Changing masks - need to change pressure??

If you go from a nasal mask to a full face mask, do you need to change your pressure?? It just seens that you are increasing the "air space" and thus decreasing the pressure. Maybe this is too logical

Thanks

Skittles

My understanding is, no you would not have to change the pressure setting. All the machines that I know about will automatically compensate for the difference in volume. ResMed machines have to have a similar mask with an exaust rate about the same programed in order for the leak rate readout to work but the pressure should be the same.

Jerry

Even if the CPAP machine had no feedback control and didn't try to maintain your pressure, it would not be mask volume that changed the pressure. It would be leak rate. If your CPAP is set at 11. If you hooked it up through a window to a space the size of a banquet hall that leaked no more than CPAP mask, the entire banquet hall would become 11 eventually. With the space the size of even a large mask, it only takes a fraction of second to get to pressure. Any delay probably has more to do with the spin up rate of the CPAP machine.

The only way a mask could affect pressure is if it leaked enough to cause a pressure loss that the machine could not compensate for.

I've tried some masks that I suspected got dislocated in my sleep. I seem to like to nussle half my face in my pillow when I'm on my side. Depending on the mask, this introduces a leak which disappears when I go to my back. So I think possible if you're feeling a difference in effectiveness of a mask, its more to do with leaking than anything else.

John_dozer, this as a great explanation! I always figured no changes were needed, since I never read anything about it, but your explanation made it extremely clear. Thank you!

Thanks everyone for your help -- I have so many questions, and you all have been very patient in answering for me

Take Care

Skittles