Experience with providing ECMO support may influence COVID-19 related mortality

1. Mortality rate increased from 36.9% to 51.9% from early 2020 (before May 1) to late 2020 (after May 2) for COVID-19 patients treated with ECMO.

2. Experienced centers in delivering ECMO had an almost 50% reduced mortality rate compared to inexperienced centers.

Evidence Rating Level: 2 (Good)

Study Rundown: ECMO (Extracorporeal membrane oxygenation) is a complex procedure in which a patient is connected to a machine that functions as the patient’s external heart and lungs. ECMO is a form of life support that allows time for the body to heal during acute respiratory distress, such as with COVID-19. ECMO was originally not recommended for the management of COVID-19, but subsequent studies supported its usage later in 2020. In this international study, the mortality of patients with COVID-19 placed on ECMO was collected from the ELSO registry and analyzed. Eligible patients were divided in three groups based on the center and time in which they received ECMO: before May 1^st, 2020, from “early-adopting” centers (A1), after May 2^nd, 2020 at the same “early-adopting” centers (A2), and after May 2^nd at “late-adopting” centers which had not used ECMO previously for COVID-19 (B). Results showed that in-hospital mortality was significantly increased for COVID-19 patients receiving ECMO in the latter half of 2020 compared to the former. A limitation of this study is the lack of results related to disease severity of these patients. One theory for the increase in mortality would be that the patients put on ECMO did not respond to treatments that were more established later in the pandemic, indicating a more treatment-resistant lung disease. Additionally, the increased mortality between cohorts A2 and B (early vs. late-adopting) potentially indicate the experience needed for ECMO, with a reduction in mortality of almost 50% in experienced versus non-experienced centers.  These results help guide the future usage of ECMO in COVID-19.

Click to read the study in the Lancet

Click to read an accompanying editorial in the Lancet

Relevant Reading: Poor survival with extracorporeal membrane oxygenation in acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19): Pooled analysis of early reports

In-Depth [retrospective cohort]: This study used patient data from over 349 centers across 41 countries. There were 4812 patients which were included based on a criterion of ≥16 years of age and placed on ECMO in 2020 with a confirmed diagnosis COVID-19. 1182 patients received ECMO before May 1^st, 2020 (A1) at “early-adopting” centers. 2824 patients received ECMO at the early-adopting centers after May 2^nd, 2020 – Dec 31^st, 2020 (A2). 806 patients received ECMO after May 2^nd at late-adopting centers that had not previously used COVID prior to May 1^st (B).  Parameters were based on the previous ELSO study from before May 1^st which found little evidence for the effectiveness of ECMO in COVID-19. Patients in all groups were roughly 50 years old and 74% male. The risk factors between all groups were comparable and data was adjusted accordingly. Later in 2020, patients were more likely to receive non-invasive ventilation before initiating ECMO. The primary outcome was in-hospital mortality 90 days after initiating ECMO, which was noted to be: A1) 36.9% (95% CI 34.1-39.7), A2) 51.9% (50.0-53.8), B) 58.9% (55.4-62.3). The length of time ECMO was placed was also longer in A2 compared to A1 (30.7 days vs. 27.1 days, respectively). Furthermore, Experienced ECMO centers had a relative risk of mortality of 0.56 compared to that of inexperienced centers.

Image: PD

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