BiPAP/VPAP vs APAP with EPR

In researching equipment I am seeing some people on BiPAP or VPAP machines where these machine use two different pressures.
But I also see APAP machines that have EPR or A-Flex/C-Flex where a lower pressure is used to help exhalation so you are not fighting the machine as much.

I do see that they are prescribed differently and the BiPAP/VPAP machines seem to be more complex and thus more expensive but what are the real differences?

Where would a BiPAP/VPAP be used over an APAP with ARP?

I am asking so I am fully informed before I get my final data analysis and prescription for a machine. I want to make sure I fully understand the various equipment and how my needs/prescription can be met.

usually it get scripted when either the CPAP/APAP pressure is very high

OR

the difference between the inhale (IPAP) and the exhale (EPAP) is greater than 3 cm H20

OR

sometimes it's also scripted if the patient has difficulty with CPAP/APAP

tschultz wrote:In researching equipment I am seeing some people on BiPAP or VPAP machines where these machine use two different pressures.
But I also see APAP machines that have EPR or A-Flex/C-Flex where a lower pressure is used to help exhalation so you are not fighting the machine as much.

I do see that they are prescribed differently and the BiPAP/VPAP machines seem to be more complex and thus more expensive but what are the real differences?

Where would a BiPAP/VPAP be used over an APAP with ARP?

I am asking so I am fully informed before I get my final data analysis and prescription for a machine. I want to make sure I fully understand the various equipment and how my needs/prescription can be met.

The short story is the BiPap is the ultimate in exhale relief. Aflex would be my next choice.

The reason for use can be due to medical necessity (ask your doc) or a high pressure causing failure to use/adapt to cpap. Much has been posted on this forum about the reasons.

The Advanced Search feature at the top of this page will likely dig up more info.

Good Luck

And, EPR (exhale pressure relief) actually gets suspended if you're having events.

My two cents:

With my former machine, a ResMed S9 Auto running first in straight CPAP at 9cm with EPR = 3 and then in APAP at 7--8 cm with EPR = 2

I simply could not exhale with EPR turned OFF. I tried and could not---even though relatively speaking my pressure is not that high---particularly the APAP range that I was later prescribed after the week of autotitration that was done when I simply could not adjust to the 9cm that was prescribed based on the last 30 minutes of NON-REM sleep at the end of the full-night titration study where the tech skipped over 8cm due to lack of time. During the autotitration at home with my S9, my 95% pressure settled at 7.6--7.8.

In retrospect, what I noticed with EPR was that while the pressure drops at the START of the exhale, it also INCREASES during the SECOND half of the exhale phase of each breath. And that increase in pressure while I was still exhaling tickled the back of my throat during every single breath! Really, really bad. Drove me bananas. And I couldn't explain it. Along with a whole bunch of other things. And I think that this increase in pressure while I was still trying to breathe OUT is what lead to my feeling like a stuffed goose. And I think it triggered me swallowing air---I think my brain's reaction was along the lines of "What else can I do except swallow the air to make the excess air go away? After all---the machine is trying to ram all this excess air down my throat and I'm NOT DONE getting air out of my lungs yet?" Not rational, but who is when they are sleep deprived and in that half awake and half asleep trying desperately to get to sleep state anyway?

And, as I said, I could NOT simply turn EPR off. I tried. With the pressure reduced to 7--8cm, I could turn EPR down to 2, but not 1. The pressure rise with EPR = 2 was less bothersome than with EPR =3, but the pressure relief was still sufficient to get my exhale comfortably started (unlike with EPR =1).

With my current machine, a PR System One BiPAP Auto running straight in straight BiPAP mode set at IPAP = 8cm, EPAP = 6 cm, Bi-Flex = OFF, and Rise Time = 3

