in cfers when lung damage occurs they go on oxygen but not all people do. my daughter was reading 90 on no oxygen ,first started using it only at night, then we got to all the time as her fingers were turning blue. when she coughs her levels drop into the 80s .so to save her from any damage to her heart and other organs it was best to keep it on. dont know what your situation is but im sure your doc will tell you when to use it!as for my daughter we r in the process of getting on the transplant list!
