Closed chest trauma: clinical guidelines

List of Abbreviations

BP — blood pressure.

ATOR — All-Russian Public Organization «Association of Trauma Surgeons and Orthopedists of Russia».

VAC — vacuum aspiration.

VATS — video-assisted thoracoscopic surgery.

TD — thoracic duct.

PC — purulent complication.

Duodenum — duodenum.

CCT — closed chest trauma.

IMV — invasive mechanical ventilation.

CG — clinical guidelines.

CT — computed tomography.

INR — international normalized ratio.

MRI — magnetic resonance imaging.

MSCT — multislice computed tomography.

NIV — non-invasive ventilation.

TC — thoracic cavity.

ICU — intensive care unit.

PEEP — positive end-expiratory pressure.

PTE — post-traumatic empyema (pleural).

RCT — randomized clinical trials.

CH — coagulated hemothorax.

US — ultrasound.

FBS — fiberoptic bronchoscopy.

CVP — central venous pressure.

TDC — thoracic duct cistern.

TEE — transesophageal echocardiography.

HR — heart rate.

EGD — esophagogastroduodenoscopy.

PE — pleural empyema.

ECG — electrocardiography.

EchoCG — echocardiography.

AIS (Abbreviated Injury Scale) — Abbreviated Injury Scale.

CPAP (Constant Positive Airway Pressure) — continuous positive airway pressure mechanical ventilation mode.

ERAS (Enhanced Recovery After Surgery) — enhanced recovery after surgery.

ISS (Injury Severity Score) — Injury Severity Score for polytrauma.

SpO2 — oxygen hemoglobin saturation.

VAC (Vacuum-Assisted Closure) — vacuum-assisted closure.

Terms and Definitions

Injury – a disruption of the anatomical integrity of tissues or organs resulting from external impact (closed – without damage to the skin or mucous membranes, open – with damage to the skin or mucous membranes).

Trauma – an injury to human organs and tissues followed by impairment of their functions resulting from environmental factors (mechanical, physical, chemical, biological).

Multiple trauma – an injury resulting in two or more injuries (to organs, bones, etc.) within a single anatomical region.

Casualty – a patient who has sustained trauma or a wound (wounded person).

Sequelae of injuries – pathological processes arising as a result of trauma and causally related to it.

Life-threatening sequelae of injuries – consequences of trauma directly threatening the patient's life.

Complications of injuries – pathological processes resulting from trauma that have their own etiopathogenetic and clinical characteristics and develop later (typically from 3 to 14 days).

Closed chest trauma – a term encompassing all injuries in this anatomical region without disruption of skin integrity.

Pneumothorax – accumulation of air in the pleural cavity.

Paradoxical chest wall movement – pathological mobility of a chest wall segment resulting from multiple double rib fractures and the formation of a flail chest.

Clotted hemothorax – accumulation of blood clots in the pleural cavity.

Bronchial fistula – a pathology of the bronchial tree characterized by the presence of an abnormal communication of the bronchus with the external environment, the pleural cavity, or the lumen of internal organs.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Closed chest trauma (CCT) — a term encompassing all injuries in this anatomical region without disruption of skin integrity (through its entire thickness). Within the framework of these clinical guidelines (CG), CCT includes acute injuries of the chest wall and thoracic cavity organs. Complications and sequelae of CCT, specifically the following conditions, are not considered in these CG: pneumonia, pleural empyema, acute mediastinitis, acute pericarditis, sepsis, and other infectious-inflammatory complications of CCT, traumatic shock, respiratory distress syndrome, and traumatic embolism. Naturally, chest injuries with disrupted skin integrity (through its entire thickness) are not considered in these CG: open chest trauma, thoracic and thoracoabdominal wounds.

Within the scope of CCT, isolated and multiple chest injuries are distinguished and discussed in these CG. An isolated chest injury is defined as an injury present in a single part of the body (in this case, the chest). A multiple injury is defined as one where there are several injuries within the chest as an anatomical body part. Simultaneous injury to the chest and other anatomical body regions (head, neck, abdomen, pelvis, spine, limbs) is defined as combined chest trauma, which is not considered in these CG. Combined injuries resulting from multiple damaging factors (mechanical, thermal, chemical, radiation) are also outside the scope of these CG.

Conditions forming the CCT group:

• Superficial (closed) chest injuries include chest contusion and breast contusion. Clinically adjacent to them are sprains and strains of the rib and sternal ligamentous apparatus, subcutaneous injuries of muscles and tendons of the anterior and posterior chest wall (excluding bones, muscles, tendons, blood vessels, and nerves of the shoulder girdle).

• Rib fracture (closed) — a disruption of the integrity of the bone or cartilage part of a rib. Multiple rib fractures — a disruption of the integrity of the bone or cartilage parts of two or more ribs. Flail (fenestrated, shutter-like) rib fractures (synonyms: flail chest, sunken chest, pathologically mobile chest, paradoxical chest wall movement) — double fractures in which fragments of several ribs are disconnected from the bone framework of the chest, held in place only by surviving skin and soft tissues (the so-called rib window or flap) and participate paradoxically in respiratory movements of the chest: sinking in during inspiration (with a decrease in intrathoracic pressure) and bulging during expiration (with an increase in intrathoracic pressure).

• Sternal fracture (closed) — a disruption of the integrity of the sternal bone tissue.

• Traumatic asphyxia — a distinct symptom complex developing as a result of a sharp, significant increase in blood pressure in the superior vena cava system during brief, high-energy chest compression (e.g., when pinned against a wall by a car).

• Pneumothorax in CCT — accumulation of air in the pleural cavity.

• Hemothorax in CCT — accumulation of blood in the pleural cavity.

• Clotted hemothorax in CCT — accumulation of blood clots in the pleural cavity.

• Hemopneumothorax in CCT — accumulation of blood and air in the pleural cavity.

• Other closed lung injuries, major bronchial trauma, thoracic tracheal trauma.

  Lung contusion is a frequent and life-threatening chest injury, defined as destruction of the lung with alveolar and interstitial hemorrhage resulting from closed trauma without rupture of the lung parenchyma [1, 2].

  Lung injury (rupture) — injury to the lung parenchymal tissue. Lung rupture is usually caused by penetrating wounds, but non-penetrating wounds and closed chest traumas can also cause lung rupture.

  Ruptures of the thoracic trachea and major bronchi are among the most severe and fatal types of chest trauma [3].

• Trauma to major blood vessels of the chest in closed trauma — injuries to the thoracic aorta and its brachiocephalic branches (brachiocephalic trunk, left subclavian and carotid arteries), superior and intrathoracic inferior vena cava, innominate, azygos, and subclavian veins, which in the acute situation manifest as profuse intrapleural hemorrhage, tension mediastinal hematoma, and/or cardiac tamponade, and in the chronic phase — by the formation of a post-traumatic pseudoaneurysm.

• Cardiac trauma in CCT — injury to cardiac structures (myocardium, endocardium, epicardium, papillary muscles, chordae, fibrous ring, and valve leaflets) ranging from mild contusion to overt avulsion/rupture, manifested by cardiovascular system disorders from moderate hemodynamic instability to cardiogenic shock and asystole.

• Esophageal trauma — disruption of the integrity of the esophageal wall caused by mechanical factors, accompanied by the development of an inflammatory process in the organ and surrounding tissues.

• Closed diaphragmatic injury — a rupture (disruption of integrity through the entire thickness of the diaphragm) in its muscular and/or tendinous part without disrupting the integrity of the chest and/or abdominal walls, with or without injury to abdominal and thoracic cavity organs.

• Closed trauma of the thoracic lymphatic duct — disruption of the integrity of the thoracic duct wall or its major branches and collaterals caused by mechanical factors. Traumatic chylothorax in CCT — accumulation of chyle in the pleural cavity, the most frequent and typical manifestation resulting from tearing or rupture of the thoracic duct or major lymphatic vessels of the thoracic cavity draining into it [4].

• Closed thymus trauma occurs in children [5], which is not considered in these CG.

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

Closed chest trauma in general

CCT results from motor vehicle accidents, falls from a height, blunt force impacts, and other causes (direct and indirect damaging effects on vital organs of the respiratory and circulatory systems). The severity of the patient's condition is determined not only by damage to thoracic organs and structures, but also by impairments of vital functions caused by general pathophysiological mechanisms [142, 143, 146].

Pain. Nociceptive impulses from extensive receptor fields of the parietal and visceral pleura and intercostal nerves play a significant role in the pathogenesis of chest injuries.

Acute cardiopulmonary failure. In acute trauma, myocardial performance decreases due to a deficit in circulating blood volume (bleeding), the direct impact of trauma on the heart (cardiac contusion, hemopericardium), increased pulmonary vascular resistance (hemothorax, pneumothorax, pulmonary contusion, intrapulmonary hematoma, atelectasis), or systemic vascular resistance (neuroendocrine response to pain, sludged blood). When hemodynamics are restored, the acute phase of trauma ends, and the early complication period begins (not covered in this clinical guideline). Its most dangerous manifestation is acute respiratory distress syndrome (shock lung syndrome). The leading role in its pathogenesis is played by increased permeability of the pulmonary capillaries accompanied by decreased pulmonary perfusion and lung tissue hypoxia, leading to interstitial pulmonary edema. Pulmonary congestion is also promoted by myocardial dysfunction, which progresses as the distress syndrome develops, leading to acute cardiopulmonary failure.

Acute heart failure. The main role in the development of acute heart failure in trauma is played by increased venous return coupled with obstructed blood outflow from the lesser circulation, leading to elevated pressure in the pulmonary veins and capillaries (passive pulmonary hypertension), and subsequently in the arterioles (active pulmonary hypertension). This creates conditions for the development of interstitial and, subsequently, alveolar pulmonary edema. Simultaneously, arterial hypotension and hemoperfusion disorders develop in the systemic circulation.

Cardiac tamponade. Injury to the heart and pericardium may be accompanied by blood accumulation in the pericardial cavity, leading to cardiac tamponade (compression of the heart by the accumulating blood).

Acute respiratory failure. Despite differences in pathogenesis, any volume reduction (and, consequently, increase in intrapleural pressure) triggers a common pathophysiological mechanism: lung collapse — increased pressure in its capillaries — centralization of pulmonary blood flow (shunting) — ventilation-perfusion mismatch (inability to provide adequate gas exchange even with mechanical ventilation due to severe circulatory disorders of gas exchange in the pulmonary parenchyma).

Primary acute respiratory failure in trauma is caused by a compromised thoracic cage framework, pneumothorax, hemothorax, and airway obstruction: aspiration syndrome, bronchospasm, bronchial injury, foreign body obstruction (consequences of foreign bodies penetrating the thoracic cavity organs are not covered in this clinical guideline). The most important role in the pathogenesis of acute ventilatory respiratory failure is played by elevated intrapleural pressure (regardless of etiology) — pneumothorax and hemothorax, large mediastinal or intrapulmonary hematoma, dislocation of abdominal organs into the pleural cavity in diaphragmatic rupture, etc. Hypercapnic respiratory failure occurs due to hypoventilation, increased functional dead space, and increased carbon dioxide production. Hypoxic respiratory failure develops due to impaired alveolar diffusion capacity, pulmonary blood shunting, and interstitial edema.

Secondary respiratory failure is associated with pathological conditions of the cardiopulmonary system that develop after trauma: cardiogenic pulmonary edema, pulmonary embolism, respiratory distress syndrome, and severe pneumonia (not covered in this clinical guideline).

Bronchoobstructive syndrome. The key pathogenetic mechanisms are edema, dyskinesia, and obstruction of bronchioles by saliva, sputum, gastric contents, and blood. The respiratory muscles perform colossal yet inefficient work, consuming a vast amount of oxygen, while hypoxia, respiratory acidosis, and metabolic alkalosis increase. Impaired drainage in bronchoobstructive syndrome goes through three stages: compensated bronchorrhea (both sputum production and clearance increase), decompensated bronchorrhea (sputum production increases, but the mucociliary mechanism fails to transport it), and obstruction: the rheological properties of sputum change to such an extent that reflux and airway blockage occur. Bronchial obturation leads to collapse (atelectasis) of the corresponding part of the lung.

Traumatic shock (classified among life-threatening consequences of blunt chest trauma and not covered in this clinical guideline). It is one of the key pathological processes in severe trauma. Shock states, regardless of their causes, manifest identically in their final stage. Disturbances in the rheological properties of blood, its pooling and sequestration in capillaries, hypovolemia with a "low output" syndrome, and tissue ischemia with fatal metabolic disorders are observed.

Multiple organ dysfunction syndrome. The progression of the described pathological processes of the cardiopulmonary system, mediated through hypoxia and hypoxemia, triggers the development of multiple organ dysfunction syndrome: adrenal, hepatic-renal, and others (not covered in this clinical guideline).

Rib fractures

Rib fractures occur as a result of impacts, falls onto protruding objects, and chest compression.

The pathology is characterized by specific morphological features. Within the first 24 hours after trauma, macroscopic examination of the rib fracture site reveals the formation of an interfragmentary hematoma, edema, and blood imbibition of the surrounding tissues. Microscopic examination reveals numerous lymphoid and histiocytic cellular elements against the background of a small amount of unformed intercellular substance.

On the second day, changes occur in the interfragmentary hematoma within the fracture zone, revealing a soft, dark reddish-brown mass without clear margins. Characteristic changes are identified on the rib fragments: "stripping" and detachment of the periosteum by 2–4 mm from each margin; formation of a subperiosteal hematoma, causing displacement and compression of the spongy bone of the rib to a depth of 4–6 mm, predominantly at the vertebral end. Microscopy of the fracture zone reveals numerous poorly differentiated connective tissue cells forming irregular cord-like structures. In the periosteal zone, thickening and loss of the clear structure of the periosteum are observed with marked capillary stasis and venous congestion at the sites of its detachment. Five days after the injury, with continued motion of the rib fragments, characteristic plastic deformations of the bone friction surfaces appear in the fracture zone. This is the so-called "friction burn" — an area of condensed bone tissue. At the site of the interfragmentary hematoma, granulation tissue proliferation is observed with isolated fibroblastic cells. Along the demarcation line of the interfragmentary hematoma, a leukolymphocytic wall appears with sinuous resorption of damaged compact bone areas beyond the "friction burn" from the endosteal side. On the 14th day, further intensive bone resorption is observed with the formation of a distinct "resorption sulcus" immediately behind the condensation area ("friction burn") on the surface of the cortical plate of the marginal rib fragment segment. This indicates detachment of the "friction burn" area, which subsequently undergoes partial resorption and serves as the basis for primary bone callus formation. Morphological examination of the rib fracture zones 21 days later clearly defines bony trabeculae partially filling the interfragmentary gap. Thus, on days 1, 2, and 5 post-injury, no morphologically significant changes aimed at fracture stabilization are detected in the fracture zone. With respiration maintained for more than 5 days, a delay in primary bone callus formation and enhanced bone resorption at the fracture site are noted. Persistent chest instability causes "stripping" and detachment of the periosteum by 4–6 mm with subperiosteal hematoma formation, leading to microcirculatory impairment in the border areas of the rib fracture. As a result, bone nutrition practically ceases in the marginal fracture zone, and prior fragment contact in this zone is accompanied by bone condensation and necrosis followed by active sinuous resorption.

A comparison of tissue areas around isolated rib fractures with those around fragmented fractures shows that osteoblast activation, indicating cellular proliferation within them, occurs 7–9 days later than in single fractures. This is due to the fact that continuous movement of the rib fragments causes additional damage to newly formed trabecular structures; consequently, during the formation of a dense bone callus, the latter undergo double remodeling under the influence of loads at the fracture site.

