Epidemiology, Risk Factors and Outcomes of Pneumomediastinum in Patients with Coronavirus Disease 2019: A Case-Control Study

Background: Since the beginning of the ongoing Coronavirus Disease 2019 (COVID-19) pandemic, pneumomediastinum has been reported in patients with COVID-19 pneumonia and acute respiratory distress syndrome. It has been suggested that pneumomediastinum may portend a worse outcome in such patients although no investigation has established this association definitively. Research Question: We hypothesized that the finding of pneumomediastinum in the setting of COVID-19 disease may be associated with a worse clinical outcome. The purpose of this study was to determine if the presence of pneumomediastinum was predictive of increased mortality in patients with COVID-19. Study Design and Methods: A retrospective case-control study utilizing clinical data and imaging for COVID-19 patients seen at our institution from 3/7/2020 to 5/20/2020 was performed. 87 COVID-19 positive patients with pneumomediastinum were compared to 87 COVID-19 positive patients without pneumomediastinum and to a historical group of patients with pneumomediastinum during the same time frame in 2019. Results: The incidence of pneumomediastinum was increased more than 6-fold during the COVID-19 pandemic compared to 2019 (P = <.001). 1.5% of all COVID-19 patients and 11% of mechanically ventilated COVID-19 patients at our institution developed pneumomediastinum. Patients who developed pneumomediastinum had a significantly higher PEEP and lower P/F ratio than those who did not (P = .002 and .033, respectively). Pneumomediastinum was not found to be associated with increased mortality (P = .16, confidence interval [CI]: 0.89-2.09, 1.37). The presence of concurrent pneumothorax at the time of pneumomediastinum diagnosis was associated with increased mortality (P = .013 CI: 1.15-3.17, 1.91). Conclusion: Pneumomediastinum is not independently associated with a worse clinical prognosis in COVID-19 positive patients. The presence of concurrent pneumothorax was associated with increased mortality.