BiPap Settings - Opinions & Information

I currently use an S9 Autoset with settings at 16/20 with a EPR of 3 and no ramp. My sleep study titration was 18. My 95 rate on my APAP data is 17.9.

I picked up a used BiPap for a great deal and wanted to ask a few questions. I'm also trying to determine which unit to use as the backup and which to use as the primary. Used unit is PR System One REMstar BiPAP Pro with Bi-Flex.

1) Unit came with heated humidifier and two packaged tubes, looks brand new, shows 179 hours. Paid $280. I'm assuming I did ok on the deal. Would be curious to know your thoughts on what I should have paid?

2) I'm a little confused about Flex usage. I'm assuming it is similar to EPR in resmed is that valid?

3) I have assumed that a CPAP with EPR was sort of a poor mans BiPap and that the BiPap would perform the difference between inhale and exhale in a range greater than EPR and in a more efficient manner. But this concept of BiPAP with Bi-Flex really throws me. If I set EPAP at 14 and Bi-Flex at 3, does that mean that exhalation pressure is really at 11? Why turn on Bi-Flex if you are using BiPap mode? Why not just make EPAP at 11?

4) Is this machine as data capable as my S9 Autoset? I realize the software is different, but will I have access to most of the detailed data I could want?

5) What is Encore Viewer and how does it compare to Encore Pro. I've been lucky enough to get Encore Pro but didn't know if I was missing out on anything by not having Encore Viewer?

6) My assumed settings are IPAP 18, EPAP 12. Without Bi-Flex active. What would you use based on my information above?

7) Is there anything similar to the Resmed Climate Line hose that is made by Respironics for use on this unit? I realize there are 3rd party heated hoses, and reptile modifications but was unsure if there was an option from Respironics?

Thanks for your time in answering my questions.

STL Mark wrote: 1) Unit came with heated humidifier and two packaged tubes, looks brand new, shows 179 hours. Paid $280. I'm assuming I did ok on the deal. Would be curious to know your thoughts on what I should have paid?

Great deal.

STL Mark wrote:2) I'm a little confused about Flex usage. I'm assuming it is similar to EPR in resmed is that valid?

Yes, Flex is Respironics form of exhale relief. Comfort feature.
You can read a bit more about it here.
http://flexfamily.respironics.com/

For Number 3 question. I don't know enough about how BiPap works to explain it. So need to wait for someone who can explain it better than me.

STL Mark wrote:4) Is this machine as data capable as my S9 Autoset? I realize the software is different, but will I have access to most of the detailed data I could want?

With the software, yes, just as data capable. LED onscreen data sucks though. Very limited.

STL Mark wrote: 5) What is Encore Viewer and how does it compare to Encore Pro. I've been lucky enough to get Encore Pro but didn't know if I was missing out on anything by not having Encore Viewer

Viewer is patient version of the software. Less bulky. Does not provide any more patient data, in fact it doesn't offer the wave form data that Encore Pro does. So Pro is more comprehensive (and also more PITA)

Again number 6, let's wait for BiPap user input. I have no personal experience with BiPap and don't want to muddy the waters with what little I know.

STL Mark wrote:7) Is there anything similar to the Resmed Climate Line hose that is made by Respironics for use
on this unit? I realize there are 3rd party heated hoses, and reptile modifications but was unsure if there was an option from Respironics?

Not to my knowledge. Respironics new humidification system is within the machine itself in regards to temp and humidity. You can use the humidifier in the new way or in the old classic way which just heats the water chamber.
The clinician manual explains it in more detail. I have more rain out in winter. I just got my PR S1 machine last week so have not tried it to see if the new "fancy" humidification settings are any better or worse as far as rainout.
You will just have to experiment to see how it suits you. It is not cold enough now for me to have the usual rain out.
I am using the old way right now. Just heating the water chamber. I haven't even tried the other yet.

Sorry I can't answer the questions specific to BiPap use, but there are many other members here that use your type of machine and they can offer much better insight than I can.

Good luck. Heck of a good deal on the machine. Those hours are nothing.

STL Mark wrote: this concept of BiPAP with Bi-Flex really throws me

Here is what Bi-Flex looks like:


Steal of a deal!!

