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

[Albigensian]

Thanks so much for this.

MEDIAN EPAP:   What is it and why do we chase it? 

I don't understand what median EPAP is describing.    Can you clarify this?  I know what a median is, because my profession is statistics-based, but I don't know why a higher or lower median EPAP score would matter.   You write, "But on 18 Aug with EPR=1 you achieved Med EPAP of 8.52. Why? because EPR=1 did not treat the FL as well.  So the machine upped the pressure for you in an attempt for it to try and reduce your FL."   Based on this, it would seem that the goal is to have as low a median EPAP as possible because that means that the apnea is better controlled.  Is that correct?

If it is, though, I am puzzled because my AHI score on 8/18 is so much lower than my AHI score on 8/17.   So, I had much less apnea on 8/18 (especially fewer clear airway events).    So, doesn't that mean that my apnea was better controlled?    

Note:  I'm still not sure how replies are handled in this software.  I think that they go at the end of the stack and not as a direct link to the post to which they are replying.    You'll find my last night's OSCAR score close to this reply, near the end of the stack.   It's a reply to Stacey Burke's advice (which overlaps with yours -- i.e., to raise minimum and put EPR back in place).   

FLOW LIMITS:   what are they?

Thanks for calling my attention to flow limits.   I have not paid attention to them.   What are they?    I have tried to read about them but the OSCAR wiki http://www.apneaboard.com/wiki/index.php/OSCAR_Organization_-_Daily_Page#Flow_Limitation   does not explain flow limits.   All it provides is a picture of a chart.

I do have some day-to-day variation in median flow limits but, scanning through daily reports in the month prior to dropping the EPR and the month after raising it, it does seem to be the case that median flow limit was under .10 for most of the days with the EPR 3/min pressure 5 and over .10 for most of the days with EPR 1/min pressure 5.

Last night, with EPR 3 and min pressure 7, median flow limit was .15 and the chart shows a scramble of spikes during a period of disturbed sleep.    Last night also had a lot of obstructive apneas, though, which was surprising.    It was not a good night's sleep.

Correlations:   yum!  How do I interpret yours?  And track mine?

Yes, I love the idea of keeping track of what the correlations are.   But what's EPR?     Can you give me the names of the items that you're correlating?  I can guess that FL = Flow limits, but what's VT?  MV?   Qo?    Do you have a method for downloading OSCAR data or did you create a spreadsheet and input each day's data by hand?    Thanks for sharing the code to your results and your method for setting up the analysis.

Gratitude:  much!

Thanks for any additional insights you can share with me.     I don't want to spend the rest of my life in a stupor.    The tradeoff (more years of life but spend them in brain fog and lassitude) was starting to seem as if it wasn't worth it.    If I can fiddle with settings and fight off the brain fog, I would be so relieved.

[staceyburke]

I’m sorry that last night was not better. I would try raising the min by 1 to see if that will help eliminate some of the obtrusive problems. Your flow limits are still high a
Nd the rise of the min should help them also

[staceyburke]

Flow limits are apnea the same as O and H events. They are smaller and not timed but apnea all the same. You can see in my signature how apnea is classified. The ResMed raises pressure on flow limits. So if you look at you pressure chart a
Nd the flow limits chart are related.  

Flow limits stop people from getting into deep sleep and can and will wake you up. So the flow limits have a lot to do with the quality of sleep.

[Albigensian]

Thanks, Stacey.   I appreciate your coaching.  I will increase the minimum pressure tonight by one (8 min) and leave EPR at 3.   I'll post again tomorrow.

I am intrigued by your statement that "flow limits are apnea."  What is it that the flow limits chart measuring?  The guide to OSCAR does not explain this. 

Do you mean that, when we get a particular pattern of flow limits, we are in apnea?   If so, what pattern?

I see what it says in your signature but don't know how to translate that into clues about how to read the Flow Limits chart or data.   What does it mean for flow limits to be high?  The numbers on the chart and on the individual day's summary are not in 0-100 -- they are much smaller than that, so I am having trouble translating the numbers on your signature (flow limits 0-50%) into the numbers i see on Oscar.

