I have emphysema and was recently hospitalized for 4 days with a bad cough. While I was there the doctors assigned a home ox concentrator for me. This is my first experience with one at home. The one I have is ancient--the bottom machine is about 3 ft tall and makes puffing and moaning sounds! The "portable" canister I have weighs a ton. Since I am hoping to join my family in Iowa on July 24, I need some advice about a more practical version of this portable device. Help!