusion may become apparent 4–6 hours after the injury.

Bone injuries are better visualized on high-penetration radiographs in oblique projections. Rib radiography helps identify the fracture localization and the position of bone fragments. However, initial radiographs may fail to detect up to 50% of rib fractures. Therefore, the initial diagnosis of a flail chest relies more on the clinical presentation of paradoxical movements of the chest wall segment and external respiration disorders.

An important part of the radiological examination of victims includes contrast studies of the esophagus (contrast esophagoscopy, double-contrast esophagography) when mediastinal trauma is suspected. The procedure must confirm or rule out periesophageal emphysema, as well as any contrast extravasation beyond the anatomical boundaries of the esophagus. Radiological examination is the primary method as it allows for the detection of esophageal injury and associated complications. The initial radiological examination is performed at the slightest suspicion of esophageal injury without special patient preparation. If signs of emphysema or contrast extravasation are detected, an esophageal rupture is diagnosed.

Radiographs reveal signs of diaphragmatic rupture in only 25% of patients, such as elevation and indistinctness of the diaphragmatic contours, the presence of a gastric air bubble in the pleural cavity, and displacement of the nasogastric tube.

In terms of diagnostic value for chest injuries, radiography is inferior to computed tomography. Therefore, in patients with severe status and a high-energy mechanism of injury, radiography should be used for initial diagnosis only when MSCT is unavailable.

Comments: eFAST allows for the rapid detection of blood and air in the pleural cavity and can be performed not only by ultrasound specialists, but also by other members of the trauma team (surgeons, orthopaedic trauma surgeons, anesthesiologists-resuscitators). If hemothorax and/or pneumothorax is detected, thoracentesis with pleural drainage must be performed prior to MSCT. The advantage of ultrasound is the ability not only to visualize fluid or air, but also to measure the volume of fluid. Using Doppler ultrasound mode provides crucial information for surgical management regarding potential blunt trauma to the heart, great vessels of the mediastinum, and the lung root.

Comments: Chest computed tomography is the most informative diagnostic method for chest injuries. Rib, sternum, and clavicle fractures, pneumothorax, hemothorax, lung contusion, mediastinal hematomas, subpleural hematomas, and traumatic bullae are visualized within minutes. Performing CT angiography of the thoracic aorta allows for accurate visualization of contrast extravasation sites, traumatic aneurysms, and reliable identification of the bleeding source. A contraindication (including temporary) to CT is an unstable condition of the patient requiring emergency therapeutic interventions. The standard patient position is supine. The scan begins with a scout topogram in the frontal plane, followed by transverse slices from the skull base to the level of the diaphragm.

Thoracic CT provides comprehensive information on fractures and chest organ injuries, including the presence of the so-called "sharp fragment" sign—protrusion of sharp rib fragments into the pleural cavity with the risk of lung laceration. It should be noted that in some cases, a flail chest resulting from multiple double rib fractures may develop not immediately after the trauma, but 1–3 days later or even later. Contrast-enhanced MSCT diagnoses myocardial and pericardial ruptures (with cardiac herniation/luxation), hydro- and pneumopericardium, and injuries to the coronary arteries and heart valves.

Comments: MSCT is performed when the victim's condition is assessed as "stable" after undergoing ultrasound (eFAST). If hemopneumothorax is detected on eFAST, computed tomography is performed after pleural drainage. An unstable patient condition caused by ongoing internal or external bleeding, progressive respiratory failure, or the development of a shift syndrome in severe traumatic brain injury is grounds for postponing MSCT until after emergency (anti-shock) life-saving surgical interventions and stabilization of the patient's vital functions. During MSCT, the structure of chest injuries and all associated injuries must be evaluated. Particular attention should be paid to the state of the diaphragm, the rupture of which is frequently missed. The presence of life-threatening conditions (massive hemorrhage, respiratory failure, etc.) is grounds for postponing this study until after emergency surgical interventions and stabilization of central hemodynamics.

