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.
THORACIC ANATOMY AND PHYSIOLOGY: RESPONSE TO TRAUMA
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 ...