Because So Many Have Asked Me To

[Banned]

Generally, S/T mode is more comfortable because the patient tends to control the machine's pressure transition back down to EPAP. However, if a patient's own inspiration pressure/flow is not steady enough, then an S/T configured machine can be repeatedly "tricked" into prematurely cycling back down to EPAP pressure. In that latter case, PC mode becomes advantageous over S/T mode.. (because) IPAP is always timed exactly according to the value assigned to "Inspiratory Time".

Madalot, I hope that description helps.

Thank you very much, SWS,
for the description.

Even I understand it now!

In the real world, PC AVAPS mode has a noticeable mechanical 'feel' to it.
You can 'feel' the machine control your breathing.
A bit like throwing S/T into overdrive.
But may provide some improved therapy.

Banned

[Scarlet834]

I know that by posting, I am asking/inviting comments

Well, since you asked, I have a comment...

I'm glad you're here.

Thank you Dotty -- that's very sweet. I'm not sure everyone will be as welcoming or as happy, but that's okay.

I don't like the idea of leaving when so many expressed a desire to continue hearing what's going on. And like I said -- if my situation and what I've been through (and continue to go through) can help one person, it will be worth it.

And I've made up my mind that any posts along the lines that upset me before will simply be ignored.

Good to read about your progress! (And while you may continue to receive challenging posts, I doubt you will find many people on the forum who are unhappy to see you and your kitty avatar.)

[ozij]

Thank you, -SWS, that has clarified things for me too.

O.

[Madalot]

As a side note: a question that has been asked of me here is a question about spontaneous timed vs pressure control. If I understand both of these correctly, I'm actually getting both with the current settings. I have regular pressure control -- IPAP 14 (inhale is never lower than 14) and EPAP of 6. These are regular pressures, just like the bipap.

S/T AVAPS and PC AVAPS do function the same, as you have suggested. Both modes ensure the patient receives a minimum number of breaths per minute based on the Rate (BPM), and both modes are pressure-limited and time cycled.

The two modes are VERY similar. But the fact that the clinician can set the machine up in either mode implies that there is SOME functional difference. I'll try to describe that difference below:

That functional difference lies in just how long the machine's higher IPAP pressure is delivered before the machine cycles back down to lower EPAP pressure. Pressure Control (PC) and Spontaneous/Timed (S/T) modes each utilize the numeric value assigned to the machine's "Inspiratory Time" setting a little differently (Respironics machines are being described).

If the machine is set to operate in Spontaneous/Timed (S/T) mode instead of PC mode, then the machine treats that "Inspiratory Time" parameter as if it were only a maximum or upper time-limit for IPAP delivery. So if the machine is set to S/T mode, the patient's natural breathing usually controls the machine's transition back down to EPAP pressure---unless that maximum or upper time limit has been met.

By slight contrast, if the machine is set to operate in Pressure Control (PC) mode instead, then the machine treats that same "Inspiratory Time" parameter as the fixed amount of IPAP delivery time that should occur for all breaths. In PC mode, the patient's natural breathing is never allowed to control the duration of IPAP delivery. Rather IPAP is always timed exactly according to the value assigned to "Inspiratory Time".

Generally, S/T mode is more comfortable because the patient tends to control the machine's pressure transition back down to EPAP. However, if a patient's own inspiration pressure/flow is not steady enough, then an S/T configured machine can be repeatedly "tricked" into prematurely cycling back down to EPAP pressure. In that latter case, PC mode becomes advantageous over S/T mode.

Madalot, I hope that description helps. But I also hope it isn't too technically detailed...

SWS --

Thank you so much for this information. This helps A LOT, especially for me to understand why some things happen. What you describe HAS been a problem for me at times. What you've written here makes it seem like it might be possible to alleviate that with changes to the settings.

I think I'm going to print out your post and put it with my written information.

BTW -- I hope you're feeling better.

[DoriC]

SWS, Awesome! I'm trying to read your description of the two modes through Madalot's eyes and if I'm understanding some of what you're saying, I'm sure light bulbs are going on for her. It would be great if some setting changes could make the difference.