Comments: Pleural puncture is performed in the 5th–6th intercostal space along the mid-axillary line (safe triangle). Upon aspiration of air/blood, pleural drainage is performed. To prevent iatrogenic complications, it is advisable to perform thoracentesis simultaneously with ultrasound (eFAST).

Comments: ECG is highly informative for cardiac contusions; any rhythm or conduction disturbance, as well as focal changes, should be interpreted in favor of myocardial contusion. Nonspecific changes are identified, including ST-segment elevation/depression, pathological Q waves and T wave abnormalities, various arrhythmias (sinus tachycardia, bradycardia, ventricular extrasystoles, atrial fibrillation and flutter, transient intraventricular conduction disturbances, bundle branch blocks or their divisions, and various AV conduction abnormalities, including transient complete AV block). Sensitivity and specificity are 82% and 68%, respectively.

Comments: Echocardiography makes it possible to assess the amount of fluid in the pericardium and its thickness, the state of the valve apparatus, and cardiac performance. Pericardial effusion, decreased myocardial contractility (atrial and ventricular dyskinesia), and decreased cardiac output may be detected. Right ventricular ejection fraction is most commonly decreased. Intramural ventricular hematomas, rupture of papillary muscles and chordae, valvular damage and dysfunction, as well as intracardiac thrombi may be detected. The diagnostic value of the study is limited by rib fractures, hematomas, and chest wall edema, as well as the severity of the patient's condition and the operator's qualifications.

Comments: Endoscopic methods play an important role in the diagnosis of chest injuries. It should be remembered that a prerequisite for performing an endoscopic examination is effective decompression of the pleural cavity in pneumothorax or the mediastinum in mediastinal emphysema. Bronchoscopy is an objective method for diagnosing lung and airway injuries, identifying the causes of obstructive pulmonary atelectasis, and eliminating them. Indications for bronchoscopy in trauma include: suspected injury to the trachea, bronchi, and lungs; pulmonary hemorrhage of any severity; atelectasis or pulmonary hypoventilation; airway obstruction by blood, sputum, or food particles; the need for tracheobronchial tree toilet; and difficult intubation. Bronchoscopy allows for the detection of tracheal and bronchial injuries, pulmonary hemorrhage, signs of pulmonary contusion, and aspiration of blood or gastric contents. At the same time, diagnostic bronchoscopy allows for a number of therapeutic measures, such as tracheobronchial tree toilet and endobronchial drug administration during bronchoscopy. Restoration of airway patency and timely initiated treatment reduce the risk of pulmonary complications. In this regard, it is important that bronchoalveolar lavage in patients with severe polytrauma helps to effectively remove pathological contents (blood and aspirated material) from the airways and makes it possible to collect fluid for laboratory tests.

Comments: Esophagoscopy allows for the diagnosis of wounds and traumatic ruptures of the esophagus, as well as the detection of indirect signs of injury to other mediastinal organs. It should be noted that in the presence of mediastinal and soft tissue emphysema with no radiological evidence of pneumothorax, esophagoscopy is an absolute necessity to rule out esophageal rupture.

Comments: Thoracoscopy allows for the diagnosis of clotted hemothorax, hemopericardium, mediastinal hematoma, wounds of the lung, pericardium, and diaphragm, identification of the source of bleeding, and detection of foreign bodies in the pleura, lung, and mediastinum. Indications for video-assisted thoracoscopy include: 1. persistent pneumothorax refractory to treatment for 3 days after trauma, and recurrent pneumothorax; 2. clotted hemothorax of up to 2 weeks duration; 3. foreign bodies of the pleural cavity, lung, and mediastinum. An unstable patient condition is a contraindication for thoracoscopy. The advisability of emergency thoracoscopy (for ongoing intrapleural hemorrhage, tension pneumothorax) in children is extremely questionable, since even with relatively stable hemodynamics upon admission, the risk of hemodynamic disorders is extremely high. In this situation, when conservative measures are ineffective, thoracotomy is indicated.

