Physicians are finding themselves having to decide which critically ill COVID-19 patients will be able to use ECMO, potentially lifesaving therapy in short supply, reports the New York Times.

American doctors found themselves in the unfamiliar position of overtly rationing a treatment. But it was not ventilators, as initially feared: Concerted action largely headed off those shortages. Instead, it was the limited availability of ECMO — which requires expensive equipment similar in concept to a heart-lung machine and specially trained staff who can provide constant monitoring and one-on-one nursing — that forced stark choices among patients.

Doctors tried to select individuals most likely to benefit. But dozens of interviews with medical staff and patients across the country, and reporting inside five hospitals that provide ECMO, revealed that in the absence of regional sharing systems to ensure fairness and match resources to needs, hospitals and clinicians were left to apply differing criteria, with insurance coverage, geography and even personal appeals having an influence.

“It’s unsettling to have to make those kinds of decisions,” said Dr. Ryan Barbaro, a critical care physician in Michigan and head of an international registry of Covid-19 patients who have received ECMO—short for extracorporeal membrane oxygenation—about half of whom survived hospitalization.

Read more in the New York Times