Fig. 4
From: Respiratory physiology of COVID-19-induced respiratory failure compared to ARDS of other etiologies
Potential for lung recruitment in COVID-19 ARDS patients. In COVID-19 patients, recruitment-to-inflation ratio was inversely related to respiratory system compliance at low PEEP (upper left panel, Pearson’s correlation and linear regression), meaning that patients with lower baseline compliance displayed the highest potential for lung recruitment. Importantly, lung recruitability was not related to changes in respiratory system compliance (and driving pressure) induced by PEEP. With PEEP, compliance could either increase, decrease, or remain unchanged (change in compliance was defined clinically relevant when >5 ml/cmH2O), independently from the recruitment-to-inflation ratio, as shown in the upper right panel. The changes in PaO2/FiO2 induced by PEEP were independent from recruitability (lower left panel), while PEEP-induced PaCO2 changes were weakly but significantly related to the recruitment-to-inflation ratio (lower right panel,). CRS, respiratory system compliance