2.5 Other Procedures

In chest trauma, specialist consultations and additional instrumental examinations as prescribed by specialists are recommended for all patients to rule out combined and multiple injuries.

Comments: All patients with severe chest trauma and polytrauma at the inpatient treatment stage require multi-parameter monitoring in the ICU setting, including non-invasive and invasive blood pressure measurement, heart rate, respiratory rate, pulse oximetry, ECG, ultrasound of injured areas, and Doppler ultrasound of main vessels.

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

Treatment of patients with closed chest trauma is subject to the following principles regardless of the chosen management strategy:

• Restoration and maintenance of airway patency

• Pain relief

• Hemostasis and replacement of blood loss

• Adequate drainage of the pleural cavity

• Sealing and stabilization of the chest wall

• Measures aimed at the earliest possible lung re-expansion

• Infusion, antimicrobial, and symptomatic therapy

Inadequate restoration of airway patency, and as a consequence, impaired pulmonary ventilation, are among the leading preventable causes of death from trauma. Approximately 90% of blunt chest injuries in children can be managed conservatively or via pleural drainage. Indications for surgical treatment include:

• Ongoing intrathoracic hemorrhage (20-30% of the child's circulating blood volume / 1000-1500 ml in an adolescent upon pleural drain placement; 2-3 ml/kg per hour / 200-300 ml per hour in an adolescent for more than 4 hours)

• Tracheal and bronchial injuries

• Esophageal injury

• Diaphragmatic injury

• Injury to major thoracic vessels

• Clotted hemothorax

Comments: The initial evaluation of a traumatized child in accordance with ATLS begins with assessing the child's airway patency. Airway restoration must be combined with anti-shock measures, as well as the treatment of concomitant chest injuries.

3.1 Conservative Treatment

Superficial chest injuries

Comment: For soft tissue injuries of the clavicle, scapula, shoulder joint, and shoulder, the upper extremity is supported in a sling with the forearm flexed at an angle of 90-100°, and adequate pain relief is provided. Treatment of contusions consists in immobilizing the injured body part and applying cold during the first 24 hours to prevent hemorrhage and edema. Extensive hematomas are managed conservatively with ongoing ultrasound monitoring (at least once a week). When the hematoma liquefies, puncture with a large-bore needle, removal of contents under ultrasound guidance (soft tissue puncture under ultrasound guidance), and application of a pressure bandage are possible.

Rib and sternal fractures

Comments: Conservative treatment is the main method of treating rib and sternal fractures in children, consisting of pain relief and avoidance of physical activity. Effective pain relief is crucial in rib fractures. Pain control can be achieved using nonsteroidal anti-inflammatory and antirheumatic drugs. In multiple rib fractures, opioids as well as thoracic epidural blockade can be used as part of multimodal intensive care.

In multiple rib fractures accompanied by paradoxical respiration and symptoms of severe respiratory failure, transferring the patient to mechanical ventilation is indicated. With such ventilation, the rib fragments move passively on the "air cushion" of the lung, thereby creating conditions that eliminate the need for various methods of fixing the unstable chest wall.

For isolated injuries, the prognosis is favorable. Sternal fractures heal completely in about 6 weeks. Rib healing occurs in 3-4 weeks.

Pulmonary contusion

Comments: Some patients with pulmonary contusion and impaired gas exchange require mechanical ventilation. Pulmonary contusions can be complicated by acute respiratory distress syndrome (ARDS), destructive pneumonia with the formation of pneumothorax, pyothorax, bullae, and lung abscesses, which may require surgical treatment. Pulmonary contusions can resolve without complications. Conservative treatment for pulmonary contusions includes oxygen therapy, systemic antibacterial drugs, intensive therapy aimed at normalizing homeostasis parameters, therapeutic exercise (physical therapy), and physical therapy modalities. In most cases, pulmonary contusion resolves within 7-10 days.

