AVAPS-AE on MY Trilogy - Ongoing

boots wrote:That spike to 0 is a ventilator triggered breath. My patient triggered breaths are lower than hers, so mine spikes to 0 more. I believe most ventilators have that downward spike indicating the vent is giving a breath. I usually use PC-SIMV, but have ran the trilogy in timed mode and all breaths spike to 0.

Thanks. So Madalot's loaner Trilogy is probably not defective regarding how many spikes-to-zero hers generates.

A ventilator triggered breath---in one of the BiLevel PAP modes---should go from EPAP setting to IPAP setting at the moment of trigger---not to zero pressure. By contrast, the purge or null solenoid is supposed to very briefly open, thereby quickly bringing measured pressure to atmospheric reference (0cm).

I wish I was smart enough to understand everything you all are saying. I'm trying though and AM absorbing more than I did a couple years ago....

Okay...I've been on the current settings about 3 nights I think. I looked at the Daily Detail from last night and it appears to me even though the average EPAP is about 9.5, it spikes/attempts to get to the maximum a time or two, making me think it *might* be prudent to go ahead and up the max to 12.

I'm also seriously thinking about LOWERING the minimum EPAP to 8. I'm undecided at the moment which would be the best move.

And while I CAN tolerate them, I find the FOTs annoying as hell. But they can't be but so bad as I slept from about 11:30 until around 4 in one position. I CAN sleep through them (pain woke me up I know, not the FOTs).

I have also been re-reading this thread and I am bothered by the comments about the trigger sensitivity settings I'm using. I recall, I think it was Boots, saying that even someone with healthy lungs would have trouble triggering at 6L. I'm thinking about changing that as well.

The phone call I was supposed to get from my RT never came, so I couldn't ask/discuss any of this with her.

I'm rambling at this point, thinking about what my next move might be.

boots wrote:That spike to 0 is a ventilator triggered breath.

If so, I'll have to guess Trilogy does the auto-null purge right before a ventilator triggered breath. The auto-null routine would purge unwanted static pressure so that the backed up breath is delivered with the right IPAP level. If IPAP is inadvertently too high, some users induce central apneas. So I suppose the design rationale behind purging--- before a backed up breath---is to avoid worsening the central-apnea episode with IPAP that is higher than intended.

Thanks again, boots.

jnk wrote:Well, out of everyone on that list, I think "Guest" has probably come the farthest. Guest used to make some really ugly posts back in the day, as I recall...

Give it time.

It's just that nobody's said anything RFS.

Yet.

boots wrote:That spike to 0 is a ventilator triggered breath.

While that drop is always preceded by a lengthy pause (that would certainly infer that it's time for a mandatory breath to kick in), I believe that the solenoid uses that as an opportunity to auto-zero because it is devoid of noise (patient-generated effort/activity).

A schematic that may prove helpful is taken from the Respironics V60 (I cannot find a comparable schematic for the Trilogy, but I would imagine the technology would be similar):



It is absolutely clear in my mind that the patient never experiences the pressure drop of auto-zero-- in the schematic, all 4 of those solenoids could close and the patient wouldn't be affected. However, at least in this case, it would seem that solenoid 2 or solenoids 3/4 would accomplish auto-zero for their respective sensors as they open to ambient.

That schematic appears to be about nulling any pressure differential between the machine's main pressure/internal-sensor line and the proximal end sensor and line---by bringing both line-and-sensor sets to ambient pressure. I suppose that explains why we never see those spikes to 0cm on BiLevel machines that don't have proximal sensors. A picture is worth a thousand words. Thanks, Mollete.

Since I couldn't decide what change to make for last night, I didn't make any. I slept really well, barely noticing the FOTs after the first ones before I fell asleep. However, I did have a drink before bed and that's an unusual variable to add to the mix.

I admit that I'm getting a "Deer in the headlights" look when I read the technical information here. I don't feel I'm stupid, but some of this is just out of my realm of understanding. And I don't know if I'm supposed to take this information and equate it to what I should do.

I'm still hoping that I can figure out how to use AE Mode to accomplish my goal - safe and secure supine sleep. I know my doctor's biggest concern (and ~SWS has supported this) is that my Tidal Volume could be compromised and I need to watch it. So far, it has been fine so I feel I CAN keep going with this.

My RT never did call yesterday. My first request to her for a REAL phone conversation was 9 days ago. I'm afraid if I wait to talk to her, we might finish this experiment by Spring. I'm a patient person, but not THAT patient.

