Masks and AHI

[factor]

Hey all:

So should or do Masks change things like Pressure, flow, or breathing efficiency?  Not sure of the correct term.  Here is a few examples:

So let's say machine and settings are all the same. Also no leak issues.  In general only thing different is the mask.

Night 1) Dreamwear standard nasal cushion mask.  AHI = .39  1 CA.  The current mask

Night 2) ResMed N30i  AHI = 3.67 around 30 CA. The new mask.

I could only assume the structure of the N30i is larger or more volume/flow.  Which allows the CO2 to be removed faster.  Its all I could come up with the frames of the 2 masks are different.

In researching this seems to be true and there is more Flow in the N30i.

From the N30i User Guide:
Pressure-flow curve: 
Pressure (cm H2O) Flow (L/min) 
4                           20 
9                           31 
15                         41 
20                         49 
25                         55

As an aside for @Geer1.  ResMed themselves state don't use SmartStop..
SmartStop may not operate effectively when using this mask with some CPAP or bi-level devices. 

From the Dreamwear guide.
Dreamwear Nasal 
Pressure-flow curve: 
Pressure (cm H2O) Flow (L/min) 
5                          18
10                        28
15                        33 
20                        40
25                        45

As you can see there are considerable flow differences between the two masks.  I can then assume if I was to use a Full Face or another mask type or maker.  Their mask Flow could effect AHI and CO2 exchange.   Which leads me to see why some have bad experiences with new masks.  What I dont know is how to combat this or is it to be expected.  In these cases should the CA be considered Treatment emergent.  

Thoughts?

[factor]

thoughts?

[SarcasticDave94]

The only time I can think different masks may make a difference is if you have high leaks on one but not the other. I'm sure there's variance in flow and such between mask models, but maybe not enough to make a difference.

[factor]

So are you saying that any mask applied correctly should give similar results? In general should I be able to use any mask? OR do masks take getting used to? Do people use different masks regularly?

[SarcasticDave94]

Generically I think if you're using a few different masks, you might be able to get similar results if you've had them for a bit of time. But stipulation is that you have gotten decently good results with both consistently.

I don't think there's but maybe few PAP users that can get good results from any mask. I think we're each going to find a limited selection that's going to fall into the good/great category. Others will be a poor fit or some specific aspect you rate as poor. This is why not of us have a big mask collection; we're searching for good for us masks.

From my experience, there's 2 big aspects, the first one is physical mask differences, size, type, strap design, etc. as an all together thing making up that portion of the mask experience.

Second going back to a mask's type. What I mean here is specifically the full face, hybrid, nasal, and pillows are obviously each different. Each type may have a bit of a learning curve in how it applies therapy air pressure, getting used to pillows vs full face as an example, or it could be other things like 2 different companies versions of some pillows mask may have different frames or something that makes it require a time to get used to things on it.

As for changing up masks, yes I think some do intentionally change which mask they use. Maybe they created a pattern that every month they swap out the current for full face versus nasal or pillows. Some maybe just to change it up. Others change to pillows or nasal when allergy or cold season starts. Or maybe this is when they go full face instead.

I myself tried the ResMed N/P30i via swapping cushions. I found I mouth breathe too much for comfort or success. No comfort as mouth leaks caused an arousal. And leak rates were high and not well controlled. I didn't look at taping or a chin strap as a welcome extra step. So full face was easier you accept. But I tried these others to switch it up.

Hope it kinda makes sense.