Cardiac contusion

Comments: Cardiac contusions are treated similarly to myocardial infarction. Since cardiac contusions in children are pathognomonic for severe trauma within the structure of polytrauma, children receive comprehensive intensive care in the ICU against the background of multi-parameter monitoring.

Pneumothorax and hemothorax

Treatment of traumatic pneumothorax/hemothorax in blunt chest trauma consists of removing free air/blood from the pleural cavity, expanding the lung, and restoring the syntopy of the thoracic cavity organs. If the volume of air/blood in the pleural cavity is small, and the inflow of air/blood into the pleural cavity has ceased, the resolution of pneumothorax/hemothorax can be spontaneous. It is also important to consider the nature and parameters of pulmonary ventilation: whether spontaneous breathing is preserved or the child is on mechanical ventilation. Therefore, the approach to surgical treatment of traumatic pneumothorax/hemothorax should be differentiated. Several factors influence the treatment tactics for traumatic pneumothorax/hemothorax:

1. Volume of pneumothorax/hemothorax (small, moderate, large, tension/massive).

2. Presence of symptoms (phenomena of respiratory failure, changes in blood gas composition).

3. Nature of breathing (spontaneous or mechanical ventilation).

4. Effect of pleural cavity drainage (lung expansion, air bubbling through the drainage, blood outflow through the drainage).

For the effective treatment of traumatic pneumothorax/hemothorax, instrumental monitoring (ultrasound of the lungs, pleural cavities, mediastinum, chest radiography, chest spiral CT) is very important, since clinical data (auscultation, percussion) are subjective, and it is impossible to reliably determine dynamics based on them. Laboratory parameters are also unsuitable for monitoring, since in children, even with a large pneumothorax, the blood gas composition does not undergo significant changes. Among the surgical manipulations used to treat traumatic pneumothorax/hemothorax, pleural puncture and pleural drainage are most commonly used. The need for thoracotomy arises extremely rarely and is a casuistry in case of rupture/avulsion of the main or lobar bronchi and, as a rule, is combined with hemothorax. Emergency thoracoscopy is inexpedient.

Comments: In small pneumothorax, regardless of the type of breathing (spontaneous/mechanical ventilation), surgical treatment is not indicated. For monitoring, it is recommended to perform chest radiography or ultrasound examination of the lungs and pleural cavities 6 hours after establishing the diagnosis of "small pneumothorax". If, according to the control radiography data, the child shows an increase in the volume of pneumothorax to moderate or large, pleural drainage is indicated.

Esophageal injury

Comments: Conservative treatment (exclusion of oral nutrition, systemic antibacterial drugs, infusion therapy) is performed for non-penetrating esophageal injuries and the absence of a purulent process in the neck and mediastinal tissue spaces. On average, conservative treatment of non-penetrating esophageal injuries lasts 4-6 days. The lack of effect from ongoing therapy, let alone the progression of inflammatory changes, is an indication for surgical treatment. To ensure adequate trophic status, parenteral nutrition or placement of a gastrostomy for enteral feeding may be performed. The absence of esophageal changes during esophagogastroduodenoscopy (EGD) will serve as an indication for switching to oral feeding.

3.2 Surgical Treatment

Rib fractures

Comments: Flail fractures in children are extremely rare, and there is no consensus on their treatment. The need for surgical treatment of rib fractures in children arises extremely rarely. According to the literature, mechanical ventilation and effective analgesia are indicated. Surgical treatment is used for multiple (more than 3 ribs with fragment displacement) and flail fractures, i.e., when the integrity of the cage is compromised. Surgical treatment of flail rib fractures is subdivided into extra/intrapleural osteosynthesis. The method of extrapleural osteosynthesis consists in fixing mobile bone fragments through punctures or incisions to a splint, which in turn is fixed to relatively stable parts of the bone skeleton. With simultaneous damage to the ribs and sternum, osteosynthesis of the sternum is performed first, and then the ribs. In this way, it is possible to eliminate the instability of the chest wall cage, its deformation, and restore the volume of the pleural cavity. Intrapleural osteosynthesis is performed in patients who, along with flail fractures, have injuries to the intrathoracic organs. Thoracotomy ends with the placement of wires or plates on the flail areas of the ribs or sternum. Intrapleural osteosynthesis is also used in a delayed manner for significant chest deformation.

