Tracheal Trauma

The trachea is a cartilaginous tube beginning at the base of the cricoid cartilage and extending to the carina, which courses through the neck and upper chest to connect the pharynx and larynx to the lungs. It has cervical and thoracic portions, separated at the level of the thoracic inlet above and below, respectively. The trachea bifurcates at the carina into the right and left primary bronchi, through which inspired air is delivered to lung tissue and exhaled. The trachea includes 18 to 22 D-shaped rings, which are cartilaginous anteriorly and laterally and membranous posteriorly. Blood supply to the cervical portions of the trachea comes from the subclavian artery branch, where the artery enters laterally and anastomose superiorly, inferiorly, and anteriorly. The bronchial arteries branching from the aorta provide the blood supply for the thoracic portions. The trachea is near the esophagus, vagus nerve, recurrent laryngeal nerves, thyroid, carotid arteries, jugular veins, innominate arteries and veins, the pulmonary trunk, the azygos vein, and the aorta with the vertebra and spinal cord posteriorly. The study of tracheal injury is often combined with adjacent airway structures (eg, tracheobronchial trauma and laryngotracheal trauma). (see  Tracheal Anatomy) Tracheal trauma is uncommon but is typically caused by iatrogenic, inhalation, penetrating, and blunt injuries that are primarily acute (eg, a stab or crush injury) or subacute (eg, an overinflated endotracheal tube against the trachea for a prolonged period) in duration. Blunt trauma to the neck may result in shearing of the trachea, usually within 3 cm of the carina. Tracheal lacerations can be transverse, spiral, or longitudinal, with varying degrees of tissue involvement. Most experts believe the incidence of tracheal trauma is underestimated as iatrogenic injuries are underreported, and patients with traumatic injuries often die before arriving at the hospital. Depending on the mechanism, tracheal trauma may also be associated with trauma to adjacent structures, including bony disruptions of the cervical spine, vascular injury to the great vessels, carotids, jugulars, or digestive tract involvement, and has significant morbidity and mortality. Regardless of the mechanism, early diagnosis and surgical repair are crucial to reducing complications and loss of respiratory function.  A high index of suspicion resulting in the early detection of tracheal trauma is one of the most crucial factors for reducing morbidity and mortality. The clinical presentation of tracheal trauma may vary depending on the mechanism of injury and involvement of adjacent structures. Subcutaneous emphysema, pneumomediastinum, and pneumothorax with or without respiratory failure are the most common clinical features observed in acute settings. Other symptoms include blood-tinged sputum, hemoptysis, shortness of breath, dysphagia, pneumoperitoneum, and chest pain. With a high index of suspicion, the physical and radiographic signs most frequently seen with tracheal injury were dyspnea, pneumomediastinum, pneumothorax, and subcutaneous emphysema. Tracheal trauma management should be tailored to the patient's injuries, clinical presentation, and nature of the tracheal injury, which typically requires the collaboration of a multidisciplinary team. When evaluating a patient with a tracheal injury, the primary initial treatment strategy is proper airway management and treatment of concomitant injuries. A secure airway is best achieved when appropriate by awake intubation over a flexible bronchoscope and placing an endotracheal tube distal to the injury site. Management of laceration repair can then be accomplished either conservatively or surgically depending on the cause of the injury, the depth, and the concomitant injuries sustained. Despite early recognition and appropriate management, potential complications include decreased lung function, infection, vocal cord paralysis, and strictures.