Newbie's first post-Sleep Onset Central Apneas & Other ?

My vote is for a little more EPAP minimum first. Going back to the old stand by...EPAP for OAs and IPAP for hyponeas.
As to why the machine didn't go above 16 when obviously there was a need...beats me and there was time to do it so I don't know why it wanted to twiddle its little thumbs.

I had similar clusters of OAs when I was first tweaking my BiPap Auto...more EPAP fixed things fairly easily.
You can also let PS range a little...the machine may or may not feel the need to increase the PS or do it fast enough to be very effective. With more minimum EPAP you know for sure that there is more baseline pressure and not a maybe more with more PS range being available.

So if my minimum EPAP is currently 7 and PS minimum is 4, then the highest EPAP is 11? if my PS max pressure was set at 4 as well would my Max IPAP be the EPAP 11 plus 4 or 15, even if my Max IPAP setting was 18? If no, how is the PS max number used? Trying to figure out why it didn't go to 18 last night.

Thanks!

No...Minimum EPAP with PS of 4 is ultimately tied to max IPAP.
Example...when you hit 16 IPAP with PS of 4 your EPAP would be 12.
So with PS...EPAP is that PS amount below IPAP and IPAP is that PS amount over EPAP. They can both range.

With these settings...min EPAP 7 ...PS min and max at 4 and with IPAP max of 18....you could in theory see EPAP 14 and IPAP of 18.
If you add a variable PS...then the numbers change a little bit.

If the machine wants to increase EPAP it will push IPAP up...if it wants to increase IPAP it will drag EPAP up.
Don't ask me how PS figures out when it needs to vary or not vary if allowed to vary. I have never been able to find out or figure out why it does what it does in terms of varying.

EPAP minimum is going to be very similar to minimum APAP when using apap mode. So think of it as along those lines.
The starting point that holds the airway open decently for the bulk of the night but close enough to where it might need to go should the airway collapses need more pressure so the machine can get there in a timely manner.
IPAP being higher helps somewhat because for half of the breath you higher...so that helps us keep EPAP workable a little lower. Plus it is more comfortable having the difference.
So a small increase in EPAP min will also push IPAP up...and you might get the results you desire in terms of holding the airway open better with a smaller increase because of the work IPAP does.

I don't like to go over 5 (maybe 6) PS because that can lead to breathing instability...sort of like hyperventilating and the end result is a bunch of centrals from too much carbon dioxide wash out.
Could maybe be used when someone is already using very high minimum EPAP but when there's room for EPAP minimum movement upwards...I think that is the direction to go to first especially when we are seeing OAs.
My PS can go up to 5 I think it is...it rarely does...most of the time it stays around 4 even with PS being 3.5 to 5.
Just because it can go higher doesn't mean it will go higher.

jnk has a thread explaining the dance between EPAP and IPAP. It really helped me understand the relationship between EPAP and IPAP.
see if it helps you visualize the movement potentials
viewtopic.php?f=1&t=56581&p=531326&hili ... or#p531326

http://i.imgur.com/O8oQfcxh.png[/img]

So 2 nights ago the darn machine only went to 16 when set to max IPAP of 18. Night before I reset it to 18 and it went to 18 when needed. Last night it only went to 14 when I needed much more! You can see above it reached 14 at 3:24:15 and just stayed there but my bad obstructive streak lasted until 4:00. Is my darn machine broke? I might as well not use the darn machine if it can't do any better than this!

( As we had previously discussed, I had tried increasing my EPAP to 7.5 but it felt too strong so I was going to wait a couple days to try that again.)

riley525 wrote:I might as well not use the darn machine if it can't do any better than this!

Well I suppose you "could" look at it that way or you could look at it this way...."Wonder what it would be like to have those ugly clusters all night long instead of for this period of time."

Do you think maybe you might have been on your back during that ugly time frame?
It could also be REM stage...or very likely a combination of REM and supine sleeping.

You need more EPAP but if you can't tolerate it right now...maybe make an extra effort to stay on your side all night long and see if you still get the ugly clusters until you can work up to an EPAP that holds the airway open better.

Your machine isn't broken but it isn't responding (like we expect it should) during the dense clusters of OAs for some reason. We don't know why. We do know it needs a better starting point than it has right now.

The 2 most common reasons for clusters like this where the pressure isn't sufficient...supine sleeping or REM stage sleep or a combination of the 2.

Maybe you could use the ramp feature to help you start out at a more comfortable lower EPAP and then the machine can step up to the higher EPAP once you are asleep.

I am going out of town today...so I won't be here to see your responses but someone else will be here. I won't be back until late Sunday probably.

