A parallel to this
"ResMed recommends only using medical devices that have been approved by regulatory bodies who have jurisdiction for their particular countries,"
Imagine this in terms of cars:-
1) you've been driving it for months, but the MOT expired yesterday.
2) your headlight is broken, so failed the MOT
In both cases, your car is "not approved by regulatory bodies". If you drive it on the public road, you're breaking the law. And normally, that would be a bad thing. You shouldn't go for a holiday to Dorset in a car like that. But let's say a homocidal maniac is chasing you with an axe, in daytime, in a remote farm with no phone. Are you going to get in the car to drive to the nearest safe town, or not?
Normally, the choice is excellent, regulated ventilator, or very good, unregulated ventilator, and while I have some problems with the regulatory bullshit in medicine, that's normally fine. But we have a choice of very good, unregulated ventilator, or no ventilator.