Question on strange expiratory flow rate and obstruction after a recovery breath.

[THEVGE]

I have UARS and already have some threads on the forum. Trying hard to get my therapy right, but after years still no good luck. I check OSCAR every day and feel pretty comfortable with interpretation of the data, except these 2 issues. I do know since recently my left nostril is severely narrowed and (part of?) the UARS problem. I now use Alaxo nasal stents to support my nasal flow. It helps, but not much, but enough to keep using them (even during the day). My afib significantly reduced after their introduction ;-) But everything points to at least 1 other SDB problem.

This night I tried something else (not relevant for the question) and I know my flow rate is not great. But this setting does nicely show (amplified because of wrong settings) the 2 issues I keep seeing independent of my bi-level settings.

Issue 1: this strange bump during exhale. I think it is related to PS because I never saw this on CPAP/APAP, I do see it on ASV/bi-level. Later in the night this problem often goes away. But what am I seeing here? If I think about it, it is as if my airway is bouncing back after the PS-ed breath. In this case PS was 4 at trigger very high (note: for nice rounded tops I need more PS then 4, and with PS > 3.8 I will get CA's if my trigger is set any lower). So curious to an explanation of what is happening here.

   

Issue 2: this is rare, that this event is actually flagged as an obstruction. You see OK-ish breathing, a big recovery breath and boom.......obstruction. Is that not weird? What could it be? This event wakes my up several times per night, and I do not know how to interpret/prevent this. But normally this event is shorter and hence never reported as an obstruction. Until now this has been independent of therapy (CPAP/APAP/ASV/bi-level) and settings. I do notice that the impact of this event is bigger when my pressure or PS is higher (impact is that my body is turned "ON" after the event, often with pretty bad aerophagia). 

   

It seems as if I need significantly higher pressure/PS for my UARS, but this makes unknown issue number 2 more problematic. Based on what I see in the data and everything I tried (see below) it is not palatal prolapse (known to have this effect). The only thing I did not try yet is a mandibular device combined with bi-level (I do have the device, just did not get to trying yet).

I tried so much and nothing helps......
- CPAP/APAP/ASV/bi-level with a very large range of pressure (4 - almost 20; with/without EPR/PS up to 6)
- Nose mask/nose cushions/nose pillows/FFM/hybrid FFM
- Velumount soft palate brace (also combined with bi-level)
- Alaxo Hybrid soft palate stent (also combined with bi-level)
- Alaxo Xtreme nasal stent (also combined with bi-level)
- Knightbridge chin thingy

Any ideas appreciated!

[THEVGE]

I still do not know what is happening here (issue #1), apparently something strange, as it does not seem to be recognized.

To make it stranger, I recently re-started ASV and with comparable pressures, this effect does not happen. The starting pressure support of the ASV is about the same as the fixed pressure support of the bi-level. Of course there is the difference that the Resmed ASV uses a PS bandwidth of 5, som in effect a lot of the time very high PS (and even servo-ventilation). But......also with low PS, for example at the start of my sleep, the strange exhale bump is not present.

I have no clue what this is and if I should avoid it.

[Sleeprider]

This pattern is a simple breath-hold. You inhale and hold your breath and an OA is flagged because you have obstructed your own airway as you move or whatever else happened here.

 

The rebounds at the bottom of exhale are more difficult to classify. A rebound to zero is often a swallow, but in any event it is nothing more than a hesitation or slowing in expiration, not an event.  It's certainly nothing to worry about or change therapy to resolve, and it's unlikely you are even aroused by it.