Commentary: Respiratory failure in patients with Coronavirus Disease 2019 infection: Can extracorporeal membrane oxygenation help?

COVID-19 image.

ECMO is an established supportive adjunct for patients with severe refractory ARDS from infectious pneumonia. However, the exact role and timing of ECMO for patients with COVID-19 and respiratory failure remain unclear but are evolving.

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In the current issue of the Journal, Hayanga and colleagues describe evolving approaches to the use of extracorporeal membrane oxygenation (ECMO) for treatment of advanced Coronavirus Disease 2019 (COVID-19) infections in patients with respiratory failure. ECMO can be used to treat patients with severe, refractory adult respiratory disease syndrome (ARDS) from viral pneumonia and a variety of infectious agents. However, the exact role and timing of ECMO for COVID-19 patients with respiratory failure remain unclear. ECMO may improve survival in certain patients with COVID-19 with intractable respiratory failure, but patient selection and procedure outcomes need better definition. Clinical findings suggest that ARDS from influenza is different than ARDS associated with COVID-19. In one study, crude in-hospital mortality was significantly higher in a COVID-19 cohort with respiratory failure compared with a patient cohort with influenza-related respiratory failure (65.6% [n = 21/32] vs 36.3% [n = 11/28], P = .041). The adjusted hazard ratio over 60 days for patients with COVID-19 was 2.81 (95% confidence interval [CI], 1.07-7.35) after adjusting for age, race, ECMO-associated organ failure, and Charlson Comorbidity Index. These preliminary findings with a fairly large patient cohort suggest that COVID-19 respiratory failure may have some unique features that portend worse outcomes from ARDS compared with other infectious agents.

To be fair, not all studies suggest differences in patient outcomes from respiratory failure between influenza and COVID-19 infections. In one study, 35 patients with ARDS were selected for venovenous ECMO support out of 1849 adult patients in the intensive care unit with COVID-19 infection (1.9% incidence; 95% CI, 1.3-2.6). This represents 46 (95% CI, 34-61) expected patients on venovenous ECMO per 100,000 patients with COVID-19 and respiratory failure. In this study, there was no significant difference in survival between patients with COVID-19–related ARDS and influenza-related ARDS. It is likely that the criteria for ECMO in this study differed significantly compared with other reports of the use of ECMO for COVID-19 respiratory failure. For example, another contemporary study evaluated ECMO outcomes in patients with refractory ARDS associated with COVID-19 compared with respiratory failure from non–COVID-19 causes. This study found no differences in outcomes between COVID-19–related respiratory failure treated with ECMO compared with patients without COVID with refractory respiratory failure from multiple causes. This study emphasized the early use of ECMO in refractory respiratory failure in patients with COVID-19, especially because delay in institution of ECMO was nearly always fatal in this study.

It seems likely that as more experience with refractory COVID-19 respiratory failure is gained, then other advanced supportive options beyond venovenous ECMO will be used. As experience with ECMO in patients with COVID-19 expands, there is a suggestion that venovenous ECMO may not provide the best supportive option in some patients with COVID-19. One study found that 14 patients with COVID-19 and respiratory failure out of a cohort of 78 patients with COVID-19–related ARDS required conversion of venovenous ECMO to venoarterial ECMO or to hybrid ECMO.

Likewise, there may be other non-ECMO interventions that will modify COVID-19 infections and improve outcomes associated with advanced interventions like ECMO. For example, there is a trial ongoing that will evaluate the efficacy of cytokine adsorption in patients with COVID-19 as an adjunct to limit progressive organ damage from advanced COVID-19 infections. This type of adjunctive therapy during ECMO support may limit organ damage during aggressive support with other measures like ECMO. It seems likely that better definition of indications for, and choice of, supportive options for complicated COVID-19 respiratory failure will surface as experience evolves.

Given the current state of our knowledge of the treatments for respiratory failure in patients with COVID-19, it seems likely that better treatment algorithms and possibly better use of advanced supportive options will surface as the pandemic progresses. At present, further critical well-designed studies are needed to supplement existing knowledge.