Advice on setting pressure limits

[esperanca]

I'm new to CPAP treatment; started last week. I woke up numerous times my first few nights but typically do not at all. My pre-treatment in-home test gave AHI of 21 and these first few nights were around AHI 1.4-5.6, suggesting successful treatment, but I didn't feel that great. I got curious, found OSCAR, installed an SD card and now I'm starting to tweak settings.

The machine was given to me with autoset 4-18, EPR 2. On Sep 21 there's quite a few events not flagged because they're not long enough, but they're pretty clearly happening. I'm not sure if the CAs are true or if they're just "incomplete obstructions" flagged as CAs. There's a pretty constant stream of flow limitations that night. I suspect the very frequent pressure changes are waking me up and question their effectiveness. I find it difficult to get back to sleep when pressure is at the low end. Getting back to sleep when pressures are 10-12 has been, perhaps strangely, comforting.

Borrowing advice from other threads I've disabled ramp, turned EPR off and increased min pressure to 7.  Last night was pretty good. I slept well, was up out of bed only one time, and felt pretty good today. (Also starting to get mask leaks under control. I have a beard so some leak is probably inevitable.) Planning to leave settings as is for at least a few nights, but suspect I'll want to bump the min pressure up a little more to 8 or 9.

I'm looking for a little feedback on my data, advice on setting pressure limits and perhaps a little encouragement.
Thanks

         

[G. Szabo]

Your EPR tuning was seemingly beneficial; however, your CAs are not concerning , and you lost the benefit of EPR with the latest setting.
I  suggest your set your pressure min/max to 9/14 cm and EPR=1 full time.
You might want to revisit your EPR  in a few weeks and try to increase it. 

[AshSF]

Stay on a setting for at least 7 nights to evaluate. Then change pressure.

Looking at your charts, I would venture a guess that you will have the best sleep with these settings:
Mode: APAP
Max = Min = 8cm or 9cm
with EPR = 0.

YMMV.

[SeePak]

esperanca,

i agree 100% with  ashsf.

keep the EPR at zero.

I can give lots more information for why, but you can find that here on the website on WIKI,  optimizing therapy, and the EPR discussion.

[SeePak]

Welcome esperanca!

I would like to address some of your questions as well as provide you some encouragement!

Encouragement 1st !!

You have made the move to take ownership of your sleep apnea treatment and you are already taking great strides to that end by 

1...Making a change and wanting to wait to see results !

2..""Borrowing advice from other threads I've disabled ramp, turned EPR off and increased min pressure to 7.  Last night was pretty good. I slept well, was up out of bed only one time, and felt pretty good today. (Also starting to get mask leaks under control. I have a beard so some leak is probably inevitable.) Planning to leave settings as is for at least a few nights, but suspect I'll want to bump the min pressure up a little more to 8 or 9.""

I would have written exactly what you said in your post!! ( i thought it was my words actually, did you by chance copy and paste ?   LOL   just kidding )

Remembering also that Great minds think alike, but fools seldom differ!

That's the encouragement part, and your observations and conclusions/control strategy are so mated perfectly.!

For instance....

You are noticing CA events. 
Here's what's happening.....
You are exhaling CO2 faster than your body needs!
CO2 levels are a signal to breathe and when they go low you basically are told to stop breathing!! (that is the short form)
EPR is causing that, because when the exhale pressure goes lower you can exhale a larger volume for a given breath, 
so CO2 is lowered to a point where the brain says, 'oh, dont need to breathe!
Then you get jostled to wake up, take a deep breath and wipe out more CO2 to an already unstable system and you again stop breathing. !
Viscious circle and it is what happens to me AND i have seen in Oscar charts in the last little while.
This also affects hormones which when triggered can upset you for 90 min. which will also keep you awake, unable to fall back to sleep.


Breathing exercises ( see Patrick McKeown Oxygen Advantage ) will help tolerate CO2 as well, which is the 'air hunger' we feel at many times during our day and during sleep.
It's when we feel the need to gulp extra air, thinking we need more to breathe.
That is the reaction to CO2.
It is known as a phenotype for people with Sleep Apnea.
Low tolerance to CO2 
Some people dont have as little tolerance, like athletes, divers
But luckily we do gulp, during this instance, cause we get full of CO2 during the apnea and need to get that down!

And, biggest point of all, you need  to always have CPAP pressure ABOVE the point you have been titrated in a sleep study, in cm of pressure.
So if you do use EPR, that drop in pressure must remain HIGHER than the Sleep Study Titration Pressure !!

