The chest takes up one-fourth of the total body mass and is therefore often subjected to injury during trauma from any etiology. Currently, in the United States more than 16,000 deaths occur annually as a direct result of thoracic trauma.1 A patient with thoracic trauma requires logical and sequential evaluation, followed by focused therapy, which less than 20% of the time involves an operation. A physician, especially an evaluating and treating surgeon, needs to understand the anatomy, physiology, and function of each of the thoracic organs, as each decision and treatment will affect outcome. It is critical to be able to recognize when a minor intervention or damage control should be applied to a chest injury condition versus when a formal surgical and potentially complex intervention is indicated. Once an intervention is decided, it is secondarily important to realize the indications and limitations of the various patient positions and incisions. Finally, as every evaluation and therapy has its potential hazard or contraindication, the acute care surgeon realizes that many traditional concepts in thoracic trauma are continuously changing, and both traditional and emerging concepts are often controversial.
Injury to the chest and its organs may be caused by penetration (missiles, fragments, knives, needles, and other objects), blunt forces, iatrogenic misadventure, blasts, ingestion of toxic substances, and, indirectly, from medication, and fluids. Each of these etiologies has differing initial manifestations as well as evaluation and treatment approaches.2,3,4 These differences are more specifically discussed elsewhere in other chapters of this textbook.
The thoracic cavity is encased by a flexible boney cage defined by clavicle, manubrium and sternum anteriorly, and ribs that wrap around posteriorly to the spine, supported by respiratory and locomotive muscles. Separate compartments house the two lungs with their five segments that are attached by vascular structures to the central cardiovascular compartment which is further divided into anterior, middle, and posterior mediastinum. The anterior mediastinum is the space between the pericardium and sternum and mainly is occupied by the thymus, while the esophagus is posterior to the trachea, connecting the pharynx to the stomach inferiorly wrapped by left anterior and right posterior vagi. In the healthy patient, the lungs and heart are separated from their surrounding cavities by a smooth fibrous pleural and pericardial lining respectively. Following inflammation, fusion of these linings may pose more challenging surgical approaches. Prior to any procedure following thoracic trauma, the surgeon is well-advised to review the regional anatomy, determine position and incisions options for a particular technique, and consider all approaches.
Evaluation includes physical examination as well as complex and sophisticated imaging and laboratory testing.5 Imaging may involve classic ultrasound and Doppler technology tests, helical multi-slice computerized tomography (CT scans) and magnetic resonance imaging (MRI). Other tests available to the surgeon include cardiologic evaluation using EKG, echocardiogram, and even cardiac catheterization. Hematologic, clotting, and metabolic testing, as well as pulmonary function testing, are other potentially helpful adjuncts. Endoscopic evaluation of the trachea and esophagus, as well as contrast esophagrams can supplement imaging modalities.
In deciding which evaluation tools to use, first consider what the test is expected to demonstrate, and second, how the results will alter decision making or treatment. Once these questions are considered, the treating physician may well decide the tests are not needed. It is always helpful to have a progress note reflecting the decision-making process for the tests ordered (why/why not) in the patient’s medical record.
Tube thoracostomy is the most common procedure performed following chest trauma, and it is also one of the most misunderstood and underrated procedures in medicine. Of the patients with chest injury that do need surgical intervention, tube thoracostomy is the only invasive procedure that 85% of them will require. Upward of 25% of patients with chest tubes will encounter some difficulty with malposition, drainage problems, and various complications. One of the most common problems encountered is incomplete evacuation of the hemothorax, resulting in a clotted hemothorax or an empyema. Second and multiple chest tubes are frequently unnecessarily inserted as a result of misunderstanding the function of the chest tube and/or improper technique for insertion.
Tube thoracostomy following trauma should be accomplished with adequate anesthesia and analgesia. Trocar-tipped chest tubes should be avoided. Chest tubes are best inserted in the area of the ausculatory triangle in the mid-axillary line near the fourth or fifth intercostal space. Using clamps or dissecting scissors, subcutaneous tissue and muscular dissection is performed to create a tract directed posteriorly. The pleura is anesthetized with local anesthetic injection and the pleural cavity is entered with an exploring finger and not a sharp instrument. Care is taken to avoid injury to the intercostal vessels and nerve on the under surface of each rib, as such injury can produce iatrogenic bleeding and significant pain. Following a gentle digital exploratory thoracotomy, an appropriately sized chest tube (32–36 French) is directed toward the back and apex of the pleural space and attached to an appropriate collection device. This insertion site overlies the major pulmonary fissure. Care must be taken to assure that the chest tube is not placed in this fissure, the exact relative location of which can often be ascertained by preinsertion digital exploration. Autotransfusion of fresh hemothorax blood may be considered if preprocedural CXR demonstrates complete white-out suggestive of massive hemothorax—800 mL to 1500 mL of volume can be recycled this way. Up to 25% of the population has some element of visceral and parietal pleural symphysis and can contribute to subcutaneous emphysema in the absence of pneumothorax. In such instances, the insertion of a chest tube may occur into the substance of the lung, rather than the pleural space. Should a pneumothorax or hemothorax actually exist, care must be taken to insert the chest tube into the space containing the blood or air, rather than at a point of pleural symphysis.
Only approximately 15% of chest injured patients will eventually require a formal thoracotomy. The indications for thoracotomy continue to change as newer, noninvasive therapies such as endovascular removal of intravascular foreign bodies and endovascular stent graft insertions become available. Although many different injury patterns may occur in the chest and to its contents, indications for an acute formal thoracotomy follow both anatomic and physiologic parameters and include:
Loss of chest wall substance (traumatic thoracotomy)
Traumatic hemopericardium6
Evidence of free wall, septal, or valvular cardiac disruption6
Radiologic or endoscopic evidence of significant tracheal, bronchial, esophageal or great vessel injury7,8
Greater than 1500 mL blood loss from the pleural cavity following the initial tube thoracostomy9
Greater than a sustained 200 mL continuing blood loss per hour from the tube thoracostomy
Loss of cardiac function or proximal vascular control (resuscitative thoracotomy)7,10,11,12,13
Massive air leak
Demonstrable thoracic tracheal or bronchial injury
Uncontrollable hemorrhage in thoracic outlet major injury
Mediastinal missile traverse with massive blood or air loss through the chest tube or demonstrated on CT of the chest
Removal of selective foreign bodies
Massive air embolism, particularly systemic air embolism
Retained clotted hemothroax (subacute and chronic indications)14
Post-traumatic contained empyema14
Cardiac herniation (ruptured pericardium)15
In addition to the routine basic maneuvers to stabilize the trauma patient, a number of minor therapeutic interventions are available. Some, such as a needle decompression of the pleural cavity, pericardiocentesis, interosseous sternal fluid infusions, and subxyphoid pericardiotomy, have been controversial with regard to specific indications and the ultimate expected benefit. Specifically, evidence-based data are not sufficient to recommend the maneuvers. Other minor thoracic maneuvers used by the surgeon include:
Limiting the ventilator pressures to less than 40 TORR in intubated patients with acute lung injury, to prevent systemic air embolism
Video-assisted thoracoscopic surgery (VATS)
Intercostal and epidural block for pain control
Consideration of operative fixation of fractured ribs (Controversial)
