One of the leading causes of death in trauma victims is severe blunt injury to the chest. Chest injuries can occur in many types of accidents that involve blunt force trauma, such as collisions or falls. A common serious injury to the thorax in such accidents is flail chest, when multiple ribs fracture along the anterior chest wall. Flail chest is a life-threatening injury that requires immediate medical attention.
Anatomy of a Flail Chest Injury
Flail chest describes what happens when blunt force trauma to the chest causes multiple adjacent ribs to fracture and separate from the chest wall. A part of the chest will then move independently from the rest of the chest wall. Flail chest injuries occur when two adjacent ribs break in at least two places. In many cases, the flail segment of the chest will move in a direction opposite than the rest of the chest wall, called “paradoxical breathing.” This occurs due to ambient pressure in comparison to the pressure within the lungs.
During regular breathing, the diaphragm contracts, using the intercostal muscles to pull the rib cage out. Air rushes in through the trachea due to pressure decreases in the thorax. With a flail chest injury, the decrease in pressure pulls the flail segment inward while the rest of the rib cage continues to expand. When the rib cage contracts to breathe out, a flail segment pushes outward. Paradoxical breathing is painful and difficult.
Typically, a pulmonary contusion, or a bruise on the lung tissue, occurs alongside a flail chest injury. A pulmonary contusion can interfere with the natural oxygenation of the blood, causing respiratory problems for victims with both injuries. In most cases, the contusion causes respiratory issues, not the flail chest itself.
Causes and Symptoms of Flail Chest
The most common cause of flail chest injuries is car accidents, in which an object within the vehicle such as the steering column impacts the chest. Flail chest may also result from falls, especially in the elderly population. Accidents that involve crushing typically only fracture ribs at one point instead of resulting in a flail chest injury. Flail chest requires significant impact on a large surface of the thorax, creating multiple fractures in more than one rib.
Traumatic accidents severe enough to cause flail chest injuries typically require a doctor’s attention right away. A patient with flail chest may experience chest pain and difficulty breathing or shortness of breath. This is due to paradoxical breathing. The motion of the ribs in the flail segment at the site of the injury is incredibly painful to the victim, and can result in fragments of sharp bones puncturing the lung and pleural sac.
If the broken edges of the fractured ribs puncture the pleural sac or lung, it can cause a pneumothorax. This is the presence of gases or air in the lung cavity, between the lung and the wall of the chest. Pneumothorax can cause a lung to collapse. If a victim suffers pneumothorax, he or she will typically experience severe chest pain and difficulty breathing. The risk of pulmonary contusions and pneumothorax is why flail chest requires emergency medical attention.
Treatment and Prognosis
Treating a flail chest injury involves the same procedures as advanced trauma life support. In addition, flail chest requires pain management via intercostal blocks. These enable better ventilation and increased blood oxygenation. Positive-pressure ventilation can help prevent pulmonary barotraumas. The patient may require surgical chest stabilization in more severe cases. Patients with flail chest have positive prognoses for the most part, with the highest percentages of morbidity related to patients advanced in age. Each flail chest injury is different and requires different levels of treatment.
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