Understanding and adjusting "Rise Time"

For the last 10 days I have been trying some setting suggestions that were recommended by Pugsy.

The quick version of my story is I had been using the Dream Station Auto in the fixed bi-level therapy mode: IPAP 10.0, EPAP 7.5, humidification 1, tube 2, FLEX 0. My previous posts explain the reasons for the tight pressure range, etc.. This fixed mode was working relatively well, but I had ugly clusters of various obstructive events.

In an attempt to break up these clusters, the suggested settings changes by Pugsy were: AutoB therapy mode, IPAP max 11.0, EPAP minimum 7.5, PS min. 2.5, PS max 3.0. I have been using this AutoB setting, and some minor tweaks of this AutoB setting. I will post some screen shots after several more days of collecting data. Generally, I believe the AutoB setting change was a step in the right direction......however, there is one main issue that is bothering me with AutoB.

I feel that the machine is not in a good rhythm with my individual inspiration and expiration cycle. IOW, I will still be inspiring and I "sense" the machine transition to the EPAP pressure. I am then forced to either change my breathing rhythm or put up with the obvious reduction in pressure before I want it.

Finally, my question....can anyone share any knowledge or experiences when changing the machines "rise time" feature? I am weary of going thru the various options of different setting features, and was hoping I could get some feedback before I begin. The clinical manual describes "rise time" as the time it takes for the device to change from IPAP to EPAP. The feature is only available if FLEX is disabled (and mine is disabled) and the device is in Bi-Level or AutoB. Since I have flex disabled, the "rise time" has defaulted to 0. The "rise time" feature offers options 0 thru 3, with 0 equal to 150 msec., 1 equal to 200 msec. 2 equal to 300 msec. and 3 equal to 400 msec.

Will changing "rise time" make any noticeable difference in the rhythm of IPAP /EPAP...is the span of milliseconds enough to matter? Is my complaint significant, or will the machine adapt to me over the coming nights?

Thank you,

Zack

The machine doesn't "adapt" to you....you adapt to it. It won't change the way it does the inhale or exhale timing based on what you do or don't do. It really doesn't/can't remember your breathing to make those sorts of changes.
Rise time is pretty well fixed and while some people like it better than BiFlex...others don't.
Have you tried increasing that rise time....and yes it wouldn't be impossible for that slight millisecond difference in time to make a marked change in what you perceive.

Have you tried using BiFlex turned on? It's a little smoother I think than relying on rise time.

My suggestion is to simply sit down and try all the available settings in both rise time and BiFlex and figure out the one that feels the best and most closely matches your own respiration pattern.

Pugsy wrote:The machine doesn't "adapt" to you....you adapt to it. It won't change the way it does the inhale or exhale timing based on what you do or don't do. It really doesn't/can't remember your breathing to make those sorts of changes.
Rise time is pretty well fixed and while some people like it better than BiFlex...others don't.
Have you tried increasing that rise time....and yes it wouldn't be impossible for that slight millisecond difference in time to make a marked change in what you perceive.

Have you tried using BiFlex turned on? It's a little smoother I think than relying on rise time.

My suggestion is to simply sit down and try all the available settings in both rise time and BiFlex and figure out the one that feels the best and most closely matches your own respiration pattern.

I get the feeling that OP wants to take really slow breaths, which exceed the fixed TiMax time on the machine, as far as I know, there's no way to adjust the TiMax time on a respironics, only on the resmed bilevels.

palerider wrote:I get the feeling that OP wants to take really slow breaths, which exceed the fixed TiMax time on the machine, as far as I know, there's no way to adjust the TiMax time on a respironics, only on the resmed bilevels.

True but that is why I also suggested playing with BiFlex a bit. I have tried both on my PR S1 760 and I felt that BiFlex offered a smoother transition...not so abrupt and it might help and sure wouldn't hurt to try.
The machine isn't going to change what it can and can't do but maybe it will be a little easier to adjust to the machine's way of doing things.

All we need to do is get past the discomfort while awake because when asleep it isn't likely to be a problem.

RobySue has mentioned in the past that she can actually tell a rather big difference between rise time of 3 and 1...so it wouldn't be impossible for someone to find that it helps at 3. It may not be as slow as someone might really want but it's still slower than 1.
Now BiFlex feels a little different and higher BiFlex might feel faster...so that's why I say try all BiFlex settings.

Pugsy wrote:
Have you tried using BiFlex turned on? It's a little smoother I think than relying on rise time.

My suggestion is to simply sit down and try all the available settings in both rise time and BiFlex and figure out the one that feels the best and most closely matches your own respiration pattern.

When I was using fixed bi-level therapy mode, I was more comfortable and had better AHI numbers with a FLEX of 0. At FLEX 2, I believe my airway was collapsing during EPAP and I had a lot of arousals. So, I didn't use any FLEX with the AutoB therapy.

