The life-support system called ECMO may save COVID-19 patients from the brink of death, but not at the rates seen at the start of the pandemic, according to a new international study.
While about 60% of those patients survived at least 90 days in the spring of 2020, by the end of the year they were just under half.
The decrease in survival over time could be due to a combination of factors, including the critically ill patients that clinicians chose to place on ECMO as the pandemic continued, and the treatments that the patients had. received before starting ECMO.
The new findings show how important it is for hospitals that offer ECMO to carefully choose patients who have access to this labor-intensive level of care, according to the authors.
Hospitals should also develop policies that can guide such choices when ECMO circuits are in high demand due to a pandemic outbreak, they advise.
The new findings are published in Lancet by an international team co-led by ECMO experts from the University of Michigan, Singapore and Columbia University. The document uses data from more than 4,800 patients over the age of 16 who were treated with ECMO for advanced COVID-19 in 41 countries in 2020.
Data for the study was provided by the ECMO centers to a registry maintained by ELSO, an international organization dedicated to ECMO and other forms of advanced life-saving assistance.
A last-ditch option
ECMO, short for extracorporeal membrane oxygenation, has been used for decades in some hospitals to treat critically ill children and adults. It temporarily takes over both the heart and the lungs, circulating blood outside the body under the constant supervision of trained providers.
At the start of the pandemic, some experts had strong reservations about placing COVID-19 patients on ECMO for fear of harming their lungs. As more centers began to try it, the survival rate mirrored that of using ECMO in other forms of acute lung failure, as the team reported at the origin of the new article a year ago.
But all of the centers in that first study had started offering ECMO before May 2020, and most were very experienced in providing ECMO in general, says Ryan Barbaro, MD, MS, co-first author of the new paper, associate professor. at UM School of Medicine and Critical Care Physician at Michigan Medicine, UM’s academic medical center.
The new study divides patients into three groups: those treated before May 1, 2020, those treated in these early adopters hospitals after May 1, and those treated with ECMO in other hospitals from May 1 to the end of 2020. May 1 was chosen because the evidence for how best to treat critically ill COVID-19 patients had evolved significantly by that time.
“What we noticed right away was that patients treated later in the pandemic were staying on ECMO longer, going from an average of 14 days to 20 days. They were dying more often and those deaths were different.” , said Barbaro. “It shows that we need to think about who we put on ECMO and when we make the decision to remove patients who are not doing better. In the United States right now, we have places where ECMO is scarce while in the Michigan it’s not quite at this point, but we anticipate it could be. ”
In early adopter centers, mortality rates fell from 37% in the months before May, to 52% after May. In centers that did not start providing ECMO until at least May, 58% of patients died within 90 days of starting ECMO.
Patients treated with ECMO later in the pandemic were more likely to have received drugs such as remdesivir and dexamethasone, and to have received non-invasive ventilation before being intubated for full respiratory support.
Decisions and ethics during an outbreak
Keeping patients on ECMO longer takes up many resources, including the machines and tubes that make up an ECMO circuit, as well as the specially trained nurses, respiratory therapists and other staff needed to ensure the safe operation of the system. ‘a circuit.
When a hospital has a large number of patients with COVID-19 and others in intensive care, the team’s ability to provide the same level of care as before the outbreak may suffer and mortality may increase.
If many hospitals in a region or set of states are dealing with a large number of critically ill COVID-19 patients, it can be difficult to find an ECMO-enabled hospital to refer patients to. Sending more ECMO circuits – the pumps, tubes and controllers used in treatment – to these hospitals is not enough; specially trained teams, adequate blood supply and other factors are all needed to support every ECMO patient.
So, say the authors, it’s important for ECMO centers to carefully consider risk factors and personal characteristics that might make a patient more or less likely to survive if placed on ECMO, especially if he may need. to stay that way for a while. ELSO offers resources and guidelines that can help you.
The research team used methods developed by UM School of Public Health statistician Philip Boonstra to fit the data to make apples-to-apples comparisons. This allowed them to ensure, for example, that survival percentages were not affected by the fact that so many more patients were transferred out of their ECMO hospitals later in the pandemic than at the start.
In addition to working on the ELSO COVID-19 registry, Barbaro is leading a clinical observational study called ASCEND that tracks ECMO results in children and adolescents in nearly 100 hospitals around the world. While the Delta variant of the new coronavirus spreads rapidly, the research team has already noticed that the majority of pediatric patients placed on ECMO right now need it because of COVID-19.
“In these times of crisis, our ability to respond to demand presents ethical challenges, and COVID has brought out the weaknesses in our system, as well as showing how those with resources and loved ones who can advocate on their behalf are more able to learn about ECMO and seek the opportunity to care for their loved one, ”said Barbaro. “Meanwhile, hospitals in non-emergency areas need to think about the policies and procedures they will use if they experience another raise, in order to foster ethical allocation when resources are limited. “