[jacquesm]

I see where you're coming from I assume that you are talking about the device resistance when breathing in and you're worried that the adhesion between the lung sac and the cavity wall breaks.

You can pull a pretty good vacuum with just your lungs, so I'm not overly worried about that. And pressure is not a problem unless you have a weak spot in your lung.

But still, it's a good point to make and maybe the author could measure the flow resistance in both directions and optimize for that to ensure that it never becomes a problem, even in people that might have a hidden defect.

[newaccount74]

But the device resistance won't be very big, would it? If I understand correctly, you are just breathing through a tube, and this device measures the flow through the tube. Or is there something in the tube that would cause a lot of resistance?

[danielheath]

Adding some resistance is typically how you measure flow.