Flail chest (flail segment)

Flail chest is a specific and uncommon condition characterized by multiple (2 or more) fractures of two or more ribs, including chondrocostal junctions, resulting in the separation of a part of the chest wall from the rest of the skeleton (i.e., disruption of the framework). During respiration, the injured area exhibits paradoxical movement relative to the rest of the thorax: the "rib flap" sinks inward during inspiration (due to decreased intrathoracic pressure) and bulges outward during expiration (due to increased intrathoracic pressure).

Paradoxical chest movement leads to incomplete expansion of the lung on the injured side. During inspiration, due to the indrawing of the flail segment, intrapulmonary air pressure on the injured side is higher, and during expiration, due to the bulging of the "rib flap," it is lower than in the lung on the healthy side. Consequently, during respiration, air partially shuttles back and forth between the lung on the affected side and the lung on the healthy side.

Such pendular movement of air in the lungs leads to an increase in "dead" space and contributes to worsening hypoxia. Furthermore, differing pressures in the healthy and injured halves of the chest cavity, changing during the respiratory cycle, cause pendular displacement of the mediastinal organs (including the heart and great vessels), which also contributes to the development of cardiovascular disorders.

As a result of this, in more than half of the cases, acute respiratory failure develops, associated inter alia with pulmonary contusions and severe mediastinal injuries, requiring ventilatory support. Only a small percentage of casualties with pathological chest wall mobility may lack other concomitant injuries and maintain a satisfactory condition with analgesic therapy and breathing exercises [6].

Blunt chest trauma is frequently accompanied by fractures of the VII–X ribs in areas located between the posterior axillary and scapular lines. This is explained by the fact that the thorax is widest in this region. Chest trauma accompanied by disruption of the rib framework and double rib fractures, known as fenestrated or flail fractures—forming "rib flaps"—is particularly severe.

Life-threatening external respiration disorders occur when six or more ribs are fractured on one side, resulting in a 30–40% reduction in the vital capacity of the lung on the affected side.

The most severe disorders occur with the development of paradoxical respiration, when the damaged segment of the chest wall loses its firm connection with the intact section, and during inspiration, the chest wall caves in at the site of the flail chest due to the negative pressure arising in the pleural cavity. During expiration, however, bulging of the chest wall is observed at the fracture site due to increased pressure in the pleural cavity. The larger the size of the flail chest and the more mobile it is, the more severe the patient's condition. Also, the caving in of the flailing segment during inspiration facilitates the transfer of carbon dioxide-rich air from the damaged lung to the intact one, which accounts for the ventilational component of respiratory failure. The decrease in the volume of the pleural cavity during the caving in of the chest wall and pneumothorax on the injured side contribute to an increase in intrapulmonary veno-arterial blood shunting.

According to the localization of rib fractures, anterior (bilateral), anterolateral, and posterolateral flail chests are distinguished. The formation of an anterior bilateral flail chest, which involves the sternum and costal cartilages, leads to cardiovascular disorders in addition to respiratory disturbances.

Patients also tolerate anterolateral flail chest poorly. Posterolateral flail chest has a milder clinical course because it is fixed by the powerful muscular frame of the back and the patient's horizontal body position. Multiple rib fractures are often accompanied by lung injuries with the development of hemopneumothorax, cardiac and pulmonary contusions (see relevant sections).

Sternum fracture

A sternum fracture is a consequence of direct trauma and occurs in severe chest injuries, as this bone usually breaks only under significant mechanical impact. Fractures of the sternum occur mainly in motor vehicle accidents, when the driver's chest hits the steering wheel during a head-on collision or is injured by a seat belt [1].

Traumatic asphyxia

The clinical course of chest injuries has a number of specific features associated with the anatomical and physiological structure of this body part. Vital organs and major blood vessels of the chest are enclosed in a bony cage (sternum, ribs, spine), which has a protective function but can also cause injuries to them.

Traumatic asphyxia occurs with sudden compression of the chest (for example, when pinned against a wall by a car). Under conditions of reflex spasm of the glottis, intrathoracic pressure sharply increases and blood outflow through the superior vena cava system from the upper half of the body to the right heart chambers becomes obstructed. 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 (characteristic of traumatic asphyxia; there are no intradermal hemorrhages under tight clothing or bras).

In the first hours and days after trauma, traumatic asphyxia is accompanied by the development of a severe condition and acute respiratory failure.

Pneumothorax

Normally, a negative pressure (-5 to -7 cm H2O) exists in the pleural cavity, which ensures lung expansion. Therefore, in closed chest injuries with lung or bronchial damage, air enters the pleural cavity and the lung collapses (closed non-tension or closed tension pneumothorax occurs).

Air enters the pleural cavity upon injuries to the visceral pleura, pulmonary parenchyma, and airways caused by rib fragments and/or a significant sharp increase in pressure in the tracheobronchial system as a result of high-energy mechanical impact on the chest wall with reflex closure of the vocal cords.

In closed pneumothorax, the lung partially or completely collapses, and no pulmo- and/or bronchopleural communication is present.

In open internal pneumothorax, the lung partially or completely collapses, but there is a functioning pulmo- and/or bronchopleural communication through which inhaled air makes pendular movements between the healthy lung and the pleural cavity as a "dead space". Hypercapnia, hypoxemia, and acute ventilational respiratory failure, and later acute cardiovascular failure, develop.

In valvular (tension) pneumothorax, damaged lung and/or bronchial tissues act as a valve that prevents the escape of inhaled air from the pleural cavity, leading to a rapid increase in pressure in the pleural cavity and life-threatening progressive acute ventilational respiratory and acute cardiovascular failure due to lung collapse, mediastinal shift to the opposite side, reduction in the volume of the healthy lung, compression and kinking of the major mediastinal vessels, primarily the venae cavae with a deficit of venous blood return to the heart.

Hemothorax

Closed parenchymal lung injury is accompanied by the accumulation of blood in the pleural cavity (hemothorax). Injury to major chest vessels or chest wall arteries, which are branches of the aorta and subclavian artery, results in ongoing intrapleural hemorrhage.

Clotted hemothorax. Bleeding into the pleural cavity can occur with almost any injury to the chest wall tissues or intrathoracic structures. Blood entering the pleural cavity is subjected to the movement of the diaphragm and lung, which leads to defibrination of the blood with fibrin precipitation and clot formation. Within several hours after the cessation of bleeding, lysis of existing thrombus by pleural enzymes begins. However, when a large amount of blood is poured out at once, or due to post-traumatic impairment of parietal pleura function, high total blood coagulation activity, and increased activity of coagulating factors in the pleural cavity contents resulting from the influx of thromboplastin from damaged tissues, the lysis of the clot is incomplete, and the formation of a clotted hemothorax (CHT) is inevitable. Fibrin and blood clots accumulated in the cavity become organized with subsequent adhesion to the pleural layers. By the seventh day, angioblastic and fibroblastic proliferation is observed, leading to the formation of massive dense layers both around the collapsed lung and on the layers of the altered parietal pleura. Outcomes of clotted hemothorax include complete spontaneous resorption within several weeks, progression to fibrothorax and the development of a rigid lung, or infection with the occurrence of empyema of the pleura [7, 8].

Clotted hemothorax forms within 1–2 days after the cessation of bleeding into the pleural cavity in closed chest trauma. The formation of clots in the lower or posterobasal parts of the pleural cavity is facilitated by delayed diagnosis and delayed management of hemothorax, inadequate drainage of the pleural cavity, and prolonged failure of the lung to expand.

Other injury of the lung(s), injury of major bronchi, trachea (thoracic segment)

Pulmonary contusion occurs as a result of the transfer of kinetic energy from the chest wall to the lung parenchyma. Pulmonary contusion is the most frequent injury associated with bone fractures [9]. As a result of the contusion, hemorrhage occurs in the lung tissue and inflammation develops, primarily manifested by edema of the damaged lung parenchyma. Bleeding and edema cause severe functional changes, notably hypoxia, which can lead to parenchymal destruction reaching its maximum within the first 24 hours after trauma [10]. In addition, damage to the lung tissue releases a large amount of inflammatory mediators, leading to a decrease in immune resistance and increasing the risk of pneumonia [11-14].

Mechanisms of rupture of the thoracic trachea and major bronchi: 1) sudden compression of the chest in the anteroposterior direction (e.g., striking the steering wheel in a traffic accident); 2) rupture from rapid deceleration (falling from a height onto the feet); 3) severe compression injury with closed vocal cords [15].

Injury of thoracic blood vessels

The most frequent causes of major chest vessel injuries are frontal and side motor vehicle collisions, falls from a height of more than 10 meters, and accidents in mountaineering, equestrian, and ski sports.

The mechanisms of closed vascular chest trauma include: 1) the action of shearing forces between the relatively mobile and fixed parts of the vessel; 2) damage and/or compression of the vessel by bone fragments (ribs, sternum, scapula, thoracic vertebrae); 3) marked intravascular hypertension at the moment of impact. Injury to the thoracic aorta via the first mechanism is termed "deceleration syndrome" (sudden deceleration syndrome), where in 90% of cases the injury is located at the aortic isthmus (1.5–2 cm distal to the origin of the left subclavian artery), where the vessel is fixed by the ligamentum arteriosum.

In closed trauma, the vessel wall may be damaged partially (rupture of the intima only, similar to aortic dissection), but more commonly the injury involves the full thickness of the wall, engaging either the entire circumference or a part of it, resembling an aortic aneurysm rupture. With such ruptures, cardiac tamponade and/or total hemothorax develop within minutes, which is fatal at the scene in almost 80% of cases. Much less frequently, surrounding tissues (e.g., the pleura) can contain profuse bleeding and prevent instant death; in 6–20% of these patients, a stable false aneurysm subsequently forms.

Cardiac injury

In fact, any mechanism that transmits kinetic energy to the heart can cause cardiac injury: severe chest trauma from high-speed motor vehicle collisions, blunt impact to the sternum, falls from a height, blast wave exposure, or "aggressive" cardiopulmonary resuscitation. Injuries to the heart in the form of wounds caused by sharp rib fragments (puncture and traumatic perforation) are not uncommon in blunt chest trauma. Mechanical impact on the chest wall causes hemorrhage into the myocardium, subepicardium, or subendocardium. The extent of myocardial hemorrhage (and rupture) depends on the degree of filling of the cardiac chambers with blood at the time of trauma. The hydraulic effect during systole causes more severe cardiac injury than during diastole. Rupture and crushing of muscle fibers, hemorrhage from damaged vessels, and tamponade formation are possible. Cardiac contusion may also occur without damage to the bony skeleton of the chest. Myocardial hemorrhage can lead to compression of a coronary vessel and the development of myocardial infarction. The latter may also occur if a thrombus forms on the damaged intima of a coronary artery.

Diaphragmatic injury

Currently, 80–90% of closed diaphragmatic ruptures result from motor vehicle accidents. The mechanism of rupture is related to the pressure gradient between the pleural and abdominal cavities. A side impact from a motor vehicle accident is 3 times more likely to cause a rupture than any other type of impact (e.g., a fall) because it can deform the chest wall and displace the ipsilateral part of the diaphragm. A frontal impact from a motor vehicle accident can cause an increase in intra-abdominal pressure, leading to long radial tears 5–15 cm in length, most commonly in the posterolateral direction, at its embryologically weak spot [16, 17]. In isolated closed abdominal trauma, this pathology is more common than in similar chest trauma—4% and 0.8%, respectively. In closed trauma causing a sudden increase in intra-abdominal pressure, the diaphragm, as the most compliant and thin wall of the abdominal cavity, often cannot withstand the increased load and ruptures. During chest compression, the diaphragm easily bows downward and remains undamaged. Only major frontal chest deformation leads to overstretching and rupture of the diaphragm. Left-sided diaphragmatic ruptures are localized significantly more often than right-sided ones. Rupture of both halves of the diaphragm is rare.

Esophageal injury (thoracic segment)

The main mechanisms of esophageal injuries are gunshot and stab wounds, catatrauma, and motor vehicle accidents. Depending on the type of esophageal injury, the clinical picture unfolds over a time span ranging from several minutes to a day. From the moment the integrity of the esophageal wall is compromised (within 24 hours), purulent complications begin to develop: mediastinitis, cervical phlegmon, and pleural empyema. Rupture of the mediastinal pleura with the development of unilateral or bilateral pyopneumothorax is possible. As mediastinitis progresses, the patient's condition sharply deteriorates, and systemic inflammatory response syndrome, sepsis, infectious-toxic shock, and multiple organ dysfunction syndrome develop. Without appropriate treatment, the patient dies against the background of progressive sepsis.

Injury to other thoracic organs

Injury to the thoracic duct. The accumulation of lymph in the pleural cavity leads to cyanosis, tachycardia, and other signs of cardiopulmonary insufficiency. The loss of chyle is accompanied by pallor, weight loss, hypovolemia, hypolipoproteinemia, lymphopenia, and immunosuppression. The severity of these symptoms is directly dependent on the volume of chylothorax. Left-sided chylothorax has a somewhat more favorable course, in which fluid accumulation causes less mediastinal shift due to the compliance of the left dome of the diaphragm. The lung on the side of the chylothorax becomes rigid during prolonged collapse due to massive fibrinous deposits on the visceral pleura.

1.3 Epidemiology of the Disease or Condition

Closed chest trauma in general

In the structure of overall traumatology, chest injuries rank third (up to 10%) after extremity injuries and traumatic brain injuries. Mortality in severe isolated chest trauma reaches 15–30%. Among all trauma fatalities, 20% have chest injuries, which are second in frequency only to neurotrauma [18].

Superficial trauma, injury to ligaments, muscles, and tendons of the chest wall

Chest injuries without bone damage are less frequent than those with bone damage and are represented by massive hemorrhages and soft-tissue hematomas of the chest wall.

Rib fractures

Rib fractures are diagnosed in all patients with thoracic bone injuries, with 25.9% of them being radiolucent on routine chest radiographs. Double rib fractures are present in 23.7% of patients, excluding patients with flail chest (14%). Rib fractures account for 5–15% of all fractures [19]. Fractures of the 3rd to 9th ribs are more common [20]. Fractures of the first 3 ribs generally cause severe trauma with potential mediastinal involvement, neurological, vascular, and extrathoracic injuries. Fractures of the lower ribs (below the 8th) may be accompanied by concomitant abdominal injuries.

Flail chest (flail segment)

Closed chest trauma is frequently (in 75% of cases) accompanied by fractures of the 7th–10th ribs in areas located between the posterior axillary and scapular lines. A flail chest develops in 5–13% of patients with chest trauma. In blunt chest trauma, flailing rib fractures occur in 10–20% of cases and carry a mortality rate of 12.5% to 33%, partly due to the severity of associated injuries [21, 22]. Flail fractures are more common in adult patients than in children. This is due to the greater elasticity of the rib cage in younger individuals, which is why they may experience fractures of the rib cortex along the convex surface (incomplete "greenstick" fracture).

Sternum fracture

Sternum fracture occurs mainly as a result of motor vehicle accidents (in 3% of all accidents) [23, 24].

Pneumothorax, hemothorax, hemopneumothorax

The incidence of pneumothorax in isolated blunt chest trauma ranges from 20% to 40% [25, 26]. Hemothorax is detected in 8.1% of patients, hemopneumothorax in 39.3%, and pneumothorax without hemothorax in only 10.2%. Traumatic hemothorax occurs in 25–59.9% of victims, with the incidence of coagulated hemothorax varying from 4% to 30% [27, 28]. Small hemothorax is present in every fifth patient, moderate in every eighth, and large and total in every seventh. In some patients, the pathology is represented by lung injuries caused by rib fragments with the formation of a closed pneumothorax. In the majority of them, pneumothorax and hemopneumothorax are moderate to large, and in 7%—tension pneumothorax [29].

