Your opinion and aflex cflex

[dusk_to_dawn]

I am seeing an odd response to a change from aflex2 to cflex1 and wanted to get your input. While on aflex2 I was able to reduce hypopnea and eliminate OA by increasing the minimum pressure to 9-9.5. This seemed to completely eliminate the OA except possibly when I rolled on my back, which is rare. As the pressure increased the CA started increasing.
I read the increased CA could be a co2 wash out thing and that cflex could help this. When I changed to cflex1, the CA was indeed down but the OA became the bigger item. Sleepyhead also shows that it takes more pressure than prior to knock out the OA. I don't "think" I was on my back, but you know how that goes.

Can i get your thoughts on my next dwing?
Why would cflex1 "seem" to cause more OA vs. aflex2 with other settings the same?

here is the aflex2. The one OA that occurred isn't real as I was adjusting the mask.



here is the cflex1 with 24 OA vs. 0. The OAs are not in check even at 12.


here is another cflex1 with a better leak profile


Thanks!

[Pugsy]

The 2 most common causes for needing more pressure during the night when for the most part a different pressure gets the job done are supine sleeping and REM stage sleep.

Since you feel that supine sleeping is probably limited (I know it's hard to say for sure) then that still leaves REM stage sleep pressure needs. It's common to need more pressure in REM stage sleep.

I suspect what you are seeing is related more to either REM sleep or maybe being on your back and the normal night to night differences that will just happen even if we don't mess with Flex settings at all.

I have used both CFlex and AFlex and there really shouldn't be any cause and effect in terms of OAs when going down in the Flex setting. The change in the amount of reduction when going from 2 to 1 in Flex is really not that all that much and the only real difference between CFlex and AFlex is that the AFlex has a more rounded form of exhale relief. Maybe a little "gentler" in terms of timing.
Now if one form of exhale relief simply feels better then maybe you are sleeping better and thus maybe you just have more REM sleep happen and thus maybe that's why the change in pressure needs.

It's the minimum pressure that is the most critical pressure...not the maximum and the time where 12 cm pressure didn't help the OAs...that's because it just couldn't respond optimally. Just need a little more minimum pressure to better hold the airway open and prevent whatever happened when the machine needed to go to 12.
It's easier to prevent than to fix after the fact.

[dusk_to_dawn]

Pugsy,

REM sleep would be awesome. REM/better sleep has been the goal and I didn't realize the extra pressure possibly required during REM. I thought it was a bad thing, but it could be good and does make sense.

Thanks!

[Pugsy]

If you google "sleep stage" and look at the normal hypnograms you can get sort of an idea when REM is likely to happen. Typically the first REM is around 90 minutes after first sleep onset and then as the night progresses it comes on more frequently and lasts longer.

It's common for OSA to be either worse in REM or require higher pressures or maybe a little of both.
I have it myself.

The very minor differences between CFlex and AFlex are unlikely to be what you are seeing going on.
Most likely it is either REM or your are on your back and don't know it or maybe a little of both.

[dusk_to_dawn]

Pugsy,

googling rem was sure useful. I didn't realize the cycles or the timing. It seems that REM fits what is happening, but let me give you a little data. If it is REM and then hopefully the deeper stages following I may not have hit that type of REM sleep in months.

I am going to use aflex and cflex nights for a name as that is the only difference in the settings. I am very open to something else as the real reason.
For the two months prior (my first two months of cpap) I have been using aflex1 or 2 and a minimum pressure anywhere from 5 to 9.5. I had the max set to generally around 12 or 13 but it would rarely go above 11 and more typically maxed out at 10. I can't find a time when it went above 12. Two months ago when I just started there weren't many days above the 4 hour target. In the most recent 3-4 weeks, more than half of the days were ~8 hours and most all over 4. None of these "aflex" days ever had a pressure response to OA like shown above for the cflex days. I now have 4 cflex days in a row with a very similar pattern in pressure ramp and time of night for OA. I bumped min to 10 last night with the same result except a few less OA. When I look back at the numerous aflex nights, I was able to get the OA in check at a lower pressure. When I focus on the AHI, they are relatively similar. Part of me says chase the lower ahi with lower pressure, but another says to go with the higher pressure and cflex if it is indeed REM and the follow on stages.

