2.5 months into using CPAP, looking for possible adjustment recconendations.

[macaronno336]

Good morning, I have been on CPAP now for 75 days. I have been experiencing many positive benefits. But at the same time, some days are not as great as others. I am curious if this is to be expected. I recently went out of town for a few days. I noticed that my ahi, while lower i was feeling worse. I am wondering if anyone has suggestions on machine setting etc... I put my machine on CPAP mode recently and I like the way it feels, however I am asking for advice on if I shoudl keep it on. I will post 3 charts from 3 days. One before my trip, one during and one last night when i returned home.

[G. Szabo]

I guess you are feeling better because you increased the pressure to 95% (9.9cm) of the APAP setting in the CPAP setting. So, it's not the difference between CPAP and APAP but the difference in the pressure setting that matters. And you have no pressure swings either in CPAP. 

It will be a learning exercise to switch back to APAP and set the minimum pressure to your current 9.8 cm CPAP pressure. Then, you will have the currently experienced benefits with the advantage that the APAP algorithm can increase the pressure occasionally when it is needed. 

If you've had a positive experience with this altered APAP, you can slightly reduce the minimum pressure in APAP mode.

[macaronno336]

Okay, I may try that. One thing that lacked emphasis on with my charts is that, despite my ahi going down when switching to cpap mode, I was feeling worse. I am wondering what could have been the cause of that. I was away for 5 days, and consitently had my lowest scores in my cpap treatment, yet I felt worse. I wonder if being away from home had some affect of overall sleep quality.

[AshSF]

Your numbers on constant pressure are excellent. There is no point in switching to APAP to mindlessly chase the AHI from 0.99 to 0. It does not matter. And remember:

1) The machine is approximating an AHI from the waveform with its own scoring algorithm. So this 0.99 may be "statistical noise" rather than an actual signal.
2) Even if the AHI is 0.99, any AHI below 5 is not considered apnea. So consider yourself treated.

3) APAP algorithms are approximations at best. They might mess with your sleep architecture by making you go to a shallower sleep state by an abrupt change in pressure. Do you really want to go down this "optimisation" path when the reward is so slim.

If you are sleeping fine on constant pressure, keep at it. And let your body recover its sleep deficit accumulated over multiple years of sleeping with apnea. You need to plan to be in bed for 8 hrs so that you can get a full 7.5+ hours of sleep. And report back after 30 days how you feel.

[macaronno336]

Okay, thank you. I will keep it on the current settings and see how it goes!

[staceyburke]

Looking at all 3 nights, the main difference is the increase in pressure you experienced.  The ResMed increases pressure because of flow limits.  Those FL are apnea also and the way we try to stop them is with EPR.   Yours is set to 1.  I would try EPR 3 and see if that helps.  The fixed will stop the pressure from going up but it will not help with FL.  You can leave it on CPAP and still use EPR or you can go back to the variable setting.

[macaronno336]

Okay, that is interesting! I will increase it to 3 and leave the current pressure as is. Hopefully this might improve sleep quality.

[Deborah K.]

If you were more comfortable using Apap mode, I suggest you return to it.  Just set a small pressure range like 9-11.  That will still stop the pressure jumps, and I think you will feel better than you did using Cpap mode.

Good luck!  

[G. Szabo]

3) APAP algorithms are approximations at best. They might mess with your sleep architecture by making you go to a shallower sleep state by an abrupt change in pressure. ...

You are also messing with "your sleep architecture" when you are in CPAP mode and need somewhat higher pressure, but you cannot get it because of the fixed pressure. In this period, your FL increases, as Steve Burke commented above, and you are in an oxygen-deprived state. FLs and arousal "mess with your sleep architecture," too. Which "mess"  is better?

What's the evidence (if any) of APAP-caused damage to "sleep architecture," and how are these quantified?  Furthermore, how can we compare the degrees of such damages between APAP and CPAP? 

[AshSF]

I would recommend this article first:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8836615/

Then, read this paper in the sleep journal (summary below):
https://pubmed.ncbi.nlm.nih.gov/12150317/

The standard protocol is to use APAP for a time-trial to find your 99percentile EPAP pressure and set your CPAP to that.

EPR (which is like a bilevel with a Pressure support of upto 3) can reduce flow limitations, improve oxygenation and as a side-effect, it can create Central Apneas which may/may not resolve over time.

Since a user would be on CPAP for the rest of his life, it may behoove him/her to find the best CPAP pressure by experimenting with APAP for a time-trial or multiple trials, and just use that pressure going forward.

And if someone feels crappy at a certain EPAP pressure, he can always raise it in 0.5cm increments per week and see how he feels.

I went thru a similar journey when I started. I first did a 4-20 APAP. Narrowed it down to 7-11 and still felt crappy. Finally I just set my machine to fixed pressure of 8cm after taking advice from a long term member on another forum. This process took close to 6 months but the effect of constant pressure was like night and day, for me.

YMMV. But it's worth a shot to go thru the conventional process rather than going all-in on APAP and not even consider the other modality.