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Are these obstructive apneas reported by Oscar accurate? - Printable Version

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Are these obstructive apneas reported by Oscar accurate? - sarm2005 - 05-26-2021

Hello there,

I believe I have UARS based on the results of a WatchPAT study (AHI 4.8, RDI: 12.4) and have begun trying BiPAP to treat it. At the same time, I have set up a Wyze Cam to monitor for nighttime arousals.

During these first few nights of using the BiPAP, I am noticing an unusual pattern: obstructive apneas (OAs) that are preceded by the combination of elevated flow rate, small amount of mask leak, and body/limb movements (based on Wyze Cam footage). I've included a Oscar screenshot of a representative occurence of this. In the screenshot, you can see I have ~5 OAs/hour. Most of them are resulting from the pattern I've just described.

It makes sense to me why the elevated flow rate, mask leak, and the body/limb movements would all occur together. What doesn't make sense why I'm having OAs immediately afterwards. I'm wondering if anyone has ideas on if these are real OAs or if it's something else and they're being misreported as OAs?


RE: Are these obstructive apneas reported by Oscar accurate? - Ratchick - 05-26-2021

Not an expert on these things, but if you're moving around in a way that suggests arousal from sleep, the OA may well be simply "sleep-wake junk" as you shift position and go back to sleep. So it may just be that. Hopefully someone better at reading the charts can let you know for sure. Smile


RE: Are these obstructive apneas reported by Oscar accurate? - Gideon - 05-26-2021

Welcome to the forum.
Always post a full night as well as a detail that you are questioning.

The zoomed chart. Normal breathing to an arousal, you did not wake, likely you tossed had the OA, in this case a combination of holding your breath and a positional cause. Going into some recovery, deep breathing which is followed by over a minute of severely flow limited obstructive breathing followed by arousal, the classic RERA..

Otherwise your CA events are too high as are your obstructive events.

Obstructive first.
You have significant positional obstructive apnea as evidenced by the clusters of obstructive events. No pressure can fix this. This is likely caused by tucking your chin similar to kinking a garden hose to reduce or stop the flow. The fix can be as simple as a pillow fix, use fewer or flatter pillows, or use a soft cervical collar. Read the wiki article in my signature. I strongly suspect you came to these settings because your pressure was running away from you. This Positional Apnea is why.

Central Apnea.
This is a guess, but an educated guess.
You have Treatment-Emergent Central Apnea. We see a lot of this here and I suspect you are one of the lucky ones.
Your VAuto, as all pap machines do, improves your breathing efficiency who h includes your gas exchange. In this case you are likely flushing out too much CO2. How is this a problem? The need to flush CO2 out of your system is the primary drive to breathe signal. With the use of your VAuto you have reduced your CO2 level to below your apneic threshold. It is not the need for oxygen, which tends to make us breathe faster, but the need to dump CO2 which drives our breathing.

Here is what I expect to see in a 10 minute view of the central Apneas. You are breathing deeper than normal so you are flushing higher amounts of CO2 from your system. As you continue you have less CO2 in your blood which say to breathe less deep until your CO2 levels cross your apneic threshold resulting in a central Apnea. At this point you are not breathing and your CO2 is building and as you cross the apneic threshold going up you start to breathe shallowly.but increasing as CO2 builds. Then it goes too high and the Cycle repeats.

A 10 minute view of your centrals to prove this.

The fix here is to reduce your PS. Start with setting PS to 2.

And for sure work on your positional Apnea.


RE: Are these obstructive apneas reported by Oscar accurate? - sarm2005 - 05-27-2021

Thanks for the welcome Gideon and the detailed response and explanation of how higher PS can cause CAs. I'll make sure to include a full night screenshot going forwards.


RE: Are these obstructive apneas reported by Oscar accurate? - sarm2005 - 05-27-2021

Last night, I decided to lower the pressure a bit to IPAP: 9, EPAP: 6 since using those higher pressures from my original post require to tighten my mask to a level that's uncomfortable to prevent leaks and I don't think higher pressure is what's gonna resolve these OAs.

With these new settings, the CAs are much lower (possibly the lower PS of 3 helped?).

