as always, when i readabout your breathing problems, i worry a lot about you. This heartbeat-fluctuation sounds to me like a key to keep you breathing through the night.
Have you considered getting or building a device, that monitors your heartbeat and sounds an alarm in the case of a longer time without breathing? I guess you could very easily make one yourself with something like an Arduino oder similar stuff.

There are devices that can force you to breathe, like what they use for brain dead people (since in that moment, I am for all functional intents “brain dead”), and my doctors have proposed putting me on them, but I have to admit that I really do not like the idea very much. It sounds very unpleasant.