We don't oxygenate peds unless routinely below 90.    I'd also do a comparison test without a mask.  Some people drop with actiivity, so I'd be curious to see how they were after walking around or pushing a cart a similar amount of time but sans the mask. I'd also be curious as to the type of mask.  The neoprene type or other thicker matierial masks are far thicker than they need to be, the thin ones breath much better and still trap respiratory droplets, which is all they need to do.  Those using face wraps like scarves and the like are trapping much more CO2, like breathing into a pillow.