If air escapes from a penetrating injury to the neck, a definite diagnosis of TBI can be made. Hammans sign, a sound of crackling that occurs in time with the heartbeat, may also accompany TBI. Causes
Injuries to the tracheobronchial tree within the chest may occur due to penetrating forces such as gunshot wounds, but are more often the result of blunt trauma. TBI due blunt forces usually results from high-energy impacts such as falls from height and motor vehicle accidents; the injury is rare in low-impact mechanisms. Injuries of the trachea cause about 1% of traffic-related deaths. Other potential causes are falls from high places and injuries in which the chest is crushed. Explosions are another cause.Gunshot wounds are the commonest form of penetrating trauma that cause TBI. Less commonly, knife wounds and shrapnel from motor vehicle accidents can also penetrate the airways. Most injuries to the trachea occur in the neck, because the airways within the chest are deep and therefore well protected; however, up to a quarter of TBI resulting from penetrating trauma occurs within the chest. Injury to the cervical trachea usually affects the anterior (front) part of the trachea.Certain medical procedures can also injure the airways; these include tracheal intubation, bronchoscopy, and tracheotomy. The back of the trachea may be damaged during tracheotomy. TBI resulting from tracheal intubation (insertion of a tube into the trachea) is rare, and the mechanism by which it occurs is unclear.
In blunt chest trauma, TBI occurs within 2.5 cm of the carina 40–80% of the time. The injury is more common in the right main bronchus than the left, possibly because the former is near vertebrae, which may injure it. Also, the aorta and other tissues in the mid chest that surround the left main bronchus may protect it. Another possibility is that people with left main bronchus injuries are more likely to also have other deadly injuries and therefore die before reaching hospital, making them less likely to be included in studies that determine rates of injuries. Prevention
Vehicle occupants who wear seat belts have a lower incidence of TBI after a motor vehicle accident. However, if the strap is situated across the front of the neck (instead of the chest), this increases the risk of tracheal injury. Design of medical instruments can be modified to prevent iatrogenic TBI, and medical practitioners can use techniques that reduce the risk of injury with procedures such as tracheotomy. Treatment
Treatment of TBI varies based on the location and severity of injury and whether the patient is stable or having trouble breathing, but ensuring that the airway is patent so that the patient can breathe is always of paramount importance. Ensuring an open airway and adequate ventilation may be difficult in people with TBI. Intubation, one method to secure the airway, may be used to bypass a disruption in the airway in order to send air to the lungs.