Retrospective evaluation of traumatic pneumomediastinum in dogs and cats (2005–2022): 52 cases

Objective: To describe the incidence, etiology, clinical signs, diagnostics, treatments, and outcome of noniatrogenic traumatic pneumomediastinum (TPM) in dogs and cats. Design: Retrospective study of cases (2005–2022). Setting: University veterinary teaching hospital. Animals: Fifty-two patients (29 dogs, 23 cats). Measurements and Main Results: Data collected from the medical records included signalment, physical examination findings, animal trauma triage (ATT) score, clinicopathological data, imaging data, surgical intervention, length of hospitalization, supportive care, complications, and outcome. Most dogs presented with tachycardia and tachypnea, while cats presented with hypothermia and tachypnea. Subcutaneous emphysema, pneumothorax, and dyspnea were the most common clinical signs for both species. The median calculated ATT score was 3.5 in dogs and 4 in cats. The most common radiographic abnormalities other than pneumomediastinum were pneumothorax and lung contusions. The overall mortality rate was 18%, with a significantly higher survival rate in dogs (26/28 dogs [93%], 15/22 cats (68%); P = 0.03). Outcome was unknown in 1 dog and 1 cat. The only significant difference in treatment between survivors and nonsurvivors was the requirement in dogs for positive pressure ventilation. The median hospitalization period was 2 days for both species, with a shorter hospitalization in the nonsurvivors (0.6 vs 2 days, respectively; P = 0.006). Conclusions: TPM is an infrequent pathology in veterinary medicine and may be seen without an externally obvious injury. The most common causes for TPM in dogs were vehicular trauma and bite wounds, while high-rise syndrome was the most common cause in cats. Most of the cases have concurrent pneumothorax and require thoracocentesis; however, direct intervention to treat TPM is not usually required. The vast majority of cases did not undergo surgery to treat TPM. The prognosis for dogs with TPM was good but was guarded for cats.