Other injury of the lung(s), injury of major bronchi, trachea (thoracic segment)

The majority (almost 60%) of patients are diagnosed with concurrent lung injuries (contusions and lacerations) and cardiac injuries (contusions). In more than a third of the remaining patients, only the lungs are injured. In cases of severe blunt chest trauma, the presence of a pulmonary contusion should always be suspected, with an incidence ranging from 17% to 75% [30, 31]. The incidence of lung laceration in closed chest trauma ranges from 4.4% to 12% [31–33]. The clinical incidence of ruptures of the thoracic trachea and major bronchi ranges from 0.8% to 5%, but the majority of victims die at the scene due to life-threatening injuries. Pre-hospital mortality reaches 81% [34–36].

Injury of thoracic blood vessels

The incidence of blunt thoracic vascular injuries is 0.9–5.2%. Among these, the thoracic aorta, brachiocephalic artery, pulmonary veins, and venae cavae are most frequently injured. No more than 20% of patients with major thoracic vessel trauma are delivered alive to the hospital, and among those hospitalized, mortality is 60–80%. One-third of patients die from severe associated injuries (central nervous system, pelvic trauma).

Cardiac injury

Cardiac trauma in blunt chest trauma occurs in 14–54% of cases, of which 13–32% of patients present with external and internal ruptures (chambers, valves, papillary muscles, chordae tendineae, septa, coronary arteries, and pericardium), while myocardial contusions occur in the remaining cases. The right heart chambers (auricle, atrium) rupture 5–7 times more frequently than the left. Patients with blunt cardiac trauma also present with rib and sternal fractures (18–69%), hemothorax (7–64%), pulmonary contusion (6–58%), pneumothorax (7–40%), flail chest (4–38%), aortic and/or other great vessel injuries (20–40%), and spinal trauma (10–20%). In-hospital mortality reaches 91.5% for cardiac ruptures and 31% for contusions.

Diaphragmatic injury

Closed diaphragmatic injuries occur in 5.6% of cases following blunt chest trauma and in 4.0% of cases following blunt abdominal trauma [37–40].

Left-sided diaphragmatic injuries account for 60–70% of cases. This may be due to the protective effect of the liver or the weakness of the left hemidiaphragm. These injuries are most often accompanied by damage to the stomach, colon, and spleen [41]. Right-sided ruptures account for 30–40%, but are accompanied by more severe injuries because they require a higher impact energy (high-speed motor vehicle collisions) and lead to greater hemodynamic instability in patients. Typically, the liver or colon is injured in such cases. Right-sided ruptures are associated with higher mortality and a lower rate of patient survival prior to correct in-hospital diagnosis [39]. Diaphragmatic trauma is bilateral in only 3% of cases [42]. Diaphragmatic injuries are frequently associated with injuries to the aorta, kidneys, hollow organs, liver, lungs, spleen, pelvis, and ribs, as well as severe complications (deep vein thrombosis, pulmonary embolism, hemopneumothorax, pneumonia, acute respiratory distress syndrome, sepsis) with a mortality rate of 20% [39].

Esophageal injury (thoracic segment)

An analysis of publications by both domestic and foreign authors indicates that there are currently no significant randomized trials in this field, which is quite understandable given the specificity of the pathology and the extreme heterogeneity of patient groups. In the vast majority of publications, both prospective and retrospective, the number of patients rarely exceeds 20 observations. These discrepancies are explained by the fact that the authors of the publications work in specialized clinics with different patient routing systems.

1.4 Features of Coding the Disease or Condition

This clinical guideline provides information on blunt chest trauma:

• closed superficial chest trauma: breast contusion (S20.0), other and unspecified superficial injuries of the breast (S20.1), chest contusion (S20.2), other superficial injuries of the anterior (S20.3) and posterior (S20.4) chest wall, multiple superficial injuries of the chest (S20.7), superficial injuries of other and unspecified parts of the chest, including unspecified chest wall (S20.8);

• closed musculoskeletal chest trauma, excluding injuries to the thoracic spine, clavicle, scapula, and shoulder joint: closed fracture of the sternum (S22.2), rib (S22.3), multiple rib fractures (S22.4), flail chest (rib cage instability, stove-in chest) (S22.5), sprain and strain of the ligamentous apparatus of the ribs and sternum (S23.4), closed injury of muscles and tendons at the thoracic level (S29.0);

• closed isolated injuries of internal thoracic organs, excluding nerve and spinal cord injuries in the thoracic spine and axillary region: closed injury of the thoracic aorta (S25.0), injury of the brachiocephalic or subclavian artery (S25.1), injury of the superior vena cava (S25.2), injury of the brachiocephalic or subclavian vein (S25.3), injury of pulmonary blood vessels (S25.4), injury of intercostal blood vessels (S25.5), injury of multiple blood vessels of thorax (S25.7), injury of other blood vessels of thorax (S25.8), injury of unspecified blood vessel of thorax (S25.9), heart injury with hemopericardium (S26.0), other heart injuries (S26.8), unspecified heart injury (S26.9) closed traumatic pneumothorax (S27.0), hemothorax (S27.1), hemopneumothorax (S27.2), closed bronchial injury (S27.4), of thoracic trachea (S27.5), of pleura (S27.6) and other closed lung injuries (S27.3), closed injury of diaphragm, thoracic duct, thoracic esophagus, thymus and other specified organs of thoracic cavity (S27.8);

• closed multiple injuries of thoracic organs (S27.7), closed multiple injuries of the chest (S29.7), closed isolated injury of an unspecified thoracic organ (S27.9), traumatic asphyxia, crushing of the chest, crushed chest (S28.0), other specified closed chest injuries (S29.8), unspecified blunt chest trauma (S29.9).

1.5 Classification of the disease or condition

Closed chest trauma in general

Blunt chest trauma can occur with or without fractures of the chest wall bones, and with or without internal organ damage.

Classification of blunt chest injuries (by P.A. Kupriyanov [43], E.A. Wagner [44] with modifications)

Flail chest fractures (flail chest)

The following types of flail fractures are distinguished:

a) anterior bilateral: rib fractures are localized on both sides of the sternum on the anterior surface of the chest; the anterior section of the chest loses connection with the spine;

b) anterolateral: each rib breaks in two (or more) places on one side of the sternum along the anterior and lateral surfaces of the chest; the anterolateral section of the chest loses connection with the spine;

c) posterolateral: each rib breaks in two (or more) places on one side of the spine along the posterior and lateral surfaces of the chest; the posterolateral or posterior section of the chest loses connection with the spine;

d) posterior bilateral: rib fractures are localized on both sides of the spine on the posterior surface of the chest.

Pneumothorax

In blunt chest trauma, pneumothorax can be closed or tension (valvular). Closed pneumothorax can be small (limited) (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), and total (lung completely collapsed) [25, 45].

Hemothorax

Depending on the amount of blood spilled into the pleural cavity, the following are distinguished (Kupriyanov P.A., 1950):

1. Small hemothorax (up to 500 ml). Blood most often occupies the pleural sinuses

2. Moderate hemothorax (from 500 to 1500 ml). Blood reaches the angle of the scapula.

3. Large (total) hemothorax (more than 1500 ml). Blood is located above the angle of the scapula or occupies the entire, or almost the entire, pleural cavity.

Clotted hemothorax. V.I. Kovalchuk et al. (1988) identified 4 stages of clotted hemothorax formation [46]:

1. Unorganized clotted hemothorax, when morphologically there is a mass of loose fibrin with a predominance of erythrocytes, weakly adhered to the pleural leaflets. Duration up to 3 days;

2. Fixed clotted hemothorax — fibrin with a predominance of leukocytes and young connective tissue, fixing the dense mass to the pleural leaflets. Formation period from 4 to 14 days;

3. Organized CT (organized chest trauma) — fibrin with a predominance of connective tissue showing blood vessel formation, which is firmly fused to the pleural leaves. Formation period ranges from 14 to 45 days;

4. Fibrothorax — coarse fibrous connective tissue growing into the interstitial layers of the lung with shrinkage of alveolar lobules and calcification of pleural adhesions. This stage develops after one and a half months of CT existence and lasts for decades.

Thoracic blood vessel trauma

When describing thoracic vascular trauma, the following are distinguished:

- injuries to the thoracic aorta (ascending, arch, isthmus, descending), brachiocephalic trunk, left common carotid and subclavian arteries, superior vena cava, intrathoracic segment of the inferior vena cava, subclavian, azygos and hemiazygos veins, intercostal and internal thoracic arteries;

- partial (subadventitial) and complete (full-thickness) vessel wall rupture (accompanied by partial or complete interruption of the circumference), vessel compression (by hematoma, bone fragments). In thoracic aortic injury, 4 types are distinguished separately — type I (intimal tear), type II (intramural hematoma), type III (pseudoaneurysm), and type IV (rupture).

Consequences of blood vessel trauma in blunt chest trauma (not covered in these clinical guidelines):

- life-threatening consequences of injury in the form of ongoing intrapleural hemorrhage, cardiac tamponade, acute cerebrovascular accident, wall dissection (aorta, arteries);

- long-term consequences in the form of false aneurysm and arteriovenous fistula formation.

Heart injury

By morphology, cardiac contusions, ruptures (which may be accompanied not only by myocardial damage, but also involve the pericardium, valves, papillary muscles, chordae tendineae, septa, coronary arteries, and conduction system), punctures, and traumatic perforations are distinguished.

By clinical course, the following are distinguished: acute manifestations (with cardiac tamponade, intrapleural hemorrhage, and cardiogenic shock) leading to immediate or rapid fatal outcome; and subacute manifestations (subacute cardiac tamponade, myocardial infarction, valvular regurgitation, intracardiac shunts, arrhythmias) causing hemodynamic disturbances with the development of acute cardiovascular failure. Late manifestations (complications) of cardiac trauma (not covered in these clinical guidelines): persistent arrhythmias, valve insufficiency, aneurysms, septal shunts, which collectively lead to the development of chronic heart failure.

Promising for practical use is the grading of cardiac injury severity [47, 48].

Diaphragmatic trauma

Classification of diaphragmatic rupture in blunt trauma:

1. By localization of ruptures: muscular part, tendinous part, muscular and tendinous parts.

2. By rupture shape: linear, stellate.

3. By severity:

I — linear or stellate rupture up to 5 cm,

II — linear or stellate rupture 6–10 cm,

III — linear or stellate rupture greater than 10 cm,

IV — avulsion of the diaphragm from the chest wall or extension of the rupture to the pericardium.

Immediately after the diaphragmatic rupture, a post-traumatic diaphragmatic hernia begins to form, which goes through three phases in its development:

a) acute phase: at the time of diaphragmatic injury, but clinical manifestations are more often determined by concomitant internal organ injuries;

b) delayed phase (if the diagnosis is not made at an early stage and the patient's condition has relatively stabilized): the process of hernia formation begins, accompanied by transient clinical symptoms from the abdominal and thoracic organs or may be asymptomatic;

c) obstructive phase: complications of the long-standing diaphragmatic hernia (ischemia, necrosis, strangulation, perforation of herniated contents) [49].

Esophageal trauma (thoracic segment)

The overall variety of esophageal injuries (both considered within the scope of these clinical guidelines and others) is classified as follows.

Classification 1

Internal (closed) — injuries on the mucosal side

External (open) — from the connective tissue membrane or peritoneal side. As a rule, accompanied by damage to the skin of the body in wounds of the neck, chest, and abdomen.

Classification 2

I. By injury etiology:

1. Mechanical (by blunt objects, edged weapons, and firearms).

2. Physical (as a result of high barometric pressure, radiant energy, high and low temperatures).

3. Chemical (burns from acids, alkalis, oily liquids, heavy metal salts, ethanol and its surrogates).

4. Biological (due to tumor breakdown, acute and chronic non-specific and specific inflammatory and non-inflammatory diseases of the esophagus and adjacent organs).

II. By depth and extent of injury:

• Partial esophageal wall injury (with preservation of the mucosa or muscular layer depending on the direction of the damaging factor).

• Complete (transmural) injury.

• Single or multiple injuries.

III. By time elapsed since injury:

• Early — up to 24 hours.

• Late — more than a day.

IV. By phases of clinical course:

1. Shock (4–5 hours).

2. False recovery / relative well-being (6–36 hours).

3. Purulent complications (over 36 hours).

V. By level of injured esophageal segments (Brombart classification, 1956 [50]):

1. Cervical segment.

2. Tracheal segment.

3. Retropericardial segment.

4. Supradiaphragmatic segment.

5. Abdominal segment.

VI. By nature of developing complications:

1. Pneumothorax.

2. Pneumomediastinum.

3. Hemothorax.

4. Pleurisy (unilateral, bilateral).

5. Neck phlegmon.

6. Empyema thoracis (localized, generalized/spread).

7. Mediastinitis (localized, diffuse).

8. Pericarditis.

9. Peritonitis (localized, generalized).

10. Fistulae (esophagotracheal, esophagobronchial, esophagopleuropulmonary, esophagopleurothoracic, esophagoaortic).

Trauma to other thoracic organs

Injury to the thoracic duct. Traumatic chylothorax directly associated with thoracic duct injury does not have its own classification and is part of a broader classification of chylothorax, which may be useful for a practicing physician.

T.R. DeMeester classification of chylothorax [51] (according to M.I. Perelman, T.N. Sedova, V.D. Parshin [52]):

1. Congenital: thoracic duct atresia; thoracic fistula between the duct and the pleural cavity; birth trauma.

2. Traumatic: blunt trauma; penetrating trauma.

3. Postoperative: a) cervical (lymph node removal, radical neck dissection); b) thoracic (following ligation of Batalov's duct, coronary artery bypass grafting, correction of aortic coarctation, esophagectomy, resection of thoracic aortic aneurysm, mediastinal tumor removal, pneumonectomy or lobectomy, left subclavian artery surgery, sympathectomy); c) abdominal (sympathectomy, radical lymphadenectomy).

4. Diagnostic procedures: subclavian vein catheterization, left heart catheterization.

5. Tumors: malignant, benign.

6. Infections: tuberculous lymphadenitis, nonspecific mediastinitis, ascending lymphangitis.

7. Other: venous thrombosis (left subclavian or jugular veins, superior vena cava); secondary to chylous ascites; pancreatitis; idiopathic.

1.6 Clinical presentation of the disease or condition

Blunt chest trauma in general

In chest trauma, 3 leading syndromes are distinguished: pain syndrome (pain accompanies bone trauma and pneumothorax in 100% of cases), blood loss syndrome (associated with injuries to large and intercostal vessels, internal organs of the chest), acute respiratory failure syndrome (its causes are diverse: pain from rib fractures and parietal pleura rupture, flail chest, lung rupture, hemothorax, pneumothorax, pulmonary atelectasis, diaphragmatic injury, lung contusion and intrapulmonary hematomas, impaired patency of the trachea and bronchi due to accumulation of mucus and blood therein, bronchospasm, bronchial rupture, laryngospasm, central respiratory disorders (respiratory center depression). Characteristic complaints: chest pain, cough (dry or with sputum), dyspnea, hemoptysis, dizziness, general weakness, swallowing and phonation disorders, loss of consciousness.

Palpation of the chest reveals soft tissue emphysema, decreased or absent vocal fremitus, chest wall deformity, pathological mobility of the ribs and sternum, tenderness in the fracture areas, tachycardia. Palpation reveals tenderness and pathological mobility at the sites of rib, sternum, and clavicle fractures; specific crepitus ("crunching snow") in subcutaneous emphysema.

Percussion reveals a hyperresonant sound in pneumothorax, and dullness of the percussive sound in hemothorax. Percussion also makes it possible to determine the presence of air and fluid in the pleural cavity, widening and shifting of the mediastinum and cardiac dullness. It must be remembered that the percussion sound over emphysematous tissues has a tympanic shade. Pneumothorax is characterized by tympanitis with mediastinal shift to the healthy side. Large hemothorax manifests as a dull percussion sound with mediastinal shift to the healthy side. Medium and small hemothorax, extrapleural and intermuscular hematomas are indistinguishable on percussion. Significant atelectases are characterized by dulling of the lung sound with mediastinal shift to the affected side. Mediastinal emphysema is characterized by a hyperresonant sound and narrowing of the cardiac dullness boundaries. Auscultation reveals weakened or absent breath sounds in both pneumothorax and hemothorax.

