Low AHI, High Flow Limit, Unrested

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
cby1
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Low AHI, High Flow Limit, Unrested

Post by cby1 » Mon Nov 28, 2016 4:13 pm

Hello again. I've been trying to figure out why I feel bad with good AHI. I've been assuming that it's been something "non-CPAP" (psychological, medication, sleep hygiene) - and maybe it is. But in the last month, I've seen RERAs become much more prominent, and the flow limit charts aren't looking good (to me). I'm the same guy who used to get a lot of Centrals after 7 1/2 hours. That doesn't seem to happen now - if I get them, they are OAs instead.

I'd like to know how bad this is, if it looks like remaining UARS after apnea correction...you can see the CPAP (they never want to give me that BiLevel) maxes at 20 from time to time. Seems like when it's maxed, I'm probably getting rid of the flow limit via arousal.

I don't know what's changed, but I don't recall the FL looking this bad in the past. I recently had my 5th sleep study in 11 years (new sleep doc) - and again, they insisted on using a CPAP, even though I see 20 cm often enough (no EPR and no Humidity at that). Slept through it pretty much anyway. No results yet, should get them 12/7. Should have asked the doc to have them pay attention to the RDI and the RERAs. Maybe they did.

Pressure is 14-20 cm - need to go change my .sig.

Anyway, here's the screenshots - please tell me what you think. Ignore the second period - I was essentially awake for most of that.

Image

Image

I see the flat-topped individual waveforms, which I gather indicates restriction also.

Thanks.

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avi123
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Re: Low AHI, High Flow Limit, Unrested

Post by avi123 » Mon Nov 28, 2016 4:35 pm

Between 06:00 and 08:00 you had large leak rates and the Resmed APAP could not diagnose your events.

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cby1
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Re: Low AHI, High Flow Limit, Unrested

Post by cby1 » Mon Nov 28, 2016 4:49 pm

Correct. That (leaks) does not happen every night, however.

AHI < 3 happens 95% of the time, and unrested 100% of the time. I was not clear in my first post - this is a trend.

FYI, I've been on CPAP for 11 years. The "unrestorative sleep" thing was always there, and has gotten worse in the last 3 years. That said, with an untreated AHI of 78.1, I clearly need PAP.

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avi123
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Re: Low AHI, High Flow Limit, Unrested

Post by avi123 » Mon Nov 28, 2016 5:05 pm

What are you asking? Fix the leak first thing.

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Mask: Mirage™ SoftGel Nasal CPAP Mask with Headgear
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Additional Comments:  S9 Autoset machine; Ruby chinstrap under the mask straps; ResScan 5.6
see my recent set-up and Statistics:
http://i.imgur.com/TewT8G9.png
see my recent ResScan treatment results:
http://i.imgur.com/3oia0EY.png
http://i.imgur.com/QEjvlVY.png

cby1
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Re: Low AHI, High Flow Limit, Unrested

Post by cby1 » Mon Nov 28, 2016 5:46 pm

*Sigh*. Here's another of many shots that show a similar phenomenon with almost no leaks. Leaks are not the rule. My original post asked the questions, but I'll spell them out.

1. Is this Flow Limit chart "bad" - especially when my CPAP is maxed at 20 cm at the time?

2. Does this pattern of low AHI and high FL suggest some "residual UARS" after the events have been dealt with?

3. General reactions, given my complaints - can someone *other than avi* weigh in please?

Image

Thanks.

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Wulfman...
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Re: Low AHI, High Flow Limit, Unrested

Post by Wulfman... » Mon Nov 28, 2016 5:55 pm

cby1 wrote:*Sigh*. Here's another of many shots that show a similar phenomenon with almost no leaks. Leaks are not the rule. My original post asked the questions, but I'll spell them out.

1. Is this Flow Limit chart "bad" - especially when my CPAP is maxed at 20 cm at the time?

2. Does this pattern of low AHI and high FL suggest some "residual UARS" after the events have been dealt with?

3. General reactions, given my complaints - can someone *other than avi* weigh in please?



Thanks.
Check your PMs.


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palerider
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Re: Low AHI, High Flow Limit, Unrested

Post by palerider » Mon Nov 28, 2016 6:05 pm

cby1 wrote:*Sigh*. Here's another of many shots that show a similar phenomenon with almost no leaks. Leaks are not the rule. My original post asked the questions, but I'll spell them out.

1. Is this Flow Limit chart "bad" - especially when my CPAP is maxed at 20 cm at the time?

2. Does this pattern of low AHI and high FL suggest some "residual UARS" after the events have been dealt with?

3. General reactions, given my complaints - can someone *other than avi* weigh in please?
this is unusual for me, but I'd suggest, if you haven't, to try turning up the EPR. short of getting a bilevel machine to help ventilate you better through the flow restrictions, that *may* help.

it's free, and easy to try.

