Introduction
Road traffic accidents and serious falls may result in fractures of three or more portions of the rib cage, causing a flail chest. The affected portion of the chest will not be able to contribute to breathing creating severe disturbances in respiratory physiology. It is a serious condition that leads to morbidity for a long period and sometimes even death. However, these fracture patterns may not always lead to a flail chest.
Blunt trauma to the thoracic region sometimes causes fractures of the ribs, causing an independent movement of a segment of the chest wall from the remaining portion creating disturbances in the physiology of respiration, especially in geriatric patients and people with chronic lung diseases. This condition is extremely painful and accompanies other injuries; thus, they are difficult to manage. Flail chest can be seen unilaterally and bilaterally, unilateral being the most commonly encountered. They are suspected during a radiographic examination, but the final diagnosis is made after clinical examination.
What Is a Flail Chest?
Changes in the intrathoracic pressure determine air movement in and out of the lungs. The inspiratory action relies on the function of a group of respiratory muscles, which includes the external intercostal, parasternal internal intercostal, diaphragm, and accessory muscles. When the diaphragm goes down, the vertical dimension of the chest cavity increases, and negative pressure is created inside the chest. At rest, the diaphragm alone is enough to maintain adequate ventilation. During exercises and pathological conditions, the intercostal muscles come into action. In a healthy state, the lungs have elastic recoil properties, making expiration a passive process. The additional participation of the abdominal muscles and the intercostals is also seen.
The word flail means 'wave-like motion.' As the name suggests, a flail chest is the movement of a portion of the lungs independent of the remaining portion. Blunt traumas to the chest regions or road traffic accidents might result in fracture of three or more ribs in more than two places; as a result, the continuity of the chest wall is altered, leading to the free movement of the segment of the chest wall independent to the rest of the chest wall. This movement is paradoxical because when the whole chest wall moves in the outward direction, the flail segment moves in the inward direction. Three factors determine the severity of a flail chest:
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Pleural pressure.
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The extent of movement.
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The intercostal muscle activation during inspiration.
A chest wall's flail segment after trauma negatively influences inspiration, and they create pulmonary contusions, ineffective ventilation, and hypoventilation with atelectasis. With rib fracture, the dead space increases inside the thoracic cavity, which decreases the intrathoracic pressure, and since the tissue is injured, oxygen demand to the area also increases. Pulmonary contusions result in edema. Hemorrhage and some necrosis also impair the mechanism of gas exchange, thus decreasing compliance. The pain from the injury results in hypoventilation and atelectasis.
What Are the Symptoms of a Flail Chest?
The mandatory requirement for the diagnosis is the fracture of at least three ribs in more than two places which is identified through an X-ray. The most obvious symptom is the paradoxical chest movements, which indicates that the flail portion of the chest is not helping with the breathing function. Other symptoms commonly associated with a flail chest include
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Bruises and discoloration in the thoracic region.
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Tenderness over the area of rib fracture.
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Severe chest pain.
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Difficulty in breathing.
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Tissues won't get enough oxygen (hypoxia), turning the lips or fingers blue.
How Is Flail Chest Diagnosed?
A flail chest may be obvious with a history of trauma in the thoracic region with increased risk for the elderly patient. Perform physical examination on all patients with potential chest trauma. A complete physical examination of the patient is done, obtaining the vitals and measurement of oxygen saturation and respiratory rate. The examiner should observe the bilateral breath sounds and palpate the thoracic region for any pain, crepitus, or deformity. Complaints of severe chest pain are associated with a flail chest in thoracic trauma, and the patient might have tachypnea and splint and show respiratory insufficiency.
Chest movements are closely observed for paradoxical chest wall movement, a significant feature of a flail chest. While inhaling, the flail segment of the chest goes in, and the remaining portion of the chest will be pushed out and vice versa in expiration. However, the absence of paradoxical chest wall movement does not exclude the possibility of a flail chest, and it becomes more observable as the intercostals are fatigued. Trauma patients who are mechanically intubated do not exhibit paradoxical movement because positive pressure ventilation creates pressure changes. The paradoxical movements are observed once they are extubated, thus delaying the diagnosis in such cases.
The chest X-ray is the first study that helps identify flail chest; however, they are not highly sensitive and may miss some rib fractures identified through CT (computed tomography) scanning. Complete trauma laboratory investigation should be performed, including blood gas analysis. Lab investigations do not have a direct role in diagnosing flail chests but help in finding signs of respiratory failure in such patients.
How to Treat a Flail Chest?
A fracture to the ribs results in pulmonary contusions and leads to secondary complications like respiratory failure. Various treatment modalities have been developed over the years to manage flail chest. Now, they are directed more towards protecting the lungs and preventing pneumonia, the most frequent complication of a flail chest. The patients are placed immediately on 100 percent oxygen. Stabilization treatments include
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Mechanical ventilation:
The chest cavity is stabilized for patients with flail chest and lung damage. The treatment modality has helped reduce mortality to a large extent; however, the chances of developing pneumonia are more in this case. Mechanical ventilation is unnecessary for a chest flail case that is less complicated and does not involve the lungs.
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Corrective surgery:
Surgery is performed depending on the case. Patients who need mechanical ventilation for a prolonged period are not ideal candidates for surgery. In some patients, even after the lung begins to heal, the ventilator demand does not diminish. Such patients are good candidates for surgery.
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Analgesic medications for pain relief:
Opioid medications in low doses will be helpful for patients with flail chest and lung injuries; however, in high doses, they produce respiratory depression. Ideally, epidural local anesthetic medication is administered.
Conclusion
As discussed above, a flail chest is often associated with severe complications, and physicians should keep a suspicion. It happens when ribs are fractured in more than two places; however, injuries of these kinds will not always cause a flail chest. Geriatric patients are often at high risk and show more complications of flail chest. They are less often seen in children because their chest walls are highly elastic, and any involvement signifies a drastic amount of trauma and needs extra attention in their evaluation.