Auscultation makes it possible to diagnose lung injury by the weakening or absence of breath sounds, changes in their character, the appearance of rales, and pleural friction rub. Heart auscultation allows for the detection of its injuries by muffled heart sounds, tachycardia, arrhythmia, and the appearance of heart murmurs. Hearing bowel sounds over the pleural cavity is a sign of diaphragmatic injury.

Rib fractures

Assessment of respiratory rate and lung auscultation reveals weakened or completely absent breathing, as well as other clinical signs of pulmonary hypoventilation [44].

When gathering complaints, anamnesis, and according to physical examination data, the following are noted:

- severe chest pain (greatest at the fracture site), intensifying with deep breathing and coughing;

- shallow breathing, which increases the risk of pneumonia as a complication;

- lag of the chest wall in the act of breathing on the affected side;

- soft tissue edema at the fracture site;

- tenderness on palpation in the fracture area, frequently crepitus and a "step-off" deformity;

- "interrupted inspiration" sign — interruption of an attempt to take a deep breath due to pain (does not occur in chest wall contusion);

- axial load sign — with alternating compression of the chest in the sagittal and frontal planes, pain occurs in the area of the bone defect rather than at the site of compression.

In a number of cases, visualization of the fracture site(s) on subsequent rib radiography may be difficult.

In fractures of the 1st and 2nd ribs, examination and evaluation should aim to rule out associated injuries to vascular and neural structures.

Rib fractures can lead to complications, specifically:

- injury to the lung by a fractured rib, resulting in hemoptysis, subcutaneous emphysema, pneumothorax, or hemothorax;

- injury to the intercostal vessels, liver, or spleen by a fractured rib, resulting in hemothorax, hemopericardium, or hemoperitoneum;

- injury to gastrointestinal organs with clinical presentation of hollow viscus perforation;

- flail chest segment (flail chest) resulting in respiratory failure;

- pleuropulmonary shock;

- infectious complications (pneumonia, purulent pleurisy).

Flail chest fractures (flail chest)

Clinical manifestations of severe closed chest injuries are associated with a number of morphological and functional changes in the patient's body, primarily including: impaired external respiration, circulatory disorders, and the development of pleuropulmonary shock.

Impaired external respiration is caused by the development of pathological changes in the tissues of the thoracic organs, as well as severe chest pain that disrupts its excursion, and manifests as hypoxia accompanied by symptoms of cardiopulmonary failure. Respiratory and circulatory disorders are further aggravated by the accumulation of air or blood in the pleural cavity. With extensive damage to chest tissues and thoracic organs accompanied by blood loss, a shock picture frequently occurs.

In flail fractures, the clinical presentation and severity of the patient's condition are determined by the position and size of the "flail segment" as well as the amplitude of movement: the larger and more mobile the "segment," the more severe the patient's condition. Unfixed flail rib segments can displace by 4.0–4.7 cm, with pathological mobility being greater in the lower (6th–8th) ribs than in the upper (3rd–5th) ribs [53].

For timely diagnosis of flail fractures, attention should be paid to the lag of the injured hemithorax during respiration, chest deformation, and pathological mobility of the "flail segment." Moreover, the greatest mobility is observed when flail rib fractures are combined with fractures of the clavicle and sternum [54].

The most pronounced clinical picture is observed in anterior bilateral and left-sided anterolateral flail fractures.

The posterolateral "flail chest" can also be dangerous due to increased separation of the segment upon contraction of the muscles that elevate the ribs [55, 56].

Sternum fracture

Sternum fractures present with pain in the sternal area, which impairs deep breathing. Swelling and a "step-off" deformity consisting of two bevelled sternal segments can be found at the fracture site. Palpation reveals tenderness and bone crepitus.

Traumatic asphyxia

A special form of closed chest injury is traumatic asphyxia, which occurs due to brief, forceful anteroposterior compression of the chest and is caused by hypertension in the superior vena cava system.

Traumatic asphyxia occurs upon sudden compression of the chest (e.g., when a patient is pinned against a wall by a car). Under conditions of reflex spasm of the glottis, intrathoracic pressure sharply increases, and the outflow of blood through the superior vena cava system from the upper half of the body into the right heart chambers becomes obstructed. This leads to marked blood stasis in the venous network of the head, neck, and shoulder girdle, accompanied by rupture of capillaries and small vessels and the formation of petechial hemorrhages in soft tissues, including the skin and mucous membranes.

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

Pneumothorax

In localized closed pneumothorax, the general condition of patients is usually satisfactory. They complain mainly of pain in the area of rib fractures. Signs of acute respiratory and cardiovascular failure are absent. Auscultation reveals weakened breath sounds on the affected side. In medium and large pneumothorax, the clinical presentation is more pronounced. The patient is restless, complaining of chest pain and dyspnea at rest. Breathing is rapid and shallow. The affected half of the chest lags behind in the act of breathing. Percussion reveals tympanitis over it, and auscultation reveals a significant weakening or complete absence of breath sounds. The pulse is frequent with weak filling.

The most pronounced clinical picture develops in tension pneumothorax. The condition of the patients is severe; they are restless and experience pain, dyspnea, and air hunger. The body position is forced, most commonly semi-sitting. The skin and visible mucous membranes are cyanotic. Cold sweat. Swollen neck veins are visible. Progressive subcutaneous emphysema of the soft tissues of the chest is noted, with the spread of air to the neck, face (including the upper and lower eyelids), and abdomen. On the affected side, the chest is motionless, intercostal spaces are widened, and the supraclavicular fossa is smoothed out or bulging. Breathing is rapid and shallow; the patient gasps for air with an open mouth. Respiratory rate is up to 40 or more per minute. Tachycardia and hypotension are present, along with a significant increase in central venous pressure (CVP). Percussion reveals tympanitis, and auscultation reveals a complete absence of breathing on the affected side. There is a displacement of the apex beat, the boundaries of cardiac dullness, and the point of maximum auscultation of heart sounds toward the healthy side. The phenomena of acute respiratory failure rapidly progress with coughing and deep breathing.

Hemothorax. Accumulation of blood in the pleural cavity. It manifests as dullness of the percussion note and weakened breath sounds on the affected side of the chest. In large and total hemothorax, the clinical picture of acute blood loss and traumatic shock develops.

Coagulated hemothorax. The symptoms of coagulated hemothorax are nonspecific and manifest as pain in the corresponding side of the chest, fever, tachycardia, dyspnea, and progressive deterioration of the patients' condition in the absence of other causes [44]. A characteristic physical sign of coagulated hemothorax is dullness and weakened breath sounds on the affected side of the chest [44].

Thoracic blood vessel trauma

Based on the anamnesis (traumatogenesis), great vessel injury can be suspected in frontal and lateral car collisions, falls from a height of more than 10 meters, mountaineering accidents, equestrian sports, and alpine skiing. Information from ambulance (accompanying) personnel regarding transient paralysis and hemodynamic instability during transport is important. Due to the severity of the condition (often agonal), the patient with a blood vessel injury in blunt chest trauma does not make active complaints. Characteristic complaints include retrosternal and interscapular pain, general weakness, and impaired sensitivity and motor strength in the limbs.

Clinically, the typical picture of acute massive blood loss (due to ongoing intrapleural bleeding and/or total hemothorax) and cardiac tamponade and/or dissection (with aortic dissection formation) is more frequently observed, which are diagnosed by all clinical examination methods for severe chest trauma patients. The most characteristic clinical signs of great vessel injuries in blunt trauma include: hypotension, elevated blood pressure (BP) in the upper extremities, pulse and blood pressure difference between the upper and lower extremities (resembling coarctation syndrome), external signs of severe chest trauma (steering wheel or tire tread imprint on the chest wall), a growing hematoma of the supraclavicular regions and mediastinum, a harsh systolic murmur in the interscapular region, palpable rib fractures (especially 1st to 5th), sternal and/or thoracic spine fractures, and a "crushed" chest. In intrapericardial vascular injuries, there are classic signs of cardiac tamponade.

Heart injury

Any mechanism that transmits kinetic energy to the heart can cause its injury: severe chest trauma due to a high-speed vehicle collision, a blunt blow to the sternum, a fall from a height, blast wave impact from an explosion, or "aggressive" cardiopulmonary resuscitation. Due to the severity of the condition, patients with cardiac trauma may not make complaints. Chest pain radiating to the left scapula, upper extremities, and lower jaw, a sensation of skipped beats and fluttering in the heart, dyspnea, and general weakness are characteristic but nonspecific symptoms.

In a quarter of cases, cardiac trauma remains unrecognized because it can be asymptomatic or masked by injuries to other organs of the chest. In cardiac contusion, clinical symptoms develop gradually, and their regression is slow. The most frequent complaint is pain in the precordial region, which can occur immediately or several hours after the injury and may be caused both by chest wall contusion and rib fractures with pleural damage. Most often, the pain is localized at the site of the contusion, sometimes retrosternally, and may radiate to the back, both arms, or the jaw, mimicking angina pectoris. The administration of nitroglycerin** has little effect on pain intensity. There may also be complaints of palpitations, skipped heartbeats, dyspnea, or general weakness. A severe condition of the victim, involuntary urination, and defecation are characteristic.

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, pulse arrhythmia, classic symptoms of pericardial tamponade (marked dilation/swelling of neck veins, paradoxical pulse, widened cardiac percussion borders, muffled/distant heart sounds, increased central venous pressure, arterial hypertension). Cardiac auscultation also frequently reveals an increase in heart rate (HR), sometimes a pericardial friction rub, a pendular rhythm, or gallop rhythm. The main clinical manifestations in patients with cardiac tamponade are arterial hypotension, elevated jugular venous pressure, and distant heart sounds (Beck's triad). Cardiac rhythm disturbances are frequently noted, the exact mechanism of which is unknown. In isolated pericardial rupture, auscultation may reveal a "churning mill murmur".

In myocardial ruptures and injuries to intracardiac structures, symptoms develop rapidly (in some cases fulminantly) and manifest as hemodynamic instability and cardiogenic shock (up to asystole). In 5-7% of patients with cardiac ruptures, the classic picture of pericardial tamponade develops.

Diaphragmatic trauma

The clinical picture of diaphragmatic rupture is caused by two groups of symptoms related to: a) impaired diaphragmatic movement and compression syndrome due to abdominal organs displaced into the chest, b) displacement of abdominal organs [57]. One or more of the following nonspecific symptoms may be present: dyspnea, difficulty breathing, chest pain, shoulder joint pain, epigastric pain (worsening after eating), a feeling of abdominal tightness, nausea and vomiting, dysphagia, and regurgitation. Percussion may reveal shortening of the pulmonary note on the affected side, high standing of the diaphragmatic dome, and mediastinal shift to the healthy side; chest auscultation may reveal weakening or disappearance of breath sounds, and auscultation of small bowel peristaltic sounds. Clinical manifestations depend on the size, nature, and localization of the injury [58–61]. Smaller ruptures and those localized in the right diaphragmatic dome are rather difficult to diagnose and are often detected years after the injury.

It should be borne in mind that the symptoms of diaphragmatic injuries are often masked by injuries to other sites that require immediate measures [62]. It must be taken into account that diaphragmatic ruptures are rarely isolated. These patients often have concomitant chest and/or abdominal injuries, or may have concomitant head or extremity injuries. In patients with diaphragmatic trauma, pelvic fractures occur in 40% of cases, splenic rupture in 25%, liver rupture in 25%, and thoracic aortic rupture in 5-10% of cases [63]. It is important to remember the combination (albeit rare) of diaphragmatic rupture and thoracic aortic rupture due to the common mechanism of injury. Therefore, when one diagnosis is obvious, it is essential to additionally investigate the possibility of another associated injury [63].

In all patients with blunt chest trauma, the manifestations of a previously undiagnosed diaphragmatic rupture may include the following signs:

- dyspnea, suddenly (acute) onset against the background of a relatively stabilized condition after surgery or after disconnection from a mechanical ventilator, expiratory, not relieved by oxygen supply via nasal catheters, requiring transition to mechanical ventilation;

- tachycardia, unresponsive to anything, with the exclusion of hypovolemia or any cardiac pathology as the cause;

- a sharp decrease in blood oxygen saturation;

- the need to increase FiO2 in the inspired air in a patient on mechanical ventilation.

Esophageal trauma (thoracic segment)

In case of injury to the thoracic esophagus, the development of subcutaneous emphysema of the neck, pneumothorax, and/or pneumomediastinum is possible. Tension pneumomediastinum and pneumothorax lead to impaired vital functions due to mediastinal translocation with a possible reflex reaction from the recurrent laryngeal nerves. Pneumohydrothorax develops within 1 to 3 days after the injury. When draining the pleural cavity, saliva and gastric contents are not always present in the exudate, and therefore the hemorrhagic effusion is attributed to chest trauma. When draining in such situations, a temporary improvement in condition is observed, and only the appearance of saliva and food in the drain suggests esophageal rupture. In 75% of patients, the diagnosis is established more than a day after the onset of the disease. Characteristic complaints in esophageal trauma: localization and nature of pain, hypersalivation, hoarseness or nasal tone of voice. During physical examination, the state of the soft tissues of the neck and chest wall, the presence and prevalence of subcutaneous emphysema, and the localization of neck and chest wounds in case of injuries are important. When assessing dynamics, important indicators are body temperature, respiratory rate, heart rate, the amount and nature of discharge through drainage tubes installed in the pleural cavities and/or mediastinum and/or fascial spaces of the neck.

Trauma to other thoracic organs

Injury to the thoracic lymphatic duct. Patients do not present with specific complaints upon injury to the thoracic lymphatic duct. Physical examination may reveal the following findings: pallor, signs of hypovolemia, cyanosis, tachycardia, and other manifestations of cardiopulmonary insufficiency, symptoms of fluid accumulation in the pleural cavity.

2. Diagnostics, medical indications and contraindications for diagnostic methods

The optimal diagnostic algorithm for trauma implies promptness of diagnosis under conditions of limited time. In such conditions, objective research methods acquire special value: radiological (including methods requiring the administration of contrast agents and computed tomography), ultrasound (including vascular and cardiac Doppler studies), puncture, endoscopic (bronchoscopy, esophagoscopy, thoracoscopy), and X-ray endovascular.

At the beginning of the examination, a syndromic diagnostic search should be carried out for the patient. First of all, it is necessary to identify disorders of vital functions that determine the severity of the patient's condition and pose an immediate threat to their life. Once such disorders are established, it is necessary to simultaneously carry out syndromic intensive care and continue diagnostic measures. The main principle of this stage of diagnostics should be the necessity and sufficiency of information. The volume and duration of the examination depend on the level of compensation of the respiratory and circulatory systems.

However, it is obvious that a number of the characteristics required for such a unified diagnosis (especially anatomical ones) can be definitively established only after surgery, and the very logic of diagnosis formulation in emergency trauma surgery requires first of all an answer to the question: "Does the patient have indications for emergency surgery and/or resuscitation measures?". Due to the need to establish an accurate topographic diagnosis in a short period of time, objective methods of instrumental diagnostics should be used to the maximum extent on an emergency basis. The final clinical diagnosis should reflect all anatomical and pathophysiological aspects of the trauma: "BLC (nature of trauma), with damage (listing of damaged organs and anatomical structures from the most severe to the least severe); pathophysiological characteristics of the trauma (degree of shock, respiratory and cardiovascular failure, blood loss, assessment of the condition according to injury severity scales - AIS/ISS (Appendix G1), etc.".

