“It’s very concerning to see how many patients who require ventilation do not make it out of the hospital,” says Dr. Tiffany Osborn, a critical care specialist at Washington University in St. Louis who has been caring for coronavirus patients at Barnes-Jewish Hospital.

That concern is echoed by Negin Hajizadeh, a pulmonary critical care doctor at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell on Long Island, N.Y.

“We have had several patients between the hospitals across the Northwell system that have come off the breathing machine,” Hajizadeh says. “But the vast majority are unable to.”

The largest study so far to look at mortality among coronavirus patients on ventilators was done by the Intensive Care National Audit & Research Centre in London. It found that among 98 ventilated patients in the U.K., just 33 were discharged alive.