Resmed auto EPR technical question

[kurtr]

I have a newer Resmed S8 auto.
When I set it with EPR on (setting 2) with auto, I wake up feeling bad and AI is higher ie; 0.8.
When I set it with EPR off with auto, I usually feel better (not great) and AI is lower ie; 0.2.
My question is on some people, does the EPR algorithm not function well to correct the apneas.
Should I buy software to identify the problem?

Thanks very much,
Kurt

[jnk]

I have a newer Resmed S8 auto.
When I set it with EPR on (setting 2) with auto, I wake up feeling bad and AI is higher ie; 0.8.
When I set it with EPR off with auto, I usually feel better (not great) and AI is lower ie; 0.2.
My question is on some people, does the EPR algorithm not function well to correct the apneas.
Should I buy software to identify the problem?

Thanks very much,
Kurt

EPR on a ResMed, as I understand it, lowers the pressure as you breathe out in a way that can affect some people's therapy. Knowing that can help you decide whether you might need to raise your overall pressure by the same amount of EPR you use. For example, some people use an EPR of 2 and then raise their overall pressure by 2 cm to keep EPR from lowering the effectiveness of their therapy. Other people find they do not need to do that. You can use your trending data from your machine and how you feel in order to judge what you need to do. It is good to see the effect over a week or two to judge.

jeff

[dtsm]

EPR on a ResMed, as I understand it, lowers the pressure as you breathe out in a way that can affect some people's therapy. Knowing that can help you decide whether you might need to raise your overall pressure by the same amount of EPR you use. For example, some people use an EPR of 2 and then raise their overall pressure by 2 cm to keep EPR from lowering the effectiveness of their therapy. Other people find they do not need to do that. You can use your trending data from your machine and how you feel in order to judge what you need to do. It is good to see the effect over a week or two to judge.
jeff

I have a slightly different understanding. EPR does lower pressure on exhalation and does affect the average pressure. But if you're on apap, "in theory", the machine should adjust for it. I think where it comes into place is when you set the lower pressure.

In other words, if your straight cpap pressure is 9 & EPR of 3 and you go to apap, one would normally consider a 9-12 range. However, because EPR lowers pressure on exhalation, you would have to adjust to 9-15 or increase lower range by adding 3 to 9 and end up with 12-15 or 12-16/17/18/19/20 range.

When I was on apap, I had 9-12 range with EPR 3. Instead of tweaking range, I reduced EPR from 3 to 2, and then eventully to 1. But I could have, in theory, kept EPR at 3 and just increase the 9 upwards.

[jnk]

EPR on a ResMed, as I understand it, lowers the pressure as you breathe out in a way that can affect some people's therapy. Knowing that can help you decide whether you might need to raise your overall pressure by the same amount of EPR you use. For example, some people use an EPR of 2 and then raise their overall pressure by 2 cm to keep EPR from lowering the effectiveness of their therapy. Other people find they do not need to do that. You can use your trending data from your machine and how you feel in order to judge what you need to do. It is good to see the effect over a week or two to judge.
jeff

I have a slightly different understanding. EPR does lower pressure on exhalation and does affect the average pressure. But if you're on apap, "in theory", the machine should adjust for it. I think where it comes into place is when you set the lower pressure.

In other words, if your straight cpap pressure is 9 & EPR of 3 and you go to apap, one would normally consider a 9-12 range. However, because EPR lowers pressure on exhalation, you would have to adjust to 9-15 or increase lower range by adding 3 to 9 and end up with 12-15 or 12-16/17/18/19/20 range.

When I was on apap, I had 9-12 range with EPR 3. Instead of tweaking range, I reduced EPR from 3 to 2, and then eventully to 1. But I could have, in theory, kept EPR at 3 and just increase the 9 upwards.

Thanks, dtsm. Good point. I missed the "auto" part in the question above. My answer was about using CPAP. My bad. Using an auto and EPR, that would mean, for some, as you say, raising the minimum, to feel their best and get the lowest AI, as I understand it too. Or, as you say, alternatively, using less EPR. It's a balancing act.

I'm not very focused today. Keep an eye on me!

jeff

[Luc]

Kurtr,
re: "My question is on some people, does the EPR algorithm not function well to correct the apneas."

EPR is strictly used to enhance your comfort. It does not affect you apneas because it only lowers the pressure when you exhale. You cannot have an apnea event while you exhale. Only the pressure during your inhale can have an effect on your apneas. Try a test for yourself. Simulate an apnea. Take a breath and hold it... do not exhale. The EPR will not kick in and the pressure will remain constant.

[dtsm]

I'm not very focused today. Keep an eye on me!
jeff

LOL....i learned this only about 2 wks ago from reading other posts and our venerable 'Rested Gal'. Thank her too!

[jnk]

Kurtr,
re: "My question is on some people, does the EPR algorithm not function well to correct the apneas."

EPR is strictly used to enhance your comfort. It does not affect you apneas because it only lowers the pressure when you exhale. You cannot have an apnea event while you exhale. Only the pressure during your inhale can have an effect on your apneas.

I disagree. Apneas often happen at end of exhalation. That is why exhale pressure is generally considered the pressure for preventing apneas. And that is why a bilevel titration raises EPAP to get rid of apneas and raises IPAP to get rid of hypopneas. At least, that is my understanding.

viewtopic/t50770/viewtopic.php?f=1&t=50 ... 03#p467203

viewtopic.php?p=342731#p342731

[dtsm]

I disagree.

Agree with jnk.

Another thread that discusses this in depth, it's Rested Gal's explanation - viewtopic/t48002/Cflex-13-Levels.html

[Luc]

I disagree. Apneas often happen at end of exhalation. That is why exhale pressure is generally considered the pressure for preventing apneas. And that is why a bilevel titration raises EPAP to get rid of apneas and raises IPAP to get rid of hypopneas. At least, that is my understanding.

viewtopic/t50770/viewtopic.php?f=1&t=50 ... 03#p467203

viewtopic.php?p=342731#p342731

I don't know... When you are asleep, you, your lungs, the mask, the CPAP all become one air pressure system. The air pressure column that keeps your airways opened is a product of the machine delivering the pressure on inhale, not exhale. You do not deflate all that pressure on exhale. Otherwise your ears would be popping all the time. When I go to sleep with the mask on, my body gets pressurized. EPR helps me to breath out and that's it. True a lot of events occur at end of exhale... BUT even at end of exhale your air system is still pressurized. If it were otherwise then titrations at sleep labs would all have to use EPRs to determine the correct pressure.

Please correct me if I'm wrong. But that's the way it seems to me.

Luc