I would suggest that you find a center where they do the valves and/or lung volume reduction surgery. You can probably get tested for both or either at the same time. You do have to qualify, as Sandra says, so you won't know it either is an option until you've been evaluated. If neither is an option, a lung transplant is the only thing left at this point. Again, you will need to find a center that does them and be evaluated. Then you'll know enough to be able to make a fully informed decision about that. Until you really understand what's involved, you don't have enough information.

I have stage 4 COPD, I have looked into the zephyr valve and lung reduction surgery, I was not a candidate for either, so for now I am taking trilogy inhaler and trying to stay active, I use oxygen when I need it, and always when I sleep. I still can do alot, I just everything much slower, lol.
My doctor would like me to have lung replacement, I'm just not ready for that yet. Good luck, try and see if u are a candidate for the zephyr valve, that's where I would start and stay as active as u can.

I don't have stage 4 yet, but I know some people have used Google.com or Bing.com or right on this sight if you click on the 3 gray lines on the upper left side of any page, click on them. Then a drop down menu will appear and you will click on resources; there are many good articles about COPD on there.