I wish I could answer definitively, but I think I feel more rested after the last 4 nights.
What is the gold standard for a more objective determination of feeling rested?
Is it possible I didn't get to REM sleep for months?

ThankYou, it has been very helpful.

[Pugsy]

What is the gold standard for a more objective determination of feeling rested?

I don't know that there is any real objective value that is guaranteed to mean we should feel well rested.
There's so much more to getting good quality restorative sleep than just an AHI number or a leak number or even how many hours of sleep number.
I think it comes down to simply having to go on subjective feelings once we have the "numbers" within acceptable ranges.

For myself I learned a long time ago that it wasn't so much the AHI that was my trouble spot...it was hours of sleep and fragmented sleep (due to other health issues) that made much more of an impact on how I felt during the day than the AHI itself. One of my "best" days followed a night with AHI of 10.3....go figure that one.

We have to remember that not everything that is wrong with us or our sleep can be 100% blamed on OSA and thus we can't expect cpap to fix everything. It only fixes OSA problems...it doesn't help my fragmented sleep when my fragmented sleep is caused by my bum knee or shoulder.

Could the very small differences in CFlex and AFlex affect your sleep quality and thus how you feel the next day given everything else is equal...sure it could. Sometimes it's the tiniest of things that seem to tip the scale either good or bad.

Use whatever settings that let you sleep the best and feel the best and try not to put all your eggs in the AHI basket because the AHI is just a very small part in getting good restorative sleep.

[dusk_to_dawn]

Pugsy,

I have 5 days that are relatively consistent and the timing for the first burst of OA is 1-2 hours after laying down. This is consistent with the sleep stage info you referenced. I even found an objective data point that seems to confirm REM . The first REM period (OA burst) seems to last 60 minutes, possibly due to my body needing to catch up. Another burst happens again in 2-3 hours. Therefore I need about two hours of pressure at 14 to eliminate OA. I feel very rested and better than I have in months. The AHI is 5-7. You mentioned higher pressure needs for REM. Do you set your min to completely eliminate OA even during REM or set it a few notches below the max nightly pressure point and let the machine catch up for the last few cm of pressure? I'm guessing with your 10.3 AHI statement being a good day, that you are 2-3 cm below your max requirement...?

Feeling better/smarter/well-rested/sleep-educated,
Tim

[Pugsy]

I'm guessing with your 10.3 AHI statement being a good day, that you are 2-3 cm below your max requirement...?

No...it was nothing more than a fluke night. One of those times when we don't change anything that we know of and for some reason something weird happens. It was a one time only thing. I had been using the same settings for probably 3 months and getting AHI in the 2 to 3 range...and after that weird night I went back to the 2 to 3 AHI range and never changed anything.

Do you set your min to completely eliminate OA even during REM or set it a few notches below the max nightly pressure point and let the machine catch up for the last few cm of pressure?

I don't try to completely eradicate the REM events...I just try to break up the clustering and this is done by increasing the minimum but it doesn't have to be necessarily close to the maximum.

When I was in your shoes and my AHI was around 8 each night with pressures of 8 minimum and 12 max...I was hitting that 12 fairly often but when I opened the machine up to 20 it didn't really help reduce that AHI of 8 even though it went to 18. I had to increase the minimum to around 10 to finally break up the clustering and I just left the max at 20 because it often went to 18 anyway.
Now I could have used higher minimum but I once did an experiment with the minimum to see if it really changed the AHI all that much (remember I was averaging around 2 to 3 AHI at the time) and I went up slowly to 13 min and the AHI never really changed. I abandoned that experiment because I just didn't see the need to use 13 minimum all night when 10 minimum did the same acceptable job.
I have always been one to promote using the least amount of pressure that will get the job done...it really doesn't hurt to use more but I just don't see any sense in doing it myself.

So when I was using apap....10 minimum and 20 maximum were my settings. Some nights it never went above 13...some nights I would see 18. I slept through it all though so I just let the machine sort it out.