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Re: Low AHI, High Flow Limit, Unrested

Post by cby1 » Tue Nov 29, 2016 11:28 am

Thanks. I had the EPR at 3, and then tried 2, now 1 - seems like I feel a bit better in the morning on 1. What I don't really have is enough direct data comparing Flow Limit at the various EPR levels.

I tried lower because I've always used the highest EPR setting, and the sleep study used none - and I tolerated it. I also sense the machine doing it's puffing thing to check the airway at the end of exhalation sometimes - that doesn't seem to happen at EPR = 1. But clearly there's still lots of FL. I should have made it clear that the EPR = 1 was a new thing - an experiment.

I will be pushing for BiLevel (again) when I talk to the sleep doc on 12/7.

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OkyDoky
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Re: Low AHI, High Flow Limit, Unrested

Post by OkyDoky » Tue Nov 29, 2016 11:44 am

By decreasing your EPR you are actually decreasing the amount of time that you are at a lower pressure. You would need to monitor to see how that effects the FL's. I would think it would help. There are 2 ways to look at it. You could not use EPR or increase min pressure a bit and use EPR. Whichever is most comfortable and produces the results that you want.
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PEF
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Re: Low AHI, High Flow Limit, Unrested

Post by PEF » Tue Nov 29, 2016 12:29 pm

You know, I have been trying to figure out why I also feel really tired during the day often, about half the time when my AHI is always low enough to figure my apnea is technically treated.

I have 2 distinct type of nights:

1. Nights when my insomnia causes me to have a lot of trouble getting to sleep and sleeping lightly most of the night. The next day I feel really tired and crabby by noon and need a nap. I also may have a headache most of the day. My graphs look great on these nights, except for the constant activity on FL's and pressure on the graph wanting to go higher. I feel like crap, but my sleepyhead reports look great, not much leakage.

2. Nights when I sleep very well and deeply and do not feel at all tired the next day. On these nights, my AHI will be a little higher, but nothing to worry about. I will usually have somewhere between 1% and 10% in Large Leak territory. My pressure graph is showing pressure plastered against the ceiling most of the time I was asleep. FL's are higher. Insomnia does not bother me these nights, but I will have the impression of awakening several times, maybe 3 or 4, with dry mouth, needing to swallow, sore throat or stuffed nose, or fighting to keep my mask on. I will often awaken in the morning with a sore throat or stuffed nose that goes away after I am up about an hour. I feel really well rested, but have these LPRD (reflux) symptoms.

I also think I have UARS and, while my machine has helped with some of the symptoms, it has not treated it successfully.

I think this forum needs more threads on UARS and some experts.

Right now, I am running pressure at min.7.8 and max. 8.0. I am close to being in CPAP mode. If I lower the min, things get worse.

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PEF
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Re: Low AHI, High Flow Limit, Unrested

Post by PEF » Tue Nov 29, 2016 4:16 pm

Here is an interesting discussion I found on UARS from 2005 to 2009. lately, I have been doing a lot of reading about it.

viewtopic.php?f=1&t=40009&st=0&sk=t&sd=a&start=15

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Wulfman...
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Re: Low AHI, High Flow Limit, Unrested

Post by Wulfman... » Tue Nov 29, 2016 4:41 pm

PEF wrote:Here is an interesting discussion I found on UARS from 2005 to 2009. lately, I have been doing a lot of reading about it.

viewtopic.php?f=1&t=40009&st=0&sk=t&sd=a&start=15
Thanks for digging up and posting that link. Lots of interesting discussions in the forum archives on just about any subject.
Brings back memories and for some of those folks who haven't been on the forum for some time, I hope they're doing well.


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Jimmycrackhorn
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Re: Low AHI, High Flow Limit, Unrested

Post by Jimmycrackhorn » Wed Nov 30, 2016 6:09 am

Just commentating so I read all this later. I'm having similar problems.

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robysue
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Re: Low AHI, High Flow Limit, Unrested

Post by robysue » Wed Nov 30, 2016 9:53 am

cby1 wrote:*Sigh*. Here's another of many shots that show a similar phenomenon with almost no leaks. Leaks are not the rule. My original post asked the questions, but I'll spell them out.

1. Is this Flow Limit chart "bad" - especially when my CPAP is maxed at 20 cm at the time?
Perhaps. It depends on whether those FL are "real" or are artifacts that are being created by the pressure. Sludge used to occasionally post on this idea---that some people's breathing can become a bit less stable when too much pressure is applied.
2. Does this pattern of low AHI and high FL suggest some "residual UARS" after the events have been dealt with?
Maybe. Maybe not. See #1.
3. General reactions, given my complaints - can someone *other than avi* weigh in please?
Well, I'm not avi, so here's my two cents. You also write:
I've been assuming that it's been something "non-CPAP" (psychological, medication, sleep hygiene) - and maybe it is.
Because of this statetment, I'd also continue looking at several other potential causes of your current situation.