Criteria for establishing the diagnosis/condition:

1) data from the study of subjective status indicating BLC;

2) physical examination data characteristic of BLC (see section 1.6);

3) laboratory diagnostic data (see below);

4) radiation and instrumental research data (see below).

Contrast-enhanced pan-CT is considered the "gold standard" for diagnosing polytrauma with suspected chest injury [64, 65].

2.1 Complaints and Anamnesis

2.2 Physical Examination

Comments: in chest trauma, the general condition can vary widely, from minor impairment to a terminal state, and depends on the severity of blood loss and the degree of respiratory failure.

Comments: symptoms of a severe patient condition include agitation or, conversely, apathy, marked pallor or cyanosis, tachypnea, bloody discharge from the mouth and nose, jugular venous distension, soft tissue emphysema, paradoxical breathing movements, forced patient position, chest deformation, asymmetry, retraction or, conversely, bulging of intercostal spaces, ribs, sternum, lag during breathing, and flail chest.

Comments: the diagnosis of diaphragmatic injury is not always established in a timely manner. It was made prior to surgery in only 40–50% of cases for left-sided rupture and 0–10% for right-sided rupture. In 10–50% of patients, the diagnosis is not established within the first 24 hours. For this reason, diaphragmatic injury should be suspected in all emergency admissions with blunt chest, abdominal, and polytrauma. Examination of this category of patients should focus on confirming or ruling out diaphragmatic injury [37–40, 69].

2.3 Laboratory Diagnostics

Comments: potential anemia, thrombocytopenia, decreased hematocrit, and leukocytosis are of diagnostic value in assessing the severity of blood loss and the development of infectious complications.

Comments: mandatory components include the levels of fibrinogen, prothrombin, international normalized ratio (INR), and activated partial thromboplastin time (aPTT).

Comments: other parameters of the biochemical blood test may be evaluated at the discretion of the attending or on-duty physician for other diagnostic purposes.

Comments: an elevation of troponin in blunt chest trauma should be regarded as a sign of cardiac contusion. Measurement of creatine kinase MB (CK-MB) isoenzyme activity has diagnostic value, though it is difficult to interpret in the presence of other injuries. Elevated troponin T and I levels have greater specificity within 48 hours after injury; however, the interpretation of these parameters requires caution due to their insufficient sensitivity and prognostic value.

Comments: a drop in arterial blood oxygen tension below 50 mmHg while breathing ambient air and below 100 mmHg during pure oxygen inhalation is an important symptom of post-traumatic respiratory failure. Hypercapnia with flail chest (PaCO2 greater than 50 mmHg) indicates that the flail chest is functionally significant [29, 45, 143].

Comments. Characteristic tests: Gram stain (positive test), cholesterol/triglyceride ratio (less than 1), triglyceride level (greater than 1.24 mmol/L), Sudan III stain (positive test), electrophoresis (chylomicrons) [52].

2.4 Instrumental Diagnostics

Due to the objective difficulties of a classical clinical and instrumental examination of critically ill patients and the need to obtain the most comprehensive information on the nature of the injury in the shortest possible time, high-informative modern medical imaging methods—chest computed tomography (CT) and comprehensive ultrasound of internal organs—are preferred. Nevertheless, plain chest radiography in anteroposterior and lateral projections is of great importance in diagnosing the nature of chest trauma (in critically ill patients where performing the study in an upright position is impossible, the examination is performed in the patient's lateral decubitus position).

Comprehensive ultrasound examination of internal organs is one of the most informative methods for verifying the anatomical nature of trauma. In addition to high diagnostic value, its important advantage is the ability to perform the examination in critically ill patients ex tempore, including dynamically, without the need to transport or reposition the patient (directly in the operating room, intensive care unit, or emergency department). Ultrasound allows the detection of hemoperricardium, hemothorax, determination of the predominant localization of intrapleural blood (fluid) collections, and identification of the optimal point for thoracentesis or drainage. In addition, ultrasound makes it possible to assess the state of adjacent anatomical regions (abdominal cavity, neck, soft tissues of the chest wall), providing invaluable capabilities in diagnosing polytrauma. The use of Doppler ultrasound provides extremely crucial information for surgical strategy regarding potential blunt trauma to the heart and great vessels. A focused assessment with sonography for trauma (FAST) of the chest can be utilized to rapidly detect pneumothorax, hemothorax, and hemoperricardium not only by ultrasonographers but also by other specialist physicians.

Computed tomography of the chest is the most informative diagnostic method for chest injuries. Fractures of the ribs, sternum, clavicle, pneumothorax, hemothorax, lung contusion, mediastinal hematomas, subpleural hematomas, hemoperitoneum, and other injuries to adjacent anatomical regions are visualized within minutes. CT angiography of the thoracic aorta makes it possible to precisely visualize the site of contrast extravasation, the presence of traumatic aneurysms, and accurately determine the source of bleeding. A contraindication (including temporary) to performing a CT scan is hemodynamic instability requiring emergency therapeutic interventions.

Bronchoscopy (fiberoptic bronchoscopy) allows the detection of tracheal and bronchial injuries, pulmonary hemorrhage, signs of lung contusion, and aspiration of blood or gastric contents. At the same time, diagnostic bronchoscopy enables a number of therapeutic procedures: tracheobronchial tree toilet (sanation) and endobronchial instillation of medicinal products [64]. Esophagoscopy is absolutely essential for diagnosing oropharyngeal and esophageal injuries. It should be noted that in the presence of mediastinal and soft-tissue emphysema without radiological evidence of pneumothorax, bronchoscopy and esophagoscopy are absolutely mandatory investigations to rule out rupture of the trachea, bronchi, or esophagus.

Diagnostic thoracoscopy provides up to 94% accuracy [45, 70] in verifying the anatomical nature of the trauma (clarifying the nature and extent of lung injuries) and placing pleural drains in the optimal position.

Blunt chest trauma overall: radiography and computed tomography

Comments: radiological imaging methods are of decisive importance in diagnosing chest trauma. The primary method is chest radiography, which allows the detection of rib, sternum, and spinal injuries, identification of pneumothorax and hemothorax, as well as injuries to the lungs, heart, and mediastinum. During radiography, one should evaluate the presence, volume, and character of the pneumothorax or hemothorax; whether there is mediastinal shift, border widening, or blunting of heart contours; diaphragmatic contours and standing level; the presence of bone injuries (ribs, clavicles, scapulae, sternum, spine); whether there are changes in the lung parenchyma (atelectasis, hypoventilation, infiltration); the presence of mediastinal and soft-tissue emphysema; and the presence and localization of foreign bodies. Serial chest radiography is mandatory in all chest injuries. Targeted radiography should be avoided in favor of anteroposterior and lateral overview radiographs with mandatory inclusion of both hemithoraxes from the diaphragmatic sinuses to the lung apices. Standard-penetration radiographs are necessary to diagnose lung injuries, extrapleural hematomas, and hemopneumothorax. Bone injuries are better visualized on high-penetration radiographs in oblique projections.

Comments: computed tomography, which possesses high diagnostic informational value and accuracy regarding all types of injuries to the chest and its organs, provides a complete topographic picture of injuries, allows the measurement of density and volume of pathological formations, and is the method of choice under modern conditions. In polytrauma, it is recommended to perform MDCT of five zones (head, neck, chest, abdomen, pelvis) [45].

Comment: the presence of life-threatening conditions (massive bleeding, respiratory failure, etc.) provides grounds for postponing this study until after emergency surgical interventions and stabilization of central hemodynamics.

Comments: it should be taken into account that chest CT is not 100% sensitive due to suboptimal visualization of the diaphragm in some cases. A diagnosis based on chest CT can be conclusively established if abdominal organs are visualized herniating through the diaphragmatic defect [72–74]. In right-sided diaphragmatic rupture, thickening of the diaphragm, a "hump", and "tracks" from liver herniation are noted. In left-sided rupture, useful signs include a segmental diaphragmatic defect, herniation of abdominal organs through the defect, and constriction of the "waist" of the hernial structure at the site of the diaphragmatic tear [75]. Overall, sensitivity is 66.7%, specificity is 100%, positive predictive value is 100%, and negative predictive value is 88.4% [76].

Closed chest trauma in general: other instrumental diagnostic procedures

Comments: ultrasound examination is an important instrumental diagnostic method in trauma to the chest, pleural cavities, heart, and mediastinum. Ultrasound visualizes fluid and air in the pleural cavity, extrapleural hematomas, diaphragmatic injuries, pericardial fluid, and foreign bodies. The advantage of ultrasound is the ability not only to visualize fluid or air, but also to measure its volume. Modern ultrasound with Doppler imaging is the simplest and most accessible method for diagnosing injuries to the heart, great vessels of the mediastinum, and the lung root [45].

Comments: thoracentesis is performed in the 2nd intercostal space along the midclavicular line and the 6th–7th intercostal space along the posterior axillary line. To determine ongoing bleeding and the activity of the inflammatory process in the pleural cavity, the exudate obtained by puncture is subjected to hematological and bacteriological analysis. Thoracentesis may be concluded with pleural cavity drainage.

Comments: the risk of iatrogenic injuries during diagnostic puncture is particularly high precisely when air or fluid is absent in the pleural cavity.

Comments: if gastric or intestinal contents are obtained during pleural puncture and drainage performed for hemothorax or tension pneumothorax, this will be a reliable sign of diaphragmatic injury, although this situation is associated with a high risk of purulent-inflammatory complications of the pleura [26].

Comments: ECG examination is highly informative in cardiac contusions; any rhythm and conduction disturbances or focal changes should be interpreted as indicative of a cardiac contusion.

Comments: the method makes it possible to assess the amount and thickness of pericardial fluid, the condition of the valve apparatus, and cardiac performance.

Comments: this minimally invasive method makes it possible to determine the level of vascular injury and perform endovascular hemostasis. The method allows stent-graft placement in various parts of the thoracic aorta, brachiocephalic trunk, and subclavian arteries in case of their injury.

Comments: endoscopic methods occupy an important place in the diagnosis of chest organ injuries. It should be remembered that a prerequisite for 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, determining the causes of obstructive pulmonary atelectasis, and resolving them.

Comments: these interventions should be performed in all patients in the shock trauma operating room.

Comments: esophagoscopy makes it possible to diagnose esophageal wounds and traumatic ruptures, as well as to identify indirect signs of injury to other mediastinal organs.

Comments: emergency, urgent (within the first 24 hours after trauma), and delayed thoracoscopy are distinguished. It allows for the diagnosis of coagulated hemothorax, hemopericardium, mediastinal hematoma, lung, pericardial, and diaphragmatic wounds, establishment of the bleeding source, and detection of foreign bodies in the pleura, lung, and mediastinum. Indications for videothoracoscopy are: 1) moderate and massive hemothorax in the absence of signs of ongoing intrapleural bleeding with a blood output through pleural drains of up to 500 ml per hour; 2) ongoing intrapleural bleeding with a blood output through pleural drains ranging from 250 to 500 ml per hour; 3) progressive and tension mediastinal emphysema; 4) refractory tension pneumothorax; 5) persistent pneumothorax refractory for 3 days after trauma, and recurrent pneumothorax; 6) coagulated hemothorax of up to 2 weeks' duration; 7) foreign bodies of the pleural cavity, lung, and mediastinum. For the first 4 indications, thoracoscopy is performed on an emergency basis; for the rest, it is performed on an urgent (within the first 24 hours after trauma) and delayed (elective) basis. Contraindications for thoracoscopy in chest trauma are: 1) total hemothorax; 2) profuse intrapleural or pulmonary hemorrhage; 3) cardiac tamponade; 4) convincing signs of injury to major vessels and the trachea; 5) tension or refractory pneumothorax on the contralateral side of the chest; 6) unfavorable or doubtful prognosis for surgical interventions in traumatic shock; 7) presence of uncorrected life-threatening dominant injuries of another localization; 8) extensive soft tissue injuries or suppuration of the chest; 9) obliteration of the pleural cavity [45].

Rib fractures

Comments: the diagnosis of isolated rib and sternal fractures should be confirmed using standard chest radiography in two projections. In addition to fractures, it allows for the detection of lung and pleural changes—contusion, pulmonary atelectasis, hemothorax, and pneumothorax. In multiple rib fractures or severe trauma, chest CT should be preferred, including for the detection of concomitant injuries and determination of their severity. The availability of this method has made it routine in patients with severe chest trauma. In fractures of the lower ribs, abdominal injuries should be ruled out.

Flail chest (flail segment)

Comments: rib radiography allows for the identification of fracture localization and fragment position. 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 picture of paradoxical movements of the chest wall area and external respiration disorders. Chest CT provides comprehensive information on the presence of fractures and thoracic organ injuries, including the presence of the so-called "sharp fragment" sign—protrusion of sharp rib fragments into the pleural cavity lumen with the risk of lung injury.

Pneumothorax

Comments: in the British Thoracic Society guidelines (2003) [82], pneumothoraces are categorized as small and large when the distance between the lung and the chest wall is less than 2 cm and greater than 2 cm, respectively, while the American College of Chest Physicians guidelines (2001) [83] recommend dividing pneumothoraces based on the distance between the lung apex and the thoracic apex: small pneumothorax at a distance of less than 3 cm, large—greater than 3 cm [45]. To quantitatively characterize pneumothorax on a radiograph, the distance between the inner contour of the chest wall and the edge of the collapsed lung (e.g., 4 cm) and the distance from the inner edge of the chest wall to the mediastinal shadow (e.g., 16 cm) can be measured. Next, the size of the pneumothorax is calculated as a percentage. In this example, it is 25% [25].

Comments: the primary instrumental diagnostic and therapeutic method for examining the respiratory system in patients with severe polytrauma involving injuries to the airways and lungs is flexible bronchoscopy (FB). When performed under local anesthesia with respiratory support using high-frequency ventilation, FB does not cause homeostasis deterioration and allows for a practically complete examination of the trachea and 3rd-generation bronchi, as well as removal of pathological contents from their lumen and resolution of pulmonary atelectasis. Restoration of airway patency and timely initiated treatment reduce the risk of pulmonary complications by 30%. Therefore, bronchoalveolar lavage in patients with severe polytrauma helps effectively remove pathological contents (blood and aspiration contents) from the airways and enables fluid sampling for laboratory tests.

Comments: to confirm the presence of air in the pleural cavity, puncture is performed in the second intercostal space along the midclavicular line. Anesthesia—local anesthesia with a 0.5% procaine** solution. Using a fine needle connected to a syringe with procaine** via a polyvinyl chloride tube (registered pleural drainage devices should be used), in a direction perpendicular to the chest wall, advancing procaine** ahead, they hit the 3rd rib. Then the needle direction is changed upward, and along the upper edge of the rib, it penetrates the pleural cavity. Initially, elastic resistance is felt, followed by a sudden loss of resistance (yielding). The syringe plunger is pulled back. In the presence of pneumothorax, the plunger moves freely and air bubbles appear in the procaine** solution.

Hemothorax

Comments: to detect blood in the pleural cavity, thoracentesis is performed in the sixth or seventh intercostal space along the mid-axillary or posterior axillary line. After local anesthesia with a long needle connected to a syringe containing procaine** via a polyvinyl tube (registered pleural drainage devices should be used), pleural puncture is performed. Thoracentesis is performed along the upper edge of the lower rib to avoid injuring the intercostal vessels. After entering the pleural cavity (a sensation of giving way), the syringe plunger is pulled back. In the presence of hemothorax, blood or clots appear in the syringe.

Comments: Chest CT is the gold standard for visualizing a coagulated hemothorax. CT signs of a coagulated hemothorax represent a combination of objective qualitative and quantitative characteristics: the presence of pathological content, its exact volume, localization, shape, contours, structure (density, homogeneity), the ratio of solid to liquid fractions, and their shiftability.

