I was in the hospital last week for bronchitis. Now I have oxygen at home with instructions to not use if oxygen is lower than 88%. I use it when it's over 88%. Since it is rarely under 88%, how can I track what my level is? I have an oximiter which is the only way to know for sure. And, is it dangerous to not use oxygen if it falls below 88? I have a lot to learn. Thanks a bunch.