I checked Roberge et al 2010 and it seems they don't separate inhalation from exhalation in the gas measurements under the mask. I checked Sinkule et al 2012 a

I checked Roberge et al 2010 and it seems they don't separate inhalation from exhalation in the gas measurements under the mask. I checked Sinkule et al 2012 and it's quite hard to tell how the review got those numbers from that paper. Might check more when I have time later.