Time dependency and unique etiology of barotrauma in COVID-19: A retrospective cohort study with landmark analysis and pathological approach

BACKGROUND: Barotrauma frequently occurs in coronavirus disease 2019. Previous studies have reported barotrauma to be a mortality-risk factor; however, its time-dependent nature and pathophysiology are not elucidated. To investigate the time-dependent characteristics and the etiology of coronavirus disease 2019-related-barotrauma. METHODS AND FINDINGS: We retrospectively reviewed intubated patients with coronavirus disease 2019 from March 2020 to May 2021. We compared the 90-day survival between the barotrauma and non-barotrauma groups and performed landmark analyses on days 7, 14, 21, and 28. Barotrauma within seven days before the landmark was defined as the exposure. Additionally, we evaluated surgically treated cases of coronavirus disease 2019-related pneumothorax. We included 192 patients. Barotrauma developed in 44 patients (22.9%). The barotrauma group’s 90-day survival rate was significantly worse (47.7% vs. 82.4%, p < 0.001). In the 7-day landmark analysis, there was no significant difference (75.0% vs. 75.7%, p = 0.79). Contrastingly, in the 14-, 21-, and 28-day landmark analyses, the barotrauma group’s survival rates were significantly worse (14-day: 41.7% vs. 69.1%, p = 0.044; 21-day: 16.7% vs. 62.5%, p = 0.014; 28-day: 20.0% vs. 66.7%, p = 0.018). Pathological examination revealed a subpleural hematoma and pulmonary cyst with heterogenous lung inflammation. CONCLUSIONS: Barotrauma was a poor prognostic factor for coronavirus disease 2019, especially in the late phase. Heterogenous inflammation may be a key finding in its mechanism. Barotrauma is a potentially important sign of lung destruction.