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EPR or not EPR
#11
RE: EPR or not EPR
EPR or Flex is a godsend for some.

Mostly it's comfort. For some, it reduces bloating. Some people find it seems to improve their AHI, especially for centrals.

For others, it's uncomfortable or even makes their AHI worse.

For now, it seems to be an option to use as on a trial and error basis.
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#12
RE: EPR or not EPR
Zonk,

Thanks for mentioning the oft overlooked DeVilbiss and Fisher & Paykel machines.

It should be noted that the DeVilbiss SmartFlex is essentially equivalent to Resmed's EPR (and hence roughly equivalent to PR's Flex systems): It provides a fixed drop in pressure when the beginning of the exhalation is detected and the pressure is raised back up to the therapeutic setting at or just before the inhalation starts.

But the F&P SenseAwake is a different can of worms entirely: The only time SenseAwake kicks in is when the Icon+ Auto/Premo thinks you are awake; and it doesn't provide a small bit of exhalation relief, rather it drops the pressure significantly until the machine thinks you've fallen back asleep. At which point it raises the pressure back up to the therapeutic level. In other words, Senseawake acts sort of like an automated ramp button that gets pushed when the machine thinks you are awake or in danger of waking up.

But the Icon has no EEG to definitively determine whether you are asleep or not. The Icon is using nothing but the wave flow data to guess when you are awake. It bases its guess on patterns in the wave flow, and nothing else. And fact is, you just can't definitively determine whether you are asleep or awake based on just the wave flow.
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#13
RE: EPR or not EPR
The claims made by the manufacturers are exaggerations. Exhalation pressure relief seems to be a good thing, especially for beginners. The same is true of the ramp feature. Personally I never use the ramp, but I have the exhalation pressure set on its maximum setting, and I have a bilevel machine.
Sleepster

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#14
RE: EPR or not EPR
(06-07-2014, 05:41 PM)zonk Wrote: EPR useful or useless

Hi Zonk,
I find this feature useful, for helping reduce aerophagia. My aerophagia worsens with higher pressure (naturally), so whatever I can do to minimize the pressure also helps the aerophagia (and leaks). Avoiding supine position is the biggest factor, but EPR also helps.
A.Becker
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#15
RE: EPR or not EPR
(06-09-2014, 05:57 PM)becker44a Wrote:
(06-07-2014, 05:41 PM)zonk Wrote: EPR useful or useless

Hi Zonk,
I find this feature useful, for helping reduce aerophagia. My aerophagia worsens with higher pressure (naturally), so whatever I can do to minimize the pressure also helps the aerophagia (and leaks). Avoiding supine position is the biggest factor, but EPR also helps.
A.Becker
Okay, thanks for the feedback Coffee

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#16
RE: EPR or not EPR
I was googling about something else and led me to another board, thread by 'sleepydave' posted 2005, which i find quite interesting reading, thought somebody else might find interesting too

Is EPR Really Bilevel? by sleepydave

When the coming of Expiratory Pressure Relief (EPR) was first announced, I had some questions as to whether this modality would offer relief on active expiration only during the CPAP mode, and perhaps address the issues that other expiratory adjuncts were having, or if the drop in expiratory pressure were carried out all the way to the next inspiration, relying on inspiration as the trigger to terminate EPR, and thus essentially operate in a BiPAP mode.

The following waveform analyses were performed on the EPR mode at 10 cmH2O with an EPR setting of 3 cmH2O. The breath rate is approximately 12.

The first graph shows the breathing waveform on top, inspiration being an upward deflection and expiration downward, while the bottom graph is measuring pressure. The pressure settings are seen as faint numbers at the left of the pressure waveform. You can see that the EPR, reflected as a drop in the therapeutic pressure on the pressure waveform down to about 7 cmH2O, is carried out all the way to the point of inspiration, and the inspiratory effort therefore takes place at a sub-therapeutic pressure. The baseline pressure returns to 10 cmH2O, but not until after inspiration has begun. In other words, inspiration is the trigger to terminate EPR, and instead of a CPAP pressure of 10 cmH2O with an expiratory adjunct, we are effectively left with BiPAP of 10/7:

[Image: epr11.jpg]

This might not make a clinical difference if the patient ends up with the same results on BiPAP 10/7 that he would have on CPAP 10 cmH2O (which could be the case if there were only flow limitations, snores, or hypopneas). But if the new EPR-defined EPAP is below the apnea threshold, then there could be a problem.