Last night's chart shows Flow Limits all scrambled and spiked during that early morning period of noticeably poor sleep.   Should Flow Limits be below a certain number?     One person (SevereApnea) commenting on my post suggested that the median flow limit should be below .10 for most folks (presumably, in order for a person to sleep well).    My median flow limit for last night was over that number and the chart shows a lot of bounce.   Should I be looking for stability in how flow limits behaves -- so, the same kind of ups and downs across an entire night?    

I am also trying to understand Tidal Volume.    On-line resources tell me that it's the volume of air moved in and out of the lungs.   When I look back at the nights with high AHI coming mostly from lots of central (clear airway) apnea events, I see that Tidal volume spikes up during those clusters.   Does that mean that I am sucking in more air during those events -- presumably, gasping as my body finally figures out that it needs to breathe?

I am climbing down into the proverbial weeds here, but I am at a breaking point and am intent on learning everything that I can to see what can be modified.    

Thanks so much!

[staceyburke]

ResMed increase in pressure is driven by the flow limits. The pressures rise to stop the fl from becoming O or H events. The O and H events must last for 10 seconds or more ( you can see by how long each of these are by putting the mouse over it - the number there is the number of seconds your event lasted). If the event was less than 10 seconds it is a flow limit.

Hope this explanation make sense.

[factor]

In general CPAP is a foreign thing if we didn't have Sleep Apnea we would never need machines and masks.  So we, our minds or bodies revolt.  We have to overcome that fear and revolt.  We try to think of the most easy way to get by..  Some even just give up and hope to one day just get better..  These things dont generally happen.  We have to commit our minds to wearing the mask and getting used to the pressure.

I wont be as techie as some but hope this helps.

The reason your AHI got better on EPR 1 and your old settings is your airway needs more of a base pressure (I am calling the EPAP the base pressure for simplicity.) to stay open.  Think of the EPAP as the most minimal amount of force to keep your airway from collapsing.  We all need a certain amount if we dont have it the airway sags and gets more narrow. Then the snoring begins.  

4 cmh20 is the lowest the machine can go.  This is mostly for children. Adults usually need at least 7 or higher.  I need 11cmh20.

On min of 5 and epr of 3  The base pressure in the the airway is 4. On the one with AHI 5.44 the median epap 5.86 the 95% is 7.48
On min of 5 and epr of 1  The base pressure is still 4 but the difference is on the one with AHI .93 the median epap 8.52 the 95% is 10.5
This shows you airway stays open better on a higher number.  For most of the night your EPAP was 10.5 and IPAP (pressure) was 11.5

If you want to have a AHI closer to the .93.  You need to set your Min pressure higher. As other have said.  Example: If we want the base pressure in your airway to stay around 8 we would set the EPR 1 with Min Pressure to 9 epap would be 8
with EPR 2 Min pressure would be 10 epap would stay 8
with EPR 3 Min Pressure would be 11 epap would stay 8
These are just generic examples.  Not suggesting you change to this just to help understand the process..

The higher epr make exhaling easier.  Which means respiration is more efficient.  This can bring on TX emergent CA because you breath out more CO2. CO2 is what tells your brain to breath.

The other thing not helping you is Ramp.  The goal is to not have ramp.  So start working that off.  Raise the ramp pressure by 1 and decrease the time by 10 min every week until you meet you minimum pressure then turn it off.

I am sure Stacey and other will help you get there..

[factor]

I am intrigued by your statement that "flow limits are apnea." 

Watch this https://www.youtube.com/watch?v=EDorWmdxnZE

Sometimes a visual is helpful

[staceyburke]

I am going to try an analogy that may or may not make sense to you.  Lets talk about apnea as rain.
 
You are in your car (as you were asleep), and it begins to mist.  It is not enough to even turn on you wipers but you can see the water start to form on the windshield.  You just had a small Flow Limit (fl).  The line on the fl chart is very short but there. 
You drive further and the mist turns into a rain shower, not heavy but now you need to just turn on your wiper once.  You have had another fl this time the line on the fl chart is higher.
As you continue it starts raining harder and you have to speed up your wiper.  You are now in a H event.
It continues to rain and increases to a fairly hard rain.  This is a larger H event.
Now it is even raining harder and it is getting hard to see out the windshield you have moved up to an O event.  That O event could stay raining this hard or it could come as a downpour, raining so hard you can’t see where you are going even with the wiper going full speed.  This would be a large O event.
Now all of this is rain or in our case apnea.  The categorization of apnea is to show the severity of the event.  But all Flow limits, Hypopnea, Obstructive are apnea just as misting to downpour are rain.

