S9 Elite, if EPR is on, is flow limitation data accurate?

I am experimenting with pressures and use of the EPR.

I find that with 11.0 cm-H2O that I have flow limitations when the EPR is off, but I don't have it when the EPR is on.

The EPR helps with breathing, but I don't see why it would eliminate flow limitations.

Is the measurement of flow limitations compromised or interfered with by the EPR feature when it is turned on.

I tried first 12.0 and EPR, 3 cm-H2O fast, then 11.0 and EPR 3 cm-H2O fast. Then I had a suspicion it wasn't the increased pressure eliminating the flow limitations.

I tried 11.0 cm-H2O and NO EPR and I had plenty of flow limitations.

Anyone understand if the EPR interferes with flow limitation measurments?

Turning EPR on should not affect the accuracy of the flow limitation data.

Question: How much total data are we talking about at each setting? It's hard to say what's really going on if you only have a day or two of data at each setting: Our sleep is not the same every night and a "bad" night for flow limitations when EPR = off and a "good" night for flow limitations when EPR = on can explain the phenomenon if the data is very limited.

That said: Different people react differently to EPR. EPR is supposed to be a patient comfort setting, which means that for most people, there should be little or no difference in the therapy numbers regardless of the EPR setting (including OFF). But individual people do have different real reactions to EPR. For some people, setting EPR = 3 leads to a noticeable uptick in the number of events scored because the 3cm drop in pressure on each exhalation leaves their airway just a bit more prone to collapsing. (Turning EPR down or increasing the pressure setting can fix the problem.) Other individuals see a bit of improvement in their therapy numbers with EPR. Perhaps it's just because they're more comfortable so there is less "restlessness" during the night. Or perhaps it's because they have fewer problems exhaling fully against the continuous positive air pressure when there is a drop at the beginning of each inhalation.

It could be that when EPR is turned on, you are more capable of exhaling fully against the pressure, and that makes it easier for your body to properly manage the CO2 levels that trigger breathing. Hence it's possible that with EPR turned on, your breathing is simply more stable. And the fact that the breathing is more stable means that the inhalations are less likely to have odd shapes that get scored under the S9 algorithm as "flow limitations."

So the real question then becomes: Are you more comfortable when you are sleeping with EPR = ON or are you more comfortale sleeping with EPR = OFF?

sleepy1235 wrote:I am experimenting with pressures and use of the EPR.

I find that with 11.0 cm-H2O that I have flow limitations when the EPR is off, but I don't have it when the EPR is on.

The EPR helps with breathing, but I don't see why it would eliminate flow limitations.

Is the measurement of flow limitations compromised or interfered with by the EPR feature when it is turned on.

I tried first 12.0 and EPR, 3 cm-H2O fast, then 11.0 and EPR 3 cm-H2O fast. Then I had a suspicion it wasn't the increased pressure eliminating the flow limitations.

I tried 11.0 cm-H2O and NO EPR and I had plenty of flow limitations.

Anyone understand if the EPR interferes with flow limitation measurments?

Reply,

Flow Limitation (FL) could be because of anatomical malformation at the upper airway including the nose, and in such a case the EPR could act as a PEEP device ( PEEP = Positive end-expiratory pressure). See here about it:

http://en.wikipedia.org/wiki/Positive_e ... y_pressure

Notice that the ratio between the inhalation and exhalation pressures affects the closure of the lungs' alveoli during expiration. When using PEEP then the alveoli are not let to completely deflate and then the inspiration pressure could be lowered or the expiration pressure increased helping in re-inflating them (like a toy balloon). So changing the EPR between 0 and 3 would affect the existence and level of FL depending on the set pressures.

I am too lazy at the moment to go over your experimental results and see if they comply with this PEEP effect.

So Avi, what do you think? Is an EPR of 3 likely to cause the machine to report more or fewer Flow Limitations than an EPR of off?

sleepy1235 wrote: I had plenty of flow limitations.

