Tracheal Perforation in Dogs
Tracheal perforation is a loss of the integrity of the tracheal wall, in the form of a hole or rip, allowing leakage of air into the surrounding tissues and creating air pockets under the skin, air collection in the mediastinum (in between the lungs), and potentially air in the sac around the heart, free air in the chest cavity, and air in the most posterior part of the abdominal cavity (pneumoretroperitoneum). This loss of integrity can be caused by a penetrating trauma, trauma from inside the trachea, or blunt neck or chest trauma.
The severity of tracheal perforation ranges from a small perforation to complete tracheal avulsion (tearing away of the trachea). In dogs with complete avulsion, the mediastinal tissues can help to maintain the airways.
Symptoms and Types
The following signs may occur immediately after injury or up to a week later:
- Pockets of air collected under the skin
- Respiratory distress
- Lack of appetite (anorexia)
- Lack of energy
- Excessive salivation (ptyalism)
- Harsh crowing sound as dog breathes in
Penetrating cervical (neck) wounds:
- Bite wounds
- Missiles (e.g., gunshots, arrows)
Perforation by a veterinarian (iatrogenic):
- During a transtracheal wash (a saline wash and collection of tissue and fluid through [trans] the trachea when evaluating for respiratory diseases)
- Inadvertent puncture while drawing blood, or during neck surgery
- Anesthesia and intubation procedures (to maintain an airway during anesthesia)
Blunt trauma can cause intrathoracic tracheal avulsion:
- Motor vehicle accident
- Falling from great heights
Your veterinarian will perform a thorough physical exam on your dog, taking into account the background history of symptoms and possible incidents that might have led to this condition. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel. An arterial blood gas analysis may also be done to check oxygenation of blood. A pulse oximetry measurement may show less than normal (or even low) oxygen saturation.
Side view X-rays of the neck and chest are essential for diagnosis. Air pockets under the skin, air collection in the mediastinum, free air in the chest cavity, and potentially air in the sac around the heart will be seen with tracheal perforation. In cases of tracheal avulsion, the site of disruption may be visible. Abdominal X-rays may show a pneumoretroperitoneum -- air that has escaped into the space behind the lining of the stomach (peritoneum).
An examination of the interior walls of the trachea can be done by tracheoscopy to confirm the diagnosis of tracheal perforation and to estimate its severity. False-negative examinations can sometimes occur.