Most patients who require extracorporeal membrane oxygenation (ECMO) for severe COVID-19 survive, according to an international registry.
Estimated 90-day in-hospital mortality was 37.4%, and mortality among those who completed their hospitalization (final disposition of death or discharge) was 39%.
“These data from 213 hospitals worldwide provide a generalizable estimate of ECMO mortality in the setting of COVID-19,” wrote Ryan Barbaro, MD, of the University of Michigan in Ann Arbor, and colleagues reporting the findings in The Lancet. The data were also presented at the virtual Extracorporeal Life Support Organization meeting.
Early reports of ECMO use in COVID-19 suggested that mortality could be greater than 90%, leading some to recommend withholding it, the group noted. More recent reports have suggested higher success rates, albeit with small numbers.
“Considering the severity of hypoxemia in patients requiring ECMO, I’m intrigued by noting that at least 40% (if probably not more) had some reasonable recovery,” commented Behnood Bikdeli, MD, of Brigham and Women’s Hospital and Harvard in Boston.
The findings were “consistent with previously reported survival rates in acute hypoxaemic respiratory failure, supporting current recommendations that centres experienced in ECMO should consider its use in refractory COVID-19-related respiratory failure,” the researchers concluded.
However, there was no comparator data for outcomes in a similar cohort of patients who did not undergo ECMO, Bikdeli noted. “Such an analysis likely requires a second data source, and exclusion of some patients (sickest of the sick) but could be informative.”
The study included 1,035 patients age 16 years and older with confirmed COVID-19 who had ECMO support initiated between Jan. 16 and May 1, 2020, at 213 hospitals in 36 countries, as recorded in the Extracorporeal Life Support Organization Registry.
The median age of these patients was 49, most were men (74%), and 70% had been treated elsewhere before being transferred to the registry-participating hospital (47% of these had ECMO initiated before transfer).
Patients’ status at data cutoff was 6% still hospitalized, 30% discharged home or to an acute rehabilitation center, 10% discharged to a long-term acute care center or unspecified location, 17% transferred to another hospital, and 37% deceased.
Fully 94% of the patients got venovenous ECMO support. Venovenous ECMO for acute respiratory distress syndrome patients had an estimated 90-day in-hospital mortality rate of 38.0%.
Independent predictors of mortality in ECMO-supported patients with COVID-19 were: age, immunocompromised state, chronic respiratory disease, pre-ECMO cardiac arrest, degree of hypoxemia, presence of acute kidney injury, and use of ECMO for temporary circulatory support (venoarterial rather than venovenous ECMO support).
“Strengths of this study include the breadth of international participation and its use of experienced and trained Extracorporeal Life Support Organization site data managers to collect data,” the researchers wrote. Also, the time-to-event analysis accounted for potential bias when not all patients have reached final disposition.
Limitations included the “self-selected” experienced centers that participated in the registry, which may not be generalizable to those inexperienced with ECMO. Also, the final outcome 90 days after ECMO initiation was unknown for patients discharged home or to an acute rehabilitation center, long-term acute center, or another hospital. But, the researchers noted, for patients who survived to hospital day 40 or beyond and remained there, “estimated in-hospital mortality 90 days after the initiation of ECMO was 14.1%.”
Barbaro disclosed being Extracorporeal Life Support Organization Registry chair and receiving grants from the National Institutes of Health.