intermittent sky high leak rate

[BB63]

I just had my second night of improved sleep thanks to the EPR change, so I guess the improvement wasn’t a fluke! My mask leak improved also, and my tape for keeping the mouth sealed should arrive tomorrow!

Here are a few of the zoomed in Flow Rate anomalies I mentioned previously, see attached pdf file. Are these ‘suspected’ anomalies significant, or are they just typical/normal-ish? I’m asking because my sleep still isn’t right despite the recent improvement and I am concerned that I might be having arousals which prevent deep sleep.

I'm researching arousal detector methods now.

The attached PDF contains the complete OSCAR data summary and some zoomed in Flow Rate data, with notes.

TY


AB

[Dormeo]

I believe the underlying cause of the pauses between breaths is that you are currently somewhat close to your "apneic threshold."

We get the "breathe now" signal from our neuro-chemical regulatory system when the CO2 levels in the blood rise to a particular level. If more efficient breathing is washing out some CO2, then the levels may not rise as quickly as they might, resulting in a pause between breaths. If the pause is long enough, it's a central apnea event. At an extreme, people using high pressures, or high pressure support/EPR, will see an increase in CAs. With time, our bodies often adapt, and this phenomenon abates.

The repeated pattern is related. You are seeing a subtle waxing and waning of breath. My understanding is that the waxing creates a bit of a washout of CO2, which then somewhat decreases your urge to breathe -- not entirely, but your breaths become less deep. After some of that waning breath, the CO2 builds back up and you breath more deeply. After some repetitions, things settle back down.

None of this is anything to worry about. You're not even having central apneas as part of this phenomenon. It is all very likely to sort itself out, and even if it is slow to do so, it's nothing to worry about.

About machines: it's early days, but it looks as though you might well benefit from more pressure support/EPR than the Autoset can provide. So you might want to consult the Supplier List (top of the page) and start keeping your eye out for a used ResMedVauto Aircurve.

In the meantime, you can see you you feel as the EPR of 3 continues and as you get your leaks under greater control. If you start sleeping well and feeling good during the day, I wouldn't mess with success. But if you still feel you're experiencing problems, a VAuto would make a good next experiment.

[BB63]

TY Dormeo,

I would have never guessed that it might be a lack of CO2 in my body!!!! But, the cyclic nature of the anomolies seen in the zoomed in flow rate supports the "apneic threshold" issue, I think.

Last night was my first night with Somnifix, so here's an update on the Large Leak issue. I had a several Large Leaks, but far less than I had without the Somnifix tapes. I was impressed how well the adhesive held up! Despite the manufacturers recommendation that they shouldn't be reused, it seems like the adhesive is still in good shape and I will probably try reusing the same strip tonight.

==========

Further, I found that my AHI had dropped from ~1.5 down to .14, with only one Hypopnea during my entire sleep period. I also had a single RERA. I was stunned! I'm not sure if the reduction in AHI was caused by a pressure change I made though, I did drop the max pressure very slightly last evening (from P Max 14 to P Max 13.6).

But, here's the RUB........

When I zoom in on the Flow Rate plot, I see no reason for the Hypopnea event! But, the marker for it is there on the trace. The 4 breaths that happen just before the Hypopnea event are identical and consistent, there is no 10 second lack of flow to cause the Hypopnea event.

I've attached a zoomed in Flow Rate and a screen capture showing the the entire sleep session.

Why did the CPAP flag this Hypopnea when the plot doesn't show 10 seconds of abnormal Flow Rate immediately proceeding the Hypopnea marker?

AB

[Dormeo]

Congratulations on the AHI and leak control! Would you say you feel more rested today, or are things about the same?

The flags for hypopneas (and flow limitations) generally lag the events themselves. It looks to me as though the H flag is for the series of breaths starting just before 2:28:15. I think what actually happened was that you had an arousal and knocked your mask loose, with the ensuing brief large leak making it hard to say what was actually going on.

I note that your flow limitations are worse with the minimum pressure of 8.6 than they were with the minimum of 9. If you're feeling well rested, then stick with whatever settings are most comfortable for you. If you think you could feel better rested, however, you might consider inching the minimum up, .02 cm at a time, waiting a few days between changes to see how it goes.

[BB63]

WOW, TY!!!!

I already bumped the pressure up slightly, after realizing the Flow Limit got worse-the small reduction I made was for testing only and was temporary.

I noticed there were event's well before the Hypopnea was flagged, but I don't think I ever saw another trace with such significant lag, my memory is that the events are immediately after the Flow Rate flatlines for 10 seconds.

The Leak Rate event might have happened while I was not fully asleep yet, I have a memory of not going to sleep right away...so I might have been shifting position when the Leak Rate soared!

I'm loving those Somnifix strips-they sure did eliminate most of the Leak Rate issues!

Not sure if I'm feeling more rested though-my first impression upon waking is that my sleep wasn't improved. Will see how the day goes though.

TY

AB

[Dormeo]

Yes, my observation is that the lag occurs with hypopneas and FLs but not with OAs or CAs. Keep us posted, and do keep careful track of how you feel. With your AHI and leaks in such good shape, the subjective assessment will be especially important.

[Gideon]

Note that hypopnea is not tied ti a single breath and a 'single' event can be a reduced volume over several breaths being lower than a moving average which is what this appears to be.

[Dormeo]

Thanks for the clarification, Bonjour. I hadn't understood that a moving average is used as a (moving) benchmark. Good to know!

[Gideon]

Ask yourself, how does your machine know what YOUR normal is, as opposed to MY normal. This is how. And it is one reason why flow limits often get seriously underreported

[BB63]

Ask yourself, how does your machine know what YOUR normal is, as opposed to MY normal.  This is how.  And it is one reason why flow limits often get seriously underreported

The most recent posts by Bonjour and Dormeo speak VOLUMES, and makes damn good sense and for me at least, it ties together much of the recent info I've acquired by reading the forum and looking at my own raw data. The concept of 'averaging' is one subject that doesn't seem to be made clear from reading documentation and clinical definitions that lay people have access to!

Thank you both for making this clear!

Regarding Flow Limits, which I still have....even though the pressure isn't quite maxed out, I still get flow limits to some degree. Increasing the EPR to 3 greatly improved the Flow Limits for me. However, I am at times (not all the time) still getting brief periods of Flow Limits in the 25 to 35% ranges. And, it's been suggested that I need a BiLevel machine that has a treatment algorithm that I could benefit from. But, I'm still curious as to WHY/HOW my Flow Limits exist without having the pressure maxed out? Doesn't a Flow Limit require a maxed out pressure before it is flagged as such? Or, can the CPAP predict (or hypothesize) the Flow Limits existence by merely looking at the slope of the  inhalation and exhalations in the Flow Rate data?

The forum is invaluable to me-I hope others appreciate it and recognize the good work done here as much as I do.

AB