Surgical treatment for sternal fractures is performed when fragments are displaced by more than the bone thickness. As a rule, open fixation of fragments is performed using Kirschner wires, wire, or screws.

Pneumothorax and hemothorax

Comments: It is advisable to use a single point for puncture/drainage of the pleural cavity, regardless of what needs to be evacuated from the pleural cavity: blood, fluid, or air. Both air and fluid are drained equally effectively through a drain installed in the "safe triangle" area. The "safe triangle" is the area bounded anteriorly by the lateral border of the pectoralis major muscle, posteriorly by the anterior border of the latissimus dorsi muscle, and inferiorly by a horizontal line at the nipple level. For even greater simplicity, the optimal point for thoracentesis is the 5th-6th intercostal space along the midaxillary line. This area is called safe because the muscle layer on the chest wall is thinnest at this site, and accordingly, thoracentesis is least traumatic here.

In moderate pneumothorax/hemothorax, surgical tactics depend on the type of breathing. If the child is breathing spontaneously, one can limit oneself to pleural puncture. However, if according to control study data the pneumothorax persists or increases, it is necessary to perform pleural drainage placement. When diagnosing a moderate pneumothorax in a patient on mechanical ventilation, it is recommended to immediately perform pleural drainage.

Comments: After placing the pleural drain, it is necessary to establish passive drainage according to Bülau. Further treatment tactics for traumatic pneumothorax/hemothorax depend on the drainage result (degree of lung expansion) and the absence or presence of signs of continued inflow of air/blood into the pleural cavity. Early evacuation of blood from the pleural cavity is the main means of preventing the occurrence of fibrothorax and pleural empyema, as well as creating optimal conditions for pleural cavity drainage and lung expansion.

If follow-up examinations (radiography, ultrasound) show complete lung re-expansion following passive pleural cavity drainage, or if the volume of air/blood in the pleural cavity is minimal and there are no signs of respiratory failure, the treatment can be considered effective and no additional procedures are required.

Comments: Indicators of effective treatment include the absence of respiratory failure, cessation of bubbling, and lung re-expansion on follow-up radiography.

Comments: If air bubbling persists for 48 hours of active drainage in a patient with clinical and laboratory subcompensation, and the lung remains collapsed by more than 1/3, this indicates injury to a major bronchus. In such cases, DVAT with selective bronchial blockade is indicated.

Comments: Thoracotomy is indicated in patients with an unstable condition. A standard anterolateral thoracotomy is performed in the 5th intercostal space. Thoracoscopic surgery can only be performed in a "stable" patient in a specialized hospital setting, usually on a delayed basis.

Comments: A standard anterolateral thoracotomy is performed in the 5th intercostal space.

Comments: Cessation of drainage bubbling is an indication to decide on its removal.

Comments: The goals of surgical intervention for retained hemothorax are the evacuation of blood and clots and the release of adhered lung areas. Thoracoscopy performed within the first 3–7 days after trauma successfully evacuates the clot, reduces the rate of complications (including empyema of the pleura), and shortens the patient's hospital stay.

Injury to the aorta and major vessels

Comments: Thoracotomy is performed, with temporary cross-clamping of the proximal aorta and aortic repair. Paraplegia may occur in 5–17% of patients postoperatively (the incidence of complications increases with the duration of aortic cross-clamping). In a review of 468 children with aortic injuries, 72% were in the thoracic aorta, and multiple surgical approaches were undertaken, including primary suture (24%), synthetic graft (21%), patch graft (10%), and endovascular stent (4%). Survival in this study was 61%. With the advancement of endovascular technologies, endovascular stenting has also been successfully used in children.

