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Thoracic Trauma

Thoracic Trauma

1. Definition Trauma to the chest is usually divided into blunt and penetrating injury. Proper emergency care and resuscitation are integral parts of the management of these patients, who may have airway obstruction, life-threatening hemorrhage, and severe associated injuries.

BLUNT THORACIC TRAUMA

1. Chest Wall Injuries

A. Rib fracture is the most common thoracic injury
B. Significant intrathoracic injury may be present without rib fracture in children due to rib cage elasticity
C. Narcotics and intercostal nerve blocks are sufficient for simple rib fractures
D. Patients with flail chest should be supported with mechanical ventilation for several days to regain chest wall stability
E. Consider tracheostomy for prolonged intubation to minimize laryngeal injury and facilitate pulmonary care
F. First rib fracture indicates significant force, and aortography is indicated if the patient also has brachial plexus deficit, absent radial pulse, pulsating supraclavicular mass, or widened mediastinum

2. Pulmonary Injuries

A. Pulmonary contusion probably occurs to a varying degree in all thoracic injuries and is a major component of flail chest
B. Significant hypoventilation and shunting from contusion requires judicious fluid management and ventilatory support, if indicated
C. Partial, complete, and tension pneumothorax should all be managed promptly with chest tube insertion
D. Subcutaneous emphysema should prompt investigation for pneumothorax but is not in itself an indication for chest tube placement
E. Hemothorax should be managed with early chest tube drainage to prevent clot formation and incomplete evacuation
F. Surgical exploration is recommended if initial output is more than 1000 ml or chest tube drainage is more than 100 ml/hr for 4 hours
G. A clotted hemothorax should be evacuated early by thoracotomy to improve pulmonary function and prevent late fibrothorax

3. Tracheal/Bronchial Injuries

A. Most tracheal injuries are cervical and range from crush injuries to compete tracheal separation
B. If endotracheal intubation is not possible, a surgical airway should be obtained
C. Primary repair of tracheal lacerations or separation should be performed, if possible
D. Blunt trauma typically causes a circumferential laceration of either main bronchus with complete separation
E. Only 50% of patients will have a pneumothorax with this injury, and hemothorax is uncommon
F. Only 1/3 of patients are diagnosed in the first 24 hours, and only 1/2 within the first month
G. Early repair is the preferred treatment if the diagnosis is made, and requires thoracotomy with intubation of the uninjured bronchus
H. Late strictures from incomplete tears or parenchymal isolation from complete tears can be repaired with bronchoplastic procedures, but may require pulmonary resection

4. Cardiac/Great Vessel Injuries

A. Myocardial contusion is the most common injury and is suspected with EKG changes and serial enzyme elevations
B. Coronary artery injury can result in thrombosis and myocardial infarction
C. Atrial or ventricular rupture is usually fatal, although the pericardium may restrict bleeding enough to allow survival to the ER
D. The patient should be monitored in the ICU and may require heparinization for coronary thrombosis and anti-arrhythmic therapy
E. Echocardiography and angiography are indicated for tamponade and post-injury murmurs, which suggest valvular insufficiency or septal defect
F. Aortic rupture is also usually fatal, but can result in formation of a false aneurysm, typically at the aortic isthmus
G. Patients with a widened mediastinum on CXR should have prompt aortography, which will demonstrate an intimal tear
H. Surgical repair should be done promptly, as fatal hemorrhage can occur at any time
I. Techniques include LA-FA bypass, proximal aorta-distal aorta shunting, and cross-clamping without cardiopulmonary bypass

5. Diaphragm Rupture

A. Most lacerations occur on the left hemidiaphragm and result from automobile accidents
B. Usually, the stomach herniates and undergoes volvulus, massively dilates, and causes left lung collapse and mediastinal shift to the right
C. Gastric distension can also result in perforation and should be prevented by NG tube placement
D. Splenic and liver injury is also common in this setting
E. The diaphragm can be repaired either through the chest or abdomen, and all tears should be closed in double-layer fashion

PENETRATING THORACIC TRAUMA

Comment: Knowledge of the type of weapon in gunshot wounds is useful, as unbalanced or hollow-point ammunition can cause extensive internal destruction despite small entrance wounds. In addition, such missiles can fragment and embolize. It is important to remember that any penetrating injury to the fourth interspace or below may well have passed through the diaphragm, and attention given to possible intraabdominal injury.

