ResMed Pressure Support

"One raises delivered EPAP by raising EPAP Min. Changing PS just changes the distance between IPAP and EPAP, so decreasing PS and leaving EPAP Min where it is mostly just lowers your delivered IPAP."

For the last month I have had the following settings. Min EPAP 7.0 Max IPAP 18.0 Pressure Support 4.0. When I put the mask on the pressure goes to 11.0 and is never less than that. During the night the IPAP varies up to 15.0 in some cases. So when the IPAP is 15.0 the EPAP has gone to 11.0 with a PS of 4.0. From the reading I have done of past threads on this Forum it seems that the EPAP pressure is what keeps the airway open... or keeps it from closing between breaths. If in the above case the PS was 3.0 then the EPAP would be 12.0 instead of 11.0.... higher. To me it would seem that the only time the min EPAP comes into effect is at the initial start up or if for some reason during the night the machine makes the IPAP low enough to trigger it.

I am sure you know a lot more about this than I do but the above is the logic I followed in lowering the PS setting... and it seemed to have positive results. I slept all night and had a much lower AI and AHI than when I had the PS set to 4.0. As I said before, that is only one night and maybe an anomaly.

Thanks again,

Ed

IFLEW wrote: When I put the mask on the pressure goes to 11.0 and is never less than that.

Yes, that is the point. You started out with IPAP at 11, as you say, since your minimum EPAP is 7 and PS was at 4 and 7+4 is 11. (I explain that mostly for the lurkers, not you.) And so if you start out with minimum EPAP at 7 and PS at 3, THEN you start out with IPAP at 10, as you say. So you have lowered where your IPAP starts out, and in doing so, you have changed the lower limit of the IPAP, according to how ResMed autobilevels work.

It is true that if events raise your IPAP from threre, it will drag your EPAP up along with it. But my understanding is that the consensus here among patients is that the best way to lower the estimated "AI" (which on a ResMed is a MUCH more important number than the estimated "HI," according to what I've read in others' experiences) is to get your lower limit up close to what you need to prevent apneas. That is true with autobilevels in the same way it is true of regular APAPs, since it is the EPAP in bilevel that addresses apneas, generally speaking.

That being said, if what you are doing is working for you, I think that's great. We are ALL thinking outside the box here, since the manufacturers and many docs feel all autos should be left wide open, 4 to 25. Autobilevel is a new enough technology that few of the boxes are set in stone enough to worry about stepping outside of them. The results are what matters.

My personal feeling is that a PS of 3 isn't all that different from a PS of 4, so no harm no foul. I was only trying to pass on what passes for standard among all of us nonstandard users who are naughty enough to tweak our own pressures.

jeff

That's what I thought, that the EPAP governed the dance. So how the h*ll is this VPAP Auto really an Auto?

Slinky wrote:That's what I thought, that the EPAP governed the dance. So how the h*ll is this VPAP Auto really an Auto?

What you set EPAP at governs where the dance will begin...at what level. With IPAP starting along 4 cms above that (if you have PS set at 4.)

From that point on, either IPAP or EPAP can change "automatically."

With a ResMed VPAP Auto or VPAP Auto 25:

If EPAP is the one that needs to go up while autotitrating, it will push IPAP on up, too...to keep that 4 cm PS difference between them.

If IPAP is the one that needs to go up while autotitrating, it will pull EPAP upward...again, to keep that 4 cm PS difference between them.

At least, that's how I understand it, and I could be stating it wrong.

jnk wrote:my understanding is that the consensus here among patients is that the best way to lower the estimated "AI" (which on a ResMed is a MUCH more important number than the estimated "HI," according to what I've read in others' experiences) is to get your lower limit up close to what you need to prevent apneas. That is true with autobilevels in the same way it is true of regular APAPs, since it is the EPAP in bilevel that addresses apneas, generally speaking.

I agree.

My thoughts about EPAP setting on a bilevel machine (and min EPAP on the BiPAP Auto.)

November 2007 - EPAP is for more than just comfort exhaling.
viewtopic.php?p=227068#p227068

December 2007 - my understanding of how a bipap titration is done.
viewtopic.php?p=231786#p231786

May 2008 - discussion with RonS about importance of EPAP setting.
viewtopic.php?p=265020#p265020

jnk wrote:That being said, if what you are doing is working for you, I think that's great.

I agree again.

jnk wrote:My personal feeling is that a PS of 3 isn't all that different from a PS of 4, so no harm no foul.

In agreement there, too!

I am going to resurrect this thread for a progress report. I have slowly lowered the Pressure Support setting and am now at 2.4 with a Min EPAP of 7.4. As I lowered the Pressure Support my numbers improved markedly. For the last two weeks at the 2.4 setting my AI is either 0.0 or 0.1. I was running in the 4-6 range before playing with the Pressure Support setting. I have also made minor adjustments to the headgear which has improved the leak number. I am sure this has also contributed to my reduced AI. My max IPAP remains set at 18 but with the current Pressure Support of 2.4 the IPAP rarely exceeds 13. Before the IPAP was in the 15-16 range on most nights and I suffered from a bloated feeling and flatulence. My theory of the setup (completely non medical but with some engineering background) is that since EPAP is what diminishes the Apneas my lower Pressure Support allows me to get the EPAP setting I need without as high a pressure on the IPAP phase. I know that the IPAP is what floats but since it is dragging the EPAP with it (on a ResMed machine) you could also look at it as the EPAP floating and IPAP just running a certain number above it.

In any event my sleep and better yet my feeling the next day has improved remarkably. If any of you out there that play with your own settings on a ResMed machine are not getting the results you want I would suggest varying the Pressure Support number downward... just to see.

Good Health and Good Sleeping,

Ed

Thanks for the update, IFLEW.

Very interesting. Glad you posted how it's been going for you. That can help others.