Diaphragmatic injury

Comments: a confirmed diagnosis of diaphragmatic rupture must be considered an indication for emergency surgery due to respiratory failure caused by lung compression from abdominal organs herniated into the pleural cavity, as well as the risk of incarceration and necrosis of these abdominal organs. The goal of surgery is to eliminate the compression syndrome (returning abdominal organs to their natural anatomical positions) and repair the diaphragmatic defect. Surgical tactics and the choice of approach depend mainly on the dominant chest or abdominal organ injury. Operative repair of the diaphragmatic rupture can be performed via laparotomy, thoracoscopy, or thoracotomy. In most cases, laparotomy is performed with preliminary pleural drainage. In stable patients with a confirmed diagnosis of diaphragmatic injury and if the surgeon has sufficient experience, video-assisted thoracoscopy may be considered. However, even in this case, closing a defect located at the pericardial level is highly problematic.

Esophageal injury

Comments: Thoracotomy is used as a surgical approach in patients when it is necessary either to suture ruptures of the thoracic esophagus or to perform resection in cases of total destruction. Laparotomy is used as a surgical approach in patients with ruptures of the lower thoracic and abdominal esophagus to suture esophageal defects and drain the mediastinum. Fundoplication is performed in patients with ruptures of the lower thoracic esophagus. Endoscopic treatment of traumatic esophageal injuries (clipping of esophageal wall defects and stenting) is possible only for small defects and with appropriate surgical experience.

Chylothorax

Comments: Traumatic chylothorax usually resolves 2–3 weeks after injury. The pleural cavity is drained, and medical nutrition excluding long-chain triglycerides is prescribed [32]. If ineffective, thoracoscopy/thoracotomy with thoracic duct ligation is performed.

3.3 Other Treatment

Comments: The primary and core focus of inpatient treatment should be pain management, as it allows for adequate ventilation, effective coughing, and breathing exercises. As a rapid relief measure, widely used intravenous nonsteroidal anti-inflammatory drugs are preferred. Opioid analgesics (Morphine**, Trimeperidine**, Tramadol**), Metamizole sodium (ATC: N02B), Paracetamol** (ATC: N02BE), nonsteroidal anti-inflammatory and antirheumatic drugs (ATC M01A) (Ibuprofen**, etc.), and epidural analgesia are used for pain relief [15, 16, 78] (Table 1). Most randomized controlled trials have demonstrated the advantages of epidural anesthesia in pain control, reducing the incidence of nosocomial pneumonia, shortening ICU and overall hospital stay, and reducing the duration of mechanical ventilation.

Table 1 – Medicinal products for pain management

Comments: an example of increasing invasiveness is the transition from oxygen insufflation to high-flow nasal cannula, then to non-invasive mechanical ventilation, intubation, and invasive mechanical ventilation.

Comments: Blunt chest trauma is not an indication for emergency tracheostomy. If airway protection is urgently required, tracheal intubation is performed. Prolonged placement of an endotracheal tube may lead to severe laryngeal and tracheal complications. A number of studies have shown that early tracheostomy (within 3 days after trauma) reduces the incidence of adverse outcomes, duration of mechanical ventilation, and length of stay in the ICU. In children, the timeframe for early tracheostomy may be extended up to 7–10 days post-injury. Other advantages of tracheostomy include greater patient comfort, facilitation of nursing care (airway clearance and oral hygiene), psychological comfort, etc. The decision regarding tracheostomy should be made by a medical board with the parents' consent. The board includes: an anesthesiologist-resuscitator, neurologist, surgeon, and otorhinolaryngologist. The tracheostomy technique (open, percutaneous) depends on the clinic's preference.

4. Medical Rehabilitation and Sanatorium-Resort Treatment

The scope of rehabilitation measures for blunt chest trauma depends on the severity of the trauma, as well as multiple and associated injuries. The main goal of early rehabilitation measures in the acute period is the prevention of respiratory and systemic complications.