First: Non-OSA related sleep problems.
Any reason to believe that you are waking up a lot during the night? Any sense of spending a lot of time tossing and turning and semi-awake? How long does it take you to get to sleep at night?

On the night you posted the data, you apparently didn't go to bed until 3:15 and you got up at 9:50. That's only about 6 1/2 hours of machine time. Any chance you just need more sleep? Have you tried pushing bedtime back to 2:15 or 1:15? What happens when you go to bed earlier?

Since you mention "sleep hygiene" as a potential problem, that's something else we need to give serious thought to, particularly in light of the fact that on the night you posted, you got to bed very late and only slept for at most 6 1/2 hours.

Do you have a regular sleep schedule? If so, what's it look like?

How much caffeine are you consuming? What about alcohol?

How much daily exercise do you get? Do you get outside in the daylight for at least a few minutes every day? If so, when?

Do you spend a lot of time reading, watching tv, or web browsing in bed? Do you build in some "down time" before going to bed each night?


Second: Lifestyle considerations.
You mention "medication" and "psychological" as potential factors in how you are currently feeling What medications are you on? Any of them new? Any dosage changes?

Any excessive stress in your life? If so, is there a way to manage it?

Are you eating well? Are you taking care of yourself? Do you get enough exercise?


Finally: CPAP tweaking
Definitely bring up the idea of RDI and RERAs with the new sleep doc on 12/7. Also specifically ask the doc about your concerns about how much time you are spending at 20cm and whether a bilevel that can go to 25cm is warranted.

But also keep an open mind to the idea that it may be possible that your airway is not responding as expected to the high pressures. As I mentioned earlier, Sludge used to occasionally post on the idea that too much pressure can cause airway instability and that sometimes the answer is less pressure rather than more.

On the night you posted the data for, the lowest parts of the FL graph seem to correspond to places where the pressure has been decreasing for a while. Now it could be that the max pressure finally started stabilized the breathing OR it could be that the breathing actually started to stabilize after the pressure went down. It's difficult to tell from the "all night" picture since we can't see the individual breaths at this scale in the flow rate.

It might be useful to show close ups of the flow rate, pressure, and FL graphs for the following time windows:

4:30-4:45
4:45-5:00
7:40-8:00

Note: I don't want one picture from 4:30-5:00 because that's too much time to really see the shape of the inhalations in the flow rate graph. So please break it up into 4:30-4:45 and 4:45-5:00. And we need to see flow rate, pressure, and FL graphs.

Looking at some of the individual inhalations that are being flagged as "flow limited" may help give us a better idea of whether the FL are real or artifacts.

If you are wanting simple tweaks:

Try PR's suggestion of turning EPR up to 3cm and see what happens.

Try narrowing the pressure range. You might try using 15-19 for a few days. If the number of obstructive events does not increase AND there's any improvement in the FL curve, you could then try using 16-18 for a few days to see if things get better or worse.

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cby1
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Re: Low AHI, High Flow Limit, Unrested

Post by cby1 » Wed Nov 30, 2016 12:24 pm

Thank you Robysue - thorough as always. Answers below:
Any reason to believe that you are waking up a lot during the night? Any sense of spending a lot of time tossing and turning and semi-awake? How long does it take you to get to sleep at night?
Not really - although some nights I will wake up every few hours - not clear what the cause is. I usually drop off within 10-15 min.
On the night you posted the data, you apparently didn't go to bed until 3:15 and you got up at 9:50. That's only about 6 1/2 hours of machine time. Any chance you just need more sleep? Have you tried pushing bedtime back to 2:15 or 1:15? What happens when you go to bed earlier?
I do need more - generally get 7 1/2 - 8 - machine is always on - for 11 years . And yes, I need to get to bed earlier.
Do you have a regular sleep schedule? If so, what's it look like?
No - and that's an issue. Tends to be 1-9, but varies. That's my fault.
How much caffeine are you consuming? What about alcohol?
No Caffiene (anxiety issue; not clear if OSA caused, or "primary" anxiety). Alcohol, 2-3 beers (*not* under-reported) with dinner most nights.
Do you spend a lot of time reading, watching tv, or web browsing in bed? Do you build in some "down time" before going to bed each night?
Nothing in bed - but I also don't schedule any down time.
You mention "medication" and "psychological" as potential factors in how you are currently feeling What medications are you on? Any of them new? Any dosage changes?
Any dosage changes would have been minor. Let me PM you the list.
Are you eating well? Are you taking care of yourself? Do you get enough exercise?
Diet could use improvement; I do cardio 6-7 days/week, resistance training 1x/week. Currently also PT for a long-standing back problem.

Regarding the EPR, it had been at 3 since I got the machine in April (until my recent experiment). I will consider the pressure range tweaks with EPR at 3 - they sound reasonable. Images for periods you requested:

Image

Image

Image

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