ABSTRACT
Objective:
To compare the lung mechanics and outcomes between COVID-19-associated acute respiratory distress syndrome and non-COVID-19-associated acute respiratory distress syndrome.
Methods:
We combined data from two randomized trials in acute respiratory distress syndrome, one including only COVID-19 patients and the other including only patients without COVID-19, to determine whether COVID-19-associated acute respiratory distress syndrome is associated with higher 28-day mortality than non-COVID-19 acute respiratory distress syndrome and to examine the differences in lung mechanics between these two types of acute respiratory distress syndrome.
Results:
A total of 299 patients with COVID-19-associated acute respiratory distress syndrome and 1,010 patients with non-COVID-19-associated acute respiratory distress syndrome were included in the main analysis. The results showed that non-COVID-19 patients used higher positive end-expiratory pressure (12.5cmH2O; SD 3.2 versus 11.7cmH2O SD 2.8; p < 0.001), were ventilated with lower tidal volumes (5.8mL/kg; SD 1.0 versus 6.5mL/kg; SD 1.2; p < 0.001) and had lower static respiratory compliance adjusted for ideal body weight (0.5mL/cmH2O/kg; SD 0.3 versus 0.6mL/cmH2O/kg; SD 0.3; p = 0.01). There was no difference between groups in 28-day mortality (52.3% versus 58.9%; p = 0.52) or mechanical ventilation duration in the first 28 days among survivors (13 [IQR 5 - 22] versus 12 [IQR 6 - 26], p = 0.46).
Conclusion:
This analysis showed that patients with non-COVID-19-associated acute respiratory distress syndrome have different lung mechanics but similar outcomes to COVID-19-associated acute respiratory distress syndrome patients. After propensity score matching, there was no difference in lung mechanics or outcomes between groups.
Keywords:
COVID-19; Coronavirus infections; Respiratory distress syndrome; Respiratory mechanics; Critical care; Critical care outcomes
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(A) The cumulative distribution of tidal volume was lower in the non-COVID-19 group; however, the majority of patients in both groups received lung-protective ventilation with tidal volumes equal to or lower than 8mL/kg of ideal body weight. (B) The cumulative distribution of the ventilatory ratio was similar between groups. (C) Distribution of tidal volume vs. plateau pressure for each patient in which the data were available. Most patients fell within the limits of lung-protective ventilation (lower-left corner), defined as plateau pressure equal to or lower than 30cmH2O and tidal volume equal to or lower than 8mL/kg of ideal body weight.
There was no statistically significant difference in the cumulative frequency distribution of static respiratory compliance adjusted for ideal body weight between groups (p = 0.23). IBW - ideal body weight.