During the flu pandemic of 2009—when large numbers of patients were hospitalized with severe respiratory failure—many doctors turned to a type of life support system called ECMO.

ECMO (short for extracorporeal membrane oxygenation) can act as an artificial lung but is more invasive than mechanical respirators—and more complicated to administer. Despite the extra risk and effort, many believed ECMO saved the lives of people struggling with acute respiratory distress syndrome (ARDS), which is associated with a mortality rate that can exceed 50% in the more severe cases.

The use of ECMO for patients with ARDS increased rapidly after the pandemic, but many experts still had considerable doubt that the existing evidence justified its use.

Daniel Brodie, MD, director of the Adult ECMO Program at Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, participated in the design of a clinical trial seeking to provide more answers. The results, published last month in the New England Journal of Medicine, answered some questions, but others still linger.

The CUIMC Newsroom recently spoke with Dr. Brodie about the trial, called EOLIA.

What is ECMO and why are doctors using it more and more?

ECMO is a device used to support patients with severe pulmonary or cardiac failure. In the setting of respiratory failure, which was the indication for its use in the EOLIA trial, ECMO acts as an artificial lung, delivering oxygen to the blood and removing carbon dioxide via a membrane outside the body.

ECMO may be used to support patients with low levels of oxygen or high levels of carbon dioxide in their blood that cannot be adequately managed with conventional invasive mechanical ventilation or other traditional techniques.

Why was a new study of ECMO needed?

The influenza pandemic in 2009 and the publication of the CESAR trial that same year had created great enthusiasm for providing ECMO in the most severe cases of ARDS, yet methodological issues limited the strength of conclusions that could be drawn from these studies.

The EOLIA trial sought to build on prior work, in part, by ensuring that investigators adhered as much as possible to best clinical practices for patients in both the ECMO and control groups.

The patients included in the EOLIA trial had the most severe forms of ARDS, a small portion of the approximately 140,000 cases of ARDS that occur annually in the United States, with the highest expected mortality. Patients had an average age in the 50s, and the predominant cause of ARDS was bacterial or viral pneumonia.

What’s your own experience with ECMO?

Our ECMO program at NewYork-Presbyterian/Columbia is one of the largest and most innovative programs in the country. We have been using ECMO here since the 1980s.

In the last decade, we greatly expanded our adult ECMO program as advances in technology made ECMO safer. We use ECMO on over 200 patients a year. In 2017, our program was designated a Platinum Level Center of Excellence in Life Support by the Extracorporeal Life Support Organization (ELSO). Worldwide, only three adult ECMO centers were awarded platinum status that year, the first in which it was ever awarded.

The results of EOLIA have been described as negative in some ways, but positive in others. What’s your take?

The EOLIA trial randomized patients with very severe ARDS to standard-of-care conventional management or ECMO combined with very lung-protective ventilation. We compared each group’s mortality at 60 days (mortality was 46% in the conventionally managed group and 35% in the ECMO group), but the difference did not meet statistical significance (p = 0.09).

When looking at the totality of the results, however, there are positive conclusions that can be drawn. A significant number of patients randomized to the control group (28%) seemed to the clinicians caring for them to be failing conventional management and “crossed over” to receive ECMO as salvage therapy. The key secondary endpoint of treatment failure at 60 days (defined as death in the ECMO group and death or crossover to ECMO in the control group) showed a statistically significant benefit in favor of the ECMO group.

ECMO also was well-tolerated, with a lower than expected rate of serious side effects.

Will the study change the way doctors use ECMO? And where does the field go from here?

It is too early to say whether the EOLIA trial will fundamentally change the way ECMO is used in clinical practice.

However, I do think that it will provide clinicians with some level of security that the use of ECMO is not overtly harming their patients relative to standard of care and can be justified if they believe it’s in their patient’s best interest.

Perhaps this study may also encourage a more structured approach to the organization of ECMO programs. However, there is still much more to learn about when to initiate ECMO during ARDS and how best to manage patients once they are receiving ECMO support.

It’s important to note that the EOLIA trial focused on one particular application of ECMO: its use in adults with very severe forms of ARDS. There is still much to be understood about ECMO for different indications, including its role in patients with severe cardiac failure.