My mom has severe emphysema, and has been on continuous O2 for 2 years, delivered through nasal cannula at 3L. She is s/p CVA, CHF, and
mild MI. She also has chronic pancreatitis
(s/p alcoholism)and HTN. She still smokes about a pack of cigarettes per/day. When on O2 her sats can be as high as 98%. When off of O2, she can go into the 70s. She is constantly using "pursed lip breathing", has a chronic, productive cough, and a barreled chest.