3) I have assumed that a CPAP with EPR was sort of a poor mans BiPap and that the BiPap would perform the difference between inhale and exhale in a range greater than EPR and in a more efficient manner. But this concept of BiPAP with Bi-Flex really throws me. If I set EPAP at 14 and Bi-Flex at 3, does that mean that exhalation pressure is really at 11? Why turn on Bi-Flex if you are using BiPap mode? Why not just make EPAP at 11?

I think you're right; I see no purpose for flex-exhale relief in BIPAP mode. If the EPAP is 14 and Flex is 3, the pressure at the beginning of the exhale is 11, rising to 14 during the exhale. It could be useful if you decided to run straight CPAP, or conceivably for a short adapting period after you have increased pressure settings, but even in that case, most of those who post here don't bother with it.

STL Mark wrote: 1) Unit came with heated humidifier and two packaged tubes, looks brand new, shows 179 hours. Paid $280. I'm assuming I did ok on the deal. Would be curious to know your thoughts on what I should have paid?

That machine, new, withOUT a humidifier, is $2000. You got a STEAL of a deal!

STL Mark wrote: 2) I'm a little confused about Flex usage. I'm assuming it is similar to EPR in resmed is that valid?

Flex is simply a comfort feature. Try different settings to find what is most comfortable for you.

STL Mark wrote: 3) I have assumed that a CPAP with EPR was sort of a poor mans BiPap and that the BiPap would perform the difference between inhale and exhale in a range greater than EPR and in a more efficient manner. But this concept of BiPAP with Bi-Flex really throws me. If I set EPAP at 14 and Bi-Flex at 3, does that mean that exhalation pressure is really at 11? Why turn on Bi-Flex if you are using BiPap mode? Why not just make EPAP at 11?

I'm not sure I really understand it all either. I switched from APAP to BiPAP about three months ago. I found the transition very easy. I wouldn't worry too much about it. I would guess others with more experience may chime in. If not, you could consider posting this as a specific post all it's own.

STL Mark wrote: 4) Is this machine as data capable as my S9 Autoset? I realize the software is different, but will I have access to most of the detailed data I could want?

Yep. If you have Encore Pro, which I think you said you did, you should be all set to go. (Although I don't have the S9 to compare, but I've read they are very comparable.) Pugsy is right, the LED info is terrible. Don't even bother with that.

STL Mark wrote: 5) What is Encore Viewer and how does it compare to Encore Pro. I've been lucky enough to get Encore Pro but didn't know if I was missing out on anything by not having Encore Viewer?

Don't bother with Viewer if you have Pro. That would be taking a step backwards. Everything View provides is already in Pro.

STL Mark wrote: 6) My assumed settings are IPAP 18, EPAP 12. Without Bi-Flex active. What would you use based on my information above?

I'm really not good at settings, so I'll leave that to others.

STL Mark wrote: 7) Is there anything similar to the Resmed Climate Line hose that is made by Respironics for use on this unit? I realize there are 3rd party heated hoses, and reptile modifications but was unsure if there was an option from Respironics?.

My experience is you will not need anything like a Climate Line hose, unless you live in extreme climates, or like your bedroom to have extreme temps/humidity. The PR System One machines have some sort of smart humidifier. It can detect the ambient temperature and humidity, and compensate the amount of humidity provided in the hose. I have had VERY little problem with rain out, and it has been winter here, and COLD. If you do have problems, I know others who use PR machines have really liked the Aussie Heated Hose, or the Pad-a-cheek hose covers.

STL Mark wrote: 1) Unit came with heated humidifier and two packaged tubes, looks brand new, shows 179 hours. Paid $280. I'm assuming I did ok on the deal. Would be curious to know your thoughts on what I should have paid?

A very, very sweet deal indeed!

2) I'm a little confused about Flex usage. I'm assuming it is similar to EPR in resmed is that valid?

Yes and no. Yes, it's exhale relief. But Flex does NOT reduce the pressure by a fixed amount on every single exhale. Rather, there is some kind of algorithm that reduces the pressure by a variable amount in Flex, but EPR reduces the pressure by a fixed number of cm on every single breath. See the graph that jnk provided up thread and you'll see the amount of relief provided by Flex varies not only on the setting (1, 2, or 3) but also on each breath: Deeper exhales seem to trigger larger reductions in pressure.

Flex varies in another way from EPR as well: The return to full (EPAP) pressure happens half-way through the exhale on a PR BiPAP; the return to full (CPAP/APAP) pressure happens about 3/4 of the way through the exhale on the Resmed S9 Autoset as I recall. Not enough of a difference for most people to feel, but I could tell a difference. While EPR was useful to me when I still had the S9, I found Bi-Flex irritating and bothersome to the point of distraction and turned it off almost immediately. But I have really low EPAP pressures.