When I first got the PR S1, I played around with it for about 30 or 40 minutes because it's got a really nice demo feature that lets you see how the different Bi-Flex and Rise Time settings actually feel at your particular pressure settings and adjust them in real time. That's when it became very clear to me that the really annoying tickle in my throat that's been one of my biggest comfort issues---and a major insomnia trigger to boot---has been coming from the noticeable rise in pressure during the second half of the exhale phase of each of my breathes if EPR/Bi-Flex is turned on. When I had Bi-Flex turned on, no matter what it's setting (1, 2, or 3), there was the annoying push of air down my throat before I was ready and I was feeling like the goose being stuffed for Christmas. When Bi-Flex was turned off, there was no annoying push of air, and I didn't feel like a stuffed goose any more, and I can exhale against 6cm of pressure even if I can't against 8cm. Playing with the Rise Time settings allowed me to fine tune how long it takes the PR S1 to increase the pressure from 6 cm to 8 cm after I start my inhalation. For me, since my resting respiration rate and my sleeping respiration rates all seem to be in the neighborhoods of 12-16 breaths, Rise Time = 3 (which translates to making the PR S1 take about 0.4 seconds to raise the pressure, if I recall correctly) seems to work---it's long enough where I don't feel like it's stuffing air down my throat any more.

Now the annoying tickle problem has not been solved completely by the switch to the BiPAP. But it is much, much less of an issue than it was with the S9. And the progress on resolving the tickle problem has also gone a long way in resolving the aerophagia problem because I'm no longer swallowing air as a way of trying unconsciously to get rid of the tickle caused by the excess of air.

Conclusion
Why is the ResMed EPR (and the PR S1 Bi-Flex) so noticeable to me in the first place? I think it's really just that I'm hypersensitive to certain kinds of stimuli and I've got a really, really sensitive back the throat and highly developed gag reflex to begin with. And I think when GumbyCT writes "The short story is the BiPap is the ultimate in exhale relief," it is important to understand that the reason someone like me finds BiPAP as being medically necessary is that in order to tolerate PAP therapy, the only way we can get the required exhale relief is where the increase in pressure takes place during the first part of the INHALATION stage of the breath instead of during the last part of EXHALATION stage of the breath; and BiPAP provides that kind of change in pressure while APAP/CPAP with pressure relief in the form of EPR/A-Flex/C-Flex does not.

Great information and I was not aware that the EPR feature in the ResMed operates only in CPAP mode. I was leaning heavily to wanting to get a ResMed S9 AutoSet machine but am now thinking that I may be better off with a PR System One with A-Flex as it provides the possibility of exhaust releif in both CPAP and APAP modes. I also see that there are differences in the C-Flex, A-Flex vs the EPR which result in the EPR being the less favorable, but this I am only deriving from everything I have read and not personal use yet. I don't have my prescription yet but do know that at end of my titration study the pressure was quite high and exhalation was a bit of a problem. This is why I am thinking that a machine with some relief capability is a better option if BiPAP is not prescribed and needed.

tschultz wrote:Great information and I was not aware that the EPR feature in the ResMed operates only in CPAP mode.

EPR works on the ResMed S9 in both CPAP and APAP mode. If my writing was misleading I apologize. During the time I had the S9, I had two prescribed settings:

• (1) Straight CPAP at 9 cm, which I used with EPR = 3 in order to be able to exhale.
  (2) APAP with range 7--8 cm, which I used with EPR = 2 in order to be able to exhale.

In both modes the S9 is designed to temporarily turn EPR off when it detects apneas and hypopneas occurring. The rationale behind this (as I understand it) is that if the S9 detects an apnea or hypopnea, it knows that you need the full pressure for the ENTIRE breath cycle to prevent the collapse of the upper airway. Hence it temporarily overrides the EPR setting. As soon as the breathing pattern returns to normal, the EPR is restored. This is, of course, presumably happening when you are asleep. I have to admit that since I turned Bi-Flex off on my PR System One machine, I didn't pay attention to the corresponding part of the PR S1 user manual and I don't have it handy right now. However, it seems likely that PR also has some kind of algorithm for temporarily turning off C-Flex/A-Flex if the System One is detecting events.

I was leaning heavily to wanting to get a ResMed S9 AutoSet machine but am now thinking that I may be better off with a PR System One with A-Flex as it provides the possibility of exhaust releif in both CPAP and APAP modes. I also see that there are differences in the C-Flex, A-Flex vs the EPR which result in the EPR being the less favorable, but this I am only deriving from everything I have read and not personal use yet. I don't have my prescription yet but do know that at end of my titration study the pressure was quite high and exhalation was a bit of a problem. This is why I am thinking that a machine with some relief capability is a better option if BiPAP is not prescribed and needed.

