Penetrating Chest Trauma

Etiology

Chest trauma can be a result of penetrating or blunt trauma. While blunt trauma is more common, penetrating trauma can be acutely life-threatening. It is important to know the mechanism of injury as management may vary. Additionally, the directionality of penetration will dictate the investigation and intervention. Depending on the penetrating trauma, immediate operative intervention may be needed, making early diagnosis integral to survival. The penetrating injury should also be taken into consideration; for example, stab versus missile injury to the chest can result in different patterns of injury. Gunshot and stabbing account for 10% and 9.5% of penetrating chest injuries, making these the most common etiology of penetrating trauma.[3]

Epidemiology

All age ranges are at risk for chest trauma. After head and extremity trauma, chest trauma is the third most common blunt injury and quickly rising to second.[3][4] Gunshot and stabbing account for 10% and 9.5% of penetrating chest injuries in the United States. This incidence changes worldwide, and it is as high as 95% in countries engaged in war.[5][6][7][8][9][10]

Evaluation

Early recognition of trauma to the chest is a priority. The first 3 steps of trauma evaluation involve evaluation, recognition, and intervention of potential injuries to “the box.” Following a routine method of TRAUMA PROTOCOL evaluation reduces missed injuries. Injuries to the heart and lungs are usually serious, and early diagnosis is vital since they have the highest mortality if missed. Injuries to other thoracic structures also need to be considered; the ribs, clavicle, trachea, bronchi, esophagus, and large vessels, including the aorta and veins, need to be evaluated in the secondary and tertiary survey.

Since the trajectory of penetrating injury can vary, a thorough evaluation is key.

The primary survey identifies immediately life-threatening injuries. These injuries should be addressed at the time of identification.

Potential injuries that should be ruled out include:

• Large hemothorax
• Large pneumothorax
• Pericardial effusion with or without tamponade
• Hemoperitoneum (depending on trajectory)

Once the initial exam is complete and adjunct imaging is complete, a secondary survey may reveal:

• Rib fractures
• Small hemothorax
• Small pneumothorax
• Pulmonary contusion
• Chest wall contusion

There are physical exam findings that increase suspicion of chest trauma. Open wounds should be considered as possible points of entry and or exit. When discussing missile injury, it is imperative to refrain from documenting entry vs. exit points since this is a forensic notation, and incorrect documentation can have legal ramifications.

Diagnostics

While chest radiography prevails, it does have limitations. Since chest radiography is achieved in the supine position, small and medium-sized pneumothoraces and hemothoraces may be missed.[11][12][13][14][15][16]

The extended-Focused Assessment with Sonography in Trauma (eFAST) may be done with the primary survey, especially in an unstable patient. eFAST allows for quick identification of chest areas with air and/or blood and helps focus definitive management.

The 4 views of the traditional Focused Assessment with Sonography in Trauma (FAST) exam include the cardiac (subxiphoid) window, right upper quadrant (RUQ, or Morrison’s pouch), left upper quadrant (LUQ), and suprapubic (bladder) window. The presence of a black collection outside of an organ, viscera, or pericardia suggests a positive FAST exam.

The eFAST includes pulmonary views and also evaluates for pneumothorax and hemothorax, in addition to the traditional 4 views. eFAST should be started in the area where there is the highest suspicion for injury. If the thorax is of concern, then this is where the eFAST should begin. This includes anterior chest wall evaluation between ribs for pneumothorax and looking for the continuation of the spinal stripe caudal to the diaphragm in the RUQ and LUQ windows to evaluate for hemothorax. The spinal stripe can be present in cases of pleural effusion. Similar to a positive FAST exam, any presence of fluid in the trauma patient is assumed to be blood.

Computed tomography (CT) is more sensitive and specific. However, this requires the patient to be stable for transport.

Other adjuncts include endoscopy, bronchoscopy, and electrocardiography to complete evaluation when warranted.

Treatment / Management

Once the ABCs (airway, breathing, circulation) have been addressed, injury-specific interventions should be undertaken.

Immediate, life-threatening injuries require prompt intervention, such as emergency tube thoracostomy for large pneumothoraces and initial management of hemothorax. For cases of hemothorax, adequate drainage is imperative to prevent retained hemothorax. Retained hemothorax can lead to empyema requiring video-assisted thoracoscopic surgery.

The majority of thoracic trauma can be managed non-operatively. However, 15% of patients require operative management, and surgery should not be delayed when appropriate. Operative exploration of thoracic injuries should be considered if tube thoracostomy drainage exceeds 1000 to 1500 mL immediately, or there is an output of about 200 mL per hour for 2 to 4 hours or ongoing resuscitation (blood transfusion, persistent hypotension) with no other discernable cause.[17][18](B3)

In cases where cardiac arrest is imminent, emergency department thoracotomy (EDT) may be indicated for resuscitation. The best survival results are seen in patients who undergo EDT thoracotomy for thoracic stab injuries who arrive with signs of life. Per the Western Trauma Association Critical Decisions in Trauma resuscitative thoracotomy success of EDT for patients arriving in shock with penetrating cardiac injury approximates 35% and 15% for all penetrating wounds.[19]

Admission

Asymptomatic patients with penetrating thoracic injuries and normal imaging on presentation should be observed for the development of a delayed pneumothorax or hemothorax.[20] A repeat examination and imaging should be performed in a delayed fashion. There is no good evidence indicating how long that delayed evaluation should be; however, at least 6 hours is most appropriate by convention. If the reevaluation is unremarkable, the patient can be discharged from the emergency department, with instructions for strict return if the patient develops increasing shortness of breath, painful swallowing, or chest pain.(B3)

Minor injuries may simply require close monitoring and pain control. Care should be taken in the young and the elderly. Patients with 3 or more rib fractures, a flail segment, and any number of rib fractures with pulmonary contusions, hemopneumothorax, hypoxia, or preexisting pulmonary disease should be monitored at an advanced level of care.[21][22](B2)

Pain Control

Pain control greatly affects mortality and morbidity in patients with chest trauma.[23] Pain leads to splinting, which worsens or prevents healing. In many cases, the inability to cough leads to the collection of secretions, eventually leading to pneumonia.  Early analgesia should be considered to decrease splinting. In the acute setting, IV push doses of short-acting opioids should be used.[24](A1)

Other pain control options include interpleural nerve blocks, transdermal patches, intravenous patient control analgesia (PCA), and epidural analgesia.

Nonnarcotic transdermal patches are safe pain management options for many patients. They should be considered for patients with persistent chest wall pain despite lack of confirmed rib fractures, for patients being discharged, or as an adjunct treatment for those who are admitted.

Antibiotics

Prophylactic antibiotics administration for tube thoracostomy for blunt thoracic trauma does not reduce the incidence of empyema or pneumonia when placed with sterile technique.

They should be considered in cases of grossly contaminated wounds or in cases where the sterile technique was interrupted.[25](B3)

All patients with penetrating injury should have up-to-date tetanus vaccination.

Differential Diagnosis

A complete primary, secondary, and tertiary survey should be completed to avoid missed or confounding injuries.

Directionality plays a large role in injury patterns. While a wound may be in the right thorax, it may be associated with liver injury, intentional injury, among others, based on the trajectory of the injury.

When evaluating penetrating trauma due to missiles, a general rule of thumb to account for all possible injuries is that "wounds plus retained missiles" should be an even number.