Background: COVID-19-associated ARDS supported by vv-ECMO results in a high in-hospital mortality rate of more than 35%. However, after cannulation, no prognostic factor has been described to guide the management of these patients. The objective was to assess the association between static respiratory compliance over the first 10 days post vv-ECMO implantation on 180-day mortality.

Methods: In a multicentric retrospective study from three ECMO referral centres, all patients with COVID-19-associated ARDS supported by vv-ECMO were included from 03/01/2020 to 12/31/2021. Patients were ventilated with ultra-protective settings targeting a driving pressure lower than 15 cmH2O.

Results: 122 patients were included. Median age was 59 IQR (52 ? 64), 83 (68%) were male, with a median body mass index of 33 (28 ? 37) kg/m2. 6-month death was 48%. Over the first ten days, compliance increased in 180-day survivors (from 18 (12 ? 25) to 20 (15 ? 27) mL/cmH2O) compared to non-survivors (from 12 (9 ? 20) to 10 (8 ? 14) mL/cmH2O, p interaction< 0.0001). A time varying multivariable Cox model found age, history of chronic lung disease, compliance from day 1 to day 10 and sweep gas flow from day 1 to day 10 as independent factors associated with 180-day mortality.

Conclusions: In COVID-19 associated ARDS, static respiratory compliance course over the first ten days post vv-ECMO implantation is associated with 180-day mortality.