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Overview of Thoracic Trauma

By

Thomas G. Weiser

, MD, MPH, Stanford University School of Medicine

Last full review/revision May 2020| Content last modified May 2020
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Thoracic trauma causes about 25% of traumatic deaths in the US. Many chest injuries cause death during the first minutes or hours after trauma; they can frequently be treated at the bedside with definitive or temporizing measures that do not require advanced surgical training.

Etiology of Thoracic Trauma

Chest injuries can result from blunt or penetrating trauma. The most important chest injuries include the following:

Many patients have simultaneous hemothorax and pneumothorax (hemopneumothorax).

Pathophysiology of Thoracic Trauma

Most morbidity and mortality due to chest trauma occurs because injuries interfere with respiration, circulation, or both.

Respiration can be compromised by

  • Direct damage to the lungs or airways

  • Altered mechanics of breathing

Injuries that directly damage the lung or airways include pulmonary contusion and tracheobronchial disruption. Injuries that alter the mechanics of breathing include hemothorax Hemothorax Hemothorax is accumulation of blood in the pleural space. (See also Overview of Thoracic Trauma.) The usual cause of hemothorax is laceration of the lung, intercostal vessel, or an internal... read more Hemothorax , pneumothorax Pneumothorax (Traumatic) Traumatic pneumothorax is air in the pleural space resulting from trauma and causing partial or complete lung collapse. Symptoms include chest pain from the causative injury and sometimes dyspnea... read more , and flail chest Flail Chest Flail chest is multiple fractures in ≥ 3 adjacent ribs that result in a segment of the chest wall separating from the rest of the thoracic cage; it is a marker for injury to the underlying lung... read more . Injury to the lung, tracheobronchial tree, or rarely esophagus may allow air to enter the soft tissues of the chest and/or neck (subcutaneous emphysema) or mediastinum (pneumomediastinum Pneumomediastinum Pneumomediastinum is air in mediastinal interstices. The main causes of pneumomediastinum are Alveolar rupture with dissection of air into the interstitium of the lung with translocation to... read more Pneumomediastinum ). This air itself rarely has significant physiologic consequence; the underlying injury is the problem. Tension pneumothorax Pneumothorax (Tension) Tension pneumothorax is accumulation of air in the pleural space under pressure, compressing the lungs and decreasing venous return to the heart. (See also Overview of Thoracic Trauma.) Tension... read more Pneumothorax (Tension) impairs respiration as well as circulation.

Circulation can be impaired by

  • Bleeding

  • Decreased venous return

  • Direct cardiac injury

Complications

Because chest wall injuries typically make breathing very painful, patients often limit inspiration (splinting). A common complication of splinting is atelectasis Atelectasis Atelectasis is collapse of lung tissue with loss of volume. Patients may have dyspnea or respiratory failure if atelectasis is extensive. They may also develop pneumonia. Atelectasis is usually... read more Atelectasis , which can lead to hypoxemia, pneumonia, or both.

Symptoms and Signs of Thoracic Trauma

Symptoms include pain, which usually worsens with breathing if the chest wall is injured, and sometimes shortness of breath.

Common findings include chest tenderness, ecchymoses, and respiratory distress; hypotension or shock may be present.

Decreased breath sounds can result from pneumothorax or hemothorax Hemothorax Hemothorax is accumulation of blood in the pleural space. (See also Overview of Thoracic Trauma.) The usual cause of hemothorax is laceration of the lung, intercostal vessel, or an internal... read more Hemothorax ; percussion over the affected areas is dull with hemothorax and hyperresonant with pneumothorax.

The trachea can deviate away from the side of a tension pneumothorax.

In flail chest Flail Chest Flail chest is multiple fractures in ≥ 3 adjacent ribs that result in a segment of the chest wall separating from the rest of the thoracic cage; it is a marker for injury to the underlying lung... read more , a segment of the chest wall moves paradoxically—that is, in the opposite direction from the rest of the chest wall (outward during expiration and inward during inspiration); the flail segment is often palpable.

Subcutaneous emphysema causes a crackling or crunch when palpated. Findings may be localized to a small area or involve a large portion of the chest wall and/or extend to the neck. Most often, pneumothorax is the cause; when extensive, injury to the tracheobronchial tree or upper airway should be considered. Air in the mediastinum may produce a characteristic crunching sound synchronous with the heartbeat (Hamman sign or Hamman crunch). Hamman sign suggests pneumomediastinum Pneumomediastinum Pneumomediastinum is air in mediastinal interstices. The main causes of pneumomediastinum are Alveolar rupture with dissection of air into the interstitium of the lung with translocation to... read more Pneumomediastinum and often tracheobronchial tree injury or, rarely, esophageal injury.

Diagnosis of Thoracic Trauma

  • Clinical evaluation

  • Chest x-ray

  • Sometimes other imaging studies (eg, CT, ultrasonography, aortic imaging studies)

Clinical evaluation

Five conditions are immediately life threatening and rapidly correctable:

Diagnosis and treatment begin during the primary survey (see Approach to the Trauma Patient Approach to the Trauma Patient Injury is the number one cause of death for people aged 1 to 44. In the US, there were 243,039 trauma deaths in 2017, about 70% being accidental. Of intentional injury deaths, more than 70%... read more ) and are based first on clinical findings. Depth and symmetry of chest wall excursion are assessed, the lungs are auscultated, and the entire chest wall and neck are inspected and palpated. Patients in respiratory distress should be monitored with serial assessments of clinical status and of oxygenation plus ventilation (eg, with pulse oximetry, arterial blood gas tests, capnometry if intubated).

