Static Compliance and Driving Pressure are Associated with ICU Mortality in Intubated COVID-19 ARDS

Abstract Background: ascertaining whether respiratory system static compliance (Crs), driving pressure (DP), and tidal volume normalized for ideal body weight (VT/kg IBW) at the 1st day of controlled mechanical ventilation (CMV) are associated with intensive care unit (ICU) mortality in COVID-19 acute respiratory distress syndrome (ARDS).Methods: observational multicenter cohort study. All consecutive COVID-19 adult patients admitted to 25 ICUs belonging to the COVID-19 VENETO ICU network (February 28th-April 28th, 2020), who received CMV, were screened. Only patients fulfilling ARDS criteria and with complete records of Crs, DP and VT/kg IBW within the 1st day of CMV were included. Crs, DP and VT/kg IBW were collected in sedated, paralyzed and supine patients.Results: 704 COVID-19 patients were screened and 241 enrolled. Seventy-one patients (29%) died in ICU. The logistic regression analysis showed that: i) Crs was not linearly associated with ICU mortality (p-value for non-linearity=0.01), with a greater risk of death for values <48 ml/cmH2O; ii) the association between DP and ICU mortality was linear (p-value for non-linearity=0.68), and increasing DP from 10 to 14 cmH2O caused significant higher odds of in-ICU death (OR 1.45, 95%CI 1.06-1.99); iii) VT/kg IBW was not associated with a significant increase of the risk of death (OR 0.92, 95%CI 0.55-1.52). Multivariable analysis confirmed these findings.Conclusions: Crs <48 ml/cmH2O was associated with ICU mortality, while DP was linearly associated with mortality. DP should be kept as low as possible, even in the case of relatively preserved Crs, irrespective of VT/kg IBW, to reduce the risk of death.