key: cord-0993085-8jq7rfb6
authors: Whebell, Stephen; Zhang, Joe; Lewis, Rebecca; Berry, Michael; Ledot, Stephane; Retter, Andrew; Camporota, Luigi
title: The need to define “who” rather than “if” for ECMO in COVID-19
date: 2022-05-17
journal: Intensive Care Med
DOI: 10.1007/s00134-022-06732-y
sha: ef7e74ca5e7164119289e7323e595b43db792b8c
doc_id: 993085
cord_uid: 8jq7rfb6

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ity of our results, and indeed any retrospective cohort study. The decision for ECMO initiation is complex and made more so by constantly evolving understanding of a novel disease. Our methodology found matches across a period of nearly a year, during which our understanding of coronavirus disease 2019 (COVID-19) developed, national selection criteria varied, and patient characteristics changed. It is likely these variances contributed to the finding of many close matches based on clinical and physiological data. The finite nature of ECMO as a resource must also be considered, and this was indeed at the forefront of clinicians' minds worldwide during this time. The United Kingdom (UK) significantly expanded its ECMO capacity, and due to collaboration between UK ECMO centres to facilitate "out of area" transfers and the establishment of "surge" centres, we are not aware of any patients being declined ECMO due to lack of availability. However, the observed closeness of matches must be a source of introspection. It is possible patients who would have benefited from, and should have received ECMO, remained untreated. We agree the "imperceptible difference" remains a concern, as analysable data may not paint the entire picture for all referrals. Despite this, we are re-assured by the factors discussed, and the significant degree of unmeasured confounding that would be required to nullify the treatment effect found.

This study focuses on treatment within a UK pathway, which concentrates care amongst experienced centres. Strict criteria led to a more 'well' starting population, compared to other studies demonstrating worse outcomes on ECMO. Despite this, we agree that it is hard to argue for limitation of ECMO provision. However, in this context, careful evaluation of ECMO initiation criteria must be undertaken to understand who will derive the most benefit. Future prospective research should focus on "who" not "if ".

Survival benefit of extracorporeal membrane oxygenation in severe COVID-19: "perceived futility" and potential underestimation of ECMO's effect

Where is the imperceptible difference?

Survival benefit of extracorporeal membrane oxygenation in severe COVID-19: a multi-centre-matched cohort study

Correction to: Survival benefit of extracorporeal membrane oxygenation in severe COVID-19: a multi-centre-matched cohort study

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