The S9 AutoSet is a great machine, and the data available from the on-board LCD is much more useful than the minimal information provided by the PR S1. The S9 is also a whole lot quieter in my humble opinion, but that might just be because the frequency the PR S1 hums at is in a range that my hearing is still well within the normal range, while the S9's hum is at a bit higher frequency and it might be just high enough to be drowned out by my tinnitus. But in my case, the S9 AutoSet simply did not work well for me. For what it is worth, I do NOT believe I would have done any better with a PR System One Auto than I did with the ResMed S9 AutoSet. From what I can gather, the PR S1 Bi-Flex supposedly feels a lot like A-Flex running on the PR S1 in Auto mode (and C-Flex+ in CPAP mode, if I recall correctly). And in that case, I would have had exactly the same problems with the PR S1 Auto that I had with the ResMed S9 AutoSet in both Auto mode and CPAP mode with EPR turned on. Namely, I would have still been bothered by---or rather disturbed by---the fact that I can sense an increase in pressure when it occurs during the second half of the EXHALATION phase of each breath.

Now the thing is, most people don't seem to have as sensitive backs of throats as I do. And most people don't seem to be anywhere near as sensitive to noticing the fact that the pressure starts to increase during the second half of the exhalation phase of the breath with EPR/A-Flex/C-Flex/etc.

My own advice: If at all possible try both machines set at your own pressure setting for at least a few minutes with the mask you plan on using. My DME was really good at letting me do this when I was first choosing between the S9 Auto Set and the PR S1 Auto. For me, I really preferred the S9 with EPR. It was quieter and EPR felt smoother although neither felt "good" to me. [BiPAP is much better to my oversensitive back of throat.] Ask if you can have a chance to breathe with each machine at your pressure settings for 10 minutes before making a decision. That's really the only way you can decide for yourself if there is enough difference between the ResMed's EPR and the PR's A-Flex/C-Flex algorithms for you to tell a difference between them. And whether you find one or the other more comfortable.

robysue wrote:In retrospect, what I noticed with EPR was that while the pressure drops at the START of the exhale, it also INCREASES during the SECOND half of the exhale phase of each breath. And that increase in pressure while I was still exhaling tickled the back of my throat during every single breath! Really, really bad. Drove me bananas. And I couldn't explain it.

I have absolutely no doubt you sensed that, robysue. However, unlike C-Flex/A-Flex, Resmed's EPR is not designed to increase pressure during exhalation. Rather, Resmed's EPR is designed to increase pressure when positive flow (inhalation) is detected---in the same way that Resmed BiLevel/VPAP does. So I'm thinking when that throat-tickling happened to you, either your breathing pattern fooled EPR to prematurely trigger to inhale pressure, or those pressure increases that tickled your throat were the central-apnea sensing FOT signals.

BTW, excessive, brief leak spikes can prematurely trigger IPAP---as they look like the start of positive/machine-outbound flow to a sensor. Also, expiratory pauses with a brief inhale "hitch" or false start---before true inspiration---can prematurely trigger IPAP. Anyway, the EPR=3 diagram below helps us to see that EPR is designed to commence the rise to inhale pressure when positive patient flow gets started after that post-expiratory pause. Again, if the post-expiratory pause is long, then FOT detection oscillations might kick in and "tickle".
http://www.internetage.ws/cpapdata/resm ... ochure.pdf
https://www.cpap.com/DisplayNewsletter/ ... ue-19.html

robysue wrote:it is important to understand that the reason someone like me finds BiPAP as being medically necessary is that in order to tolerate PAP therapy, the only way we can get the required exhale relief is where the increase in pressure takes place during the first part of the INHALATION stage of the breath instead of during the last part of EXHALATION stage of the breath; and BiPAP provides that kind of change in pressure while APAP/CPAP with pressure relief in the form of EPR/A-Flex/C-Flex does not.

In any event, by design EPR is NOT supposed to switch early during exhale as C-Flex and A-Flex do by design.

robysue wrote:However, it seems likely that PR also has some kind of algorithm for temporarily turning off C-Flex/A-Flex if the System One is detecting events.

