Fig. 2.

Patients with SARS-CoV-2 and Acute Respiratory Distress Syndrome (ARDS). Lung mechanics were measured using esophageal manometry to remove the component of the chest wall from the respiratory system values. (A) Respiratory system (red bars) and lung compliance (blue bars) measurements in each of the 40 patients. There was wide variability in the distribution of lung and respiratory system mechanics overall without clear differentiation of phenotypes by degree of compliance. The distribution of mechanics appears similar to other known cohorts of non-SARS-CoV-2 related ARDS. With mechanics appearing more as a continuum as opposed to unique phenotypes, cutoffs appear arbitrary in nature. The black dotted line differentiates the proposed “L” from “H” types, and the light grey dotted line differentiates the equally arbitrary cutoff from severe (compliance <25 ml/cmH2O) to moderately impaired mechanics (compliance 25-40 ml/cmH2O) (B) Comparison between respiratory system and lung compliance illustrating the expected excellent correlation. The solid line represents the slops of this correlation. (C) Comparison of end inspiratory (light grey) and end expiratory (dark grey) airway and transpulmonary pressures. This illustrates that despite the good correlation, there is wide variability for the corresponding transpulmonary pressure illustrating the variability inherent to the chest wall mechanics. The dotted line illustrates the line of identity. There was an unpredictable and inconsistent and underestimation of transpulmonary pressure by the corresponding airway pressure as seen by the variable offset from the line of identity. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)