A couple of years ago, I switched to APAP, thinking it would be more precise, and also cure my occasional burping issues. Well, in the last week, I've been awakened twice because of burping. Last night, when I checked my pressure during this episode, it was at 19! I've never been prescribed higher than 15, so I'm sure it was too high. But, why? Something wrong with the machine? Could it be my chin strap is too loose? (It doesn't feel like it.) Could my nose be stuffy without me realizing it? I don't get it. What should I do?