Incidence and risk factors for pneumomediastinum in COVID-19 patients in the intensive care unit

OBJECTIVES The incidence of pneumomediastinum (PNMD), its causes of development and its effect on prognosis in the coronavirus disease 2019 (COVID-19) are not clear. METHODS Between March 2020 and December 2020, 427 patients with real-time reverse transcriptase-polymerase chain reaction-confirmed COVID-19 admitted to the intensive care unit were analysed retrospectively. Using receiver operating characteristic analysis, the area under the curve (AUC) for initial invasive mechanical ventilation (MV) variables such as initial peak inspiratory pressure (PIP), PaO2/FiO2 (P/F ratio), tidal volume, compliance and positive end-expiratory pressure was evaluated regarding PNMD development. RESULTS The incidence of PNMD was 5.6% (n = 24). PNMD development rate was 2.7% in non-invasive MV and 6.2% in MV [odds ratio (OR) 2.352, 95% confidence interval (CI) 0.541-10.232; P = 0.400]. In the multivariate analysis, the independent risk factors affecting the development of PNMD were PIP (OR 1.238, 95% CI 1.091-1.378; P < 0.001) and P/F ratio (OR 0.982, 95% CI 0.971-0.994; P = 0.004). P/F ratio (AUC 0.815, 95% CI 0.771-0.854), PIP (AUC 0.780, 95% CI 0.734-0.822), compliance (AUC 0.735, 95% CI 0.677-0.774) and positive end-expiratory pressure (AUC 0.718, 95% CI 0.668-0.764) were the best predictors for PNMD development. Regarding the multivariate analysis, independent risk factors affecting mortality were detected as age (OR 1.015, 95% CI 0.999-1.031; P = 0.04), comorbidity (OR 1.940, 95% CI 1.100-3.419; P = 0.02), mode of breathing (OR 48.345, 95% CI 14.666-159.360; P < 0.001), PNMD (OR 5.234, 95% CI 1.379-19.857; P = 0.01), positive end-expiratory pressure (OR 1.305, 95% CI 1.062-1.603; P = 0.01) and tidal volume (OR 0.995, 95% CI 0.992-0.998; P = 0.004). CONCLUSIONS PNMD development was associated with the initial P/F ratio and PIP. Therefore, it was considered to be related to both the patient and barotrauma. PNMD is a poor prognostic factor for COVID-19.