Brain fog, lack of energy -- why did dropping my EPR make such a difference?

[staceyburke]

The numbers are hard to understand. A flow limit by definition is 0 to 50% obstruction. The chart show a % of that. So topped out it would be 100% of 50%. If it is 50% it would be 50% of 50% or 25% blockage. 

Like I said hard to understand the numbers.  I look for the height of the line, close Groups and if any look like a mountain shape (which would indicate a longer event rather than a short event).

Remember these are not timed - anything under 10 seconds. .

[SarcasticDave94]

Great analogy Noah. No really it's a good working description.

If it still is necessary to help teach our OP Albigensian about Central Apnea, I'm aware of 3 types of Central Apnea. My description follows.

1. treatment emergent, meaning you didn't have an issue with Centrals before CPAP usage. You can know if this application is true if you had little to none CA on your sleep diagnostic report. Diagnosic is the test without PAP. They wired you up, you probably slept, they tell you that you had this amount of sleep with x events and were this or that type. To see for sure what the report says, request your DETAILED copy for yourself. HIPAA law permits you to request and receive.

1A. Treatment emergent will be likely if the diagnostic had less than 50% total events as Central, but you had CA appear during PAP use and/or during Titration, the sleep test with PAP and mask with varying pressure sets. You can and should ask for this test result also.

1B. To treat the TECA, avoid the cause with appropriate settings like EPR or on BPAP, a low PS setting. Avoid Ramp also. Why do TECA occur? PAP makes your formerly low efficiency breathing higher than what your body has labeled normal. TECA will likely diminish with time as the body reprograms itself to it's new more efficient breathing with PAP.

2. Next up is the Central Apnea I call pre-existing or pre-dominant, meaning they showed up on the diagnostic test in 50% or greater than Obstructive. This is my type BTW. This type CA can't be avoided in CPAP APAP BPAP machines that don't have breath backup rate capability. Machines that actually treat pre-existing CA are ASV as best choice, secondly ventilator types with AVAPS and a backup rate.

3. Next is idiopathic centrals, or a fancy way of saying medical cause unknown. Treatments likely follow pre-existing CA in category number 2.

[Geer1]

I have to disagree with Staceys definition of flow limitations and I think it is confusing the topic.

Flow limitations are not the same as apnea, nor are they the same as hypopneas. The value Resmed assigns to flow limitations is complex and not a simple percentage of restriction. Some information on its value can be seen at this link.

http://www.apneaboard.com/wiki/index.php...limitation

The best way to think of flow limitations is that they are individual breaths that show signs of restriction. Higher flow limitation value assigned by Resmed means that individual breath had more restriction based the complicated formula they use.

Apneas are cessation or near cessation of breathing (80+% reduction of flow) for at least 10 seconds. Hypopneas are a 50-80% reduction of flow for at least 10 seconds. Hypopneas can be caused by partial apneas, shallow breathing or flow limitations although many times flow limitations do not end up triggering hypopneas flags because of a slow gradual decrease of flow rather than fast 50% reduction required for a hypopnea.

There are 2 main variables for treating apnea. EPAP (minimum pressure which on an autoset is pressure - EPR) and PS (which on an autoset is EPR). EPAP is the pressure that holds your airway open and prevents it from collapsing. If you are having obstructive apnea then you often need higher EPAP (although there are instances it doesn't help and too high of pressure can also cause issues). When using APAP mode like you are then EPAP fluctuates so you need to look at what EPAP was when obstructive apneas occured not determine it from min or max pressure settings. Since EPR gets subtracted from pressure on these autoset units higher EPR causes lower EPAP (at least at the beginning of the night before pressure increases from APAP mode) and this can cause more obstructive apnea if you increase EPR without also increasing pressure.

PS/EPR helps increase air flow through airway. This helps treat flow limitations because flow limitations are only a partial restriction so the extra pressure increases air flow through this restriction. PS/EPR can make central apnea worse because this extra flow reduces carbon dioxide levels in your lungs which reduces carbon dioxide levels in your blood. Carbon dioxide levels in your blood is what your brain uses to decide when it needs to breath so if carbon dioxide levels are low it may decide to take a break from breathing (central apnea) until carbon dioxide levels rise and kick start breathing effort again. Treatment emergent central apnea occurs in some patients because the CPAP machine lowers carbon dioxide levels below what their body was previously used to, sometimes they will go away after your body gets used to having lower carbon dioxide levels (but sometimes they do not).

So self titrating CPAP is as follows.

Step one: find minimum EPAP that stops majority of obstructive apnea from occuring. With an APAP machine you can leave pressure a bit low and allow it to adjust but you don't want to set it too low. They key to remember is these machines only increase pressure after your breathing has been an issue, they aren't proactive nor do they use old data to determine where an effective minimum EPAP is. That is your job in this first step.