Comments: the radiological presentation of a coagulated hemothorax is highly variable and depends on the stage of its development. In early stages, radiological examination in the vast majority of cases reveals hemothorax opacity that does not shift with changes in body position. It is much less common to detect inhomogeneity of this opacity, and in the second stage—the appearance of multiple horizontal fluid levels in the upper part of the opacity. It should be noted that a hemothorax volume of less than 300 cm³ is not detected on conventional chest radiography. In diagnosing retained pleural effusion in blunt chest trauma, ultrasound of the pleural cavities is superior to chest radiography. Ultrasound allows visualization of the hemothorax with high accuracy, although the sensitivity of the method depends on the operator's qualification. Also, the method does not allow a full assessment of changes in the chest cavity due to the inaccessibility of certain areas of the pleural cavity and signal attenuation in an air medium (lung, pneumothorax).

Comments: a characteristic sign of a coagulated hemothorax is negative results from pleural punctures at multiple sites. If a pleural drainage is functioning, the cessation of fluid output despite the presence of opacity on the chest radiograph is a reliable sign of a coagulated hemothorax.

Injury of thoracic blood vessels

Comments. Signs of chest vascular trauma on instrumental examination include:

- on chest radiography — fractures of the sternum, scapula, clavicle, first rib and/or several ribs on the left; blurred contour of the aortic arch, widening of the mediastinal shadow greater than 8 cm, "weird" mediastinum, deviation of the left main bronchus greater than 140^° downwards from the trachea, loss of the paraspinal line, calcification layering in the aortic arch, lateral deviation of the nasogastric tube in the esophagus, lateral displacement of the trachea, apical pleural hematoma; massive left-sided hemothorax;

- in comprehensive internal organ ultrasound (FAST protocol) — a large volume of fluid in the left pleural cavity, fluid in the pericardial cavity (tamponade), mediastinal and lung root hematomas associated with major vessels are visualized;

- on mediastinal ultrasound — intra-aortic lesions are detected (intimal tear, intramural hematoma and/or aortic dissection);

- on duplex scanning of the aorta — changes in the linear blood flow velocity and the configuration of the Doppler curve in the aorta, brachiocephalic arteries, and root vessels of the lungs;

- on transesophageal echocardiography (TEE) — intimal tears, intramural hematomas, and aortic dissection are diagnosed. Despite the sensitivity and specificity of the method of 100% and 98%, respectively, due to potential bleeding from the forming hematoma and/or aneurysm at the time of the study, TEE has limited value in chest vascular trauma;

- on chest CT — mediastinal hematoma, total hemothorax, contrast extravasation, intimal tears and dissections, traumatic aneurysms, and/or thrombosis at the pseudoaneurysm level. The sensitivity and specificity of the method reach 93 and 86%, respectively;

- on retrograde thoracic aortography (indicated not only for diagnosing the localization of the injury, but also for planning rational surgical access and endovascular treatment) — intimal tears and complete tears of the aortic/arterial wall with contrast extravasation, pulsating hematomas, and forming false aneurysms are detected. The sensitivity and specificity of the method are 100% and 98%, respectively;

- on diagnostic thoracoscopy — tense (pulsating) mediastinal hematomas, fluid in the pericardium (tamponade).

Heart injury

Comments. Signs of cardiac injury on instrumental examination include:

- on chest radiographs — enlargement (to a spherical shape) of the cardiac silhouette;

- on ECG — non-specific changes in the form of ST-segment elevation/depression, the appearance of a pathological Q wave and pathological T waves, various arrhythmias (sinus tachycardia, bradycardia, ventricular extrasystole, atrial fibrillation and flutter, transient intraventricular conduction disturbances, bundle branch blocks or their divisions, various AV conduction disturbances, including transient complete heart block) are detected. Accuracy and specificity are 82% and 68%, respectively;

- on TTE and TEE — pericardial effusion, decreased myocardial contractility (atrial and ventricular dyskinesia), and cardiac output may be detected. The right ventricular ejection fraction is more frequently decreased. Intramyocardial hematomas in the ventricles, papillary muscle and chordal ruptures, valvular injuries and dysfunctions, as well as intracardiac thrombi can be identified. The informativeness of the studies is limited by rib fractures, chest wall hematomas and edema, as well as the patient's severity and the operator's qualification;

- on MSCT and contrast-enhanced MSCT — myocardial and pericardial ruptures (with the formation of cardiac herniation/luxation), hydro- and pneumopericardium, injury to the coronary arteries and heart valves are diagnosed;

- on myocardial scintigraphy — zones of myocardial injury are detected. The technique is labor-intensive with low sensitivity (61%) and specificity (74%).

Diaphragmatic trauma

Comments: the following radiological features (one or more) may indicate a possible diaphragmatic injury: decreased lung volumes, hemothorax opacity, atypical pleural effusion, high standing of the diaphragmatic dome or lack of its visualization, fluid levels in the stomach and intestine above the normal anatomical location of the diaphragm, colonic interposition.

X-ray semiotics may depend on the side of the lesion. Thus, in rupture of the right diaphragmatic dome, an intense, oval-contoured shadow is identified in the right hemithorax, protruding above the diaphragmatic dome or merging with it. In rupture of the left dome, lucency areas originating from the stomach or bowel loops are more frequently detected in the left hemithorax. In left-sided rupture, widening of the mediastinum is possible, necessitating differential diagnosis with aortic injury.

Given that in half of all cases there is no herniation of abdominal organs into the chest cavity, a chest X-ray does not always allow for a diagnosis. The sensitivity of diaphragmatic radiography is no more than 60%. It does not allow for direct visualization of the diaphragmatic defect [71]. Nevertheless, the absence of visualization of the diaphragm on a chest X-ray is an independent risk factor for such an injury [59].

Comments: Pleural ultrasound should be used only as an auxiliary method, allowing for tentative differentiation of loculated pleural effusion from the stomach and bowel loops. However, the method is insufficiently sensitive for diagnosing pulmonary, aortic, cardiac, and musculoskeletal injuries [88].

Comments: MRI can be used in a stable patient with an uncertain diagnosis when thoracotomy or laparotomy is not necessary, or for delayed diagnosis.

Comments: Examples of reasons why MSCT cannot be performed include the lack of a computed tomography scanner, patient non-transportability, and a sharp drop in blood oxygen saturation during repositioning. It is advisable to administer barium sulfate** via a nasogastric tube. In this case, the gastric wall, contrasted with barium sulfate**, is not restricted by the diaphragmatic dome, and the nasogastric tube, having passed the level of the diaphragm, goes upward and appears in the chest cavity, which is a pathognomonic sign.

Comments: diagnostic methods such as thoracoscopy and laparoscopy are not standalone methods for diagnosing diaphragmatic injury. They imply mandatory inspection of the diaphragm in patients undergoing thoracoscopic/laparoscopic diagnostics or surgery for blunt chest/abdominal trauma or unclear chest/abdominal pathology. They may be performed in stable patients when other diagnostic methods are uninformative and a persistent diaphragmatic rupture is suspected [26].

Esophageal trauma (thoracic segment)

Comments: during the examination, it is necessary to confirm or exclude emphysema of the periesophageal tissues, as well as possible contrast medium leaks beyond the anatomical boundaries of the esophagus. The radiological examination method is primary, 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. The method includes overview multi-position radiography of the neck and chest with evaluation of the mediastinum, lungs, and pleural cavities, as well as contrast examination of the esophagus with a barium sulfate** suspension. Soft tissue radiography of the neck and chest radiography in multiple projections are indicated for the assessment of soft tissues (edema, emphysema), lung tissue aeration, detection of pathological contents in the pleural cavities (pneumothorax, hydrothorax, pneumohydrothorax, unilateral or bilateral), foreign bodies, contours of the shadow of the mediastinum (mediastinal widening, pneumomediastinum), cardiac pulsation, as well as diaphragmatic mobility and the state of the bone framework. To objectify the detected changes and assess the dynamics of the process, fluoroscopic examination must be completed with radiography. Periesophageal tissue emphysema occurring within the first hour indicates esophageal injury even in the absence of contrast medium leakage beyond its boundaries. Neck emphysema can appear with any localization of esophageal perforation and manifests as single air bubbles up to 0.5 cm in diameter in microperforations up to massive linear radiolucencies extending to the chest wall. Pneumothorax in esophageal perforations with mediastinal pleural injury manifests as the presence of gas from the apex to a total pneumothorax. On overview radiological examination, fluid accumulation is detected on the side of the esophageal injury and is visualized as a homogeneous opacity in the pleural cavity. A change in the configuration of the mediastinal shadow—its widening and opacification, smoothness and fuzziness of contours—is detected no earlier than 6–8 hours after the esophageal injury. Overview multi-position radiological examination allows for the detection of radiopaque foreign bodies in neck and chest injuries (knife, bullet, shrapnel, spoon, metal dental prosthesis, etc.) and determines their size and localization. Radiocontrast examination of the esophagus should preferably begin with water-soluble contrast media that do not contain barium sulfate**, since leakage of barium sulfate** suspension into the mediastinum and pleural cavities requires its thorough removal. If such an examination is uninformative, a liquid barium sulfate** suspension is used. The use of barium sulfate** in the contrast examination method of the esophagus greatly facilitates finding the site of injury in it during surgery when opening the mediastinum. During radiological examination, attention should be paid to contrast leaks beyond the walls of the esophagus, recording the localization of the injury (right or left lateral walls; anterior or posterior; bilateral).

Comments: The primary objective of the initial ultrasound examination is to assess the condition of the pleural cavities and pericardium. The method makes it possible to detect minimal fluid volumes, which cannot be found on X-ray examination. Dynamic ultrasound examinations are aimed at detecting free or loculated fluid in the pleural cavities and pericardium, assessing its volume, localization, and character, and enabling timely correction of surgical tactics and treatment.

Comments: Esophagoscopy is a method that allows the depth and extent of esophageal wall injury to be determined. Esophagoscopy for the initial confirmation of a diagnosis of esophageal trauma is possible, but is not a mandatory study method, since any increase in intra-esophageal pressure leads to the spread of infection through the mediastinum, and air insufflation in the presence of undrained pleural cavities is fraught with the development of tension pneumomediastinum or pneumothorax. During esophagoscopy, it is usually not possible to assess the true size of the defect because air escapes through the injury zone. Determining the distance from the lower edge of the defect to the esophagogastric junction is important for choosing the surgical approach and the feasibility of fundoplication. When performing upper GI endoscopy (FEGDS), it is necessary to assess the feasibility of intraluminal VAC therapy or clipping of the esophageal wall defect.

Comments: During differential diagnosis in suspected esophageal injury, bronchoscopy is of great importance. This is because subcutaneous emphysema is one of the symptoms indicating organ injury. However, this symptom may be the result of tracheal injury, as well as trauma to other organs and diseases. Bronchoscopy allows the cause of emphysema to be clarified and the localization of the injury in the trachea to be established.

Comments: Computed tomography of the chest organs is a method for diagnosing injuries to chest organs, including the esophagus. The advantage of the method is the ability to simultaneously visualize structures in the studied slice in the transverse plane with their quantitative processing by density, linear dimensions, and volume of various areas, as well as the presence and localization of foreign bodies, even in the presence of subcutaneous emphysema, pneumothorax, and pronounced subcutaneous adipose tissue. No special preparation is required for X-ray computed tomography of the neck and chest. The standard positioning is supine. The study begins with a longitudinal scout view in the frontal plane, followed by transverse slices from the skull base to the level of the diaphragm. To increase the resolving power of the method, an image "enhancement" technique is used, based on the intravenous administration of contrast agents. To assess the mobility of pleural cavity contents and for differential diagnosis of intra- and extrapulmonary collections, CT slices are taken while changing the patient's body position. CT is not the primary diagnostic method for esophageal trauma, but in the postoperative period, it provides important information for detecting undrained purulent collections and assessing the dynamics of the inflammatory process in the mediastinum.

2.5 Other Procedures

Comments: The first group includes patients in extremely grave condition with vital function impairments. Injuries to the heart, great vessels, lung root, and severe polytrauma are most likely. Patients must be immediately transferred to the operating room, where all necessary examinations—physical examination and identification of clinical symptoms of injury, radiography, ECG, pleural and abdominal ultrasound, and echocardiography—are performed simultaneously with resuscitation measures. The objective of the diagnostic stage is solely to determine the side of predominant lesion, the types, and, in polytrauma, the sequence of surgical approaches. It should be remembered that the primary objective is to initiate surgery as quickly as possible and perform definitive hemostasis. The second group includes patients in serious condition, but without vital function impairments. Diagnostics and intensive care should be performed in the anti-shock operating room or anti-shock ward. The examination includes only the necessary minimum: physical examination, chest CT, ECG, pleural and abdominal ultrasound, echocardiography, and pleural puncture or drainage as indicated. Further examination is performed after surgery and stabilization of the patient's condition. The third group includes patients in moderate condition, without life-threatening impairments, with stable hemodynamics. Their examination is performed in the shock trauma room or anti-shock ward and includes all necessary studies (physical examination, chest CT or chest radiography, ECG, general [clinical] blood and urine tests, general clinical blood chemistry, pleural and abdominal ultrasound, echocardiography, pleural puncture or drainage as indicated, endoscopy as indicated, and specialist consultations). The fourth group includes patients in satisfactory condition. All clinical and instrumental examinations are performed in the emergency department.

Comments: Diagnostic studies performed in the hospital against the background of anti-shock measures must be characterized by high sensitivity and reliability with minimal time expenditure. The scope and sequence of diagnostic studies depend on the mechanism of injury and the severity of the patient's condition.

Comments: In the case of unstable hemodynamics, impairments of external respiration and ongoing bleeding should be identified and eliminated first. In a critical condition of the patient, syndromic diagnosis and the execution of resuscitation measures and surgical operations aimed at eliminating syndromes that can lead to the patient's death in a short time are permissible.

Comments. The simplest monitoring measures include the following procedures.

1. Visual assessment: general condition of the patient (satisfactory, moderate, severe, extremely severe, agonal state, clinical death), skin color, assessment of breathing (rate, depth, etc.). Body temperature measurement is mandatory.

2. Respiratory monitoring: presence or absence of breathing, breathing assessment is performed, auscultatory sounds are listened to, saturation is measured if a pulse oximeter is available, and continuous pulse oximetry is performed if a cardiac monitor is available.

3. Hemodynamic monitoring: determination of the pulse on the radial artery (if impossible, on the carotid arteries), non-invasive blood pressure measurement, pulse rate (beats per minute on average) on the pulse oximeter. If a cardiac monitor is available, heart rate (HR) monitoring, ECG curve, pulse oximetry are performed, and if necessary, catheterization of the (usually radial) artery and measurement of invasive blood pressure are carried out.

4. Neuromonitoring: assessment of general neurological status, assessment of the level of consciousness over time.

Comments. Indications for performing (initiating) hemodynamic monitoring:

• severe disease or injury of the cardiovascular and respiratory systems with pronounced functional impairments;

  • age-related functional impairments of one or more organ systems;

  • acute massive blood loss of traumatic and surgical origin (> 2.5 L);

  • sepsis;

  • shock or severe hypovolemia of any origin;

  • respiratory failure (PaO2 < 60 mmHg, SaO2 < 90% in a spontaneously breathing patient or PaO2/FiO2 < 300 mmHg in a mechanically ventilated patient);

  • acute kidney injury (urea > 20 mmol/L, creatinine > 200 µmol/L).

• It is recommended that all patients undergoing mechanical ventilation and vasopressor support undergo cardiac function (cardiac output) monitoring using echocardiography, as well as an assessment of tissue oxygen consumption, sensitivity to infusion therapy, and tissue edema in the late phase (depending on the technical equipment of the intensive care unit) [143].

GCR CLEL 5Grade of Recommendation C (Level of Evidence — 5).

