Extracorporeal membrane oxygenation without invasive mechanical ventilation for acute respiratory distress syndrome: an international cohort study

Rationale: In acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) without invasive mechanical ventilation (IMV) is particularly challenging. Objectives: To study ARDS patients treated with ECMO to avoid IMV-'primary awake ECMO'-or with extubation during ECMO support - 'extubated ECMO'. Methods: International retrospective cohort of adult ARDS patients treated with ECMO without IMV at 14 centers in 8 countries (2015-2024). The primary outcome was mortality 90 days after ECMO initiation. Measurements and main results: Among 307 adult patients with ARDS, 113 received 'primary awake ECMO' and 194 were extubated on ECMO. Ninety-day mortality was 30.1% in the 'primary awake ECMO' group and 14.9% in the 'extubated ECMO'. Strategy failure occurred in 46 patients (40.7%) and 47 patients (24.2%), respectively, most frequently within the first 10 days. In multivariate analysis, strategy failure was associated with 90-day mortality (hazard ratio 7.67 (3.44-17.11); P < .001 in 'extubated ECMO'; hazard ratio 5.95 (2.63-13.46); P < .001 in 'primary awake ECMO'), while higher age and longer time from ICU admission to ECMO cannulation were associated with 90-day mortality in 'extubated ECMO' and 'primary awake ECMO', respectively. The leading cause of strategy failure was worsening of respiratory failure, followed by agitation/delirium in 'primary awake ECMO' and inability to clear secretions in 'extubated ECMO'. Conclusions: Patients selected for 'primary awake ECMO' and 'extubated ECMO' presented different baseline characteristics, strategy failure, and 90-day mortality rates. However, strategy failure was consistently associated with 90-day mortality in both groups.