Rationale

Severe cases of acute respiratory distress syndrome (ARDS) may require prolonged (>28 days) extracorporeal membrane oxygenation (ECMO). In non-resolving disease, recovery is uncertain and lung transplant may be proposed.

Objective

This study aims to identify the variables influencing survival and to describe the functional status of these patients at six months.

Methods

Retrospective multicentre observational cohort study including patients requiring ECMO support for COVID-19 related ARDS for more than 28 days. Multivariate analysis was performed using Cox regression in preselected variables and in LASSO (least absolute shrinkage and selection operator) selected variables. In a post-hoc analysis to account for confounders and differences in awake strategy usage by centers, treatement effects of the awake strategy were estimated using an augmented inverse probability weighting estimator with robust standard errors clustered by center.

Results

Between 15 March 2020 and 15 March 2021, 120 patients required ECMO for more than 28 days. Sixty-four patients (53.3%) survived decannulation, 62 (51.7%) were alive at hospital discharge and 61 (50.8%) were alive at six-month follow-up. In the multivariate analysis, age (1.09; 95% CI 1.03-1.15, p=0.002) and an awake ECMO strategy (defined as as the patient being awake, cooperative, and performing rehabilitation and physiotherapy with or without invasive mechanical ventilation at any time during the extracorporeal support) (0.14 95% CI 0.03-0.47; p=0.003) were found to be predictors of hospital survival. At six months, 51 (42.5%) patients were at home, 42 (84.3%) of them without oxygen therapy. A cut-off point of 47 ECMO days had a 100% [95% CI 76.8-100] sensitivity and 60% [95% CI 44.3-73.6] specificity for oxygen therapy at six months, with 100% specificity being found in 97 days.

Conclusions

COVID-19 patients who require ECMO for more than 28 days can survive with non-limiting lung impairment. Age and an awake ECMO strategy may be associated with survival. Longer duration of support correlates with need for oxygen therapy at six months.