Severe coronavirus disease 2019: Is it acute respiratory distress syndrome?

The outbreak of coronavirus disease 2019 (COVID-19) poses a major global threat. Although we have learned a lot about COVID-19 from clinical studies and autopsy findings, there is still a lot of confusion. One of the biggest controversies is whether severe COVID-19 can be diagnosed as acute respiratory distress syndrome (ARDS). Severe COVID-19 may meet ARDS Berlin criteria, but it differs from ARDS caused by other etiologies and is characterized by later onset time, relatively normal lung compliance in some cases, significant hypercapnia, lung CT findings, and significant coagulation activation in lungs. Some reports classify COVID-19-related ARDS into different phenotypes, but most of them are based on observational studies, with high bias. To date, we have not fully understood the pathophysiology of COVID-19-related ARDS. Premature phenotyping may mislead mechanical ventilation strategies. We expect evidence from large clinical studies. © 2021, Peking Union Medical College Hospital. All rights reserved.