The main criticism I see here is that without prolonged testing it's very possible for a piece of equipment like this to do harm to a person. On the other side

The main criticism I see here is that without prolonged testing it's very possible for a piece of equipment like this to do harm to a person. On the other side I see people saying that for those that can't get a ventilator and are going to die anyway, why not use it. I'm curious if that category of patients exists though. With Covid are doctors able to make that call at any point? I've heard lot of Hail Mary treatments criticized because unlike in the movies there are many ailments where there's not really a clear point where someone's not coming back. Anyone know if it's a common scenario with this where a doctor knows someone is def going to die but there is still time left to do meaningful treatment?