Thoracic Trauma:
The thoracic cage consists of the ribs, costal cartilage, sternum, and thoracic vertebrae. It houses the lungs, heart, diaphragm, and major blood vessels. Injury to this region can result from blunt or penetrating mechanisms, and can affect pulmonary, cardiovascular, and skeletal systems. Thoracic trauma generally requires significant MOI, such as high speed MVC, firearms injuries, stabbings, or falls from significant height.
Most common manifestations of injury are those that affect ventilation, oxygenation, or circulation.
Common Thoracic injuries:
Flail Chest: This is a condition in which 2 or more adjacent ribs are fractured in at least 2 places. This creates a detached segment of the chest wall. When Flail chest occurs, the patient presents with paradoxical chest wall movement; meaning that when the patient inhales, and the rib cage expands, the flail segment moves inward. The opposite occurs on exhalation. This condition limits the ability of the chest to properly expand on the affected side, and causes hypoventilation. Flail chest also raises the possibility of lung injury as sharp fragments may perforate the lung tissue itself. Treatment involves stabilization of the flail segment with bulky dressings, in order to splint it and reduce paradoxical movement.
Pulmonary contusion: This is an injury to the lung tissue itself, following blunt chest trauma. Lung tissue tears and localized bleeding and inflammation occurs, creating an area that is no longer able to participate in gas exchange. This creates a ventilation-perfusion mismatch, and leads to a rise in arterial CO2 (Hypercarbia). The systemic effects include hypoxemia, acidosis, and end organ damage if not corrected in the ED.
Rib fractures: Likely the most commonly encountered injury, rib fractures can occur with a variety of blunt mechanisms. The most common presentation is crepitus on palpation, hypoventilation, and sharp pain in the affected area during inspiration. Treatment in the prehospital environment is simply to provide analgesic and assist in oxygenation and ventilation as needed. The patient often hypoventilates due to the pain.
Pneumothorax: A simple pneumothorax occurs as a closed-chest injury and does not always have a traumatic mechanism. In trauma, these patients present with unilateral, pleuritic, chest pain, and diminished breath sounds on the affected side. A more significant concern is a Tension pneumothorax. This occurs in both open and closed chest injuries; although more often in the open variety. Air continues to enter the pleural space with every breath, gradually collapsing the lung on the affected side. In severe tension pneumothorax, the pressure causes a mediastinal shift which puts pressure on the heart and great vessels. Compression of the superior vena cava results in a drop in cardiac preload and may result in hypotension. The major concern comes from patient's with an open chest wound that presents with bubbling of blood and fluid at the site (a sucking chest wound). If the hole is larger than that of the glottic opening, air is more likely to enter through the wound during inspiration than it is through the airway. This leads to rapid buildup of a tension pneumothorax. Open chest wounds are treated with a one-way valve dressing (Asherman seal or 3 sided dressing), and closed pneumothorax is generally treated with needle thoracostomy. The triad of signs for a tension pneumothorax includes: JVD, Hypotension with a narrow pulse pressure, and diminished or absent breath sounds on the affected side.
Hemothorax: This occurs in the same manner as a pneumothorax, with the exception that it is blood rather than air that invades the pleural space. The major notable difference in assessment is absence of JVD.
Pericardial tamponade: The most common mechanism is penetrating chest trauma that involves the heart. In a tamponade, blood begins to pool in the pericardial sac surrounding the myocardium. As the blood builds up, there is less and less space for the heart to contract. Think fo it as squeezing the heart. The most common presentation is known as Beck's triad: Hypotension with narrow pulse pressure, JVD, and muffled heart sounds. Another common finding is electrical alternans on the ECG.
Myocardial contusion: This is bruising of the heart muscle. Because the anterior portion of the heart sits behind the sternum, major trauma here can lead to blunt trauma to the heart itself. Tissue damage, edema, and localized ischemia can cause ectopic beats, re-entry pathways, and cardiac arrhythmias.
Commotio Cordis: A blunt force trauma to the chest, that occurs during the relative refractory period of the heart's repolarization cycle, can trigger V-fib and asystole.
Traumatic aortic dissection. Rapid deceleration forces can cause shearing forces at the points where the ascending aorta is fixed in the thoracic cavity. Tearing in these areas can lead to overt tears and profound bleeding into the chest, or dissection between the layers of the vessel. In most cases the patient bleeds out very quickly and loses consciousness, without regaining it.
Spinal injuries: In any patient with penetrating trauma to the chest, it should be assumed that a spinal injury is also present.
Like the abdomen, the thoracic region houses many vital organs and vessels. We can ultimately only treat what we can see and assess for in the field. This includes:
Flail chest
Pneumothorax
Penetrating injuries
Injuries such as pulmonary and myocardial contusions, tamponade, and aortic dissections cannot be corrected outside of the surgical setting. Our job is to recognize these conditions or the possibility that they may be present, and to do our best to treat the symptoms that occur in conjunction with them. Always go back to ABCs, control life threatening bleeding, establish IV fluids, and provide rapid transport.
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