“It’s just a bridge to keep them going,” Marco Garrone, an emergency-medicine physician in Turin, Italy, told The Daily Beast. “It’s just a sort of last-ditch resort to buy time for them to heal… for the whole body to overcome the illness.”

But unlike with some other respiratory diseases, there is no proven treatment for COVID-19. Doctors around the globe have reported survival numbers that show how difficult it is for an intubated patient to outrace the disease. Garrone and his colleagues say only 20 percent make it, while a London study found a slightly larger proportion.

“These patients do extremely badly on mechanical vents,” Garrone said. At the same time, ventilators also represent the only hope for those whose oxygen levels continue to plunge—explaining why U.S. governors are so desperate to make sure they have enough.