[Madalot]

SWS, Awesome! I'm trying to read your description of the two modes through Madalot's eyes and if I'm understanding some of what you're saying, I'm sure light bulbs are going on for her. It would be great if some setting changes could make the difference.

You are right on the money on this, Dori!! Not only are light bulbs going off, but my head is spinning and reeling (in a good way).

There is no doubt my vent is in Spontaneous/Timed mode. And what SWS says makes sense to me and I can say that probably 95% of the time, it works very well for me and is fairly comfortable. But there are times that the machine switches to EPAP when I'm still trying to inhale, thus making me gag and choke. It doesn't happen very often, but it does happen on occasion. I'm not sure switching to PC mode would be better -- it "appears" from SWS's description that PC mode would be worse, but I need to run the entire scenario through my brain to figure it out!!

Good Information and so helpful. Thanks!

[DoriC]

Although I realize it's not really the same, it reminds me of the Flex feature that didn't match Mike's breathing pattern which is short inhales/long exhales. When we first started cpap he kept complaining that the machine made him "breathe too fast" and I observed that he was almost hyperventilating. I finally figured out that the flex was starting his inhale before he had finished exhaling and we eventually turned it down and then completely off.

[Madalot]

Although I realize it's not really the same, it reminds me of the Flex feature that didn't match Mike's breathing pattern which is short inhales/long exhales. When we first started cpap he kept complaining that the machine made him "breathe too fast" and I observed that he was almost hyperventilating. I finally figured out that the flex was starting his inhale before he had finished exhaling and we eventually turned it down and then completely off.

Yep -- and some of these machines have so many settings that it can be frustrating and sometimes overwhelming to figure them all out. And the vent is even worse with so many settings! I think there "may" be an issue with conflicting settings on my vent. Maybe. Perhaps.

There are TONS of settings -- Inhale/Exhale Ratio, Inspiratory Time, Breath Rate, Apnea Breath Rate, Rise Time -- and then of course, you add the AVAPS settings into this mix. I think it's VERY likely that some of my issues are directly related to possible conflicting settings -- a setting that totally conflicts/contradicts with another setting, thus making things happen that maybe shouldn't.

But on a positive note, I DO think we're closer. And I think as has been suggested, it may be time to look at ALL the settings again, specifically looking for things that conflict.

[jnk]

. . . there are times that the machine switches to EPAP when I'm still trying to inhale . . .

SWS,

Ya reckon there might be any way to increase Ti Max on that rig?

[bailachel]

Welcome back!

BTW, my kitty avatar likes your kitty avatar a lot.

[Madalot]

. . . there are times that the machine switches to EPAP when I'm still trying to inhale . . .

SWS,

Ya reckon there might be any way to increase Ti Max on that rig?

I think there is. But as I've said, there are so many settings and I'm not sure which ones need adjusting to solve the problem.

[Madalot]

Welcome back!

BTW, my kitty avatar likes your kitty avatar a lot.

I can see why!! This kitty (black and white one) IS one of mine. We adopted him from the local Humane Society last year. His owners suddenly decided they didn't want him anymore and just dropped him off. We found him at the local Petsmart and when we saw him, he had already been there for over a week and there was no interest in him. We adopted him in the nick of time!!

Thanks for the welcome back.

[jnk]

. . . there are times that the machine switches to EPAP when I'm still trying to inhale . . .

SWS,

Ya reckon there might be any way to increase Ti Max on that rig?

I think there is. But as I've said, there are so many settings and I'm not sure which ones need adjusting to solve the problem.

I know less than nothing about your machine, Madalot. But the first bilevel I got (an S7) came with maximum-inpiratory-time set at the default, which was way too short for me. I had to expand that window to more than 3 seconds to keep the machine from waking me up every time it cut off the length of my inspiration.

Odds are that may have nothing to do with what you are experiencing. Just letting you know that I have some fellow-feeling about that irritating sensation.

jeff

[-SWS]

it may be time to look at ALL the settings again, specifically looking for things that conflict.

If anybody has a copy of the Trilogy provider's manual, I'll be more than happy to carefully look at all the settings. That might turn out to be a very fruitful discussion in this thread.