In the second graph, the waveforms are superimposed to show more clearly that inspiration is occurring at a sub-therapeutic level:

[Image: epr12.jpg]

There is a time limitation associated with the termination of EPR. In the next graph, you can see how the EPR eventually terminates and returns to baseline. In this instance, the breath rate was approximately 6, so the time to EPR termination was appoximately 5 seconds. The first arrow represents EPR termination, while the second signifies patient breath:

[Image: epr13.jpg]

And here again, the graphs are superimposed to show the return to baseline relative to inspiration:

[Image: epr14.jpg]

This means that eventually, there will be a return to baseline CPAP if in fact, an apnea occurs, and at the most, only one breath would be missed. Is the net result clinically relevant? I'm not sure either way. But if you're generating negative intrathoracic pressure or creating arousals, then there could be an issue.

In re: putting EPR in the AutoSet mode, that could be an effective way to overcome this supposed shortcoming of EPR. If events were to start occurring at, in this case, "10 cmH2O of CPAP". then baseline pressure could be raised, theoretically, to "13 cmH2O of CPAP", or effectively BiPAP 13/10. Course now we're right back where we started. The only outstanding question would be if the 13/10 format was better tolerated than the straight 10.

But how would the algorithm work? If the apnea identification in AutoCPAP is 10 seconds, and the EPR terminates at (in this case) 6 seconds, how would it know to increase the CPAP (really the "EPAP" segment of EPR) to address apneas? I would assume that flow limitations would be properly addressed with CPAP increase (because you're really raising the "IPAP" segment of EPR).

As an aside, therein lies the problem once you start talking about Auto-BiPAP. Do you increase the IPAP, and keep EPAP fixed, or do you vary the EPAP as well, looking to address apneas. You're gonna need two totally separate algorithms, and they can't interfere with each other.

There are a couple of options available with EPR. It can be used during the ramp period only, which would offer significant patient comfort during a time where the perhaps the greatest period of patient difficulty occurs. After the ramp period is over, it returns to the set pressure.

Before you select full-time EPR, though, and carry EPR throughout the night, you should consider how your particular situation might respond to this modality. And I think the key to EPR, AutoCPAP with EPR (should that ever come about) and AutoBiPAP will be how apneas are addressed. You might be OK dealing with hypopneas, snores and RERAs if you're of the belief that BiPAP can properly address these issues. And that's a whole 'nother discussion




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#17
RE: EPR or not EPR
very interesting find, and it bolsters what was going on in the back of my head about EPR from looking at the pressure waveform.

thanks

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#18
RE: EPR or not EPR
RE:Fisher & Paykel SensAwake

The fact that SensAwake is advertised to "provide a prompt and significant relief in pressure to the lowest most comfortable level upon waking" makes it sound as though SenseAwake is an automated "hit the ramp button" feature.

The big problem I see with the Fisher & Paykel SensAwake system is that the Icon has no EEG and hence it can't really tell when you are awake and when you are asleep. They're basing the SensAwake trigger on changes in the airflow that are associated with wake breathing and arousals. Unfortunately, those breathing changes include a change in RR and increased TV and MV and less regularity in the breathing pattern. And, unfortunately, those kinds of changes in breathing pattern can also happen as you go into REM. So it's entirely possible for the SensAwake algorithm to decrease the pressure at the wrong time in the sleep cycle.

RE: DeVilbiss Intellipap SmartFlex
This is works very much like Resmed's EPR system in the sense that the pressure is dropped by a fixed, constant amount on every exhalation. The difference between SmartFlex and EPR is the shape of the mask pressure curve---i.e. the particulars about how the pressure is increased back up to the therapeutic pressure setting. The talk of rounding sounds reminiscent of the PR Flex systems; but without graphical pictures that show both the mask pressure curve and the typical respiration pattern for patient, it's hard to say for sure.
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#19
RE: EPR or not EPR
I have IPAP = 12, EPAP = 9, and Bi-Flex = 3. This the machine delivers three different pressure levels: 12, 9, and 6.

When I inhale I get 12, when I exhale I get 6. When I stop exhaling it rises from 6 to 9. When I start inhaling it rises from 9 to 12.

I have a PRS1 BiPAP. I've been told it works differently on a ResMed VPAP.
Sleepster

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#20
RE: EPR or not EPR
(06-27-2014, 10:41 AM)Sleepster Wrote: I have IPAP = 12, EPAP = 9, and Bi-Flex = 3. This the machine delivers three different pressure levels: 12, 9, and 6.

When I inhale I get 12, when I exhale I get 6. When I stop exhaling it rises from 6 to 9. When I start inhaling it rises from 9 to 12.

I have a PRS1 BiPAP. I've been told it works differently on a ResMed VPAP.

that's not how I've been told xflex works... not saying you're wrong, just that it's contrary to what I've heard.

that is how epr works on resmed, but vpaps don't have epr. the vpap s does have something called 'easy-breath', but I've never looked into figuring out what that is, since I run mine in vauto mode, which doesn't offer easy-breath.
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