Unfortunately, you are probably correct and I will just have to try all the available settings

palerider wrote:
I get the feeling that OP wants to take really slow breaths, which exceed the fixed TiMax time on the machine, as far as I know, there's no way to adjust the TiMax time on a respironics, only on the resmed bilevels.

You are correct. My normal breathing cycle is probably slow, with a SH reported mean inspiration time of 2.7-3.2 secs.

Thanks for the tip about the respironics versus resmed bipap machines. I never realized that.

You know if the only issue with using BiFlex was that a few airway collapses tried to occur with whatever EPAP you were using ....that's easier to fix then your slow breathing...just use a tad more EPAP to start and the airway won't collapse.

My suggestion is at least try BiFlex (at whatever setting feels the best) and let's see if we need to maybe adjust EPAP a wee bit to compensate.

Pugsy wrote:RobySue has mentioned in the past that she can actually tell a rather big difference between rise time of 3 and 1...so it wouldn't be impossible for someone to find that it helps at 3. It may not be as slow as someone might really want but it's still slower than 1.
Now BiFlex feels a little different and higher BiFlex might feel faster...so that's why I say try all BiFlex settings.

I agree with the difference in rise time, with the resmeds you can twiddle risetime between 100ms and 900ms, iirc, and that's a huge difference, the short rise time is almost like a whack in the lungs, whereas the longer one is much more gentle... but, then, the rise time twiddling isn't available in the mode I use.. so it was just for experiments sake.

I know some people (slow breathers?) don't like biflex because they feel that the pressure increase at the end of the 'expiration' time feels like the machine is pressuring them to take a breath... when it's not really, but that little pressure bump can feel that way.

Pugsy wrote:You know if the only issue with using BiFlex was that a few airway collapses tried to occur with whatever EPAP you were using ....that's easier to fix then your slow breathing...just use a tad more EPAP to start and the airway won't collapse.

My suggestion is at least try BiFlex (at whatever setting feels the best) and let's see if we need to maybe adjust EPAP a wee bit to compensate.

I will try some FLEX and rise settings.

In the fixed bi-level mode I tried everything from EPAP 6.0 thru 8.0, and FLEX 3 thru 0. By far, the most comfortable and the best AHI reports, was with EPAP 7.5 and 0 FLEX.

I will report back when I get enough information to show a trend. You have been very helpful.

palerider wrote:
I know some people (slow breathers?) don't like biflex because they feel that the pressure increase at the end of the 'expiration' time feels like the machine is pressuring them to take a breath... when it's not really, but that little pressure bump can feel that way.

Your statement explains the other main reason that I finally arrived at 0 FLEX after trying all the different settings for EPAP in fixed bi-level therapy mode. As I mentioned previously, the other reason was the pressure decrease before I finished my inhalation.

zack243 wrote:

palerider wrote:
I know some people (slow breathers?) don't like biflex because they feel that the pressure increase at the end of the 'expiration' time feels like the machine is pressuring them to take a breath... when it's not really, but that little pressure bump can feel that way.

Your statement explains the other main reason that I finally arrived at 0 FLEX after trying all the different settings for EPAP in fixed bi-level therapy mode. As I mentioned previously, the other reason was the pressure decrease before I finished my inhalation.

based on my experiences, I believe you'd be happier with a resmed aircurve machine, they allow more tweaking of the pressure, and they don't have the biflex pressure changes that bother you.

on the resmed you can lengthen the time it allows you to inhale up to 4 seconds, and it never raises the pressure until you start to breath in.

palerider wrote:
based on my experiences, I believe you'd be happier with a resmed aircurve machine, they allow more tweaking of the pressure, and they don't have the biflex pressure changes that bother you.

on the resmed you can lengthen the time it allows you to inhale up to 4 seconds, and it never raises the pressure until you start to breath in.

That resmed aircurve may be a better fit for me. Thank you for that information.

Aside from purchasing the aircurve, can you recommend any successful strategy for switching my PR dream station to the resmed?

Zack,

I would presume you have the provider manual for your machine, but on page 6, it explains Rise Time and the options:

Rise Time
Rise time is the time it takes for the device to change from EPAP to IPAP. This screen allows you to adjust the rise time so you can find the desired setting. This is only available if Flex has been disabled and the device is in Bi-level or Auto Bi-level mode.
• 0 (off) reduces the Rise Time feature to the lowest setting (off = 150 msec).
• 1 sets Rise Time to 1 (200 msec).
• 2 sets Rise Time to 2 (300 msec).
• 3 sets Rise Time to 3 (400 msec).

Rise Time Lock
This enables you to lock the Rise Time setting if you do not want the patient to change it.

And, I realize you quoted most of that in your first post, but it seems the discussion has deviated from it......to other settings.


Den

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zack243 wrote:Aside from purchasing the aircurve, can you recommend any successful strategy for switching my PR dream station to the resmed?

there's really nothing much more to it... if you haven't had the dreamstation very long, you might be able to get your DME to swap it, if not, you might be able to get someone here on the forum to see if they can help you, greyghost4 had a couple aircurve vauto machines last I heard.