Chest injuries often produce life-threatening derangements of ventilation or perfusion. An orderly, well-defined process for the initial evaluation and treatment of patients with thoracic injury is guided by the same principles and priorities as for patients with other injuries. The evaluation begins with an organized and rapid primary survey designed to recognize and treat immediately life-threatening problems. The first priority is to ensure an adequate airway. An airway can often be established by clearing any blood or debris from the oropharynx and pulling the mandible or tongue forward. Severely injured patients commonly require nasotracheal or orotracheal intubation. Cricothyroidotomy or tracheostomy is necessary occasionally, especially in patients with severe maxillofacial trauma. The second priority is to ensure adequate ventilation. If the patient is not breathing, intubation must be performed promptly. If ventilation is inadequate because of open or tension pneumothorax, these problems should be addressed at this stage of care. The next consideration is control of external hemorrhage and restoration of circulation. External hemorrhage is controlled best by direct pressure. Inadequate perfusion generally results from either hypovolemia or pump (cardiac) problems. Operation is often required as part of the resuscitative effort to control hemorrhage that is producing hypovolemia. Pump problems can be recognized by distended neck veins and are caused by one of four conditions: (i) tension pneumothorax, (ii) pericardial tamponade, (iii) coronary air embolism, or (iv) cardiac contusion/myocardial infarction. These conditions should be addressed sufficiently to provide adequate perfusion early in the initial treatment of the injured patient. For most patients suffering blunt trauma, urgent treatment of thoracic injury is accomplished during the primary survey because the most common blunt chest injuries can be controlled by endotracheal intubation or tube thoracotomy. In this setting, thoracotomy is indicated for cardiac tamponade, a massive hemothorax, or uncontrolled massive air leaks. Neither pulmonary nor cardiac contusions mandate delay in the diagnosis or definitive treatment of extrathoracic injuries resulting from blunt trauma.

Focused assessment sonography for trauma (FAST) has become routine as part of the secondary survey at many institutions and may be a valuable tool to assess for thoracic injuries. For example, extended FAST diagnoses clinically occult pneumothoraces with greater efficacy than plain x-ray.² Additionally, the ability to evaluate for blood in the pericardial space is excellent with reported
sensitivities of 96% to 100% and a specificity of 100%, or essentially equivalent to pericardial window.³ Cardiac ultrasonography may also be used for evaluating the hemodynamic effects of a pericardial effusion and for diagnosing structural injuries to the heart. The complete echocardiographic examination, however, requires much more time and expertise and should therefore be relegated to appropriate personnel in the later stages of evaluation.

During the initial resuscitation, placement of chest tubes can serve as both therapeutic and diagnostic procedures. Although the two most common indications for chest tube placement in this setting are pneumothorax and hemothorax, signs and symptoms of these conditions may not be readily apparent. Additionally, in the patient in shock, inadequate breathing or circulation may preclude taking time to differentiate between various causative conditions. Because the procedure is quick, relatively safe, and simple, the liberal use of chest tubes for patients in extremis is encouraged. Tension pneumothorax, the most common and easily treated immediately life-threatening thoracic injury, may accompany blunt or penetrating trauma. It results from a disruption in the respiratory system that allows air to escape from the lung parenchyma or tracheobronchial tree into the pleural space, thereby increasing intrathoracic pressure. This increased pressure is transmitted to all the cardiac chambers and retards venous return to the heart, resulting in hypotension. The classic signs of tension pneumothorax, which include decreased breath sounds, percussion tympany on the ipsilateral side, tracheal shift, and distended neck veins, are commonly absent or manifested incompletely in a busy emergency department. The diagnosis is often suspected on the basis of presence of shock with evidence of adequate venous filling on physical examination and recognition of asymmetric motion of the two sides of the chest. Treatment of suspected tension pneumothorax should not be delayed in patients with hemodynamic compromise.

