Thoracic trauma is the second leading cause of traumatic death in the United States.
All patients require a rapid primary survey focused on patient airway, breathing, and circulation and stabilization of any emergent life–threatening conditions.
Emergent life threats in thoracic trauma include airway obstruction, tension pneumothorax, open pneumothorax, massive hemothorax, and pericardial tamponade.
In select penetrating trauma victims who suffer witnessed loss of vital signs, emergent thoracotomy can be a lifesaving procedure.
Thoracic trauma accounts for more than 16,000 deaths in the United States annually and constitutes approximately 25% of all trauma related mortality. For clinical purposes, patients can be divided into blunt and penetrating categories based on the mechanism of injury. Approximately 80% of cases of significant blunt thoracic trauma are secondary to motor vehicle collisions (MVC), whereas most cases of penetrating trauma in the United States are due to stab wounds and low–velocity handgun injuries.
Injuries that occur after blunt thoracic trauma include fractures (sternum/ribs), flail chest, pulmonary contusion, myocardial injury, and aortic injury. Although fractures to the sternum and ribs are usually not life–threatening, displaced and/or multiple rib fractures are an exception. Evaluate for injury to underlying structures—the mediastinum and great vessels with ribs 1–3, the lungs with ribs 4–8, and the liver or spleen with ribs 9–12. Flail chest occurs when ≥3 contiguous ribs are fractured in ≥2 places, thereby creating a “free floating” segment of the chest wall.
Pulmonary contusions are focal regions of bruised lung parenchyma resulting in alveolar hemorrhage and edema, which can significantly impair normal respiratory function. They typically develop over several hours post injury and are often missed on the initial patient assessment.
Blunt myocardial injury (BMI) should be considered in any patient with significant direct trauma to the anterior chest wall. Myocardial contusions present as regions of “stunned” tissue that clinically behave analogous to myocardial infarctions. Rarely, patients with significant BMI may progress to outright cardiogenic shock due to impaired pump function or dysrhythmia.
Blunt aortic injury (BAI) is seen in patients when a rapid decelerating force causes significant sheer strain and secondary rupture of the aorta. More than 80% of cases occur at the site of the ligamentum arteriosum just distal to the takeoff of the left subclavian artery. Roughly 20% of patients with BAI will survive to emergency department (ED) presentation because of the tamponading effects of an intact adventitia. As the presenting symptoms and clinical picture are highly variable, a high index of suspicion for BAI should be maintained for any patient with the appropriate mechanism of injury.
Injuries common after penetrating thoracic trauma include pneumothorax, hemothorax, cardiac injury, pericardial tamponade, great vessel injury, and tracheobronchial injury. Pneumothoraces (PTX) are rather common after penetrating thoracic trauma, but can also be seen in blunt injuries when a fractured rib lacerates the underlying pleura. A simple pneumothorax occurs when injured lung tissue creates an air leak in the potential space between the visceral and parietal pleura. An open or communicating PTX occurs when a large open defect in the thoracic wall allows communication between the intrapleural space and the environment. Defects greater than two thirds of the diameter of the trachea will lead to severe respiratory impairment. A tension pneumothorax arises when an injury to the thoracic wall and/or underlying bronchopulmonary structures allows the progressive accumulation of air into the intrapleural space. Rising intrathoracic pressure will eventually inhibit the venous return of circulating blood to the right atrium, resulting in cardiovascular collapse and ensuing pulseless electrical activity (PEA) arrest. Tension PTX is a clinical diagnosis that requires immediate intervention.
Hemothoraces (HTX) develop secondary to the accumulation of blood into the intrapleural space after injury to the lungs, heart, or thoracic vasculature. Each hemithorax can accommodate up to 40% of a patient’s circulating blood volume. Massive HTX (accumulation >1,500 mL) is an emergent life–threatening condition that can induce severe hypoxia and systemic hypotension.
Penetrating cardiac injury (PCI) can be rapidly fatal. Occasionally patients, especially those with stab wounds to the anterior heart, will survive to ED presentation because of the tamponading effects of an intact pericardium. Accumulating fluid in the pericardial space will eventually collapse the right side of the heart, resulting in cardiac arrest. Pericardial tamponade is an emergent life threat requiring immediate intervention.
Penetrating great vessel injury (PGVI) presents with massive HTXs with persistent high–volume bloody chest tube effluent. Suspect venous air embolism (VAE) in patients with penetrating vascular trauma, especially involving the subclavian vein, who suddenly decompensate into PEA arrest without alternative explanation.
Tracheobronchial injury can be seen in both blunt and penetrating trauma and should be suspected in patients with an appropriate mechanism and either extensive subcutaneous emphysema or a persistent high–volume air leak after chest tube placement.
A detailed history is usually deferred until the completion of the primary survey and stabilization of any evolving emergent life threats (Table 87-1). The severity of the mechanism should be estimated to determine the potential for underlying injury. Emergency medical service (EMS) personnel are an invaluable asset. Clues to significant injuries after an MVC include lack of seat–belt restraint, dashboard deformity, significant intrusion into the passenger compartment, prolonged extraction, ejection from the vehicle, and on–the–scene death of other occupants. Sudden deceleration mechanisms, such as falls greater than 30 feet or an MVC greater than 30 mph, should raise concern for potential vascular shearing injuries. With penetrating trauma, the type of stabbing implement should be ascertained.
An assessment of patient vital signs is the cornerstone of the primary survey. Progressive sinus tachycardia and systemic hypotension indicates a serious cardiovascular derangement that should be addressed immediately. Significant hypoxia could indicate an underlying pulmonary contusion, HTX, or PTX.
Inspection of the patient’s neck might reveal jugular venous distension indicative of pericardial tamponade or tension PTX or tracheal deviation indicative of an evolving tension PTX. Examination of the thorax should begin with gross observation. Chest wall asymmetry with regional paradoxical movement during respiration indicates underlying flail chest. A large open defect in the chest wall with audible air movement during respiration indicates a communicating PTX. Penetrating wounds either located within or transecting the “cardiac box” are most likely to involve the heart and surrounding mediastinal structures and require a more extensive work–up. The anterior cardiac box is defined as the region medial to the nipples extending between the suprasternal notch and xiphoid process. The posterior cardiac box is defined as the region between the medial borders of the scapulae extending from the superior border of the scapulae to the costal margin (Figure 87-1). Palpation of the chest wall can detect point tenderness indicative of an underlying fracture of the thoracic cage or soft tissue crepitus suggestive of an underlying PTX or tracheobronchial injury.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