The IPAP jumped from 11 to 14 in 8 minutes then it just stayed there, so I had 30 more minutes of Obstructive apneas at 14 Pressure. Does the EPAP limit somehow kick in to keep the IPAP down? I understand it should take some time to kick in it just seems like a really long time to be stuck there. Thanks for you help, sorry I am sad and frustrated today. The averages aren't horrible but when you have 41 apneas in 40 minutes...I am going backwards. Started this journey on September 20, 2016, I just thought I would be further along with getting this pressure thing resolved....

I'd make a comment, but then I'd get accused of 'bashing' respironics again.

oh hell... any way you could trade your machine for a resmed aircurve vauto?

Is the Resmed more responsive? I bought my machine due to $10,000 deductible that I have so I could trade it in or something. I should have researched this beforehand! I usually over-research...

riley525 wrote:Is the Resmed more responsive? I bought my machine due to $10,000 deductible that I have so I could trade it in or something. I should have researched this beforehand! I usually over-research...

much more responsive.

Thanks, Palerider! Looks like it moved pretty fast. I just don't get what the deal is with mine. It moved pretty fast from 11 to 14 last night and then just stuck there. The night before the bad cluster didn't look as bad and it hopped on up to 18 really quick. The lack of consistency concerns me but maybe it looks at something else to help it decide to continue to increase?? I obviously don't know...

riley525 wrote:It moved pretty fast from 11 to 14 last night and then just stuck there. The night before the bad cluster didn't look as bad and it hopped on up to 18 really quick. The lack of consistency concerns me but maybe it looks at something else to help it decide to continue to increase??

It would be useful to see the worst cluster (zoomed in to show individual breaths) on the night where the machine increased the IPAP pressure to 18 as well as this snippet from last night where the machine sat at 14 throughout the long cluster.

I don't want to start a resmed vs resprionics war with palerider, but I want to offer this thought:

That string of OAs from last night's data looks like it might just be a string of CAs that are being misclassified as OAs. And it could be that your PR machine is worried that your breathing did not stabilize after increasing the EPAP from 7 to 10 and IPAP from 11 to 14 cm. It's important to realize that your machine increases the EPAP in response to OAs, and the IPAP is only increased if IPAP-EPAP = min PS = 4 in your case. And PR BiPAPs (and APAPs) are pretty conservative when it comes to continuing to increase the pressure when there is little or no evidence that the flow rate is becoming more stable with the increased pressure.

And Palerider is right: Resmed machines are much less conservative about continuing to increase the pressure as long as events that it regards as "obstructive" continue and the pressure is not at its maximum setting.

But whether a bilevel should or should not continue increasing the EPAP pressure (and hence the IPAP) when the breathing is not showing any signs of stabilizing after a 3 or 4 cm increase in pressure is a whole different question.

And that question that is well above my payscale, and I don't want to get into an argument with palerider or anybody else about the best answer to that question. I'll simply mention that Sludge/Mollette/Muffy/Not Muffy used to post about unstable breathing that was being caused by (potentially unnecessary) pressure increases rather than under treated OSA when he was responding to people who posted data that looked a lot like your data from last night. It's not a common problem, but it can be a real problem for a few people. Is that what's going on here? Maybe, maybe not. But Sludge is no longer here and so he can't contribute some of his expert advice on what this kind of a cluster might mean.

I will offer this suggestion as a way to see if your problem is too little pressure leading to real OAs or too much pressure leading to unstable breathing being misscored as OAs: You could try increasing the min EPAP pressure to 10 (which is your 95% EPAP) for a night or two. If more pressure is the answer to busting up and preventing your clusters, then using a higher minimum EPAP pressure setting than the 7cm you are currently using might do the trick. But if some of your clusters are pressure-induced unstable breathing being mis-scored as OAs, then more EPAP pressure probably won't reduce the number or length of these clusters and might just increase the length of the clusters.

It's also worth pointing out that you have your PS range set at 4-4.5cm. And it could also be that your airway does not like that large of a PS. You might also want to see what happens if you reduce min PS to 2 or 3 and leave max PS = 4.5. If you do this, you may want to increase the min EPAP by 1-2 cm so that your minimum IPAP is not less than what you are currently using.

In other words, I would suggest doing ONE of the following two experiments for at least 2 or 3 days:

Experiment 1: Reduce the min PS
Reduce min PS = 2 and keep max PS = 4.5. Increase min EPAP up from 7 to 8 so that your starting IPAP is only reduced to 10cm. See what happens to your median PS as well as the tendency for the long clusters of OAs to develop.

