My doctor says that my air is trapped in air pockets in my lungs, I have emphasima, stage 3 I think, and that their is a face mask I can wear at night, sometimes, that then will help me get air in my lungs. I m now on onygen 24/7 and even thou I register 97% ony in lungs, I still huff n puff and have difficulty breathing. What is the name of the face mask and where can I get it?