Your plan to have a set pressure AND NO EPR should result in less CA and OA events and MORE QUALITY SLEEP !

So,...

Looking forward to your results, how you're feeling and how that relates to the Oscar charts.



Sorry, forgot to continue with the CO2 sequence....

CO2 is necessary to get oxygen out of the hemoglobin in blood and transferred to our cells thru our body.
Low CO2 levels in our lungs due to this process i described above, deprives our body of oxygen needed for regeneration and repair and energy!

Gotta think thats gonna cause a bad nights sleep over the long haul plus exhaustion and fatigue!

[esperanca]

Thanks everyone. It's really nice to not be alone in this. My family are supportive, but they're not the ones experiencing it. The last couple nights have been fairly good. I'll stick with it for a few more before changing settings.

Part of my day job is optimizing software systems. My first step is understanding how a system reacts to stimulus while in certain conditions. This system (myself+machine) appears to be a similar optimization problem, although a bit more personal this time. Two periods from the 21st are interesting to me.

Zoom 1: Starting from the previous OA there are three periods, each about 9 mins, with the third cut a bit short. There is a small single breath disturbance 9 mins apart and pressure is decaying, but otherwise it's about 25 mins of uniform signal. If I'm interpreting this correctly, minute vent. says I take a larger breath then a few smaller ones to compensate. But then at 3:03 it gets thrown out of whack and I essentially start skipping breaths instead, trying to keep ventilation (minute vent.) to a consistent rate? The last pause is long enough to finally be flagged as a CA event.

   

Zoom 2: Respiration is relatively consistent for over one hour, then something changes at about 4:42:00. Respiration rate increases, then from 4:42:30 to 4:43:30 pressure increases in response to flow limitations. I respond with larger, slower breaths and minute vent. remains relatively stable. Is this how things are supposed to work?

   

[SeePak]

esperanca

the first chart is showing your system reaction to CO2.

One larger breath is enough to clear out CO2, which to the system is a call to stop breathing.
You have a lot of these CA events.
I believe they will be controlled with a drop in EPR
Are you aware of this process?
Check out WIKI, a lot of good stuff there!

In the second, would be good to see the flow limitation here.
You can see how your flow gets smaller for each breath, the machine adds pressure( due to flow limiting) and that gets a larger breath out of you, and you begin breathing with less frequency after that, that is, breath rate decreases a good thing really i think.

Now looking at all this, i dont get too wrapped up in it too often, even with my own charts.
Others will have finer detailed observations i'm sure.

What i see is a lot of CA events that could be controlled better i think with LESS EPR
And that could get rid of some OA events as well.

In general, your flow limits are good, would be best to include them on the graph as well.

Try using the standard graph when you present your results.
The minute and tidal graphs are kind of redundant really, each has their own value i think.

Also, as your thread is about adjusting pressure limits, it is worth repeating that your limits are pretty wide, and i believe unnecessary for your breathing type etc.
The min is too low at 4 on the recent charts your provide, 7 cm as per your personal stats would seem good, maybe 6 cm, but be careful here cause when you use EPR2, that pressure will drop to 4 cm which i am pretty sure will allow OA events in your case.
And the max is way too high, not sure how that could compromise things, maybe pressure change could be faster or slower than necessary etc, not sure?
Others will have more to say about that......

[esperanca]

It's been five nights with min pressure at 9. Here's the past three nights. 
   
   

And last night I fell asleep lying on my back, so that almost certainly contributed to the first hour or two. Not sure about the rest of the time. I'm usually a side sleeper.
   

Not sure what to consider changing next. Increase min pressure more?

[G. Szabo]

Not sure what to consider changing next. Increase min pressure more?

Indeed, higher pressure would be best to reduce flow limits and eliminate Hs. Your CAs are still not an issue.
I  suggest you set your pressure/max to 11/15 cm and EPR=1 full time.
You might want to revisit your EPR  in a few weeks and try to increase it

[Phaleronic]

esperanca,

i agree 100% with  ashsf.

keep the EPR at zero.

I can give lots more information for why, but you can find that here on the website on WIKI,  optimizing therapy, and the EPR discussion.

Yep, please don't turn EPR up on a whim, it does more harm than good. Your 99.5 percent pressure is 15.7cm and there are quite a bit of pressure changes in those charts, so I suggest moving over to cpap mode (you can use EPR if the pressure is too much during exhalation), set mode to cpap set pressure to 16cm and EPR on 1 fulltime, if you can handle that, try it for 30 minutes before bed please.