Thanks for the clarification. I think it would be helpful until you get the mucus under control just because it could help prevent you from having low oxygen at night, not knowing it and suffering the negative effects from it being low. If it is low during sleep that will impede healing. In an ideal world you wouldn’t need it of course but you are trying to get yourself back to a better baseline and are currently not in an ideal situation from how it sounds so I think it is temporarily going to be more of a positive in this situation. If you wear it while sleeping and wake up feeling more refreshed/better then you know it’s the right choice. You could always do some breathing exercises during the day as tolerated to help maintain good co2 levels. Correcting low oxygen seems pretty crucial right now. A setting of 2 liters brings the oxygen percentage breathed from 21% in normal room air up to approximately 28% so it’s still not a lot. Every 1 liter brings the oxygen up by 3-4% from room/ambient air so 3 liters would be about 31%, 4 liters about 35% ect. It’s not precise because depending on the rate and depth of breathing a person will entrain a little more or less ambient air and mix with and slightly dilute the pure oxygen being delivered. I hope that I explained that adequately.