3 Months Until Sleep Study

[Hoagie73]

My apneas have been primarily centrals. Over the past couple months my AHI had been rising. I found this quite alarming. Since my events are primarily centrals, I figured sleep position had little to do with the rise. However, I did notice a significant decrease one night after I got up to use the bathroom. Prior to using the bathroom I was at a 4 AHI. When I got back into bed I slept on my left side (I ususally start off on right side and almost always end up in the supine position). I woke up not have moved to the supine position and still on my left side. I had only had 1 apnea on my left side and it was obstructive. I found this odd. So I decided to buy a waist strap and strap a rolled up towel on my back to keep me from rolling over. I have been sleeping on my left side without rolling over for 10 days now and have not had a night with an AHI over 1.

So, my query is: How can position affect central apnea?

[Geer1]

As I theorized in my last post your "central" apnea are probably mislabeled obstructive apnea, central apnea after arousal (potentially caused by obstructed breathing), or another option is what is called mixed apnea.

Without very closely reviewing OSCAR data and looking at each apnea it is hard to know exactly what is going on. It is just worth noting that these machines are not perfect at labelling apnea type and in some cases get tricked.

Looking back at the recent screen shot showing obstructive apneas what I think might be happening is obstructive in nature but somewhat under your control. You have these obstructive periods but still take small breaths in which could easily trick the machine into falsely flagging these as central apnea imo. When I looked closer at these examples again I see that they show what could be palatal prolapse (soft palate collapsing on exhalation) or intentional exhalation through your mouth (which can be done by collapsing palate on purpose so there is minimal mouth leak). You can see this by how you take a breath in and then have very short exhalation period before flow rate slams shut until you take next little breath in, if some of your "central" apnea before show similar kind of flow rate then those are without a doubt mislabeled obstructive apnea or intentional mouth breathing.

As a test to recreate that kind of breathing to understand what is going on you can play around and try breathing in through nose on PAP and then with the right action can flip your palate up and breath out through your mouth with minimal leak or even breath through your mouth while CPAP deadheads on closed palate. Not everyone can do this but I am guessing you will be able to do so.

The question would be whether you have palatal prolapse when sleeping in supine position or if you are just mouth breathing and your body has slowly learned to breath that way for some reason. Sleeping on your side appears to fix the issue, I would assume by making it more difficult for palate to collapse. If you are having periods of more mouth leak now then that might be a sign that you were mouth breathing back then and now are still doing the same but with more mouth leaks rather than palatal collapse. If this is actual palatal prolapse and not mouth breathing then it can be tricky to treat with PAP (my theory in the past has been to reduce EPR which might be a test worth trying), palate surgery to address the issue is controversial as well.

Edit: Trial of a FFM would be sort of interesting too if you are interesting in trying one and think you are mouth breathing.

[Hoagie73]

Thank you for your detailed response Geer! I truly appreciate it.

I tape my mouth shut to the point where no air is getting in or out of my mouth. So mouth breathing won't fit into the equation. But I do think you are on to something. I have a feeling these are what you said and these are obstructive in nature and are being flagged as central. Probably due to my anatomy and the way I am breathing. The good thing is that I can control it pretty well through position. I don't mind it as long as I can get sleep. It's quite the prep though. I use a nasal strip to open my nostrils a bit, tape my mouth, and strap a rolled towel to my back. I may even add a soft cervical collar at some point.

[Geer1]

If it is palatal prolapse as I am starting to think then a cervical collar will not help. It is your soft skin where uvula hangs sealing against back of throat/airway when you try exhaling. The reason it could be dependent on your position is that when laying flat gravity will be pulling your palate towards back of throat allowing it to more easily be caught and seal airway during exhalation.

Edit: And the reason reducing EPR might help is that EPR creates a pressure differential that speeds up exhalation process. Decreasing EPR slows exhalation and could potentially reduce chances of palatal prolapse.

[Hoagie73]

Got it.

I'll try reducing epr tonight, but even at 2 I feel a bit uncomfortable. I'll see if there is a difference over a few nights. If it's a positive change I'm sure I can accustom myself to a reduced epr setting.

Thanks again!