Have you considered using the Purritan-Bennett Lipseal instead of a face
mask? I have been using the Lipseal while sleeping for the past 18 years.
The Lipseal is similar to a scuba divers mouth piece except it sits on the
outside of your lips instead of inside your mouth. This leaves your face
free so you don't have that claustrophobic feeling. The only draw back to
this device is you have to make your own head strap to hold it on while
you're sleeping. The company sends you a head strap but it is made out of a
flimsy rubber band type of material which is not strong enough to hold the
mouth piece in place and it soon breaks. I make my head strap out of nylon
webbing with Velcro on one end for adjusting the tension and the metal hook
from the original head strap on the other end. Dr. Augusta Alba from NYU
Medical Center was the person who originally told me about this device.
Good luck.
Dan, pressing his lips against the seal.