The results vary widely between hospitals. Overall, however, survival rates have decreased over time, including in large US and European hospitals. From January to May 2020, according to the international register, less than 40 percent of Covid patients died in the first 90 days after the start of ECMO. But more than half died in the months that followed. “The patients seem to be doing significantly worse,” said Dr. Barbaro.

He and his colleagues analyze whether this is related to factors such as new virus variants, less experienced care centers or changes in the treatment of patients before ECMO.

ECMO is offered in a few community hospitals that care for most Americans. The exception is Saint John’s, the Santa Monica facility where the doctor and police sergeant were treated.

An ECMO program started about a year before the advent of Covid-19. The 266-bed hospital provided therapy to 52 Covid patients during the pandemic, much like the entire Northwell healthcare system in New York, which has more than 6,000 hospital and long-term care beds.

The Saint John’s Charity Foundation, supported by the area’s affluent donor base, helped fund the ECMO program and its expansion. The hospital accepted some uninsured Covid patients for ECMO, while those patients elsewhere were often turned down despite a federal program that reimburses hospitals for their treatment.

“There are just so many inequalities,” said Dr. Hammond, director of the Saint John intensive care unit. And for every Covid patient who has survived with ECMO, there are “probably three, four, five people who will die on the waiting list”.

She and other doctors said the pandemic highlighted the need to make ECMO more widely available and less resource intensive. Until then, “we really need a sharing system,” she said. There are allocation systems for transplant organs and trauma care.