As an aside, patients in acute pulmonary failure can be administered as much as 60 (sixty) liters/min!
Yes but for the drivers at home(or up the front) that's not because they consume that much, only to create a steeper pressure gradient and force more o2 across into the bloodstream when uptake capacity is dramatically reduced.
must we "add" 13 L/pilot/min. to 11 L/pilot/min. (i.e. 24 L/pilot/min. total) or simply "replace
Replace.
Exesss o2 intake is best avoided and is harmful also. Look up oxygen toxicity.