[Albigensian]

Thanks, Brent/Factor.

I appreciate the explanations.


I already have Ramp off, so that's not a factor.

Tonight, I am planning on upping min PR to 8 and leaving EPR at 3.    

Questions about EPAP:

But, to keep learning, I want to ask a bit more about EPAP.  The Oscar Wiki says, "EPAP - (Expiratory Positive Airway Pressure) - The pressure prescribed for the expiratory (breathing out) phase of an individual on Bi-level CPAP therapy for OSA (obstructive sleep apnea)."   Prescribed?  I am confused.  That makes it sound as if it is a setting that the DME (or, now, I) would have set up. But, on my daily OSCAR chart, it looks as if EPAP is data (what actually happened) rather than a setting (an order given to the machine).   As I look at last night's data, I see that I had a median score of 8.18 for EPAP, a max of 9, and a 95% score of 8.90.   Mysteriously, there is a "Min 4" stated.   Is that buried somewhere in the clinical settings?  I set the "Pressure Min" for 7, so I don't know where that 4 came from.   Is it there because, as you said, "4 cmh20 is the lowest the machine can go"?  So, the minimum of 4 for EPAP is there by default?

Questions about EPR/Min Pressure:


I am finally beginning to understand that expiratory pressure might be the key to the "clear airway" events.  You write, "The higher epr make exhaling easier.  Which means respiration is more efficient.  This can bring on TX emergent CA because you breath out more CO2. CO2 is what tells your brain to breath."   

Two questions.  (1)  What does "more efficient" respiration mean?   It sounds like a good thing but, if it's bringing on CA's, it isn't such a good thing in my case.    Am I looking for "less efficient" respiration to (somehow) help me to hold on to enough CO2 to keep telling my brain to breathe?   On what chart would I look to see how efficient my respiration was?   
(2)  Does it seem reasonable that EPR, in conjunction with minimum pressure, could affect the rate of obstructive apnea?    Last night, I didn't have many clear airway events.  Excellent!  HOWEVER -- and here's the puzzle -- I had more obstructive events than I had on any of the nights over the past month when EPR was 1 and minimum pressure was 5.   With EPR 1/Min Pr 5, I typically had .5-.7 OA per hour.  Last night, I had 2/hr.  I can't see how obstructive apnea could be affected by EPR/Min Pr settings.    

Flow Limits: I guess I need to understand them, too

Thanks for the link to the video!  That was helpful in understanding what StaceyBurke was telling me about how "flow limits" were a form of apnea.  I still don't have a good grasp of how to read the Flow Limits chart but I am digging around to get more insight.

Much appreciated.  I'll post new data tomorrow.

[Albigensian]

StaceyBurke,

That was a terrific analogy!  I will focus on figuring out how to read the Flow Limits chart.   I am betting that those spikes are disturbing my sleep significantly, along with the more-easily-charted OA's and CA's.

What number should I be looking at to see if Flow Limits are a problem?

OSCAR gives me:    Median, 95% and Max.    Median is almost always zero, no matter what my AHI is, so it can't be useful.   This seems like some persistent error in OSCAR's arithmetic, as the Flow Limit chart can show all kinds of spikes and the median still shows as zero.  Could it be some kind of rounding error?

On the other hand, maybe I should ignore the number and just focus on what the Flow Limit chart looks like.   Do you think that there's any useful information to be pulled out of the Flow Limit chart?  If so, what would I be looking for?    Maybe I am more likely to have my sleep disturbed if there is a big number as the Flow Limit maximum?    

I am puzzled, though, by what I am looking at.   Last night's OSCAR data shows the maximum Flow Limit as .35.  But, when I look at the chart, the tallest spikes appear to go up to .67.    Can you shed any light on this?

If I should just ignore these details until I finish experimenting with Min Pressure, just say so.  It does torment me to see data that I can't interpret, though!!  (An occupational hazard.... )

Thanks for your help.