Chest trauma (Proceedings)
Traumatic thoracic injuries are prevalent in small animals, particularly in dogs. The most common causes of thoracic trauma are motor vehicular accidents and bite wounds. Other possible, although less common mechanisms include gunshot, knife wounds or being kicked by a larger animal (horse/cow). Injuries may range from mild to life threatening.
The initial evaluation of the patient with thoracic trauma should concentrate on the major body systems (heart, lungs, brain). A patient with significant thoracic trauma frequently has other injuries as well. The patient should be immediately taken to a treatment room for further therapy. An IV catheter should be rapidly placed and samples collected for determination of a packed cell volume, total solids, glucose and BUN. Supplemental oxygen should be administered if any signs of respiratory distress are present. Intravenous fluids should be given if shock is present. After the patient's condition has stabilized, further testing (such as radiographs) may be performed.
PneumothoraxPneumothorax refers to the development of free air within the pleural space. The air gets to the pleural space either from the outside or via air leakage from the pulmonary parenchyma. Radiography, thoracocentesis or auscultation may identify pneumothorax. Auscultation of dogs with pneumothorax may be misleading if respiratory sounds are louder than average. In many emergency practices, dogs showing respiratory distress may undergo thoracocentesis based upon trauma history and increased respiratory effort. Approximately 25-30 ml/kg of air generally needs to be removed to provide significant improvement to respiratory status. Occasionally, a thoracostomy tube is required to prevent either continuous or intermittent chest drainage. Generally, a dog is considered a candidate for a chest tube if it requires greater than three needle thoracocentesis in less than 12- 18 hours or if no end-point is reached during thoracocentesis.
Animals will breathe with a restrictive pattern (short shallow breaths).
Pulmonary contusion is another common traumatic thoracic injury. Pulmonary contusion occurs when blunt trauma to the chest causes alveoli to fill with blood and fluid (inflammation). Pulmonary contusion occurs in a large percentage of animals with thoracic trauma. Contusion may be identified radiographically as interstitial to alveolar infiltrates or clinically by tachypnea/increased respiratory effort in dogs following trauma. Therapy for pulmonary contusion is supportive and includes oxygen and fluid therapy as needed to maintain adequate circulating volume. Some clinicians vividly recall dogs with pulmonary contusion that appeared to rapidly deteriorate following a large volume of intravenous crystalloids. Most dogs with pulmonary contusion improve significantly in 2-3 days and recover completely in less than one week.