“COVID-19 is not like the flu at all,” says Dr. Chen Fu, clinical assistant professor of medicine at New York University Langone Medical Center, who has spent the pandemic working in the hospital’s critical-care ward. “We’re finding that these patients who are intubated with COVID-19 lung disease are extremely hard to take off the ventilator. It’s almost like a black hole.”

It’s largely this fact that is contributing to the nationwide shortage of ventilators, forcing doctors to make the kinds of existential choices—picking who gets to live and who must die—that both they and their patients would have been spared in the past. “In normal times we practice a sort of hopeful, benevolence-based medicine,” Fu says. “Whereas now we have to practice a sort of holistic justice-based medicine. I have to think about how to help society as a whole.”

That involves not just denying care to patients like Kraemer, but sometimes withdrawing it after it’s been provided. Fu and other members of the hospital staff recently faced one such mortal choice when they were treating a terminally ill patient on a high-flow ventilator—a step down from full intubation, and which is also in short supply as a result of the pandemic. The ventilator offered the dying patient not just comfort, but also a certain measure of end-of-life dignity. On another floor, however, a COVID-19 patient who had a greater chance of survival was panting for air and in desperate need of a high-flow ventilator. One machine, two patients, and Fu’s group had to make the call.