3) I have assumed that a CPAP with EPR was sort of a poor mans BiPap and that the BiPap would perform the difference between inhale and exhale in a range greater than EPR and in a more efficient manner.

Yes and no. EPR reduces the pressure by a fixed amount on every exhale like a BiPAP does, but with EPR, the pressure returns to full pressure before the beginning of the next inhale. For an ordinary BiPAP (or an S/T running in S mode instead of T mode), the pressure is raised to the IPAP pressure only AFTER the inhale starts. Again, it's a subtle difference---so subtle that many may not notice it, but I did.

And IPAP-EPAP can be set greater than 3cm, unlike EPR=3.

But this concept of BiPAP with Bi-Flex really throws me. If I set EPAP at 14 and Bi-Flex at 3, does that mean that exhalation pressure is really at 11? Why turn on Bi-Flex if you are using BiPap mode? Why not just make EPAP at 11?

Because EPAP = 11 means the pressure goes down AND stays down at 11 for the full duration of every single exhale. Whereas with EPAP=14 and Bi-Flex=3, the exhale pressure might be reduced down to 11cm for the first half of a very deep exhale. But the pressure is raised back up to 14 by midway through the exhale. And if the exhale is not a deep one, the minimum pressure during the first half of the exhale may only be reduced to 13cm or 12cm instead of 11cm.

Bi-Flex supposedly makes the transitions between the EPAP and IPAP pressures smoother, and hence potentially more comfortable for people. For people who require really high EPAP settings, Bi-Flex may also make it easier to breathe out against the EPAP pressure.

Others have fully answered questions #4 and #5.

6) My assumed settings are IPAP 18, EPAP 12. Without Bi-Flex active. What would you use based on my information above?

How did you settle on IPAP=18 and EPAP=12? I'd be worried that EPAP-12 would be is low: Your min APAP pressure is 16 and you have EPR=3. Hence during each exhale, your pressure is (temporarily) reduced no LOWER than 16 - 3 = 13 cm. In other words, you are spending NO time at all during the night at a pressure as low as 12cm when using the S9. Setting EPAP=12 means you will be spending half the night (or longer) at a pressure of 12cm since for many people, the exhale portion for each breath is a bit longer than the inhale portion of the breath. Hence running the pressures at 18/12 may well let too many events through.

I'm not a doctor, but my first guess on estimating appropriate settings would be

IPAP = 18
EPAP = 15 = IPAP - 3

since you've been using EPR=3 on the S9 and your 95% pressure level and your titration level are essentially the same and on the PR, you can only adjust pressures by 0.5 cm at a time.

And a final note: You can only use the Slimline hose (smaller hose that comes as standard equipment with the S9) if the firmware on the PR S1 is version 2.01 or later. There must be a hose setting option (15mm) in the clinical menu in order to use the smaller hose.

You found a bargain, Mark!

STL Mark wrote:3) I have assumed that a CPAP with EPR was sort of a poor mans BiPap and that the BiPap would perform the difference between inhale and exhale in a range greater than EPR and in a more efficient manner. But this concept of BiPAP with Bi-Flex really throws me. If I set EPAP at 14 and Bi-Flex at 3, does that mean that exhalation pressure is really at 11? Why turn on Bi-Flex if you are using BiPap mode? Why not just make EPAP at 11?

Bi-Flex does not drop the pressure a certain number of cms. When you start to exhale, Bi-Flex simply gives a little more drop to the BEGINNING of the already lower EPAP pressure. So, no... setting Bi-Flex at "3" will not drop an EPAP of 14 down to 11. The "0, 1, 2, and 3" for Bi-Flex settings just mean:

0 - off (Bi-Flex won't be used)
1 - "a little bit of pressure drop when you first start to exhale" (not a set 1 cm of drop)
2 - "a little more pressure drop when you first start to exhale" (not a set 2 cm of drop)
3 - "even a little more pressure drop when you first start to exhale" (not a set 3 cm of drop)

The amount of "more drop" Bi-Flex will give, at any of its three settings, depends on how forcefully your exhalation starts out. After the bit of drop Bi-Flex gives at the beginning of an exhalation, the regular EPAP pressure comes back in.

