do full face masks all have nonrebreathable valves?

[mountaincat]

I have a Respironics REMstar Pro C-flex+ device and *very* much like that it backs off pressure on the exhale so I don't feel my breathing is being messed with. Have been using nasal mask (Fisher Paykel Zest) but would really do better with full face since I do turn onto my back in the night and my mouth opens. I tried a F&P Forma full face mask but the nonrebreathing valve stymies what I take to be the "flex" feature of the Respironics. Is this going to be the case with any full face mask, e.g. Quattro? Or even one from Respironics? Thanks for any comments!

[zonk]

welcome to the forum - Yes all full face masks have anti-asphyxia valve in case airflow to the mask blocked but full face masks are the most leaky

[PaulaO2]

Moved this to the main forum where more folks will see it and be able to either assist or benefit from it.

[archangle]

The anti-asphyxia valve should have no effect on FLEX. Why do you think it does?

The valve should stay closed unless the pressure in the hose drops to near zero and the CPAP machine shouldn't be able to "see" it at all.

It may very well affect the autostart feature on some CPAP machines, since the valve will be open in that case.

[mountaincat]

The anti-asphyxia valve should have no effect on FLEX. Why do you think it does?

Thank you for the reply, Archangle. I may have some incorrect understandings; let me try to reply to your post.

With my nasal mask I feel a welcome light assist on the inhale, but then a noticeable drop off for an effortless exhale. With the Forma full face mask, it was just like breathing with no mask. So I asked myself what was different.

I thought perhaps the one-way valve would prevent the adjustment because the big holes in the full face Forma release the exhale and the device thus can't know I'm even exhaling.

My picture was that the device was keeping the exact pressure (stepped up when I inhale because I was reducing pressure in the mask and reduced when I exhale because I am adding to the pressure in the mask). I was told by the DME respiratory therapist that my device measured exactly what I used and what I breathed back. With the big holes in the Forma and the one-way valve it seems the device can't know what's going on in the mask chamber.

Archangle: The valve should stay closed unless the pressure in the hose drops to near zero and the CPAP machine shouldn't be able to "see" it at all.

mountaincat: Perhaps I don't understand the valve. I thought it was to let air in but not out back to the device.

Archangle: It may very well affect the autostart feature on some CPAP machines, since the valve will be open in that case.

mountaincat: Yes, the Forma did prevent the autostart feature from working. A bit of a nuisance, but I can live with it.

[archangle]

Archangle: The valve should stay closed unless the pressure in the hose drops to near zero and the CPAP machine shouldn't be able to "see" it at all.

mountaincat: Perhaps I don't understand the valve. I thought it was to let air in but not out back to the device.

It's possible that the airflow and pressures are enough different with the FFM to keep flex from working or to make it work differently. It may just feel different with the nasal mask because the pressure is just in your nose in one case, and on the whole face in the other. You feel a difference in pressure between various body parts more than you feel overall pressure changes.

With no pressure in the hose, the valve opens up and you inhale and exhale air from the outside, not from the hose. It blocks air going or coming from the hose.

When the hose is pressurized, it forces the valve closed, and the mask is connected only to the hose. Air inhaled or exhaled only goes up or down the hose, not out through the valve into the outside air. It works like a mask without a valve at that point. (This ignores the "exhale" vents which leak a little bit of air all the time.

The valve should not open and close as you breathe, only when you turn the machine on and off.

By the way, you could argue whether the terms "open" and "closed" should be switched around from what I said. When the valve is "open" to the outside air, it's "closed" to the hose.

If you want the machine to autostart, it may work if you cover over the anti-asphyxia port with your hand and breathe in and out for a few breaths.

[zonk]

The AutoStart feature can be enabled when using full face masks on the newer upgraded S9 machines but not on the older machines like mine.

[archangle]

The AutoStart feature can be enabled when using full face masks on the newer upgraded S9 machines but not on the older machines like mine.

Interesting. I suspect that means that the software will enable you to turn on autostart if you've set the mask type to FFM on the menu. I'll bet it's still iffy on actually starting because the air tends to go in and out the vent rather than down the hose.

That is a good point that older S9 machines won't let you enable autostart if you tell the machine you have a FFM.

[mountaincat]

Thanks for the replies and explanations. I think I understand the valve now. As long as the device is blowing air the flaps open and block off the big holes, and the flaps stay open (closing the big holes) as long as the machine is on. Therefore I am connected to the device both when inhaling and exhaling, so the "flex" feature should work essentially the same as with the nasal mask. (But maybe less sensitive because a larger chamber and more tendency to leak.) Is this right?

[w7sot]

The AutoStart feature can be enabled when using full face masks on the newer upgraded S9 machines but not on the older machines like mine.

Interesting. I suspect that means that the software will enable you to turn on autostart if you've set the mask type to FFM on the menu. I'll bet it's still iffy on actually starting because the air tends to go in and out the vent rather than down the hose.

That is a good point that older S9 machines won't let you enable autostart if you tell the machine you have a FFM.

I have one of the newer S9 autosets, and I have not had any issues with the autostart, with the FFM, and with it set to FFM in the setting - the sutostart starts with in inhale from the mask - handy feature, it lets you get all settled into bed, then you pop the hose on - and the machine turns on for ya.