However, the OAs are still there. They still follow the pattern I described in my original post where there's a body movement followed by the OA. Here's the the Wyze Cam footage corresponding to this time interval: https://www.youtube.com/watch?v=Cx5WF_6FHes. The Oscar and timestamps in the Wyze Cam footage should be perfectly synced.
- Movement at 5:09:48, OA from 5:09:50 to 5:10:10
- Movement at 5:13:20, OA from 5:13:30 to 5:13:45
- Movement at 5:16:52, OA from 5:17:00 to 5:17:10

Quote:The zoomed chart. Normal breathing to an arousal, you did not wake, likely you tossed had the OA, in this case a combination of holding your breath and a positional cause. Going into some recovery, deep breathing which is followed by over a minute of severely flow limited obstructive breathing followed by arousal, the classic RERA.

My understanding is that after an OA occurs, I'd expect an arousal. But when I look at the Wyze Cam footage and Oscar data, there isn't any movement or abnormal flow rate after the OA that would indicate an arousal. The OAs just seem to resolve on their own?

Tonight, I'll try using a flatter pillow. I have tried cervical collar on its own, but have found that it causes brief arousals at night because it's uncomfortable. But I can try the collar with the BiPAP if the flatter pillow isn't effective.


RE: Are these obstructive apneas reported by Oscar accurate? - Ratchick - 05-27-2021

I may be wrong, but I'm pretty sure that not all arousals would necessarily show overt movement. It's about brain arousal, not necessarily body arousal. But hopefully, Gideon can give you a more in-depth opinion.


RE: Are these obstructive apneas reported by Oscar accurate? - Sleeprider - 05-27-2021

Cutting PA back to 3 helped to significantly reduce CA events. You went from 11/7 to 9/6. Both are fixed pressure, but you moved EPAP the wrong direction. Take it back to 7.0 or 8.0. Is there a reason you are not setting a range of pressure that allows the Vauto algorithm to work? Why not EPAP min 7.0, IPAP max 14.0, PS 3.0 ? The clustered OA events suggest a positional issue like chin-tucking. Make sure your pillow is not too tall, or consider a soft cervical collar. http://www.apneaboard.com/wiki/index.php/Optimizing_therapy#Positional_Apnea


RE: Are these obstructive apneas reported by Oscar accurate? - SarcasticDave94 - 05-27-2021

Note that you've said in post 5 " I don't think higher pressure is what's gonna resolve these OAs". Unless the Obstructive Apnea event is caused by a positional neck kinking, you're incorrect. Higher pressure from the normally created Obstructive Apnea via an airway restriction is diminished by higher pressures.


RE: Are these obstructive apneas reported by Oscar accurate? - Gideon - 05-27-2021

I'd like to encourage you to update OSCAR. There have been literally hundreds of issues resolved and changes made since the version you are running. While I don't know of any changes that would make a big difference for you , it's always a good idea to stay current.


RE: Are these obstructive apneas reported by Oscar accurate? - sarm2005 - 05-31-2021

(05-27-2021, 06:36 PM)Gideon Wrote: I'd like to encourage you to update OSCAR.  There have been literally hundreds of issues resolved and changes made since the version you are running. While I don't know of any changes that would make a big difference for you , it's always a good idea to stay current.

Thanks. I didn't realize it was so old until you mentioned it.

(05-27-2021, 11:57 AM)Sleeprider Wrote: Cutting PA back to 3 helped to significantly reduce CA events.  You went from 11/7 to 9/6.  Both are fixed pressure, but you moved EPAP the wrong direction. Take it back to 7.0 or 8.0. Is there a reason you are not setting a range of pressure that allows the Vauto algorithm to work?   Why not EPAP min 7.0, IPAP max 14.0, PS 3.0 ?  The clustered OA events suggest a positional issue like chin-tucking. Make sure your pillow is not too tall, or consider a soft cervical collar. http://www.apneaboard.com/wiki/index.php/Optimizing_therapy#Positional_Apnea

I thought that UARS increased sensitivity meaning pressure changes could also cause awakenings. So I've avoided them while titrating.

But I decided to give the settings you've suggested a try and have been using them for a few nights. Last night, I've had my lowest AHI yet of 2.4 (see screenshot). A few of the issues I've encountered so far with these settings are:
  • The first night I was using the settings, I had aerophagia, but that seems to have gone away.
  • I also had issues with mask leaks, but using a mask liner has prevented me from waking as a result of them.
  • Last night I woke up with a sore neck and sore jaw and had bitten the inside of my mouth while sleeping. Maybe I'll try using a retainer or something to hold my jaw in place.
I think I'm overall less tired during the day, although the improvements so far have been subtle rather than a night-and-day difference. Let me know if you have suggestions for any other setting tweaks, otherwise I'll keep them as is for now.