When I awake the throat of my mouth is coated with a soft film that is reddish brown and can be scraped off with your finger. My lips have a dried cracked substance that looks like blood. The Nurse Practitioner at the sleep center looked at my throat to see if she saw any sign of thrush and she did not. She said she has not seen anything like this before. When I blow my nose my sinuses are clear. Does anyone have any idea what this could be?

Probably just brown gunk from the changes in the mouth when we mouth breathe which dries out the normal saliva.

Add some sort of oral hydration product to your bedtime routine.

Now you might try increasing the humidity setting on your machine if you can. Sometimes that will help...sometimes not but worth trying.
The problem is the oral cavity is so large that the humidity put out even at maximum simply can't keep the mouth well hydrated. Sometimes medication side effects or other health issues just make the mouth dry out faster. The humidifier was originally designed to help with the nasal cavity which is much smaller and easier to keep hydrated.

So if not using humidity...use it. If at a lower setting...increase the setting...if already at max setting...add a mouth hydrating product to nightly routing. There are many available out there and it's trial and error figuring out what works well for you.

Thanks. I have humidity so I will check the setting and I will get some kind of oral hydrating mouth wash.