I think of Bi-Flex as "icing on the cake", making the already lower EPAP pressure be a tad even lower, just at the start of the exhalation.
Very much like how C-Flex works in the Respironics CPAPs and Autopaps... a little bit of drop (not in cm's) just at the start of breathing out each time. Then the "regular" pressure comes back in. In your case, the "regular" pressure coming back in would be your EPAP pressure.

Some people are bothered by the feeling of pressure coming back in after C-Flex has done its drop at the start of breathing out.

The same annoyance can happen with Bi-Flex for some people...feeling the EPAP pressure come in after Bi-Flex has done its thing to drop the beginning of EPAP just a little.

I personally like using Bi-Flex. But it's a comfort thing, so however each person wants to use it, including "off", is the way it should be used.

If you turn off Bi-Flex, then there is another setting that you'll see farther along in the therapy setup menu. A "rise" setting that governs how fast the machine will run up to the full IPAP pressure when you start to breathe in. A fast rise time (low number in the setting) can feel like an abrupt jump up to IPAP when you start to inhale. A slower (high number in the setting) moves the pressure up more smoothly to IPAP. Of course, when I saw "slower", it's not going to make you wait for IPAP to happen. It will be a "fast "gradual" move up" to IPAP, if that makes sense. But a fast "rise" time to IPAP can feel like a sudden jump of more air happening.

robysue wrote:with EPR, the pressure returns to full pressure before the beginning of the next inhale.

That's true of C-Flex in Respironics' machines, but not true with ResMed's EPR. EPR in ResMed's Autoset and CPAP machines keeps the pressure down throughout the entire exhalation, and during any pause after the exhalation, unless the exhalation (and pause before inhalation starts) lasts x number of seconds... much longer than most people would actively breathe out. That long amount of time EPR can be in effect is why ResMed put in a safety measure to "suspend" EPR's action and return to therapeutic pressure if the person has not started to breathe in again by x number of seconds.

For the same reason, this is not the way ResMed's EPR works either:

robysue wrote:the return to full (CPAP/APAP) pressure happens about 3/4 of the way through the exhale on the Resmed S9 Autoset as I recall.

There is no return to full pressure with EPR until the person's airflow indicates inspiration has started (or it's been so long that EPR times out.) It might be a faint stutter start or a slight sucking in or change in the opening of the throat that was not intended to actually be an inhalation. Could be a slight additional downward movement of air if aerophagia was happening. But something happened in the person's airflow that made the person appear to be starting an inspiration, for the therapeutic pressure to come back in during exhalation when using EPR.

STL Mark wrote:6) My assumed settings are IPAP 18, EPAP 12. Without Bi-Flex active. What would you use based on my information above?

Since Bi-Flex does not drop the EPAP pressure a specific number of cm's...
If I were were titrated at 18 as a single pressure from a sleep study, I'd set a bilevel machine for IPAP 18 and EPAP at 16, 15, or 14. With or without Bi-Flex turned on. EPAP does not need to be adjusted to compensate for using Bi-Flex, if a person likes the way Bi-Flex feels.

I'd want to use the software for the machine while I experimented to see if EPAP 14 took care of preventing most apneas for me. If apneas were sneaking through, I'd raise the EPAP a full cm to 15. If apneas still appeared in greater numbers than I wanted, I'd raise EPAP to 16.

Using IPAP 18, EPAP 12 as you mentioned would feel like a rather extreme difference to me, but you could certainly try that if you wished. Just remember that of the two pressures, EPAP is the most important one. EPAP is the pressure that needs to be high enough to try to prevent most apneas from the get-go.

Thanks to each of you for taking time to provide my education. I feel much more informed about my new toy. 18/14 will be my trial settings and I may play with biflex. Will be fun to sleep with my new machine (hope the S9 does not get jealous).

rested gal wrote:

robysue wrote:with EPR, the pressure returns to full pressure before the beginning of the next inhale.

That's true of C-Flex in Respironics' machines, but not true with ResMed's EPR. EPR in ResMed's Autoset and CPAP machines keeps the pressure down throughout the entire exhalation, and during any pause after the exhalation, unless the exhalation (and pause before inhalation starts) lasts x number of seconds... much longer than most people would actively breathe out. That long amount of time EPR can be in effect is why ResMed put in a safety measure to "suspend" EPR's action and return to therapeutic pressure if the person has not started to breathe in again by x number of seconds.