Comments: Patients with blunt chest trauma are indicated for physical therapy for bronchopulmonary diseases and medical massage (general medical massage) for complication prevention. The choice of physical therapy depends on the type and severity of the injury and the course of the postoperative period in surgical treatment. To improve reparative processes and prevent infectious complications, decimeter-wave (DW) therapy (exposure to decimeter-range electromagnetic radiation), magnetotherapy (high-frequency magnetotherapy – inductothermy for lower respiratory tract diseases; exposure to magnetic fields for bone pathology), and laser therapy (low-level laser therapy for lower respiratory tract diseases) are used. Rehabilitation methods for unconscious patients with chest trauma on mechanical ventilation differ significantly from those for conscious, spontaneously breathing patients. The goals of rehabilitation in these patients are the prevention of respiratory complications and deep vein thrombosis. Timely implementation of early rehabilitation prevents early (pulmonary atelectasis, bronchopneumonia) and late complications (hematoma suppuration, empyema).

5. Prevention and Dispensary Observation

Comments: if residual pulmonary changes are present on imaging data at the time of discharge, instrumental follow-up examinations (ultrasound of the pleural cavities, lungs, and mediastinum, chest X-ray, chest CT) are required in the catamnesis.

6. Organization of Medical Care

Patients with a chest contusion may be delivered to or visit an emergency trauma clinic and referred to a hospital if necessary. In the absence of associated pathology, a chest contusion is not an indication for hospitalization. Patients with suspected pulmonary contusion should be routed to surgical departments and/or general hospitals for examination and to rule out life-threatening consequences. Hospitalization depends on the patient's condition and the extent of lung parenchyma injury. Medical care for all patients with esophageal trauma requires specialized hospital settings.

In accordance with Order of the Russian Ministry of Health No. 927n dated November 15, 2012, "On Approval of the Procedure for Providing Medical Care to Victims with Associated, Multiple, and Isolated Injuries Accompanied by Shock," hospitalization in a specialized hospital (Level 1 trauma center) is indicated. The shock-trauma operating room is a key unit of the trauma center to which the patient is delivered, bypassing the admission department, following prior notification by the emergency medical service.

Indications for hospitalization

1. Chest trauma complicated by pneumothorax/hemothorax

2. multiple fractures of ribs

3. Mild and moderate multiple and associated trauma

4. Admission to the ICU: severe trauma (isolated and multiple chest trauma, associated trauma)

Indications for hospital discharge

1) Clinical stabilization status

2) Lung re-expansion according to follow-up radiography

3) Absence of complications

7. Additional Information

No.

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Karaseva Olga Vitalievna – MD, Head of the Department of Polytrauma, Anesthesiology and Intensive Care, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Chief freelance pediatric specialist for polytrauma of the Moscow Healthcare Department, Moscow

2. Golikov Denis Evgenievich – Researcher at the Department of Polytrauma, Anesthesiology and Intensive Care, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

3. Gorelik Alexander Lvovich – Researcher at the Department of Polytrauma, Anesthesiology and Intensive Care, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

4. Nikishov Sergey Olegovich – PhD, Head of the Department of Traumatology, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

6. Razumovsky Alexander Yuryevich – MD, Corresponding Member of the RAS, Professor, Head of the Department of Pediatric Surgery, Institute of Motherhood and Childhood, Pirogov Russian National Research Medical University, Head of the Thoracic Department, Filatov Children's City Clinical Hospital of the Moscow Healthcare Department, Chief freelance pediatric surgeon of the Moscow Healthcare Department, Chairman of the Presidium of the Russian Association of Pediatric Surgeons, Honored Doctor of the RF, Moscow

5. Timofeeva Anna Vyacheslavovna – Researcher at the Department of Polytrauma, Anesthesiology and Intensive Care, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

