Breathing Fluid is one of the main medicines in a rangers Bodysuit back pack.
When traveling to a new planet Breathing Fluid is required just in case the planets air is un-breathable. There are over 20 stalled on Hesper's that allow one for every member on board.
Nova Prime Medical Centre
They are also used on Nova Prime. If a person can not breath well they are given one of the fluids to fix them up.
Rangers use the Breathing Fluids in tasks on Nova Prime. They are kept in their backpacks, only five are stalled.