Intrathoracic visceral injuries

Abstract

Thoracic trauma is the most common cause of death after head trauma. Thoracic trauma encompasses a wide range of injuries, from rib fractures to major vascular injuries. Thoracic trauma can be classified into two groups: blunt and penetrating. Blunt trauma accounts for 90% of all thoracic traumas. Although penetrating traumas are less common, they have a higher mortality rate.After chest trauma, various forms of lung injuries can occur, including parenchymal injury, contusion, laceration, pulmonary hematoma, and traumatic pulmonary cysts. Lungs can be injured in trauma patients through direct or indirect mechanisms. Severe lung injuries can be seen in approximately one-third of cases exposed to thoracic trauma. Pulmonary contusion is the most common lung injury in thoracic trauma. It is seen in 30-75% of severe chest trauma cases. It can occur in both penetrating and blunt traumas. Trauma patients with pulmonary contusion are at higher risk of complications such as pneumonia, acute respiratory distress syndrome (ARDS), or persistent respiratory failure compared to other trauma patients. In some series, the mortality rate has been reported as 11% in patients with severe isolated pulmonary contusion, and this rate can increase up to 22% if there are accompanying other trauma findings. When compared, ARDS developed in 17% of patients with isolated pulmonary contusion. This rate can increase up to 78% in cases with two or more accompanying organ injuries. Depending on the degree of parenchymal lung damage, many pathophysiological changes occur, leading to respiratory failure. Bleeding and bronchospasm in unaffected lung segments further impair alveolar functions. Additionally, pulmonary functions are often impaired due to increased mucus production, decreased clearance from the airways, and decreased surfactant production as a result of trauma. This manifests clinically as hypoxia, hypercapnia, and increased respiratory effort. Patients may present with tachypnea, rales or wheezing, and sometimes hemoptysis. The clinical appearance of lung parenchymal injury is insidious. Respiratory failure and radiological findings may occur hours after trauma. Generally, radiologically observed pulmonary contusion improves within 3-5 days, but lung functions may worsen in the late period. This is usually due to local inflammatory response due to trauma, blood accumulation in alveoli, secondary systemic inflammatory response in accompanying other organ injuries, and hospital-acquired infections.Immediately after trauma, interstitial bleeding occurs along with interstitial edema within the first 1-2 hours. During this period, lung structure is preserved. However, intense infiltration of monocytes and neutrophils is observed. Within 24 hours after trauma, fibrin is seen due to the accumulation of protein, red blood cells, and inflammatory cells in the airspaces. As a result, massive edema increases, and the structural organization of lung tissue begins to deteriorate. At 48 hours, granulocytes, neutrophils, and macrophages accumulate with a large amount of fibrin and cell debris originating from type II alveolar cells. At this stage, dilated lymphatic vessels filled with protein are observed. These changes pass with minimal amount of scar tissue and almost complete healing within 7-10 days after trauma.Patch-like alveolar infiltrations resembling interalveolar bleeding can be seen on chest X-rays. These separated patch-like infiltrations can merge over time to cover the entire lobe or lung. Computed tomography is much more sensitive in detecting pulmonary contusions compared to routine chest X-rays. Arterial blood gas analysis may show hypoxia, hypercapnia, and respiratory alkalosis.Patients with pulmonary contusion should be hospitalized for careful monitoring due to the possibility of rapid deterioration. Oxygen can be administered based on arterial blood gas analysis. © 2021 Akademisyen Kitabevi A.Ş. All rights reserved.