Prevalence and Risk Factors of Pneumomediastinum and Subcutaneous Emphysema in COVID-19 Patients: A Retrospective Cohort Study

Background: Pneumomediastinum (PM), the presence of air in the mediastinum, is a rare condition. Severe COVID-19 patients are at an increased risk for PM and subcutaneous emphysema (SCE) due to alveolar rupture from diffuse lung injury. Despite the increased prevalence of PM in COVID-19 patients, the optimal treatment approach remains debated. Objectives: This study investigated the prevalence, outcomes, and associated risk factors for PM and SCE in COVID-19 patients. Methods: In this retrospective cohort study, COVID-19 patients aged 18 - 80 with a positive PCR test and chest CT scan from April to December 2021 were included. Cases of PM and SCE were identified, and an equal number of age, sex, and severity-matched COVID-19 patients were selected as the control group for comparison. Results: Of the 1 557 patients, 89 (5.71%) developed PM. Among these patients, 63 (4.04%) developed SCE. Patients with these complications had significantly longer hospital stays. No significant association was found between comorbidities and the occurrence of PM or SCE. The use of Venturi and non-rebreather masks (OR = 3.075, 95% CI: 1.658 - 5.705), non-invasive ventilation (NIV) (OR = 16.941, 95% CI: 6.545 - 43.851), and invasive mechanical ventilation (IMV) (OR = 5.703, 95% CI: 2.595 - 12.533) were significantly associated with these complications (P < 0.0001). The mortality rate among severe COVID-19 patients with PM was 43.8%, and 47.6% among those with SCE. Conclusions: Pneumomediastinum and SCE are rare complications in COVID-19 patients, associated with prolonged hospitalization. The use of certain respiratory support methods, including NIV and IMV, significantly increased the risk of these complications. Both PM and SCE are linked to high mortality rates, highlighting the need for careful management in affected patients.