Unraveling Pneumomediastinum in COVID-19 Patients: Insights from a High-Volume-Center Case-Control Study.

Background: Pneumomediastinum (PNM) is a severe complication in COVID-19 patients, potentially exacerbating morbidity and requiring heightened clinical attention. This study aims to identify risk factors, clinical characteristics, and outcomes associated with PNM in COVID-19 patients hospitalized for respiratory failure in our institution.

Methods: Among 4513 patients admitted in our institution and testing positive for COVID-19 infection during the peak of the COVID-19 pandemic in Italy (1 March 2020 to 31 July 2020), we conducted a single-center, retrospective case-control study focusing our analysis on those with severe disease (respiratory failure). The cohort included a total of 65 patients (32 with PNM and 33 without PNM in the same period). Data were retrospectively collected from hospital records, including demographics, comorbidities, smoking history, clinical and laboratory findings, and imaging results. Statistical analyses were performed using Fisher's exact test and Student's t-test, with significance set at α = 0.05.

Results: Patients with PNM were significantly younger (54.9 ± 18.5 vs. 65.4 ± 14.3 years, p = 0.0214) and exhibited higher inflammatory markers, particularly white blood cells count (WBC) at admission (11.4 ± 5.4 vs. 6.5 ± 4.1, p < 0.0001). Although smoking status, body mass index (BMI), and major comorbidities did not differ significantly between groups, COPD was more prevalent in the PNM group (46.9% vs. 15.1%, p = 0.0148). Radiologically, ground-glass opacities (GGOs) and consolidations were more frequent in PNM patients (93.7% vs. 51.5%, p = 0.0002; 78.1% vs. 42.2%, p = 0.0051, respectively). PNM was associated with longer hospital stays (28.5 ± 14.9 vs. 12.0 ± 7.2 days, p < 0.0001) and a higher need for invasive mechanical ventilation (53.1% vs. 30.3%, p = 0.0619). However, mortality rates did not differ significantly between groups.

Conclusions: PNM in patients with severe COVID-19 infection is associated with younger age, elevated inflammatory markers, and extensive lung involvement, contributing to increased morbidity and prolonged hospitalization. Early detection and tailored management strategies, including optimized respiratory support and aggressive anti-inflammatory therapies, are crucial in mitigating the adverse outcomes associated with PNM. Further research is needed to validate these findings and improve clinical protocols for managing this complication.