AHI double with FFM than nasal mask

[Hydrangea]

I am really curious about what is going on.  I had been using the Dreamwear nasal mask, and I've loved it.  But sometimes I need to breathe through my mouth here and there, so I recently got an Amara View FFM.  I used the Amara View 3 nights in a row, and then switched to the Dreamwear for 2 nights, and then switched to the Amara again last night. 

What I've found is that with the Amara View, my AHI is twice that with the Dreamwear.

Also, I found that my machine went into higher pressures with the Amara than with the Dreamwear. 

Is this normal?  Is it a personal thing for each person?  Or... is it something else?

Here are screenshots of my last 2 nights (1st is with Dreamwear, 2nd is with Amara View).  The previous 2 nights (where I also did 1 night Amara, 1 night Dreamwear) reflect this same pattern.






I've seen you ask some people what some possible variants might be, so I'll put out some here for you.  This is at sea-level, same location, same sleep partner.  For the 2 nights prior to these 2 nights, I saw this same pattern, and I was at 4,000 ft altitude with no sleep partner.  Because of that consistency of what I can see as only the mask being the variant, I felt confident coming here and asking your thoughts on if masks make a difference in AHI.

P.S.  Having a sleep partner who interrupts my sleep is a bummer.  I kinda want to suggest that everyone (IRL) goes and gets a sleep study!

[DeepBreathing]

I noticed that changing between the Quattro Air and the Simplus resulted in a small increase in AHI and slightly higher pressures. These are both full face masks but the Simplus has a much larger volume than the Quattro. It would seem reasonable that a similar change would be evident when going between a nasal mask and an FFM.

In any case the increase in AHI is very small in absolute terms so I wouldn't worry too much about it. Your machine should be able to compensate.

[Jimsp1]

I had the same experience. Even with low leak rates with the Amara View my AHI was averaging about 3. Immediately upon switching to the Dreamwear nasal mask my AHI dropped to under 1. My only theory is that the Amara was pushing slightly back on my jaw. In any event the Dreamwear is so much more pleasant to use even if the AHI hadn't dropped I would have stayed with the Dreamwear mask.

[Sleeprider]

Hydrangea, the difference in pressure and AHI between your nasal and FFM are not that unusual. First, your pressure is very very low. Considering the volume difference between nasal pillows and a FFM, the mask pressure will be lower in a FFM, especially with EPR or Flex active. I would not hesitate to increase the minimum pressure 2-3 cm for FFM use. In your case, I would also increase the maximum pressure to 12. Also, are you changing the mask type or resistance setting when making the mask change? Finally, your AHI is under 2, even with FFM, so none of this is very urgent, but if you want similar results, you will need more minimum pressure when using the full face.

[AshSF]

My pressure ranged from 7-14 while using a resmed f10 FFM.

On a P10, I use a constant 8 pressure and have lower AHIs.

[Hydrangea]

Hydrangea, the difference in pressure and AHI between your nasal and FFM are not that unusual.  First, your pressure is very very low.  Considering the volume difference between nasal pillows and a FFM, the mask pressure will be lower in a FFM, especially with EPR or Flex active.  I would not hesitate to increase the minimum pressure 2-3 cm for FFM use.  In your case, I would also increase the maximum pressure to 12.  Also, are you changing the mask type or resistance setting when making the mask change?   Finally, your AHI is under 2, even with FFM, so none of this is very urgent, but if you want similar results, you will need more minimum pressure when using the full face.

Thank you all for your input.  I was in the midst of chaos from moving, selling houses, etc., so I apologize for not responding.  But your responses were all very helpful to me... and I've been pondering them ever since.

Sleeprider - I've not changed the mask type or resistance setting because (at least according to the PR info I've found) both the Amara View and the DreamWear are an x1 for the DreamStation.  Honestly, that does not make sense to me, as (like others mentioned here) the volume in the two seems to be quite different.  But, who knows?!  So, no, I've not changed that when switching masks.  Would you advise me to?  If so, what should I change it to, and for which mask?  I have my DreamStation set on x1.

Since reading your response to my thread, I did widen the range of my auto pressure (I changed it to 7-15).  Now, when I use the Amara View, the 95% pressure is between 12-15.  When I use the DreamWear, the 95% is between 7.5-9.

My follow-up questions are these:
- Should I widen the auto pressure any further? 
- Should I change the pressure settings each time I change from DreamWear to Amara View and vice versa?  (ie: when I use the DreamWear, set it at 6-11; when I use Amara View, set it at 10-17... or... something else?)

[Sleeprider]

Well, it's been a month since my last response, and you've come a long way since. I always used non-resprionics masks, so left resistance at 0 and never thought much of it. Go with the recommendation or nothing, and I think it won't make much difference. Your experience of different pressure needs for nasal vs FFM isn't unusual. As long as your machine can keep up, no problem. If you have higher events with the FFM, then you know to increase minimum pressure by 2 or 3 cm.

Your pressure selections seem to make sense to me, and you've been around long enough to figure it out. The only question is why do you change masks?

[Hydrangea]

 The only question is why do you change masks?

Some nights I just cannot breathe through my nose. 

Sometimes my nose is just too stuffy, due to environmental things. But I'm learning that the humidity from the mask will often help things loosen up, and it's ok. 

One night I drank far too much alcohol to be able to keep control of my breathing and keeping my mouth closed, but I still wanted the therapy, so the FFM made that much easier. 

And as I've been experimenting with the various sizes of DreamWear cushions, I've realized I get a much better flow of air from the wider slits in the size Medium Wide. But the Medium fits my cheeks better.  So when I obtain some extra Medium cushions, I'm going to experiment with cutting a longer slit in them.

Thank you for the validation and the tips. I very much appreciate it.