Comments: for heavier patients undergoing mechanical ventilation and vasopressor support, echocardiographic assessment of cardiac function is the method of choice. For conscious patients, spontaneously breathing and receiving vasopressor support, a passive leg raise test is also recommended to assess the dynamics of cardiac output changes. An integrated approach to hemodynamic monitoring in intensive care of critical conditions is necessary, with assessment of mean arterial pressure, CVP, and central venous saturation (ScvO2). Assessment of sensitivity to infusion therapy (leg raise test, dynamic parameters); assessment of cardiac output along with tissue oxygen consumption (S(c)vO2, arteriovenous difference (Da-vO2)); assessment of tissue edema in the late phase — extravascular lung water index; reliable preload assessment are mandatory.

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

Treatment of patients with blunt chest trauma is carried out in accordance with the following principles regardless of the chosen tactics:

• Restoration and maintenance of airway patency.

  • Pain relief.

  • Hmostasis and replenishment 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.

• It is recommended that during emergency care for blunt chest trauma, primary attention be paid to airway patency (for the timely diagnosis of obstruction or potential obstruction) and the prevention of oropharyngeal or tracheal aspiration, in order to increase the effectiveness of emergency care [1, 66].

GCR CLEL 5Grade of Recommendation C (Level of Evidence — 5).

Comments: airway management is paramount in chest trauma and is one of the key aspects of emergency care. Most importantly, one must correctly diagnose airway obstruction or potential obstruction, eliminate it, and maintain the patient's breathing. No emergency medical situation, other than cardiopulmonary shock, threatens life as much as airway compromise. Inadequate airway management, and the resulting impaired ventilation, are among the leading preventable causes of death from trauma. During the initial assessment and treatment of a patient with severe blunt chest trauma, airway management is performed first, followed by breathing and circulation (the ABC approach: Airway, Breathing, Circulation). When providing emergency care to an injured patient, a systematic approach must be used with a primary focus on the airway. If any patency abnormalities are found, they must be corrected immediately. Therefore, it is necessary to be able to properly assess, restore, and maintain airway patency, thereby ensuring adequate pulmonary ventilation and oxygenation.

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: prolonged endotracheal intubation can lead to severe laryngeal and tracheal complications. Several studies have shown that early tracheostomy leads to a reduction in the incidence of hospital-acquired pneumonia, duration of mechanical ventilation, and length of stay in the ICU [89]. Other advantages of tracheostomy include greater patient comfort, including psychological comfort, facilitation of nursing care (airway clearance and oral hygiene), among others.

Comments: administration of antibiotics for longer than 24 hours does not reduce the risk of surgical site infection, but contributes to the selection of resistant strains.

Comments: the prescription of 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, this monitoring makes it possible to solve other important tasks: to provide adequate antibiotic therapy for patients; to assess the rate of patient colonization and environmental contamination by various microorganisms, including those of epidemiological significance; to identify strains that have gained priority spread in a particular medical organization, and to assess the microbial landscape of the institution as a whole and its departments; to predict the development of the epidemiological situation regarding these diseases (complications).

Comments: measures to eliminate life-threatening injuries to the thoracic anatomical region (in accordance with damage control surgery tactics) include arrest of intrapleural, pulmonary, and other bleedings, restoration of effective external respiration (pleural drainage for tension pneumothorax, mechanical ventilation for flail chest, diagnostic and therapeutic bronchoscopy for aspiration syndrome, etc.), resuscitative thoracotomy for cardiac arrest, and closure of tracheal and major bronchial ruptures. Most commonly, these are combined with laparotomy for parenchymal and hollow organ ruptures, external fixation of pelvic fractures, decompressive craniectomy for intracranial hematomas, etc. These interventions are performed in parallel or in accordance with the severity of each injury: from the most severe and dangerous to the less severe and dangerous. Remaining injuries are addressed after vital functions stabilize, following the same principle on an urgent or delayed basis.

Rib fractures

Comments: the first and primary direction of in-patient treatment should be pain relief, as it allows maintaining adequate ventilation, productive cough, and engaging in breathing exercises. As a rapid assistance measure, widespread intravenous administration of nonsteroidal anti-inflammatory drugs should be preferred, although side effects are the main reason for their premature discontinuation. Most randomized controlled trials have demonstrated the benefits of epidural anesthesia in pain control, reducing the incidence of nosocomial pneumonia, shortening the duration of mechanical ventilation, and decreasing length of stay in the ICU and hospital.

Comments: tight chest wrapping in rib fractures is contraindicated because it leads to a sharp restriction of chest mobility, worsens pulmonary hypoventilation, and contributes to the development of pneumonia.

Comments: on-lay plate and intramedullary fixation of broken ribs are permitted [97, 132, 141, 142]. At the same time, the main goal of restoring the integrity of the rib cage is not the reduction and consolidation of fractures, but the restoration of adequate pulmonary ventilation [45, 143].

Flail chest (flail segment)

Comments: if this rule is followed, the likelihood of displacement and compression of mediastinal vessels is significantly reduced.

Comments: currently, it is considered appropriate to perform surgical fixation of flail chest fractures without thoracotomy. The best approach for this is a posterior paravertebral approach, video-assisted thoracoscopic surgery (VATS) through a muscle-sparing mini-access. The advantage is the absence of dissection of traumatized soft tissues, a reduced risk of wound suppurative-inflammatory complications and complications associated with prolonged mechanical ventilation. This technique allows for satisfactory stabilization of the rib cage, even in bilateral rib fractures with flail sternocostal segment, ensures early weaning of the patient to spontaneous breathing, enables early mobilization, reduces the number of suppurations and pulmonary complications, and shortens the length of stay in the intensive care unit and hospital [53].

Sternum fracture

Comments: despite the severity of a sternal fracture, it does not require any special treatment other than analgesic therapy [1].

Traumatic asphyxia

Pneumothorax

Comments: the site of drainage depends on multi-positional chest radiography or CT data. In the absence of pleural adhesions, a drainage tube with a diameter of at least 5 mm is inserted through the 2nd intercostal space at the midclavicular line or in the so-called "safe triangle", which is bounded anteriorly and superiorly by the edge of the pectoralis major muscle, posteriorly by the edge of the latissimus dorsi muscle, and inferiorly by a horizontal line drawn through the nipple (4th intercostal space between the anterior and middle axillary lines) [25, 45]. Pleural drainage can be passive (with a G. Bulau underwater seal, Bobrov's bottle, etc.) and active (aspiration). Electric suction devices are used for aspiration (preferably with the capability of creating a controlled negative pressure of up to 30–40 mm H₂O). In persistent open internal pneumothorax due to ongoing air leak from the lung, alternating passive and active drainage is advisable.

Comments: delayed lung expansion or failure to expand may lead to the development of acute and chronic empyema of the pleura, as well as a trapped lung.

Hemothorax

Comments: early evacuation of blood from the pleural cavity is the main means of preventing the development of fibrothorax and pleural empyema, as well as creating optimal conditions for lung expansion. The placement of a large-bore drain is advisable.

Comments: the goals of surgical intervention for clotted hemothorax are: fragmentation and evacuation of clotted blood, as well as decortication of the compressed lung. VATS is performed. If the hemothorax cannot be eliminated via video-assisted endoscopic surgery, conversion to a traditional thoracotomy is performed. Intrapleural fibrinolytic or proteolytic therapy is a very effective method of treating early (up to 2 weeks old) clotted hemothorax, along with VATS [45, 143].

Comments: it has been shown that VATS performed in the first 3–14 days after trauma successfully evacuates the clot, reduces the rate of thoracotomy and complications, including pleural empyema, and shortens the patient's hospital stay. In later periods, a thoracotomy approach is preferred.

GCR CLEL 5Grade of Recommendation C (Level of Evidence — 5).

Comments: in closed chest trauma, thoracoscopy can perform all the same types of operations as in penetrating wounds: stopping low-intensity intrapleural bleeding from damaged chest wall vessels, suturing lung and diaphragmatic lacerations, and mediastinal decompression [45, 143].

Thoracotomy is indicated in cases of a simultaneous initial output of 1 liter of blood or more immediately after pleural cavity drainage, as well as prolonged bleeding at a flow rate exceeding 250 ml/hour [91, 45, 143].

The most frequent source of intrapleural bleeding in closed trauma is the intercostal vessels. To stop such bleeding, the most rapidly executable methods should be used—for example, placing pericostal sutures (distal and proximal to the bleeding site), compressing the intercostal vascular bundle against the rib. Attempts to isolate the bleeding vessel, clip it, etc., should be considered an error, as this leads to unjustified blood loss and waste of time. Suturing lung lacerations (or secondary injuries caused by rib fragments) to reduce the duration of single-lung ventilation, which can have an extremely negative impact on the patient's condition, should be performed in the fastest and simplest way: by oversewing the wound tract with a stapling device, wedge resection of the contused lung area, etc. In this situation, more complex methods used in elective thoracic surgery should be considered an error.

Aortic rupture

Heart and pericardial injuries

Other injury of the lung(s), injury of major bronchi, trachea (thoracic segment)

Comments: in case of ruptures of the crests (spurs) of large bronchi, bronchial sealing can be performed by temporary endobronchial clipping (without thoracotomy) [139, 143].

Diaphragmatic injury

Comments: in a surgical hospital, the established diagnosis of diaphragmatic rupture should be considered an indication for emergency surgery due to respiratory failure caused by lung compression by abdominal organs displaced into the pleural cavity, as well as due to the risk of strangulation and necrosis of these abdominal organs. The detection of a diaphragmatic defect should be considered grounds for establishing a high risk of organ strangulation. In addition, uncorrected diaphragmatic defects generally lead to the formation of a diaphragmatic hernia [55, 97, 138]. Severe cardiovascular symptoms should not be regarded as an absolute contraindication to surgical treatment. They may be caused by the displacement of abdominal organs through the diaphragmatic defect into the pleural cavity (reflex effect, direct compression) and require only brief preparation for surgery. The goal of the surgery is to eliminate the compression syndrome (reduction of abdominal organs into their natural anatomical conditions) and eliminate the diaphragmatic defect [107, 138].

Comments: if diaphragmatic rupture is isolated or dominant, and diaphragmatic rupture is diagnosed, thoracotomy on the affected side must be performed. In such situations, indications for emergency and urgent thoracotomy may primarily include other life-threatening conditions: profuse intrapleural hemorrhage, rapidly progressing pneumothorax, suspected cardiac and great vessel injury, ongoing intrapleural hemorrhage with blood loss of 300 ml/h or more, refractory tension pneumothorax, open pneumothorax with massive lung injury, and esophageal injury [108, 138].

Comments: with a confirmed diagnosis of diaphragmatic injury in stable patients, as well as when the surgeon has sufficient experience, video-assisted thoracoscopy may be considered. However, even in this case, closing an injury located at the pericardial level is extremely challenging [60]. In closed thoracoabdominal injuries, up to 22% of diaphragmatic wounds can be closed during video thoracoscopy, while in thoracoabdominal stab/gunshot wounds, this is achieved during video laparoscopy in only 8% of cases [138].

Esophageal injury (thoracic segment)

Comments: on average, conservative treatment for partial esophageal wall injuries lasts 4–6 days. Lack of response to therapy, and especially progression of inflammatory changes, is an indication for surgical treatment.

Comments: depending on the side of the esophageal injury, left-sided, right-sided, or bilateral approaches are used (in cases of multiple esophageal injuries).

Comments: in patients with such traumatic injuries, reflux of gastric contents occurs through the esophageal wall defect into the mediastinum and pleural cavities, which significantly complicates the treatment of this group of patients and requires fundoplication.

Comments: the presence of purulent mediastinitis and pleural empyema is not a contraindication to this surgery.

Injury to other thoracic organs

Injury of the thoracic duct

Comments: the frequency of pleural punctures depends on the rate of chyle accumulation, the manifestation of signs of respiratory failure, and impaired cardiac activity due to lung compression, mediastinal shift, and kinking of large veins. Sometimes pleural puncture must be performed urgently for vital indications. Preference should be given to pleural drainage and establishing continuous suction with a negative pressure of 14.7–19.6 kPa (150–200 mm H₂O). The presence of such a drain makes it not only possible to completely remove the accumulated chyle, but also to perform daily monitoring of the volume of fluid lost. In addition, drainage allows for more effective re-expansion of the collapsed lung.

Comments: a pleuroperitoneal shunt is an alternative to external drainage. It is indicated for patients whose general condition prevents them from undergoing a more invasive surgical procedure, while chylorrhea persists despite conservative therapy [110, 111]. The surgical technique of shunt placement is similar to standard pleural cavity drainage. It can also reduce nutrient, fluid, and cellular losses compared to external drainage. Patients should be informed about the need for periodic flushing of the shunt. In 10% of cases, the shunt may become obliterated by fibrin, necessitating replacement. The drainage of fluid into the abdominal cavity leads to chylous ascites, which does not cause significant problems.

Comments: pleurodesis is an alternative method to reduce chylothorax. If a thoracic drain is already in place, this can be performed through its lumen. Chemical pleurodesis is indicated for refractory chylothorax in debilitated patients at extremely high risk for surgery. In other patients undergoing surgical treatment, chemical pleurodesis may also be used intraoperatively as a component of the operation after ligation of the thoracic duct.

Comments: thoracoscopic surgeries on the thoracic duct currently match open interventions (thoracotomies) in their capabilities while involving less tissue trauma.

4. Medical Rehabilitation and Sanatorium-Resort Treatment

Comments. Rehabilitation methods for patients with chest trauma who are unconscious and on mechanical ventilation differ significantly from those for conscious, spontaneously breathing patients. The goals of rehabilitation in these patients are to prevent respiratory complications and deep vein thrombosis. Respiratory techniques are combined depending on the patient's general condition and the type of injury (unilateral or bilateral serial rib fractures, flail chest, pulmonary contusion, pleural effusion, bronchial injury). Timely initiation of early rehabilitation prevents early (pulmonary atelectasis, bronchopneumonia) and late complications (hematoma suppuration, empyema) [116].

First (hospital) stage of rehabilitation

Comments: these protocols include patient education and preoperative preparation, avoidance of routine invasive procedures without proven efficacy (mechanical bowel preparation, preoperative fasting), multimodal analgesia, specialized anesthetic management protocols, avoidance of routine use of catheters and drains, and early mobilization of patients starting from the first to second postoperative days (activation and verticalization).

Comments: according to the International Association for the Study of Pain, pain is not only a multifaceted syndrome, but also a risk factor for the development of complications associated with chest trauma. The presence of pain can impair respiratory excursions, disrupt ventilatory function, and exacerbate breathing mechanics disorders caused by inflammation and potential contusion already present in a patient with blunt chest trauma [120]. Furthermore, shallow breathing impairs the bronchial drainage function, causes sputum retention, and suppresses the cough reflex. A cough reflex suppressed by pain leads to atelectasis and increases the risk of pneumonia. Inadequate analgesia in a patient with blunt chest trauma leads to decreased lung compliance, ventilation-perfusion mismatch, hypoxemia, and acute respiratory distress syndrome [121, 122]. Inadequate pain control can result in insufficient sleep, malnutrition, psychological stress, depression, agitation, prolonged recovery, and limitation of normal daily activities [123, 124]. Untreated pain has a strong adverse effect on central and peripheral hemodynamics, the gastrointestinal system, and renal function [125-127]. Timely and adequate analgesia in chest trauma not only reduces the number of complications, but also shortens the length of hospital stay and treatment costs [128, 129].

Physiotherapy in patients with blunt chest trauma is an area of clinical practice that requires further study and scientific substantiation. A small number of available low- to moderate-quality studies support the use of interventions such as early mobilization and verticalization, in-bed and out-of-bed functional activity, deep breathing and positive expiratory pressure exercises, active coughing, and adjunctive physical therapy procedures to reduce the incidence of complications and shorten hospital stay [130].

