How to qualify for BiPAP

I believe that to qualify for bipap:

1.  Patient must be able to spontaneous breath
2.  Patient must not crash when you take them off. 

#2 there is something that's often overlooked.  Many times I've put someone on a BiPAP because their SpO2 was low and as soon as you take them off to give them a drink of water their SPo2 drops.  If they crash when you take them off the BiPAP you now have two choices:

1.  Intubate
2.  Make the patient a DNR

I can see some good arguments for this discussion, however, I have never seen a patient who could not come off the BiPAP survive unless intubated.  It's just not a good situation.  It's basically a tortuous way to end your life.