C-Flex and A-Flex do not suspend. Unlike the Resmed case, C-Flex/A-flex has no reason to suspend----since full CPAP/APAP stenting pressure is achieved before exhale is over. Resmed literally NEEDS to suspend EPR by design (unlike Flex) BECAUSE that EPR pressure is not back up to full therapeutic pressure by the end of exhalation. And that's where incipient and expiratory end-phase apneas sometimes require full stenting pressure. Resmed handles that situation by suspending EPR altogether, and Respironics handles that situation by being up to full therapeutic pressure well before the end of each exhale. BiLevel titration protocol during NPSG handles that same situation by setting EPAP pressure to CPAP pressure.

Additionally, you might find BiFlex applied on top of ordinary BiLevel pressure-cycling to be more comfortable.

Good discussion thus far.

Am I right in assuming that the VPAP Auto 25 will do everything that a S9 Autoset will?

I am selling my S9 Elite CPAP machine and will be buying one of the above machines

tschultz wrote: ...I was not aware that the EPR feature in the ResMed operates only in CPAP mode...

Err, I have the S8 AutoSet II. I use it in auto mode with EPR set to 2 and the auto function works great ranges up and down as it should. They didn't change this when they created the S9 models.

Jayjonbeach wrote:Good discussion thus far.

Am I right in assuming that the VPAP Auto 25 will do everything that a S9 Autoset will?

No.
The VPAP Auto 25 does not use the enhanced algoritm which the S9 has. You may find it raising pressure in response to open airway apneas - somthing it should not do. You may also find it does not raise pressure in response to obstructive apneas at pressure higher than 10. Much depends on your breathing pattern. Furthermore, on its own, it also does not have the data recording/reporting capabilities of the S9 - IIRC, you need a Reslink module (nla) to get the full details of your breathing from a VPAP Auto 25.

Jayjonbeach wrote:...Am I right in assuming that the VPAP Auto 25 will do everything that a S9 Autoset will?

Nope, the VPAP Auto is from ResMed's pre-S9 models.

Jayjonbeach wrote:...I am dumping my outdated technology (IMO) S9 Elite CPAP machine and will be buying one of the above "smarter" machines that actually adjust to your breathing and act proactively to events, rather than just feed you the same pressure all night no matter how you are breathing, sleeping, not breathing, etc. (which clearly is NOT working for me)

Your Elite is a straight CPAP machine. I think what you want is an autotitrating CPAP machine, commonly called an APAP. It is set to a pressure range, typically a little less and a bit more than your titrated pressure. The pressure it delivers is based on your preceding 5 breaths and what it detects from your breathing pattern. It increases pressure in response to certain breathing irregularities that are assumed precede an event; it begins to decreases pressure when stable breathing is established because it's goal is to deliver the least amt of pressure that maintains stable breathing. The S9 also has the ability detect obstructed or unobstructed (clear) airways in addition to collecting additional information compared to the S8 APAP. The common name for the ResMed APAPs is AutoSet.

Muse-Inc wrote:

tschultz wrote: ...I was not aware that the EPR feature in the ResMed operates only in CPAP mode...

Err, I have the S8 AutoSet II. I use it in auto mode with EPR set to 2 and the auto function works great ranges up and down as it should. They didn't change this when they created the S9 models.

It was only on the pre II vesions that you couldn't use EPR in Auto mode.
And on those the only EPR "fast" (square shaped0. The S8 II has enhanced EPR, and in cpap mode lets you choose between "Fast" EPR and "Medium". "Medium" is acutally the enhanced EPR (where do they take all those terms from???). For me "Fast" EPR gives a rushed feeling. "Medium" does not.

ozij wrote:...

Thanks Ozij, great info!

Thanks for all the information, I am so glad I started this tread. It has helped so much with understanding the nuances of the various machines and I am guessing that my original choice of the ResMed S9 AutoSet may be the right one after-all.

I am eager to get going on treatment and hope I can find a local DME that will let me try out each machine before I have to chose. I am still pushing to get my prescription - I am afraid the waiting is actually killing me.

CPAP treatment = Canadian Patient Awaits Proper treatment