A-Flex Off - AHI cut in half.

[NorthernGuy]

So, I had been messing with the Flex (A-flex) comfort setting on my Dreamstation with little discernible effect on my AHI and only minor comfort differences.

I finally just turned it off (disabled it) and my AHI dropped from 6-7 to 2-3 instantly and has remained there for over a week. I had been stuck at around 6-9 for months just moving the bottom number up slowly and seemed to plateau.

There was no difference between Flex 1,2, and 3 settings, but Flex 'off' really improved my apneas (all of them Clear (CA), OA, Hypopneas - pretty much equally, not just one type).

Any interpretation on what such a big improvement without A-flex means and what else I could tweak to possibly go even lower?

My settings APAP 8-20 (really only ever gets to 13.5) with a 90% average reading of about 10.5-11.0 since I disabled Flex.

I can post more Sleepyhead data, but it doesn't look any different (no obvious patterns to timing or pressure) to me, just fewer overall.

[OpalRose]

That AHI drop is impressive. If keeping the AFlex setting off doesn't bother you, then that's the way to go.

I don't see any reason to keep your max number at 20 when your 90% is 13.5. Why not bring it down to 15.

The only other question I have is....are you using ramp and at what setting? If you don't need it, then keep it off. If you do need to use ramp, keep the start setting of ramp closer to your minimum setting of 8 .......mabye around 6.

[chill]

I had a similar result from turning it off. I think that is when my CA stopped too. Having this can result in expelling too much CO2 in some people (CO2 washout) which then leads to you not breathe right away which the machine then scores as a CA (I think I am remembering that correctly). Also having this on means that your pressure is reduced for part of your breathing cycle which can result in collapse of our airway.

To improve your AHI, try increasing your minimum to 9 (can go to 8.5 then 9 if the full jump bothers you). I have gone from 8 to 12.5 now and my AHI is very rarely above 1. My 90% number has also gone up as I did this. My main reason for increasing the pressure is continued sleepiness during the day which I attribute to waking frequently at night. My theory is that the frequent wakings are UARS and that a higher pressure will reduce that. The experiment is still in progress. I have an appoint with a sleep doctor in a month to discuss my problems. I have not been to this clinic before so I don't know how that is going to turn out, it will be an interesting conversation.

[trish6hundred]

Hi NorthernGuy,
You might try lowering your maximum pressure from 20 to 15 CM H2O and see how that gose for you.
Good luck to you, let us know of your progress.

[vsheline]

Hi NorthernGuy,

A-Flex settings of 1, 2 and 3 all add 2 cmH2O of pressure relief during exhalation, plus each setting adds a different amount of additional "Flow based" pressure relief at the start of exhalation based on the how hard we are are exhaling. So there is a big difference between OFF and the lowest setting 1.

A-Flex settings of 1, 2 and 3 differ in how much additional Flow based pressure relief is added while we are actively exhaling.

A-Flex settings of 1, 2 and 3 also differ in how early the pressure starts dropping toward the end of inhalation as we are trying to finish up the last portion of our inhalation.

When A-Flex is 3, the pressure starts dropping the earliest, well before we have finished inhaling. I hear this can take some getting used to.

[Sn00zeAlarm]

When I turned off EPR, most of my CA's seemed to be converted to Hypopneas instead.

[natyprueba]

Hi NorthernGuy

If anybody knows the A-Flex equivalent setting for my machine AirSense10 please let me know.
Is very attractive to cut in half mi AHI, but I don't have any idea what setting are you talking about.
I got down one complete unit in my AHI, because my Dr. eliminated my step in my machine and it goes from 4 to 12 cms in less than 5 minutes and keep there for ever. I was in 4 something AHI, now I am in 3 something (really nice), but I prefer to keep going down.
Tks in advance.

[chill]

The Resmed equivalent function is called EPR and has a setting of 1 (least) to 3 (most) as well as Off.

[NorthernGuy]

I finally got around to checking in on all of the replies - Thank you all.
I will try gradually raising my lower pressure and drop my upper pressure back to ~15.

I wasn't trying to say that turning off 'A-flex' would work for lots of people, but more wondering what the drastic cut in AHI by turning it off means about my particular type sleep apnea. I do think the CO2 washout due to A-flex theory by Chill may be correct in lowering CAs. I do notice that I don't exhale as completely or easily with the A-flex off. By morning the resistance is not noticeable.

Surprising there aren't any intermediate settings between 'Flex 1' and 'Off'. There is not much difference in feeling between the Flex 1-3, but turning off does have a different (but not bad feeling).

I do not use ramp at all - settings below 8 have me starving for air, so 8 is just fine to start.

[OMyMyOHellYes]

This result does not surprise me. Counter intuitively, I find many of the "comfort" features (ramp, EPR (A/C-Flex), heated humidification, etc) are often impediments to better control and actual comfort. Of course, YMMV.

OMMOHY