Experiment 2: Increase the min EPAP to 10cm
Leave the min PS = 4 and see if starting the night at 14/10 gives you better results than starting the night at 11/7 does. You'll need to keep an eye on whether the increased EPAP causes areophagia problems as well as seeing if starting with a min EPAP that is much closer to or at your current 95% EPAP level gives you better results or worse results in terms of the clusters.

robysue wrote:That string of OAs from last night's data looks like it might just be a string of CAs that are being misclassified as OAs.

then, it should treat them as OAs, since it's flagging them as OAs.

robysue wrote:And it could be that your PR machine is worried that your breathing did not stabilize after increasing the EPAP from 7 to 10 and IPAP from 11 to 14 cm. It's important to realize that your machine increases the EPAP in response to OAs, and the IPAP is only increased if IPAP-EPAP = min PS = 4 in your case. And PR BiPAPs (and APAPs) are pretty conservative when it comes to continuing to increase the pressure when there is little or no evidence that the flow rate is becoming more stable with the increased pressure.

the documented respironics OA hypopnea response algorithm is:

Karin Gardner Johnson and Douglas Clark Johnson wrote:If 2 apneas or 1 apnea/1 hypopnea or 2 hypopneas-increases by 1 and holds for 30 s. NRAH logic limits max pressure to 11 or 3 higher than preapnea baseline. If more apneas within 8 min decrease pressure by 2/15 min down to 1 over level that prevents snore then holds pressure for 10 min. Pressure will continue to increase in response to 2 hypopneas.

I note the "NRAH logic limits max pressure to 11 or 3 higher than preapnea baseline", and wonder if that is what's limiting the machine and preventing it from continuing to respond during those long strings of flagged obstructives.

the same folks document resmeds response as:

Karin Gardner Johnson and Douglas Clark Johnson wrote:Increases pressure based on current pressure every 10 s of apnea: increment max 3 when pressure is 4. Increment drops linearly down to 0.5 when pressure is 20.

I've often said that with respironics machines getting the minimum pressure high enough is more critical than with resmed machines, and that documented difference may be part of why I've seen behavior that supports that idea.

sleepyhead documents NRAH thusly:

NRAH Index

Non-Responsive Apnea/Hypopnea Index. A non-responsive apnea/hypopnea flag is generated when a patient has apneas and or hypopneas that do not respond to increased pressure from a pressure therapy device. It is detected when the patient has at least 2 apneas and/or hypopneas, the pressure level of the therapy device increases at least 3 cm H2O, and the patient continues to have apneas and/or hypopneas. Total Events / Total Session Hours = Index.

Palerider,

We've been through this argument before and there's no point in rehashing it.

The fact is that Resmed and PR have differences in their design philosophies when designing their Auto algorithms.

And your problem is with the PR engineers who have made certain decisions based on the AASM guidelines for manual titration in in-lab PSGs and perhaps with the AASM guidelines themselves: One of those AASM guidelines specify that the tech doing the titration is supposed to wait after each pressure increase to see if the breathing stabilizes, and the PR Auto algorithm has been designed with that guideline in mind. Resmed engineers have made a different choice about that particular AASM guideline.

Both auto algorithms have been thoroughly tested and both auto algorithms have won FDA approval as effectively treating OSA. Some people do better with Resmed machines. Some people do better with PR machines. And I think for most people, the choice of machine is not really all that important once the machine's settings are optimized.


And it's also important to understand that both the Resmed FOT and the PR PP algorithms for distinguishing between OAs and CAs is not perfect. Sludge also wrote about that when he was still around. And in both cases, the errors are not symmetric: Both the Resmed FOT and the PR PP algorithms are more likely to mis-score a CA as an OA rather than mis-scoring an OA as a CA. The reason why is simple: From a physiological point of view, a central apnea may or may not be associated with a blocked or partially blocked airway since the airway can collapse or partially collapse after a CA has started.

robysue wrote:Palerider,

We've been through this argument before and there's no point in rehashing it.

I'm not arguing anything, I'm pointing out documented differences in the algorithms, riley525 can make up her own mind as to which machine is likely to do a better job, for her.

robysue wrote:And your problem is with the PR engineers who have made certain decisions based on the AASM guidelines for manual titration in in-lab PSGs and perhaps with the AASM guidelines themselves: One of those AASM guidelines specify that the tech doing the titration is supposed to wait after each pressure increase to see if the breathing stabilizes, and the PR Auto algorithm has been designed with that guideline in mind. Resmed engineers have made a different choice about that particular AASM guideline.

if I respond to that, I will be arguing.

robysue wrote:Both auto algorithms have been thoroughly tested and both auto algorithms have won FDA approval as effectively treating OSA.

again, FDA approval does not hinge on effectiveness, it hinges on whether the benefit likely outweighs the risk. provent is FDA approved, but ineffective.

It would be useful to see the worst cluster (zoomed in to show individual breaths) on the night where the machine increased the IPAP pressure to 18 as well as this snippet from last night where the machine sat at 14 throughout the long cluster.

This is the one that reached 18. I did notice this one had snoring in it.


This is the one from last night, where it got stuck at 14.


Thank you robysue and palerider so so so much for your input. You two are awesome! It's nice to have such a depth of knowledge on the 2 top systems that you two provide!