-SWS, jnk, and myself discussed this issue at length back in January in this thread: Subject: BiPap Settings - Opinions & Information Discussion starts on page 2 and runs through page 3. -SWS did some really great editing on the wave form graphs provided by both PR and Resmed advertising.

To take the PR vs. Resmed debate out of consideration, -SWS provided graphs comparing the EPR Easy Breathe wave form on the Resmed APAP/CPAPs to the Resmed VPAPs. And the Resmed EPR Easy Breathe wave form on the S9 CPAP/APAPs is not the the same as the Easy Breathe wave form on the S9 VPAPs: The VPAPs do NOT start to increase pressure until the inhale has clearly begun, but the Resmed CPAPs/APAPs using EPR do start subtly increasing the pressure earliler---the start of the increase is during the (brief) time when there is very little airflow---a time that to me feels like part of my EXHALE since I've not started taking air back into my lungs.

For the same reason, this is not the way ResMed's EPR works either:

robysue wrote:the return to full (CPAP/APAP) pressure happens about 3/4 of the way through the exhale on the Resmed S9 Autoset as I recall.

There is no return to full pressure with EPR until the person's airflow indicates inspiration has started (or it's been so long that EPR times out.) It might be a faint stutter start or a slight sucking in or change in the opening of the throat that was not intended to actually be an inhalation. Could be a slight additional downward movement of air if aerophagia was happening. But something happened in the person's airflow that made the person appear to be starting an inspiration, for the therapeutic pressure to come back in during exhalation when using EPR.

Again---look at the graphs provided by -SWS in the above cited link: They are for what goes on with NORMAL breathing under the EPR Easy Breathe algorithm on the Resmed CPAP/APAPS, the Easy Breathe algorithm on the Resmed VPAPs, and the PR Bi-PAPs with Bi-Flex turned on. -SWS has edited the pics to show exactly when each system starts its increase in pressure relative to the patient's airflow. And EPR is NOT as "late" during the exhale as the Resmed's VPAPs Easy Breathe algorithm, which really does not start the increase until after the patient has clearly initiated an inhale.

Put in about 6.25 hours with the machine. AHI 8.5 from what everyone has told me I need to add to EPAP if I want that down lower. It was interesting to try something other than my S9. Since AHIs on that tend to be less than 1, I would have to work more with tuning this machine to my needs before I could compare how I feel the morning after.

robysue wrote:-SWS, jnk, and myself discussed this issue at length back in January in this thread: Subject: BiPap Settings - Opinions & Information Discussion starts on page 2 and runs through page 3. -SWS did some really great editing on the wave form graphs provided by both PR and Resmed advertising.

robysue wrote:Again---look at the graphs provided by -SWS in the above cited link: They are for what goes on with NORMAL breathing under the EPR Easy Breathe algorithm on the Resmed CPAP/APAPS, the Easy Breathe algorithm on the Resmed VPAPs, and the PR Bi-PAPs with Bi-Flex turned on. -SWS has edited the pics to show exactly when each system starts its increase in pressure relative to the patient's airflow. And EPR is NOT as "late" during the exhale as the Resmed's VPAPs Easy Breathe algorithm, which really does not start the increase until after the patient has clearly initiated an inhale.

Your "above cited link" simply returns to one your previous post in the thread we are already in.

I think you meant to make your link go to this previous topic:
"CPAP vs APAP vs BiPAP (poll)"
In which -SWS's marked graphs begin on page 2:
viewtopic.php?p=555318#p555318

ResMed says of their EPR: "Pressure relief is triggered by patient expiration and ends at the start of inspiration."

http://www.resmed.com/assets/documents/ ... ow_eng.pdf

So, if a ResMed machine ever ended EPR before the start of inspiration for me, or as Robysue put it . . .

with EPR, the pressure returns to full pressure before the beginning of the next inhale.

. . . I would consider that to be a malfunction of the machine and would report it to ResMed immediately, since that would mean their statement was false in my personal case. I would assume my breathing contained some false starts of inspiratin that were fooling my machine, since Respironics machines are designed to return to full pressure during exhale, but ResMed machines are not, as the above quote makes clear.

It is a shame that ResMed's EPR apparently did not work properly for one patient: Robysue. But that does not change what the feature is designed to do--and that I understand it generally does quite well for by far the majority of patients--which is to raise pressure up from the EPR pressure AT the start of inspiration, not before the start of inspiration.