Step 2: Use higher EPR to treat flow limitations or lower EPR to reduce centrals. Find the point where you maximize EPR without inducing too many centrals and then over time if centrals become less common you can continue to try raising EPR to further treat flow limitations. Remember when you adjust EPR is also affects EPAP setting so you want to adjust both in tandem once you have determined ideal EPAP levels.

Treating flow limitations often gets high priority on here but as you noticed central apnea can actually cause more issues than the flow limitations. It is often more important to minimize centrals and then slowly try to test the flow limitations. Not all flow limitations need to be treated and neither do all apnea need to be treated. The key is to find the balancing point that gives you the best overall results and this is often determined by how you feel rather than data and chasing 0 apneas/flow limitations.

[Gideon]

The Flow Limit chart
Flow Limits are one of several factors ResMed uses in it's algorithm to indicate an increase in pressure is needed. On a ResMed machine you will see a high correlation between the Flow Limit Chart and pressure increases. Just as you are having issues identifying flow limits ResMed (your machine ) has similar issues. What ResMed came up with is a "Flatness Index" which is what is actually charted the Flow Limit chart. Look at the flow limit chart and the Flow Rate chart in a zoomed view where you can see the individual breaths.

See these parts of the OSCAR Guide.
http://www.apneaboard.com/wiki/index.php...tucking.29
See how the tops of the breaths are clipped, flat, or jagged. These are flow limits. The following chart shows how the top of the breaths look and their specific cause.
The goal would be to have most of your breaths rounded which is normal.
http://www.apneaboard.com/wiki/index.php...low_shapes

[Geer1]

From Gideon's link the RERA example later on does a great job of proving that Resmed flow limitation recorded value has nothing to do with flow rate restriction.

5:35:55 there is a clearly flow limited breath but no flow limitation value recorded. 5:54:00 to 5:54:45 the flow limitations are roughly constant but reported flow limitation value varies from 0.1 to 0.8.

http://www.apneaboard.com/wiki/images/5/52/RERA_1.png

Flow limitation reported values are at best an indication of flow limitation severity.

[SevereApnea]

Fascinating thread with great input by all. (Health warning: another Loooonng post [yawn] )

@Albigensian

Nasal vs Full face Mask:

Certainly worth a go, you will only know if you have tried it for a while, a week maybe.

Best not to overthink this. Just try it.

For me: 
Nasal mask = uncontrollable mouth leaks.
(side note: nasal mask leaks still occur but less of a problem)
The leak occurs because the pressure in the mouth from the CPAP is higher than atmospheric pressure.
Your mouth acts like a valve: if the valve has a high threshold for leaks to occur, you won't mouth leak.
If your mouth leak threshold is low, you will need to control the "valve" with something like mouth tape, Alice bands, other stuff.

Oranasal mask (aka Full Face mask) won't give you mouth leaks per se...*
Why? because the pressure inside the mask is the same at the level of your nostrils and your lips. 
Hence you eliminate the Mouth Leak ...

*Unless you get mask leaks first: so you get mask leak first, the pressure in the mask falls and if it falls below your mouth leak threshold, then you have both mask leaks and mouth leaks, dry mouth, more fun etc! If you can control the mask leaks you will be up and running!

AHI
Once your AHI is less than 5 and you are feeling OK then there is so much day to day variation between AHI readings it's not worth stressing about.
The goal is not AHI 0, in fact I regard that as overtreated.


Eventually you won't even focus on the AHI, just how you feel. 

Obtructions:
I ignore my OSA score. I only worry about them if the OSA are long, say 30 - 50 seconds and clustered.
Other than that they are normal, and I am quite happy with them. Most of us have them. That is why a normal value for AHI is < 5 and not = 0.

I try (hard!) to ignore the day to day variations: and prefer try and look for trends. Wood for the trees etc.

Flow limits: enough discussion already. Don't try and understand the Proprietary reasons for the difference of appearances of
FL chart and numbers. As Gideon said in #24 if you really want to see FL zoom in on the Flow Chart.

"It does torment me to see data that I can't interpret, though!!"

Yes it can do your head in. The numbers you want to focus on are the ones that make you feel better.
Establish a scoring for yourself wrt sleep quality, side effects etc and then try and establish what effects what.
Try and find a pattern between the two. You are well on the way already!

@SleepHenry.
Exactly, that's right, for me, maybe not others.
There are many other factors that effect this, for example: random variation (each night is different), sleep deprivation, pressure settings, diet,
level of hydration, exercise, stress, medication and many more.
Still I find these are significant correlation numbers.
How many nights? N= 264 running total for this year 2021.