Could you state what your data shows or post a chart?

1. avi123. Thanks for the link and info.


My basic question is this.

>>>>> For the S9 does the EPR feature interfere with the measurement of flow limitations.

Could the absence of flow limitations be caused by an issue with the S9 algorithm that detects flow limitations being interfered with by the EPR.

Could there be a flow limitation problem still there, but undetected due to the EPR?

That is the primary question of my post.

I have always had flow limitations since I had a CPAP with detailed data capability. I was increasing the pressure from 8 to 9 for a week and then to 10 for a few days still getting flow limitations.

So fed up I went to 12 with EPR. I added in EPR because it was a little straining to breath against 10 cm-H2O. The flow limitations largely vanished. Then I tried 11 with EPR and there were no flow limitations.

Then I had a suspicion that the EPR was probably the reason the flow limitations vanished. Tonight I am trying 10 with EPR. My guess is that the flow limitations will be gone. Then I will try 9 with EPR, then 8, my original setting with EPR.

Though perhaps as an engineer who uses statistics I should have replicates in my investigation, I will hold off on that. I have multiple episodes of flow limitations, about 50% of my sleep time as reliable as the sun rising in the East.

So back to the primay question. Does the flow limitation metrology work when the EPR mode is on?

If the EPR mode invalidated the flow limitation metrology then these various tests mean nothing.

So the primary question is whether the flow metrology works when the EPR mode is on.

There must be many of us who use these machines. I am looking for information on the web and coming up with nothing.

sleepy1235 wrote: I have always had flow limitations since I had a CPAP with detailed data capability. I was increasing the pressure from 8 to 9 for a week and then to 10 for a few days still getting flow limitations.

So fed up I went to 12 with EPR. I added in EPR because it was a little straining to breath against 10 cm-H2O. The flow limitations largely vanished. Then I tried 11 with EPR and there were no flow limitations.

so, you cranked up your pressure and you're surprised you got different numbers, and decided to pin it on the EPR?

read again what robysue answered you.

my s9 vpap scores flow limitations and it's doing the equivilent of EPR.

I think I found the answer.

viewtopic.php?f=1&t=54518&start=30

The Fast mode interferes with the wave form.

I am going to try medium instead.

sleepy1235 wrote:I think I found the answer.

viewtopic.php?f=1&t=54518&start=30

The Fast mode interferes with the wave form.

I am going to try medium instead.

huh, the way I read that, fast mode might cause false *positives* but you're compaining of percieved false *negatives*...

sleepy1235 wrote:I think I found the answer.

viewtopic.php?f=1&t=54518&start=30

The Fast mode interferes with the wave form.

I am going to try medium instead.

I have my doubts about that. My menu (ResMed AutoSet S9 purchased 12/2013) allows selection of EPR 1, 2 or 3 when in Auto mode.

Here is a night when I was running pressure min 10, max 20 and EPR 3.



I could tell by feel that EPR was actually running at 3. Maybe they changed the controlling software.

he's not saying epr doesn't work on his elite, he's saying he thinks that it causes the machine to not register flow limitations, which is... wrong.

palerider wrote:he's not saying epr doesn't work on his elite,

I wasn't replying to the OP, but to the link Sleepy posted,which says in part,

MODERATE AND FAST ARE DISABLED IN AUTOSET MODE

Setj wrote:

palerider wrote:he's not saying epr doesn't work on his elite,

I wasn't replying to the OP, but to the link Sleepy posted,which says in part,

MODERATE AND FAST ARE DISABLED IN AUTOSET MODE

ah, yes, that's not the epr setting that's talking about, that's the "epr inhale" setting, which you won't see in autoset mode, only cpap mode.

sleepy1235 wrote: I have multiple episodes of flow limitations, about 50% of my sleep time as reliable as the sun rising in the East.

You may be interested in this thread - viewtopic.php?f=1&p=911353#p911353

If you find it interesting, please bump it to the top. I had hoped to hear from more users.