At least, that is how I understand it.

Jeff, that's how I understand it, too.

I don't doubt that while using EPR, robysue did, indeed, feel the start of therapeutic pressure come back in before she felt that her exhalation (including any pause at the end of her exhalation) was finished. But to me, that's indicative of an anomaly in robysue's breathing. Since she suffers from aerophagia, perhaps a trickle of air getting pushed down when her exhalation is waning or during the pause... the slight amount of air getting pushed down could, I suppose, mimic the start of breathing in, when robysue was not actually "inhaling" at all.

Or it could be that subtle, perhaps involuntary, movements inside her mouth or throat open the space inside just enough to mimic the start of an inhalation. I know that I can deliberately trick EPR (or a bilevel, for that matter) into "thinking" I'm starting to breathe in when I'm not...just by "opening" the back of my throat downwardly, as if saying "AHHHHHH." Doesn't take much airflow difference to trigger that change to "more pressure again."

But it does take "something" to trigger EPR to allow the therapeutic pressure to start back in. And to trigger IPAP to start its pressure rise in ResMed's VPAP bilevel machines. If that "something" is a glitch, blip, stutter (whatever) in the person's own particular way of breathing out, then the start of more pressure coming in, in a way that feels premature to the person is due to something going on in their own breathing...not in the design of the machine with EPR.

I agree, Jeff. I don't think EPR is designed to let higher pressure start back in before a normal exhalation is finished, or during any pause at the end of exhalation. Not unless it times out, and the number of seconds it takes for timing out to happen with EPR is longer than most people normally breathe out -- even as a occasional long drawn out sighing exhalation, and even with a pause after breathing out.

If I understand correctly, with EPR, if a person takes more than 10 seconds after exhaling (or perhaps the timing includes the seconds spent breathing out) before starting to breathe in again, EPR will suspend and allow the therapeutic pressure to come back in. If anyone sitting there tries that with a stop watch, slowly breathing out and then deliberately not breathing in again after finishing their exhalation.... watch ten seconds tick by. Either way, ten seconds including time spent breathing out, or ten seconds after exhalation is finished... ten seconds is a long time to wait before drawing a new breath. A long time before EPR decides "this is getting too long" and lets the regular pressure back in

EPR keeps the pressure down until a person starts to breathe in again (or something happens in the person's breathing to make the machine think they are starting to breathe in again...which is what I believe happens in robysue's respiration) or...until EPR times out.

Mark,

The interesting things I notice about the Encore chart you provided are:

1) A really, really ragged leak line. And that's the UNINTENDED leak line---so it's only showing the EXCESS leak rate and not the total leak rate. Now it's true nothing is flagged as a Large Leak, but nobody seems to know how PR actually defined "large leak" in its software. But there are folks out there who have NEVER seen a large leak even when they have had unintentional leak rates twice their mask's intentional flow rate and (well) above the 24 L/min unintentional leak rate used by ResScan. Did you have more problems than normal with leaks on this night?

2) Lots and lots of CAs and NO OAs flagged by the PR S1. And I have no idea why this would happen and no idea why the number of CAs would be much higher on the S1 BiPap than the S9 AutoSet.

3) A fair number of hypopneas are flagged as well since the HI = 2.7. [Could it be that the PR S1 is simply scoring some events as H's that the S9 does not? I don't know enough about either machine's scoring algorithms to answer that question.]

4) Some snoring episodes are flagged too.

I know that when I run my machine in BiPAP AUTO mode, the following things affect the pressure level in the following ways:

• CA's are not supposed to do anything to the pressure level
  OA's increase EPAP (and IPAP if IPAP = EPAP+2)
  H's increase IPAP (and EPAP if IPAP - EPAP = PS)
  FL's increase IPAP (and EPAP if IPAP - EPAP = PS)
  VS's increase EPAP (and IPAP if IPAP = EPAP + 2)
  RERA's increase IPAP (and EPAP if IPAP - EPAP = PS)---I think

Not quite sure if I'm remembering RERA's correctly. The rest I'm sure about. And PS = "Pressure Support" = max allowable difference between IPAP and EPAP. It's not a setting that you find on a fixed BiPAP.

Now if those CA's of yours were OA's, then I'd agree that you need to bump up the EPAP a bit. But since they are CA's, it's not clear that increasing the EPAP is warranted. Maybe try running in with the current settings for a few more days and see if those CA's start to come down? I really don't know.