[chazu]

I'm not a doctor, but I imagine that using this device on someone without any air in their lungs might cause some sort of bleeding or abrasion in the lung tissue. Of course, if I'm choking I ccould care less...

...I'm terrified of choking, fwiw.

[tripletmass]

Their lungs are cheerfully cranking out carbon dioxide for the chance to do it again, so running out of residual volume or pulling nitrogen into gas has a lot of give. So you're the one with the strong negative response when people suggest hitting an exercise heart rate and recovering with solid food (root vegetables,) eh?