Second stage of rehabilitation

Third (outpatient clinic) stage of rehabilitation

The main objectives of rehabilitation for patients with chest injuries at this stage are the further restoration of the patients' physical condition and working capacity, ensuring the completion of treatment for injury consequences and complications, active monitoring for the early diagnosis of potential late complications, treatment of concomitant chronic pathologies, medical-labor examination, and preparation of patients for the sanatorium stage of rehabilitation. Therapeutic exercise, breathing exercises, and physiotherapy are performed. Ensuring adequate high-calorie nutrition is important.

Sanatorium stage of rehabilitation

Selection for local, climatic, mud, and balneological sanatoriums is carried out after the patients have completed inpatient and outpatient treatment, taking into account the specifics of the trauma, the course of the traumatic disease and its complications, and the compensatory capabilities of the cardiovascular and bronchopulmonary systems, in accordance with Order No. 256 of the Ministry of Health and Social Development of Russia dated November 22, 2004 (with amendments and additions of January 9, December 24, 2007, December 24, 2008, July 23, 2010, December 15, 2014) "On the procedure for medical selection and referral of patients for sanatorium-resort treatment." Patients are referred there 4–6 months after injuries and surgeries, without wounds, external fistulas, drains, or external fixation devices, provided they have well-healed postoperative and other scars, and cardiopulmonary insufficiency of no higher than stage I B.

The objectives of the sanatorium stage are:

• consolidation of the results of the hospital and outpatient rehabilitation stages;

• restoration of impaired functions and further development of compensation (and adaptation) mechanisms of the bronchopulmonary, cardiovascular, and nervous systems;

• increasing the body's resistance to adverse environmental factors;

• body hardening and active recreation;

• implementation of psychological rehabilitation measures and preparation for professional activities.

Medical rehabilitation of patients who have undergone severe chest trauma at the sanatorium stage involves the widespread use of climatotherapy and physical therapy, natural resort and preformed physical factors, medical nutrition, and maintenance therapy. Convalescents admitted to the sanatorium are prescribed a sparing motor activity regimen (with light physical exertion) for 2–3 days. Upon completion of the adaptation period, they are transferred to a sparing-training regimen (with moderate physical exertion) and a training regimen (with general physical exertion of pronounced impact). This is guided by the general condition, functional parameters of the cardiovascular and respiratory systems, taking into account the nature of the trauma and surgical interventions, the specifics of the postoperative course and traumatic disease, the time elapsed since the trauma and surgery, and concomitant pathology [144].

5. Prevention and Dispensary Observation

Closed chest trauma in general

Diaphragmatic injury

Comments: specific preventive measures to avoid diaphragmatic injury in blunt chest and/or abdominal trauma do not exist. Only the prevention of post-traumatic diaphragmatic hernias, which can occur in cases of small and unrecognized diaphragmatic ruptures long after blunt chest trauma, can be addressed. Following surgical intervention for a diaphragmatic rupture, follow-up by an outpatient surgeon is required for 1 month with a control chest X-ray performed before the resumption of work activity. This is because unrecognized or inadequately sutured diaphragmatic defects can lead to the formation of a diaphragmatic hernia.

Esophageal injury (thoracic segment)

6. Organization of Medical Care

Blunt chest trauma in general.

All specialists providing first aid at both the pre-hospital and hospital stages must know the signs of airway obstruction and possess skills in maintaining the patient's breathing while ensuring cervical spine protection. The possibility of successful airway management increases with the availability of special equipment and the skills for its proper and safe use. Guaranteed capabilities for safely performing airway management procedures (e.g., endotracheal intubation, cricothyroidotomy, tracheostomy) must be ensured at all levels (pre-hospital, hospital). These procedures are considered mandatory for emergency medical service (EMS) teams, which implies the provision of ready-to-use equipment regardless of the patient's location (at the pre-hospital stage, in hospital surgical or trauma departments). The necessary equipment must be stored in special kits in each department. Safety guarantees also imply that personnel performing various procedures are well-trained to execute them successfully with a minimum number of complications. This includes skills acquired during basic training (vocational training schools for physicians and nurses), and subsequent education should help maintain these skills. Given the potential complications during pre-hospital airway management (e.g., in esophageal intubation), it is necessary to have tools to verify the correct placement of the endotracheal tube wherever endotracheal intubation is performed.

To successfully provide care to all patients during the diagnosis of polytrauma involving the chest in a trauma center, it is necessary to take into account the following features of such injuries and structure the work accordingly [131]:

• the need to examine patients in a shock-trauma operating room;

• time constraints;

• the priority of radiological and instrumental diagnostic methods;

• the need to use injury severity and condition scoring scales;

• multidisciplinarity, the need to involve a wide range of studies and specialists;

• clarification and adjustment of the diagnosis during the course of treatment.

The shock-trauma operating room is a key unit of the trauma center (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 Polytrauma, Multiple and Isolated Injuries Accompanied by Shock"), where the patient is delivered, bypassing the admission department, after prior notification by the ambulance service. Such an operating room is on 24-hour standby and is not intended for emergency or elective general surgical interventions. The multidisciplinary on-duty team includes a surgeon, an orthopedic trauma surgeon, an anesthesiologist-resuscitologist, a neurosurgeon, a cardiovascular surgeon, and an endoscopic surgeon. In the shock-trauma operating room, urgent medical examinations, central venous and urinary bladder catheterization, and if necessary, tracheal intubation and mechanical ventilation are performed; blood and urine samples are taken for laboratory tests; ECG, ultrasound of the subdiaphragmatic spaces, pleural sinuses, pelvic cavity, and pericardium (FAST — Focused Assessment with Sonography for Trauma) to detect fluid are performed; plain radiography of injured parts of the body is carried out; endoscopic examinations, invasive diagnostic procedures, emergency and urgent surgical interventions, as well as monitoring of functional parameters during the management of traumatic shock, are conducted [131].

After emergency surgical interventions and anti-shock therapy, patients are transferred for intensive care and intensive monitoring to the surgical intensive care unit, and subsequently, upon stabilization of vital functions, to the trauma or surgical department, or to the polytrauma or thoracic surgery department.

Rib fractures.

Patients with isolated uncomplicated rib fractures should receive specialized surgical care at the outpatient stage provided by a surgeon or an orthopedic trauma surgeon.

Due to the fact that rib fractures can be a component of blunt chest trauma or polytrauma, the routing of such patients may be determined by the severity of the polytrauma and the patient's general condition, as well as the capabilities for providing emergency specialized thoracic surgical care.

Upon emergency hospitalization of patients to a Level 1 medical institution, specialized surgical care must be provided by a surgeon.

After the patient's condition stabilizes and they are resuscitated from shock, rapid transport to a higher-level multidisciplinary hospital (Level 1 or 2 trauma center) with a thoracic surgery department is indicated.

In the presence of other musculoskeletal system injuries, management of the patient is carried out jointly with an orthopedic trauma surgeon [132].

Indications for hospitalization in a medical organization [19, 21, 133]:

A: hospitalization in a surgical or trauma (preferred) department:

1) fracture of three or more ribs;

2) fractures of the 1st and 2nd ribs;

3) presence of severe and polytrauma (injuries);

4) presence of severe and/or decompensated comorbid pathology, including in elderly patients, as well as in the risk of decompensation of such pathology;

B: hospitalization in the ICU: multiple and polytrauma rib fractures, including in patients with severe and/or decompensated comorbid pathology, as well as in the risk of decompensation of such pathology.

Flail chest (rib cage segment).

Patients with multiple and flail rib fractures should be hospitalized in a thoracic surgery department for surgical stabilization of the chest wall framework, and due to the risk of intrathoracic complications and respiratory failure.

Diaphragmatic injury.

Due to the fact that diaphragmatic injury is a component of blunt chest trauma or polytrauma, the routing of such patients should be determined by the severity of the polytrauma and the patient's general condition, as well as the capabilities for providing emergency specialized thoracic surgical care.

Specialized surgical care on an emergency basis can be provided in a Level 1-2 trauma center. Surgical intervention for diaphragmatic injury can be performed by a surgeon performing emergency surgery for closed chest/abdominal trauma in the presence of other indications.

If the patient with closed chest trauma is in a stable condition and there are no indications for emergency surgery (laparotomy or thoracotomy), the surgical intervention for diaphragmatic rupture may be delayed (within the first 12 hours from admission), and a thoracic surgeon must be involved, or the victim must be evacuated to the next stage of specialized care — a multidisciplinary hospital with a thoracic surgery department [134].

Esophageal trauma.

The provision of medical care to all patients with esophageal trauma requires the conditions of specialized thoracic surgery departments and/or specialized hospitals, and only in the absence of such an opportunity is its provision justified in general surgical departments and/or hospitals.

One of the methods for preventing esophageal injuries available to a practicing physician is informing the population about potential causes of esophageal trauma and the danger of self-treatment methods due to developing severe complications, and the need to seek medical attention immediately.

It is also necessary to train and improve the qualifications of specialists (endoscopists, anesthesiologists-resuscitologists, surgeons) aimed at studying clinical manifestations, diagnosis, and treatment of esophageal injuries.

Both methods under consideration are matters of healthcare organization rather than practical thoracic surgery.

Indications for discharge of patients with closed chest trauma.

Stabilization of the general condition, clinical and radiological improvement.

7. Additional Information

The prognosis for uncomplicated fractures of the 1st-2nd ribs is favorable. Union occurs in 3-4 weeks. Complete union of the sternum occurs in 5-6 weeks.

With fractures of 3 or more ribs, bilateral fractures, and extrathoracic injuries, the risk of complications and mortality increases significantly [19, 21, 133]. In fractures of more than 6 ribs, mortality reaches 15% [135]. Flail chest is the most life-threatening condition due to the development of severe complications (mediastinal flutter, respiratory and cardiovascular failure, pleuropulmonary and traumatic shock). Even with timely and adequate treatment, mortality ranges from 25% to 39%, partly due to the severity of concomitant injuries [6, 22, 44, 132]. Mortality is higher in patients older than 45 years [136, 137].

In isolated diaphragmatic injury, the prognosis after surgical treatment is favorable. In polytrauma, the prognosis is determined by the severity of concomitant injuries. Mortality in this case ranges from 5 to 30% [37–40].

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

Conflict of interest: the working group members declare no conflict of interest regarding the development of these clinical guidelines.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

1. surgeons;

2. thoracic surgeons;

3. cardiovascular surgeons;

4. trauma and orthopedic surgeons;

5. anesthesiologists-intensivists;

6. cardiologists;

7. emergency medicine physicians;

8. admission department physicians;

9. general practitioners (internal medicine);

10. district general practitioners;

11. general practitioners (family doctors);

12. radiologists;

13. ultrasound diagnostics physicians;

14. functional diagnostics physicians;

15. paramedics;

Material for formulating the thesis-recommendations (sections 2, 3, 4, 5 of the clinical guidelines) was collected 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 in the eLIBRARY.RU system, and in English in PubMed, Scopus, and Google systems (query tracking was not performed); titles, abstracts, and full texts (if available) for the most relevant entries were reviewed; when sources of varying 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, and the strength of the recommendations was determined according to Table 3 (Appendix No. 2 to the Requirements for the Structure of Clinical Guidelines, Composition and Scientific Validity of Information Included in Clinical Guidelines, approved by Order of the Ministry of Health of the Russian Federation No. 103n dated February 28, 2019).

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

Table 2. Rating scale for levels of evidence (LE) for prevention, treatment, and rehabilitation methods (preventive, therapeutic, rehabilitative)

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

Esophageal trauma. When searching for scientific publications, various combinations of keywords were used: «esophageal injury», «esophageal perforation», «mediastinitis», «surgery». To minimize potential errors, each publication was evaluated by two independent members of the working group.

Procedure for updating clinical guidelines.

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

Appendix A3. Reference Materials

No.

Appendix B. Physician Action Algorithms

Diagnostic algorithm for blunt chest trauma [45, 143]

Appendix C. Patient Information

No.

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

Appendix G1 — AIS/ISS Injury Severity Score

Name:

Abbreviated Injury Scale (AIS).

Injury Severity Score (ISS).

Source: AIS [138]; ISS [138, 139].

AIS developer website: https://www.aaam.org/abbreviated-injury-scale-ais/

Type (underline):

- rating scale

- index

- questionnaire

- other (specify): __________________________________________________

Purpose: assessment of injury severity.

Content (template):

Key (interpretation):

Polytrauma severity (Injury Severity Score — ISS) in points is equal to the sum of squares of the Abbreviated Injury Scale (AIS) severity scores of the three most severely injured of the following six body regions <*> [138,139]:

1. head and neck;

1. face;

2. chest;

2. abdomen, retroperitoneal space, and pelvic contents;

3. extremities, pelvic girdle;

4. external injuries.

--------------------------------

<*> Note: division of body regions by ISS does not correspond to AIS division [138].

Criteria for assessing polytrauma severity (Injury Severity Score — ISS) [138, 139]:

1. mild: less than 17 points;

2. stable: 17–25 points;

3. borderline: 26–40 points;

4. critical: more than 40 points.

Example of ISS polytrauma severity calculation [138]:

Appendix G2. Useful Information

Fig. 1. Causes of respiratory failure in chest injuries [45, 143]:

1 — pain from rib fractures and parietal pleura rupture;

2 — flail chest;

3 — lung lacerations;

4 — hemothorax;

5 — pneumothorax;

6 — pulmonary atelectasis;

7 — diaphragmatic rupture;

8 — pulmonary contusion and intrapulmonary hematomas;

9 — tracheal and bronchial obstruction due to accumulation of mucus and blood, bronchospasm;

10 — bronchial rupture;

11 — laryngospasm;

12 — central respiratory disorders (respiratory center depression).

Fig. 2. Diagram of pleural puncture [45, 143]:

1. needle in lung tissue;

2. needle above the fluid level in the pleural cavity;

3. needle in the fluid-containing cavity; 4 - needle in blood clots or fibrinous deposits;

4. needle in the liver.

Indications for thoracoscopy in blunt chest trauma [45, 143]:

1. Moderate and large hemothorax without signs of ongoing intrapleural hemorrhage with blood drainage from the pleural cavity up to 500 mL/hour.

2. Ongoing intrapleural hemorrhage with blood drainage from the pleural cavity ranging from 250 to 500 mL/hour.

3. Suspected hemopericardium.

4. Progressive and tension mediastinal emphysema.

5. Refractory tension pneumothorax.

6. Persistent pneumothorax unresponsive to treatment for 3–5 days post-trauma and recurrent pneumothorax.

7. Clotted hemothorax of up to 2 weeks duration.

Contraindications for thoracoscopy in blunt chest trauma [45, 143]:

1. Total hemothorax.

2. Profuse intrapleural or pulmonary hemorrhage.

3. Cardiac tamponade.

4. Conclusive signs of major vessel and tracheal injury.

5. Tension or refractory pneumothorax on the contralateral side of the chest.

6. Unstable hemodynamics and subcompensated acute respiratory failure.

7. Presence of uncorrected life-threatening dominant injuries in other anatomical regions.

8. Extensive soft tissue injuries or suppuration of the chest.

9. Pleural obliteration.

Fig. 3. Diagram of paravertebral block in rib fractures [45, 143]

Indications for emergency thoracotomy in blunt chest trauma [45, 143]:

• total hemothorax;

• ongoing intrapleural hemorrhage with drainage output exceeding 250 mL of blood per hour;

• cardiac tamponade;

• ruptures of major vessels;

• refractory pulmonary hemorrhage with risk of asphyxia;

• tension pneumothorax refractory to closed pleural drainage and video-assisted thoracoscopic surgery;

• tracheal and major bronchial ruptures with progressive mediastinal emphysema despite pleural and anterior mediastinal drainage;

• complete esophageal ruptures;

• extensive diaphragmatic ruptures;

• tracheal foreign bodies causing asphyxia that cannot be removed via rigid bronchoscopy.