Penetrating chest wounds should not be probed. However, their location helps predict risk of injury. High-risk wounds are those medial to the nipples or scapulae and those that traverse the chest from side to side (ie, entering one hemithorax and exiting the other). Such wounds may injure the hilar or great vessels, heart, tracheobronchial tree, or rarely the esophagus.

Patients with symptoms of partial or complete airway obstruction following blunt trauma should be immediately intubated to control the airway.

In patients with difficulty breathing, severe injuries to consider during the primary survey include the following:

  • Tension pneumothorax

  • Open pneumothorax

  • Massive hemothorax

  • Flail chest

A simple, rapid assessment of patients with thoracic trauma and respiratory distress during the primary survey

A simple, rapid assessment of patients with thoracic trauma and respiratory distress during the primary survey

In patients with thoracic trauma and impaired circulation (signs of shock Shock Shock is a state of organ hypoperfusion with resultant cellular dysfunction and death. Mechanisms may involve decreased circulating volume, decreased cardiac output, and vasodilation, sometimes... read more ), severe injuries to consider during the primary survey include the following:

  • Massive hemothorax

  • Tension pneumothorax

  • Cardiac tamponade

Other chest injuries (eg, blunt cardiac injury, aortic disruption) may cause shock but are not treated during the primary survey. Simplified, rapid approaches can help differentiate among rapidly correctable causes of shock due to chest injuries (see Figure: A simple, rapid assessment for chest injuries in patients with shock during the primary survey A simple, rapid assessment for chest injuries in patients with shock during the primary survey Thoracic trauma causes about 25% of traumatic deaths in the US. Many chest injuries cause death during the first minutes or hours after trauma; they can frequently be treated at the bedside... read more ). However, hemorrhage should be excluded in all patients who have shock after major trauma, regardless of whether a chest injury that could cause shock is identified.

A simple, rapid assessment for chest injuries in patients with shock during the primary survey

A simple, rapid assessment for chest injuries in patients with shock during the primary survey

* Hemorrhage should be excluded in all patients who are in shock after major trauma, regardless of whether a chest injury that could cause shock is identified

† Neck vein distention may be absent in patients with hypovolemic shock.

Treatment of injuries affecting the airway, breathing, or circulation begins during the primary survey. After the primary survey, patients are clinically assessed in more detail for other severe chest injuries as well as less severe manifestations of the injuries considered during the primary survey.

Imaging

Imaging studies are typically required in patients with significant chest trauma. Chest x-ray is virtually always done. Results are usually diagnostic of certain injuries (eg, pneumothorax, hemothorax, moderate or severe pulmonary contusion, clavicle fracture, some rib fractures) and suggestive for others (eg, aortic disruption, diaphragmatic rupture). However, findings may evolve over hours (eg, in pulmonary contusion Pulmonary Contusion Pulmonary contusion is trauma-induced lung hemorrhage and edema without laceration. (See also Overview of Thoracic Trauma.) Pulmonary contusion is a common and potentially lethal chest injury... read more and diaphragmatic injury). Plain x-rays of the scapula or sternum are sometimes done when there is tenderness over those structures.

In trauma centers, ultrasonography of the heart is typically done during the resuscitation phase to look for pericardial tamponade; some pneumothoraces can also be seen.

CT of the chest is often done when aortic injury Aortic Disruption (Traumatic) The aorta can rupture completely or incompletely after blunt or penetrating chest trauma. Signs may include asymmetric pulses or blood pressure, decreased blood flow to the lower extremities... read more is suspected and to diagnose small pneumothoraces, sternal fractures, or mediastinal (eg, heart, esophageal, bronchial) injuries; thoracic spine injuries also will be identified.

Laboratory and other testing

Complete blood count is often done but is mainly valuable as a baseline for detecting ongoing hemorrhage. Arterial blood gas results help monitor patients with hypoxia or respiratory distress. Cardiac markers (eg, troponin, creatine phosphokinase muscle band isoenzyme [CPK-MB]) can help exclude blunt cardiac injury.

ECG is typically done for chest trauma that is severe or compatible with cardiac injury. Cardiac injury may cause arrhythmia, conduction abnormalities, ST segment abnormalities, or a combination.

Treatment of Thoracic Trauma

  • Supportive care

  • Treatment of specific injuries

Immediately life-threatening injuries are treated at the bedside at the time of diagnosis:

Immediate resuscitative thoracotomy Thoracotomy Thoracotomy is surgical opening of the chest. It is done to evaluate and treat pulmonary problems when noninvasive procedures are nondiagnostic or unlikely to be definitive. The principal indications... read more can be considered for trauma victims if the clinician is proficient in the procedure and the patient has one of the following indications:

  • Penetrating thoracic injury with a need for cardiopulmonary resuscitation (CPR) of < 15 minutes

  • Penetrating nonthoracic trauma with a need for CPR of < 5 minutes

  • Blunt trauma with a need for CPR of < 10 minutes

  • Persistent systolic blood pressure of < 60 mm Hg due to suspected cardiac tamponade, hemorrhage, or air embolism

Pearls & Pitfalls

  • In trauma patients with respiratory distress or shock and decreased breath sounds, tube thoracostomy can be done before imaging studies are obtained.

In the absence of any of these criteria, resuscitative thoracotomy is contraindicated because the procedure has significant risks (eg, transmission of blood-borne diseases, injury to clinician) and costs.

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