Authors: Chiumello D, Cressoni M, Gattinoni L

PMID: 32228035 PMCID: PMC7233352 DOI: 10.1164/rccm.202003-0817LE


In northern Italy, an overwhelming number of patients with coronavirus disease (COVID-19) pneumonia and acute respiratory failure have been admitted to our ICUs. Attention is primarily focused on increasing the number of beds, ventilators, and intensivists brought to bear on the problem, while the clinical approach to these patients is the one typically applied to severe acute respiratory distress syndrome (ARDS), namely, high positive end-expiratory pressure (PEEP) and prone positioning. However, the patients with COVID-19 pneumonia, despite meeting the Berlin definition of ARDS, present an atypical form of the syndrome. Indeed, the primary characteristic we are observing (and has been confirmed by colleagues in other hospitals) is a dissociation between their relatively well-preserved lung mechanics and the severity of hypoxemia. As shown in our first 16 patients (Figure 1), a respiratory system compliance of 50.2 ± 14.3 ml/cm H2O is associated with a shunt fraction of 0.50 ± 0.11. Such a wide discrepancy is virtually never seen in most forms of ARDS. Relatively high compliance indicates a well-preserved lung gas volume in this patient cohort, in sharp contrast to expectations for severe ARDS.

Keywords: COVID-19, SARS-CoV-2, ARDS, acute respiratory distress syndrome