My cats are deathly afraid of the machine and everything connected with it.

You all realize that Vicks inhalers are known to be addictive? Also spray decongestants can be addictive and then they lose their effectiveness - pretty sure the saline nose sprays do not become addictive

I just got my machine and the cats won't even come in the room till I take the mask off and turn it off - not that I am missing them waking me up at 5 AM but I wonder if they will learn to ignore it and start coming back in the room