First, I am not a respiratory therapist and you should definetely talk to them first and or your doctor. But I delivered Medical O2 for about 6 years. Sounds like you might be on Liquid (LOX) with a converter. Great system if you lose electrical power. You still have O2.
Inogen....things to consider
Litre Flow- What do you require? Some machines may not give you what you need.
Pulse Dose or Continous flow. Pulse dose means you get a shot of O2 when you inhale through the nasal cannula. Continous means always O2 flowing. Big consideration with battery life!
I know the commercials on TV are making it sound great, but I would also ask about maintenance and what happens during a failure.
I am the guy who was on call during those 6 years and was delivering O2 tanks at all hours of the night, because of power outages. At best the Inogen would run 3-4 hours on a full battery.
So bottom line, in my opinion, it is a portable oxygen concentrator, that is being sold as a complete solution. They are convenient but may not give you the O2 you need when required.
My husband and I both have sleep apnea and are on oxygen at night and we have an oxygen concentrator. It is a huge thing, but they make portable ones. We do have an oxygen tank for backup in case of power outages, though. It has been very reliable. We had to replace it after about five years...that seems to be about the life span. Medicare covered it.
I am on 03 units and have been for a long time. I only use it at night. I am supposed to use it in the day also but it slows me down. I do wood working and have a big garden and have 5 beef munching on my pasture. I am a light sleeper and my tank makes noise, I want quiet.
A concentrator is NOT quiet. But most people put the actual concentrator in another room and just run a long oxygen line into the bedroom. The noise doesn't bother us, so the concentrator is in the bedroom, but my sister in law puts hers in another room. But it is a big home concentrator. A portable might not be noisy. Ours is also set at three for my husband and we have a "Y" splitter with an in-line regulator for my side reducing it to one.