[Treatment] Shallow breathing, low tidal volume and strange flow rate pattern

[Tayy]

Hello,

I'm using a Resmed Airsense 11 AutoSet since two weeks.
I'm monitoring my data in Oscar and it seems like I have some strange breathing patterns, as well as a relatively low tidal volume and minute vent.

It looks like I'm breathing too shallow during the "even sleep phases".
In the other sleep phase, it seems like I have some kind of periodic breathing. It seems like it would be in a specific sleep phase (maybe REM), because the charts are pretty even but then it starts to become uneven after about an hour every time.

My AHI actually looks really good but I still wake up a few times during the night and I don't feel refreshed after waking up.
I think the few CAs appear when I'm falling back to sleep again, so they aren't "real" CAs.
I have some Flow limitations but not that many.

During the even phases, I'm breathing shallowly (the flow rate can be less than 20 at it's peak). During the uneven phases, my flow rates look like waves, with dips to 8 or less and peaks to 60).
My med tidal volume is 360 and minute vent is 6.25.
According to a calculator and other topics from apneaboard, the tidal volume should be around 450 - 600 for my height and weight.


In the other night, I had a med tv of 380 and med mv of 6.5 but I was awake more often as the other night.


FYI:
I already had a thread (last year) about self titration with a DS Auto BiPAP but I didn't continue using it because I was out of country for a few months and after I received an e-mail I've send my DS to the supplier, got a new machine and sold it for a new Resmed Airsense 11 AutoSet. The Resmed algorithm seems way more comfortable for me. I hope I didn't make a mistake selling the BiPAP machine.

Can anyone please take a look at my charts and help me with my issues?

Thank you in advance!

[Tayy]

Some more screenshots.

[AeroM]

I also have episodes like this. Are they hypopneas?

[Sleeprider]

The oscillations in respiratory volume are usually a result of a delayed feedback loop in respiratory drive that relates to the CO2 in your blood and the chemical changes that signal the carotid body, which is responsible for your autonomic respiratory rate and volume. https://pubmed.ncbi.nlm.nih.gov/12897806/ This is a complex chemo-receptor and when a lag-time occurs, we see alternating hypoventilation and hyperventilation, and even central apnea. This can sometimes be mitigated with PS / EPR on the machine, and I believe some medications like Diamox (acetazolamide) can dampen the oscillation, especially when related to altitude induced central apnea. Enhanced expiratory rebreathing space (EERS) has also shown some ability to deal with this. In your case, there is very little apnea and we are mostly just looking at chart issues that, without CPAP, would never be apparent. I don't think you actually have a problem, but you can experiment with different EPR levels to see if it makes a difference.

[Tayy]

Hello Sleeprider,

thank you for your reply.

I find this hard to understand since English isn't my native language, but it's even hard to understand with machine translation.

"The oscillations in respiratory volume are usually a result of a delayed feedback loop in respiratory drive that relates to the CO2 in your blood and the chemical changes that signal the carotid body, which is responsible for your autonomic respiratory rate and volume."
Do you mean the oscillations during the "uneven" sleep phases or the oscillations between the "even" and "uneven" phases (so the whole night)?

"This can sometimes be mitigated with PS / EPR on the machine, and I believe some medications like Diamox (acetazolamide) can dampen the oscillation, especially when related to altitude induced central apnea."
I already use EPR = 3, or do you mean that I should reduce EPR?
I don't live in high altitude.

"In your case, there is very little apnea and we are mostly just looking at chart issues that, without CPAP, would never be apparent. I don't think you actually have a problem, but you can experiment with different EPR levels to see if it makes a difference."
Yes, it is true that I almost have no apnea. The thing is that I wake up multiple times during the night since a decade and it seems like I wake up when I have these "uneven" sleep phases. The waking up feels normal, just like before CPAP, so I guess I might have the same pattern when I don't use CPAP.
The problem is that I already got tested for sleep apnea with a home test (AHI = 7,1) and I was in two different sleep labs but I wasn't able to sleep like at home. I had a very hard time to sleep and woke up way too often. That's why I think I had an AHI of only 3,0 and 3,4 (other sleep lab) there.
None of the tests recorded RERAs, but that's what I think I might have.
I'm just looking and my reports and I see that I had hypopneas during REM (not that many) but I guess this shows that I have the same patterns without using CPAP.
The other thing is that there were "Flattenings" recorded, I guess these are flow limitations? They occured during the whole night.
Unfortunately, there are no numbers on the results. It only shows AHI, oxygen and the sleep phases.

I attach screenshots from another night. I also used a oximeter.
During the "uneven" phases, my heart rate is also uneven. But I don't have meaningful SpO2 desaturations.


Is there such a thing as central flow limitations?

Thank you!

[Sleeprider]

Reduce your EPR level from 3 to 2, and it should help with these oscillations.