[Jim-]

I wonder if it will actually get built and used due to the critical nature of the Medical Field, even amidst this emergency.

The good thing; at least you'll have a working Ventilator.

On the other, your life depends on this frankenstein'd together machine made with hospital spare parts.

[bayesian_horse]

It's not as bad as you think. The ventilator is only one part of the solution. There are also sensors for heart rate and oxygen consumption, maybe even CO2 (though that's expensive) and Human beings involved in monitoring everything.

First, most of these patients are probably not completely breathing-depressed to the point they don't breathe on their own at all. That extends the time necessary to fix anything.

If indeed one of these ventilators malfunctions, it is probably visible at once. In case of loss-of-function an operator can immediately grab the bag and resume ventilation. In other failures he can disconnect the device and reconnect a non-mechanized manual bag in seconds.

This can even be done by volunteers with minimal training, in such emergency situations.