Lastly, and hopefully to put an end to this long post of mine here is some more data, if you like that kind of thing.
[attachment=35884]
Last year I looked at days where I had the same Pressure Settings and Machine Settings and the same mask.
I only changed the EPR and looked at the effect on the Achieved Median EPAP and 95% EPAP.
When I lowered the EPR (red numbers) the EPAPs went up (green numbers) and vice Versa.
For example between 20 and 21 March the increase in EPR from 0 to 3 gave a fall in EPAP values and so on.

I just include this in response to your original post and hope this gives you some idea of how this kind of works for some of us. 
Of course if you change the Min Pressure and Max Pressure and EPR at the same time things will get a bit more messy!
Caveat Emptor etc.

So if you are on a fixed CPAP of say 7 cm H20 with EPR 0 and you then want to increase the EPR to 1 for some reason, you will want to also increase the CPAP value to around 8 cm H20 otherwise your EPAPs will fall to around 7, and may fall below the level you need to stave of (most of) your Obstructions.

Hope this helps a little.

Above all, have fun with this.

Glad to see you taking ownership of your own therapy.

[Albigensian]

Thanks, SD!    To help anyone reading this thread to see if it applies to their case, I want to explain that the available evidence suggests that I have treatment emergent central apnea.    I did an at-home sleep study (attached to my original much-too-long-and-too-detailed post) that classified 87% of the apneas recorded as "obstructive" and 4% as "central."   So, if that at-home sleep study report is reliable, I have what SD defines as treatment-emergent central apnea.

As SD notes, this generally goes away as the person using the machine gets used to it.  In my case, though, that did not happen:   I'm almost 11 months into therapy and have been stumbling around in a stupor for a very long time!  

SD defines treatment-emergent apnea as:   "1. treatment emergent, meaning you didn't have an issue with Centrals before CPAP usage. You can know if this application is true if you had little to none CA on your sleep diagnostic report. Diagnosic is the test without PAP. They wired you up, you probably slept, they tell you that you had this amount of sleep with x events and were this or that type. To see for sure what the report says, request your DETAILED copy for yourself. HIPAA law permits you to request and receive."

[SarcasticDave94]

OK if you're still having issues with Central Apnea after 11 months of PAP therapy, this becomes more like idiopathic CA, unknown medical cause. If idiopathic CA applies then a machine like a ResMed AirCurve 10 ASV is going to be a better therapy choice. To get there, you need to talk with your doctor about the poor therapy results. Ask to get a titration using ASV, or BPAP then to ASV settings to see results.

What does a current standard OSCAR show? Be ready to show other views of others ask so they can dig deeper into the data.

[factor]

Based on the 2 Daily screenshot you provided.  The reason you have TXeCA still is because you have been on the wrong pressure settings for 11 months.  Most anytime you change settings you can expect some CA.  Its like turning up and down the Air condition it wont just change immediately.  Even when you get everything dialed in you will still have CA every now and again.  Likewise if you gain or loose 10 pounds or go on some new medication it might change.  An example for me is if I eat any kind of Dairy after around 3pm my AHI will be higher.  

Once you find a good setting you need to stay on that for weeks to see if you can string some good nights together.

Can we get some new Screenshots?

[Albigensian]

Thanks, SD.   I think it's pretty clear that my "clear airway" events (as they're called in OSCAR) are treatment-emergent central apneas.    My at-home sleep study is attached to my first post.    It shows 87% of my apnea events as "obstructive" and 4% as "central," so it didn't suggest that I had pre-existing central apnea.  I don't think that there's anything more detailed that I could request from that at-home sleep study:   it was a simple affair, with a monitor around my chest, a clipped-on pulse oximeter on my finger, and an nasal cannula.   You can't get the same level of detail as you get with an in-lab sleep study.  Despite that, though, it was clear about the predominance of obstructive apnea.

SD points out that TECA typically disappear over time, but I started on therapy 11 months ago and they didn't start to retreat until I began fiddling with the EPR and minimum pressure about a month ago and got the results that have led to this thread's heading.

So, for anyone reading this thread to see if their problem is covered in it, I'm learning that my "clear airway events" are what SD describes here:   "1. treatment emergent, meaning you didn't have an issue with Centrals before CPAP usage. You can know if this application is true if you had little to none CA on your sleep diagnostic report. Diagnosic is the test without PAP. They wired you up, you probably slept, they tell you that you had this amount of sleep with x events and were this or that type. To see for sure what the report says, request your DETAILED copy for yourself. HIPAA law permits you to request and receive.

1A. Treatment emergent will be likely if the diagnostic had less than 50% total events as Central, but you had CA appear during PAP use and/or during Titration, the sleep test with PAP and mask with varying pressure sets. You can and should ask for this test result also.

1B. To treat the TECA, avoid the cause with appropriate settings like EPR or on BPAP, a low PS setting. Avoid Ramp also. Why do TECA occur? PAP makes your formerly low efficiency breathing higher than what your body has labeled normal. TECA will likely diminish with time as the body reprograms itself to it's new more efficient breathing with PAP.