Madalot, if you'd like, in this discussion we can also explore not only the concept of spontaneous breathing rate, but how spontaneous-breathing variability itself can sometimes present clinicians with a HUGE challenge when trying to set machine backup rate optimally.

. . . there are times that the machine switches to EPAP when I'm still trying to inhale . . .

SWS, Ya reckon there might be any way to increase Ti Max on that rig?

I think there is. But as I've said, there are so many settings and I'm not sure which ones need adjusting to solve the problem.

If the Trilogy set up menu offers the Ti ("Inspiratory Time") parameter while setting up AVAPS S/T modality, then Ti will be the Respironics equivalent of that Resmed parameter called Ti Max (but specifically in AVAPS S/T mode).

Otherwise, the machine backup rate and I:E ratio are going to be the most relevant setup parameters. In the meantime, let's take a look at what Resmed has to say about BiLevel machines prematurely cycling from IPAP to EPAP:

Recent studies show that almost all patients on bilevel therapy experience mouth leaks, which interfere with a device's triggering sensitivity from IPAP to EPAP. Poor triggering sensitivity results in poor synchrony of the patient's spontaneous breathing pattern and the bilevel's assistance. Asynchrony causes the patient to exhale against a higher pressure, increasing work of breathing and reducing the comfort and quality of therapy

http://www.resmed.com/us/clinicians/tre ... clinicians

So Madalot, any problematic leaks you might have while sleeping are clearly worth working on...

P.S. My vote so far goes for those two kitties in the sink!

[Madalot]

it may be time to look at ALL the settings again, specifically looking for things that conflict.

If anybody has a copy of the Trilogy provider's manual, I'll be more than happy to carefully look at all the settings. That might turn out to be a very fruitful discussion in this thread.

Madalot, if you'd like, in this discussion we can also explore not only the concept of spontaneous breathing rate, but how spontaneous-breathing variability itself can sometimes present clinicians with a HUGE challenge when trying to set machine backup rate optimally.

. . . there are times that the machine switches to EPAP when I'm still trying to inhale . . .

SWS, Ya reckon there might be any way to increase Ti Max on that rig?

I think there is. But as I've said, there are so many settings and I'm not sure which ones need adjusting to solve the problem.

If the Trilogy set up menu offers the Ti ("Inspiratory Time") parameter while setting up AVAPS S/T modality, then Ti will be the Respironics equivalent of that Resmed parameter called Ti Max (but specifically in AVAPS S/T mode).

Otherwise, the machine backup rate and I:E ratio are going to be the most relevant setup parameters. In the meantime, let's take a look at what Resmed has to say about BiLevel machines prematurely cycling from IPAP to EPAP:

Recent studies show that almost all patients on bilevel therapy experience mouth leaks, which interfere with a device's triggering sensitivity from IPAP to EPAP. Poor triggering sensitivity results in poor synchrony of the patient's spontaneous breathing pattern and the bilevel's assistance. Asynchrony causes the patient to exhale against a higher pressure, increasing work of breathing and reducing the comfort and quality of therapy

http://www.resmed.com/us/clinicians/tre ... clinicians

So Madalot, any problematic leaks you might have while sleeping are clearly worth working on...

P.S. My vote so far goes for those two kitties in the sink!

Because you are so sweet, I put the kitties in the sink back on. Just for you.

I am open to discussing any and all aspects of the settings. I think just the little we've discussed here has been extremely helpful.

Leaks -- interesting thought. The Trilogy's monitor shows the leak rate. According to my RT, anything in the 30's is considered normal and anything below 60 is not cause for concern. My leak rate tends to stay in the upper 30's or low 40's.

Masks have been an ongoing problem for me since day 1. I am currently using the 431 FF Mask and it seems to be the best of those I've tried. I purchased a 432 online thinking the foam might be helpful and give me extra cushion and seal. All it did was give me a serious blister on my cheek!! I plan to keep it and use it, just without the foam. I also have a brand new mask, a Respironics FF Mask with gel -- I just haven't gotten around to trying it yet.