CPAP and nasal congestion

You might consider going to an Ear, Nose and Throat doctor to see if you have enlarged turbinates.  These are fleshy things in your sinuses that warm and humidify the air inhaled through your nose.  When you lie down, sometimes they become engorged with blood (cause they are a type of erectile tissue apparently).  Some peoples turbinates get enlarged and never get any smaller, so when they become engorged, you feel like you need to use Afrin, or something similar.

If this is the case, the doctor will put you under general anesthesia, and basically roto-rooter out your turbinates to make them smaller.  You won't feel better immediately because the tissue inside will be swollen and covered with scabs.  After about 6 weeks, though, you will be able to lie down and breath through your nose.

You might also consider getting one of those mouth appliances that pull your jaw forward while you sleep.

I got on the CPAP and had the kind of mask that just goes over the nose.  The pulmonary PA kept having a dang hissy fit because I was using Afrin.  She gave me two other medicines, Flonase and something else, but they actually made my nose block up even more!  She never had any other suggestions other than to just say that I shouldn't be using Afrin, she would never allow it in her home, and on and on.

Finally, on my own, I decided to see an ENT because I had my  nose broken years previous and thought maybe I had a deviated septum.  Went to see the ENT and that's when I found out about the turbinates.  The ENT also suggested that I see a dentist who makes mouth appliances for people who have sleep apnea.  All this has helped immensely.

I'm just still so aggravated with the pulmonary PA.  I went there so that THEY could figure out how to  help me breathe better.  What about other people with the same problem?  I'm sure they are still getting berated by that PA and struggling to breathe at night.

Hehe, sorry about that rant!   Bitter much?  Grr!

Well, good luck!  I hope you find the answer to your question!

Fluticasone Propoionate Nasal Spray!  (Flonase)   Its a common steroidal prescription nasal spray and is used in CPAP therapy alot, it is not habit forming, like some sprays.   It could be allergies, a cold, too much humidity, swelling.... but whatever it is, you still need your sleep.  Ask your primary care Doc, about it and see if it makes sense for you.  

I love my CPAP and wouldn't sleep without it. 

Buy a neti pot and use it every night.  Play with your humidity setting -- too low irritates my nose, but too high causes congestion.