Thoracic Trauma

• Thoracic trauma accounts for approximately 20% of all deaths secondary to trauma.
• Many of these deaths are preventable if they are recognized and treated early on in the trauma evaluation process.
• Approximately 10-15% of patients with thoracic trauma require operative exploration and intervention.
• The most common causes of death in the immediate post-injury period are usually related to a major vascular injury or a major airway obstruction.

Rib Fractures

• Simple rib fractures represent a relatively common occurrence in the setting of blunt thoracic trauma with an incidence of approximately 50%.
• The most common sites for simple rib fractures to occur is at the site of impact or at the posterior angle of the rib, the area of the ribs’ greatest structural weakness.
• Ribs 4-9 are the ones most often fractured.
• The presence of fractures involving ribs 9-12 should alert one to the possibility of an associated abdominal trauma injury due to their location over the liver and spleen.
• Fractures of the upper ribs 1-2 usually indicate a significant amount of blunt force has been applied to the patient’s thorax as these ribs are well protected by other structures, and the presence of these fractures increase the chance of significant intrathoracic injury.
• Rib fractures occur more commonly in the adult patient population because of the relative inelasticity of the rib cage in adults when compared to those of pediatric trauma patients.

Clinical Evaluation

• The major goal is to detect the presence of underlying thoracic injuries such as pneumothorax, hemothorax, pulmonary contusion or significant vascular trauma.
• Clinical findings typically noted with rib fractures are point tenderness at the fracture site, increased pain with respiration or truncal motion, crepitus at the point of tenderness, ecchymosis, splinting and muscle spasm over the affected area of the chest wall.
• When the involved rib is compressed at another anterior or posterior location distal to the fracture site pain is illicited at the site of the rib fracture.
• An upright PA chest radiograph and pulse oximetry reading should be obtained on every patient with suspected rib fractures. A “rib series” is generally not indicated as it provides little additional information.
• Approximately 50% of rib fractures are not visualized on the initial chest radiograph and trauma to the cartilaginous areas of the thoracic cage is generally not visualized thus making the identification of rib fractures a purely clinical diagnosis in a large percentage of cases

Treatment

• The major goal in the treatment of simple rib fractures is adequate pain control. Inadequately treated pain may interfere with the patient’s ability to have normal ventilatory function. This decrease in ventilation can lead to atelectasis and possible pneumonia.
• The use of rib belts and various types of chest wall binding devices is not routinely recommended. While providing symptomatic relief, these devices restrict normal chest wall motion and ventilation putting the patient at further risk for developing atelectasis.
• In some cases for relief of severe pain an intercostals nerve block using a long-acting local anesthetic agent is indicated to assist with pain control.
• Hospital admission is generally reserved for those patients at risk for respiratory compromise such as elderly patients and those with significant underlying pulmonary disease.
• In the vast majority of patients rib fractures heal in a 3 to 6 wk period without complications.

Flail Chest/Pulmonary Contusion

• Flail chest is the fracture of three or more adjacent ribs at two or more locations creating a segment of the chest wall that has no bony continuity with the rest of the patient’s chest wall.
• This free floating segment of chest wall allows paradoxical chest wall motion of this segment compared to the remainder of the chest wall which in turn leads to inadequate ventilation.
• The major complication is direct trauma to the underlying lung parenchyma, which leads to the development of a pulmonary contusion.

Clinical Evaluation

• Flail chest is not always readily apparent due to chest wall splinting.
• As the splinting begins to gradually resolve secondary to progressive muscle fatigue, the paradoxical chest wall motion may be noted.
• The use of a tangential light source or palpation of the patients chest wall may be useful in helping to detect the early subtle presence of paradoxical chest wall motion.
• The patient may also be noted to have chest wall tenderness, crepitus and ecchymosis.
• Dyspnea may also be present.
• Chest radiograph may demonstrate the presence of multiple rib fractures in a pattern suggestive of the presence of a flail chest.
• Evidence of a pulmonary contusion may also be radio graphically noted although this finding often is not present initially.
• An arterial blood gas demonstrating evidence of hypoxia may also give contributory evidence to the presence of a flail chest and/or a pulmonary contusion.

Treatment

• Initial therapy should be directed towards the ABCs of trauma resuscitation.
• Administration of supplemental oxygen, pulse oximetry and cardiac monitoring are necessary.
• Adequate ventilation and oxygenation must be maintained.
• Intubation may be required.
• The placement of a thoracostomy tube is indicated in the presence of an associated pneumothorax or hemothorax.
• If hypotension or signs of hypovolemic shock are not present, it is prudent to avoid the overly aggressive use of crystalloid intravenous solutions which may lead to overhydration with subsequent worsening of any pulmonary contusion that may be present.
• It is extremely important to continually reassess the patient with flail chest or pulmonary contusion looking for any early signs of respiratory compromise or hypoxia and initiating rapid aggressive treatment.
• Appropriate use of parenteral analgesics is indicated for adequate pain control.

Sternal Fractures /Blunt Myocardial Injury (Myocardial Contusion)

• The fracture of the sternum requires a significant amount of energy to be directly applied to the anterior thoracic wall.
• The most common mechanism for this to occur is in a motor vehicle accident when the patient’s anterior chest contacts the steering wheel or other structures including the seat belt at a high rate of speed.
• The major concern regarding sternal fractures is not the fracture itself but the possibility of injury to mediastinal structures such as the myocardium and the aorta.
• Blunt myocardial injury/myocardial contusion, which represents myocardial injury secondary to the blunt force applied to the anterior chest, may occur with or without associated sternal fracture.
• Fortunately blunt myocardial injury occurs relatively infrequently.
• Recent study data indicates that sternal fractures can occur in up to 3% of motor vehicle accidents, and the associated morbidity and mortality rates are much lower than previously believed. The mortality rates for an isolated sternal fracture is approximately 0.7%.

Clinical Evaluation

• The patient typically complains of pain over the sternal area that increases with respiration or truncal motion.
• Point tenderness is usually illicited over the area of sternal injury.
• There may be in some cases signs of external trauma such as ecchymosis, crepitus and abrasions.
• A lateral chest radiograph is the best way for detecting a sternal fracture as they are generally difficult to visualze on a standard radiograph.
• The fracture may also be seen on a CT scan of the chest.
• Evaluation of underlying cardiac contusion includes an EKG and cardiac enzymes.
• The presence of a normal EKG and cardiac markers has been demonstrated to indicate patients at low risk for cardiac contusion.
• Continuous cardiac monitoring of high risk patients is indicated as cardiac arrythmias are the major complication of blunt cardiac injury.

Management

• The patient should receive adequate analgesia during the course of their emergency department evaluation. In selected cases after short term monitoring and observation patients may be discharged home with oral analgesic agents and appropriate close follow-up.
• Patients with dysrhythmias and EKG changes should be admitted for observation and further cardiac evaluation including echocardiogram and cardiac enzymes for possible blunt myocardial injury/myocardial contusion.
• Some of the dysrhythmias that may be seen in the setting of blunt myocardial injury include unexplained sinus tachycardia, premature ventricular complexes, atrial fibrillation and bundle branch blocks. Acute ST segment EKG changes can also occur.
• Dysrhythmias are treated only if the patient becomes unstable.