Association between lung compliance phenotypes and mortality in COVID-19 patients with acute respiratory distress syndrome.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) in COVID-19 is associated with a high mortality rate, though outcomes of the different lung compliance phenotypes are unclear. We aimed to measure lung compliance and examine other factors associated with mortality in COVID-19 patients with ARDS. METHODS: Adult patients with COVID-19 ARDS who required invasive mechanical ventilation at 8 hospitals in Singapore were prospectively enrolled. Factors associated with both mortality and differences between high (<40mL/cm H2O) and low (<40mL/cm H2O) compliance were analysed. RESULTS: A total of 102 patients with COVID-19 who required invasive mechanical ventilation were analysed; 15 (14.7%) did not survive. Non-survivors were older (median 70 years, interquartile range [IQR] 67-75 versus median 61 years, IQR 52-66; P<0.01), and required a longer duration of ventilation (26 days, IQR 12-27 vs 8 days, IQR 5-15; P<0.01) and intensive care unit support (26 days, IQR 11-30 vs 11.5 days, IQR 7-17.3; P=0.01), with a higher incidence of acute kidney injury (15 patients [100%] vs 40 patients [46%]; P<0.01). There were 67 patients who had lung compliance data; 24 (35.8%) were classified as having high compliance and 43 (64.2%) as having low compliance. Mortality was higher in patients with high compliance (33.3% vs 11.6%; P=0.03), and was associated with a drop in compliance at day 7 (-9.3mL/cm H2O (IQR -4.5 to -15.4) vs 0.2mL/cm H2O (4.7 to -5.2) P=0.04). CONCLUSION: COVID-19 ARDS patients with higher compliance on the day of intubation and a longitudinal decrease over time had a higher risk of death.