Apnea Clusters?

[harryd91]

Hi,

Just wondering if anybody thinks this is normal or has any idea what might be causing it. Since switching from nasal pillows to a full face mask my AHI has gone down dramatically and I feel better for it however am still getting quite tired later in the day (from about 1pm onwards). Have stopped napping in the day so maybe I'm just getting used to good sleep habits but I'm just concerned that I'm getting these apnea clusters.

Have attached a screenshot of last night's resscan (am using an S8 so can't do OSCAR/SleepyHead). Most days aren't usually this bad but it when it happens it's usually at the same time in the night. Also included summary report - I switched to the full face mask on October 25.

Settings are min 11 / max 20 autoset.

Thanks

[Pugsy]

Welcome to the forum.

When we see clusters like that we usually think either someone is on their back or they are in REM stage sleep or maybe a combination of both.

Both supine sleeping and REM stage sleep can cause OSA to worsen and need more pressure.

[Sheriff Buford]

I get clusters early in the morning just before I awake. Not much I can do about it. The machine is doing what its suppose to do (ramp up the pressure and treat it)…. so I live with it. Stay with the mask that makes you feel better. I don't know how long you've been on the machine, but give it time.

Sheriff

[Pugsy]

Clusters early in the morning....those wee hours before we sleep...are highly suspicious of it being REM related because that happens to be when REM happens more often and last longer.

Google "sleep stages" and look at the normal hypnograms...you can see the normal cycling of REM throughout the night.
Typically first REM happens approx 90 minutes (or so) after sleep onset and is fairly brief in terms of duration.
Then as the night goes on we cycle into REM more frequently and the time spent in rem increases. Those wee hours of the morning are where we have more REM cycling and those cycles will last longer.

If it's a random and rare occurrence then it may not be a big deal and can be ignored but if more than random and happening with almost every REM cycle then maybe it shouldn't be ignored. The fix is easy....more baseline pressure holding the airway open so it doesn't collapse so easily.

Maybe some people don't have a problem except when 2 common causes happen at the same time....REM and being on their back.
One without the other might not be a problem but add them together and it's a small problem.

I have a lot of experience with REM worse OSA...my OSA is 5 times worse in REM than in non REM. Supine sleeping for me doesn't really do much one way or the other (extensive testing with side sleeping only showed REM alone was my own particular issue) but for other supine sleeping plays a significant factor.

It's a relatively easy fix for either though....more baseline pressure either in fixed format or more minimum pressure if using auto adjusting mode. Might not need much more...never know until you try....sometimes as little as 1 cm more can make a big difference.

[harryd91]

Thanks - I think you are probably right about the REM thing as I never really sleep on my back. Pretty sure I woke up with a start last night as well whilst dreaming so that seems to add up.

Have increased my minimum pressure to 11.4 now so hopefully that will help. I'm wondering as well if my mask is a little too tight so will loosen that too.

Have been on the CPAP for a couple of months and using the FFM for about 3 weeks. I'm sure it's working as I can actually do things like stay awake all day or lie down and read a book now without nodding off! Have noticed the last week or so I've been waking up far less during the night. But still feel like I'm not 100% there yet so just trying to iron out these issues.

[Miss Emerita]

It's good to hear you've found a mask that works for you and that you're seeing signs of improvement. If the pressure increase doesn't do the trick for the clusters, one other hypothesis to test is that you are somehow tucking your chin down toward your chest. The fix for that would be to try a soft cervical collar or an anti-snore collar.

[Geer1]

I am a bit surprised by how little your pressure setting adjusted considering the number of hypopneas and apnea cluster. Curious if those with more experience feel the same way? Is that to do with it being an older machine that doesn't adapt as quickly as the new ones do? Seems like it would help if the pressure was more adaptive, more minimum pressure would likely help if that isn't possible.

Have you tried increasing minimum pressure prior to this? Seems like your results improved on Nov 8, maybe just due to the FFM and getting used to it though.

[Pugsy]

I am a bit surprised by how little your pressure setting adjusted considering the number of hypopneas and apnea cluster. Curious if those with more experience feel the same way? Is that to do with it being an older machine that doesn't adapt as quickly as the new ones do? Seems like it would help if the pressure was more adaptive, more minimum pressure would likely help if that isn't possible.

The ResMed auto adjusting algorithm underwent a rather major renovation with the release of the S9 models after the S8 models.
Event detection criteria as well as response changed significantly. Back when the S8 was the latest and greatest the fact that S8 users commonly saw large numbers of hyponeas with the machine twiddling its thumbs was a common occurrence.
Can't really compare the S8 to the S9 or AirSense because essentially totally different algorithms involved....apples and oranges despite being same brand.

[harryd91]

I am a bit surprised by how little your pressure setting adjusted considering the number of hypopneas and apnea cluster. Curious if those with more experience feel the same way? Is that to do with it being an older machine that doesn't adapt as quickly as the new ones do? Seems like it would help if the pressure was more adaptive, more minimum pressure would likely help if that isn't possible.

Have you tried increasing minimum pressure prior to this? Seems like your results improved on Nov 8, maybe just due to the FFM and getting used to it though.

When I first got the machine it was set to minimum 4 - I increased to 9 at the end of october and again to 11 on the the 8th which explains the improvement there but as Pugsy says the s8s algorithm typically recorded higher counts of hypopneas and also didn't respond to them.

I guess I probably do need a higher baseline but was hesitant to go much past 11 as I heard it can induce centrals?

[Pugsy]

Higher pressures triggering centrals isn't nearly as common as people want to make it out.
Centrals can be triggered by as little as 5 cm pressure...they aren't something that only happens when the pressures go over 10 cm.
Yes, a few people might have a line in the pressures where above the line the centrals pop up and below it they don't but that's really a very, very small percentage of people who see that happen.

The majority of cpap users won't have an issue with centrals...there are people whose starting minimum pressure is 17 cm...and they don't have anymore centrals than someone whose starting pressure is 7 cm.

Back when the S8 was the latest and greatest everyone tended to believe in that 10 cm line which is why the S8 won't go hyponea killing above 10 cm unless a lot of flow limitations are happening along with them.
The way of thinking about centrals has changed a lot since the S8 machine was the top machine.

[Geer1]

Thanks Pugsy, that is what I figured. Glad to see the technology is improving.

harryd921, your data shows a clear improvement both times you raised your minimum pressure. 9 cm helped and then 11 made a good dent so probably starting to get close. I would keep slowly increasing pressure(0.5-1 cm every few days or once a week etc) and watching data. When the improvement tails off you can decide what you think is the best pressure to set minimum at.

Edit: Flicking through your past days data might show you periods where the pressure increased higher, might be some information worth reviewing as well.

[harryd91]

Thanks everyone - will try increasing gradually and see where that gets me