6. Kharitonova Anastasia Yuryevna – PhD, Head of the Endoscopy Department, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

7. Shavrov Andrey Alexandrovich – MD, Chief Researcher at the Department of Polytrauma, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

8. Yanyushkina Olga Grantovna – Researcher at the Department of Polytrauma, Anesthesiology and Intensive Care, Research Institute of Emergency Pediatric Surgery and Traumatology – Dr. Roshal Clinic, Moscow

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

1. pediatric surgeons

2. traumatologists-orthopedists

3. surgeons

4. thoracic surgeons

5. anesthesiologists-resuscitators

6. emergency physicians

7. Educators of medical educational institutions

8. Students, residents, postgraduate students, continuing education course attendees.

Material collection for the formulation of recommendation statements (sections 2, 3, 4, 5 of the clinical guideline) was carried out by analyzing relevant clinical guidelines, practical manuals, and articles from peer-reviewed scientific journals known to the members of the working group. The search for articles from peer-reviewed scientific journals was performed using queries in Russian on eLIBRARY.RU and in English on PubMed, Scopus, and Google (query tracking was not performed); titles, abstracts, and full texts (if available) for the most relevant entries were reviewed; when sources of various publication dates were available, priority was given to more recent publications. The level of scientific evidence supporting the recommendation statements was assessed according to Tables 1 and 2. The strength of recommendation statements was determined according to Table 3.

Table 1. Scale for assessing levels of evidence (LE) for diagnostic methods (diagnostic interventions)

Table 2. Scale for assessing levels of evidence (LE) for prevention, treatment, and rehabilitation methods (preventive, therapeutic, rehabilitation interventions)

Table 3. Scale for assessing grades of recommendation (GR) for prevention, diagnosis, treatment, and rehabilitation methods (preventive, diagnostic, therapeutic, rehabilitation interventions)

Procedure for updating clinical guidelines.

The clinical guidelines update mechanism provides for their systematic revision—at least once every three years, as well as upon the emergence of new evidence-based data regarding the diagnosis, treatment, prevention, and rehabilitation of specific diseases, or the presence of justified additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

• Order of the Russian Ministry of Health No. 562n dated October 31, 2012 "On Approval of the Procedure for Providing Medical Care in the Profile 'Pediatric Surgery'.

• Order of the Russian Ministry of Health No. 203n dated April 14, 2025 "On Approval of Criteria for Assessing the Quality of Medical Care".

Appendix B. Physician Action Algorithms

Appendix C. Patient Information

The prognosis in uncomplicated chest injuries is favorable.

In pulmonary contusions, the risk of inflammatory complications increases significantly. In polytrauma, the prognosis is determined by the severity of concomitant injuries. Mortality in this case ranges from 25 to 40% [4]. The main causes of severe chest injuries, including within the structure of polytrauma, are road traffic accidents and falls from a height (catatrauma).

Appendix G. Assessment Scales, Questionnaires, and Other Evaluation Tools

Appendix G1.

Name:

Abbreviated Injury Scale (AIS).

Injury Severity Score (ISS).

Source: AIS Developer Website: https://www.aaam.org/abbreviated-injury-scale-ais/

Baker SP, O'Neill B, Haddon W Jr, Long WB. The injury severity score: a method for describing patients with multiple injuries and evaluating emergency care. J Trauma. 1974 Mar;14(3):187-196.

Content (template):

Key (interpretation):

The Injury Severity Scale (ISS) score is the sum of the squares of the highest Abbreviated Injury Scale (AIS) scores in each of the 3 most severely injured body regions

1. head and neck;

2. face;

3. chest;

4. abdomen, retroperitoneum, and pelvic contents;

5. extremities and pelvic girdle;

6. external injuries.

Injury Severity Score (ISS) criteria

• ISS <9: minor injury.

• 9 ≤ ISS ≤ 15: moderate injury

• 16 ≤ ISS ≤ 24: severe injury

• ISS ≥25: critical injury.