The technique for chest tube placement is straightforward in the trauma setting. The chest is prepared and draped in a sterile manner. A local anesthetic such as 1% lidocaine is not required in an unconscious patient, but should be used in an alert patient. The appropriate location is the midaxillary line in approximately the fifth interspace. A scalpel is used to make a 2- to 3-cm incision through all layers of the skin and subcutaneous tissue. The incision should be oriented in the direction of the interspace. A finger or blunt clamp is used to penetrate the intercostal muscles and parietal pleura. The wound should be explored with an index finger in adults or a fifth finger in children. This ensures that the pleural space has been entered and allows exploration of the chest cavity. In adults, a 36 French chest tube should then be inserted and directed posteriorly and toward the apex. This tube position is best achieved by appropriate orientation of the skin incision relative to the entrance into the chest cavity. The straight line between these two points will define the direction of the tube once in the chest. A posterior, apically directed tube allows for effective drainage of air and blood, which commonly accompanies traumatic pneumothoraces. The tube should be attached to 20 cm of suction with a water seal and collection chamber. Visual inspection of air passing through the water seal gives some estimation of the magnitude of the air leak, an important factor in assessment of suspected airway injuries. Collection chambers for hemothoraces should be of the same design. Those associated with autotransfusion devices such as cell savers have immense theoretic potential for rapid retrieval and processing of shed blood. In actual practice, however, their use is limited. For example, in a small- to moderate-sized hemothorax (<1,000 mL), the red-cell yield of an autotransfusion device would be small and not worth the associated time and expense. In a large hemothorax, the most important goal of therapy is to control bleeding, and arranging for autotransfusion may delay and obscure this most important principle. Additionally, products of autotransfusion may contain harmful cytokines, damaged cells and debris, and lack platelets and other important proteins and coagulation factors. The use of prophylactic antibiotics after tube thoracostomy is controversial. However, most clinicians would recommend use of a first-generation cephalosporin for 24 hours, ideally started before the initial tube placement.

After the primary survey, less dramatic pneumothoraces may be diagnosed, along with hemothoraces, on various imaging studies. The treatment of the occult pneumothorax, that is those seen only on computed tomography (CT) scan, deserves special mention. Placement of a chest tube in this condition requires use of good clinical judgment. Patients requiring positive pressure ventilation, those with hypotension or respiratory distress of any etiology, and those with associated complex injuries or associated hemothorax should generally be treated with tube thoracostomy. Patients with occult pneumothoraces treated without tube thoracostomy should be observed for at least 24 hours, and have a repeat pulmonary artery (PA) and lateral chest radiograph obtained.

When treating a hemothorax with tube thoracostomy, the goal is complete removal of blood. Complications such as atelectasis and empyema after chest trauma are clearly related to residual blood, fluid, and air, as can occur secondary to inadequate positioning of the tube (i.e., within a fissure), obstruction of a tube, or blood clot or loculated fluid within the chest. A persistent or
clotted hemothorax is suggested by the presence of a persistent opacification in the pleural space in a patient with a known previous hemothorax. This radiodensity can be confused with adjacent pulmonary contusion or atelectasis. Chest CT can be quite helpful in this situation. Because retained blood serves as a nidus for infection and empyema,⁴ aggressive attempts at removal are justified. Occasionally, this can be accomplished with placement of more chest tubes, but often an operative approach is needed. Video-assisted thoracoscopic surgery (VATS) may be useful for small, clotted hemothoraces and free flowing blood in patients that can tolerate singlelung ventilation.⁵ For most operators, VATS also limits ability to control bleeding and perform definitive repair of injuries. In patients with ongoing bleeding or with large, clotted hemothoraces, posterolateral thoracotomy or muscle-sparing lateral thoracotomy is generally required.

Empyema thoracis is a relatively common complication after chest trauma, occurring in 5% to 10% of patients.⁶,⁷ Etiologies of posttraumatic empyema include retained hemothorax, parapneumonic, persistent foreign body, ruptured pulmonary abscess, bronchopleural fistula, esophageal leak, and tracking through the intact or injured diaphragm from an abdominal source. The diagnosis of empyema may be difficult, and one must differentiate from pleural thickening, pulmonary contusion, and an uninfected effusion. Chest CT with intravenous (IV) contrast will usually demonstrate a fluid collection with loculations or an enhancing rim. Such radiographic findings coupled with a clinical scenario of low-grade sepsis or failure to thrive is diagnostic. Analysis and culture of fluid obtained at thoracentesis or chest tube placement confirms the diagnosis, but the fluid may appear sterile if the patient is already on antibiotics. Culture-directed (usually gram-positive organisms) or broad-spectrum antibiotics are certainly an important component of therapy, but the primary goal is removal of the infection while the fluid is still thin. The benefits associated with this principle include performance of a simpler therapeutic procedure, less risk of developing a restrictive pulmonary peel, and faster overall recovery of the injured patient. In early stages, this procedure may simply be tube thoracostomy. However, if the infected pleural process cannot be completely evacuated by chest tubes because of thicker fluid, loculations, or pleural adhesions, a formal thoracotomy with decortication is generally required.

Decortication should not be undertaken in the face of severe sepsis. Instead, antibiotics and chest drainage with tube thoracostomy, CT directed catheters, or open rib-resection drainage should be employed until sepsis is controlled. For early empyema, VATS has been successfully used for lysis of adhesions and fluid removal.⁸,⁹ Because of limited ability to perform pleurectomy with this procedure, VATS should not be used when thick peel or trapped lung is present. For adult patients with posttraumatic empyema, there is no proven role for intrapleural fibrinolytic therapy.