1. Chest Wall Injuries

A. Laceration of intercostal or internal mammary arteries can be life-threatening and operative intervention based on chest tube output
B. The pulmonary vessels are rarely the source of major bleeding unless a hilar vessel is injured
C. High-velocity missiles and shotgun wounds can produce extensive open wounds requiring immediate occlusion and intubation, followed by operative repair

2. Pulmonary Injuries

A. Most penetrating wounds only require chest tube insertion and lung expansion
B. Parenchymal injuries requiring operation can usually be oversewn without difficulty
C. Bronchial or pulmonary artery injury can require resection
D. A large vascular clamp placed across the lung hilum facilitates exploration and vessel repair

3. Base of Neck Injuries

A. The close proximity of major structures make injury highly probable
B. This can be assessed by angiography, contrast swallow, endoscopy, or surgical exploration
C. The surgical approach will vary, but median sternotomy with lateral or superior extension provides the widest exposure
D. Avoid prosthetic grafts for vascular repair if the trachea or esophagus are also injured
E. Cardiopulmonary bypass may be required if the aorta must be cross-clamped

4. Cardiac/Great Vessel Injuries

A. The right ventricle is most commonly injured, followed by the left ventricle
B. Ventricular septal defect is the most commonly intracardiac injury
C. Most patients do not reach the hospital, as the injury to the pericardium leads to exsanguination instead of tamponade
D. Hypotension that does not respond to rapid volume replacement suggests significant injury
E. CXR, EKG, and echocardiography have little diagnostic value in these patients
F. Subxiphoid pericardiocentesis is useful for diagnosis; negative deflection of the QRS complex indicates contact with the epicardium and a drain should be left in place
G. Subxiphoid pericardial window is preferred for tamponade, however, and should be performed in the operating room, as the patient may rapidly exsanguinate
H. Emergency room thoracotomy is seldom indicated, being reserved for moribund patients or rapid deterioration without time to transfer to the OR
I. Median sternotomy is the preferred approach
J. Repair ventricular lacerations with pledgetted nonabsorbable horizontal mattress sutures
K. Oversew atrial or aortic injuries
L. Coronary artery division should be managed by ligation and bypass grafting on cardiopulmonary bypass
M. Obvious septal defects or gross valvular insufficiency should be repaired; otherwise, the injury should be more adequately studied with postoperative catheterization

5. Tracheal/Bronchial Injuries

A. Tracheal injury is suggested by pneumothorax, pneumomediastinum, subcutaneous emphysema, hemoptysis, and airway obstruction
B. Following intubation or a surgical airway, an anterior collar incision is the best approach
C. Median sternotomy may be required for associated vascular injury or intrathoracic tracheal laceration
D. Avoid tracheostomy if possible when a vascular repair is in proximity

ESOPHAGEAL INJURIES

A. Blunt injury is rare; the most common cause is endoscopic perforation, followed by penetrating injuries
B. Mediastinitis is a lethal complication and early surgical intervention is recommended
C. Cervical esophageal injury should be approached through a lateral neck incision and thoracic injuries via thoracotomy
D. If the tissue is not extensively damaged, primary repair with drainage is appropriate; otherwise, the wound is left open
E. Postemetic rupture (Boerhaave's syndrome) presents with pain, fever, and shock; death can occur within 24-48 hours
F. The diagnosis is suggested by cervical and mediastinal air, widened mediastinum, and pleural effusion
G. The esophagus should be closed in two layers, the mediastinum widely opened, and the area drained into the pleural space via thoracotomy

COMPLICATIONS OF THORACIC TRAUMA

A. ARDS follows many types of injuries, but is particularly common in thoracic trauma
B. It typically begins a few hours after injury and progresses rapidly
C. Ventilatory support with PEEP and high FIO2 is the standard of care
D. Failure of ARDS to improve after 4-6 days is associated with a high incidence of death
E. Arrhythmias are common in this patient population, particularly atrial fibrillation, which can be treated with standard measures
F. Ventricular arrhythmias suggest myocardial injury or infarction and should be investigated
G. Many patients require tracheostomy and attention should be given to proper care
H. Other complications include atelectasis, thromboembolism, infection, and air embolism