Higher AHI with Full-face vs. nasal mask

scuba-do · Post by **scuba-do** » Sun Mar 19, 2006 8:36 pm

Is there any reason that my AHI would be higher on a full-face mask (Ultra-Mirage) vs. a nasal mask (Activa)? I decided to try the Ultra-Mirage because I was noticing a mouth leak with the Activa but also in case of a cold. It is actually quite comfortable, and I feel as though I can breath quite freely with it so decided I might just use it as a first-line mask. However, my AHI went from 2 to 5. I know that is still ok but concerned about using it now because I felt so good with the Activa.

twistedcherokee · Post by **twistedcherokee** » Sun Mar 19, 2006 8:50 pm

Possiblly the pressure needs to be adjusted. I went from a FF to the Oracal II and needed to lower mine back down.

Toby

NightHawkeye · Post by **NightHawkeye** » Sun Mar 19, 2006 9:10 pm

scuba-do wrote:Is there any reason that my AHI would be higher on a full-face mask (Ultra-Mirage) vs. a nasal mask (Activa)?

There is at least one good reason it can happen. If you're susceptible to the full face mask pushing your jaw back, it can induce apneas. That's what happened to me with a full face mask.

I posted about it here: viewtopic.php?p=61989&

Don't know if that's your problem or not, but it does happen.

Regards,
Bill

Snoredog · Post by **Snoredog** » Mon Mar 20, 2006 2:05 am

if those numbers are consistent over several nights I agree with Bill, the FF is probably pushing the mandible back causing more events or your getting more leaks, possibly a bit of both.

How do you feel the next day? I'd stick with the one you feel better with.

Guest · Post by **Guest** » Mon Mar 20, 2006 9:49 am

Thanks for the replies. I think that I will stick with the Activa. The leak was higher at times with the Ultra Mirage but the apneas/hypopneas don't correlate with when the leak was higher. I suspect that you are right about the mandible thing.

Guest · Post by **Guest** » Tue Mar 21, 2006 1:25 am

Do all full face masks push against the lower jaw? Isn't there one that seals under the chin? Has anyone used it?

NightHawkeye · Post by **NightHawkeye** » Tue Mar 21, 2006 5:50 am

Anonymous wrote:Do all full face masks push against the lower jaw? Isn't there one that seals under the chin? Has anyone used it?

Yes, they do, but it can vary. The physics of the situation is complicated, but there are basically two forces in play that work either separately, or in combination to push the lower jaw back. One force comes from the mask directly pushing the lower jaw back when you tighten the lower straps to prevent leaks. This is what I experienced, even though my Ultra Mirage FF mask sealed just at the edge of my lower lip. To prevent leaks I had to tighten the straps too much.

With the Fisher and Paykel you refer to, you'll get the force of the air pressure directly pushing against the lower jaw. Is this counteracted by the chin cup of the mask? I doubt it.

Will one FF mask work better for you? Probably. Doesn't look to me like there's a great deal of difference, but if you are set on getting a full face mask, then try 'em and see what works best. Don't forget the chin straps either. Try to get one that you think will work for you, because there are differences in chin straps also.

Regards,
Bill

jdacal · Post by **jdacal** » Sat Mar 25, 2006 1:20 am

I had this problem with my FF mask. My Snore index was like over 200 so the machine tended to run full blast.

When I switched to the Swift my snore index dropped really low (less than 40 I think, haven't checked in a while), and I also was able to run at lower pressure.

Higher AHI with Full-face vs. nasal mask

Higher AHI with Full-face vs. nasal mask

Re: Higher AHI with Full-face vs. nasal mask