So assuming last night's data doesn't show anything bad or unusual, it's definitely time to move forward. I guess, based on everything I've read & felt, max EPAP to 12 is probably tonight's move.

Thoughts or concerns?

Finally loaded last nights data. I did get the updated version of DirectView (which is nice). Everything looks in line for where it has been the last few days. I feel ready to proceed to Max EPAP of 12, assuming no one thinks I need more than 4 nights before moving forward.

Sounds like a plan!

I'd suggest keeping an eye on minute ventilation as well. So far tidal volumes have stayed good, but breath rate has gradually dropped just slightly. For all we know your breath rate is normalizing. When either tidal volumes or breath rate drop---while the other parameter stays more or less the same---then minute volumes naturally drop. Even though that slight downward trend might reflect normalization, consider eventually comparing nightly SpO2 as part of your validation process. You can then discuss the minute volume and SpO2 trends on your next doctor visit---should you decide to stick with AVAPS-AE mode after the experiment.

Thanks for this input -SWS. I have been uploading the data daily and watching the numbers. I had thought I might should start monitoring my oxygen levels just to be sure that wasn't being compromised. Thanks for suggesting it.

Bumped max EPAP to 12 for tonight so we'll see how it goes.

mollete wrote:A schematic that may prove helpful is taken from the Respironics V60

OK, so here's the Trilogy schematic:



making Guest's earlier comment about having only "a" solenoid valve venting "the" control pressure sensor (as opposed to multiple solenoids) to atmosphere prophetic:

Guest wrote:Solenoid Valve - The sensor board uses a solenoid valve to auto null/vent the control pressure sensor to atmosphere periodically via port 1 of the plastic manifold.

Looking at the waveforms in highly magnified view, it is apparent that the control pressure sensor has been vented to ambient at the start of machine breath, but as there is no effect on the flow waveform, the pressure to the patient is not affected by the zeroing procedure:

Another night, another morning. Uneventful again. As has been typical in the last few days, I stayed on my side until about the last hour, where it's OBVIOUS leaks are noteworthy. And thanks to the updated version of DirectView, the time on the graphs & reports is accurate. It was annoying before.

Nothing out of the ordinary on the Daily Detail. The max EPAP was set to 12, but last night it barely hit 11 with the average being just above 9. Mollete's opinion that it isn't seeing much to change seems very likely, although only being supine for an hour doesn't give it a lot of time to worry about it.

I still would like an answer about why PTB is down. It's probably not a big deal, but it IS something that has changed in the last few months. I'd really like to know if it's this machine or was doing it before.

I am uploading the data every day and occasionally putting files in Dropbox, if anyone is interested in looking at it from time to time. If a new link to it is necessary, drop me a PM or ask here and I'll provide it.

I'm also thinking I might need to force myself supine for more time AND get those leaks under control (new mask perhaps).

For now, I'll stay at max EPAP 12 for a few more nights and see how things go and how the data turns out.

Madalot wrote:Another night, another morning. Uneventful again. As has been typical in the last few days, I stayed on my side until about the last hour... The max EPAP was set to 12, but last night it barely hit 11 with the average being just above 9. Mollete's opinion that it isn't seeing much to change seems very likely, although only being supine for an hour doesn't give it a lot of time to worry about it.

True. You'll have plenty of time to test supine sleep. Congratulations on making it to the final setting of your auto-EPAP 9cm through 12cm exploration! If this final setting doesn't feel adverse, consider taking plenty of time to accumulate data (DirectView & oximetry) as well as your own subjective assessment. Then I'd suggest reverting back to your former AVAPS settings (fixed 9cm EPAP) for at least 3 or 4 days as you perform a side-by-side comparison. You might attempt to answer questions like these:

1) Which setting yields better DirectView efficacy?
2) Which setting yields better oximetry?
3) Which setting yields a better overall sleep experience?
4) Which setting yields better following-day symptoms?

Madalot wrote: I am uploading the data every day and occasionally putting files in Dropbox, if anyone is interested in looking at it from time to time. If a new link to it is necessary, drop me a PM or ask here and I'll provide it.

Are you periodically uploading to this Dropbox link or a different link: https://www.dropbox.com/sh/pnm43shsca1ggy8/Rxj81YMaji ?

mollete wrote:

mollete wrote:A schematic that may prove helpful is taken from the Respironics V60

OK, so here's the Trilogy schematic:



making Guest's earlier comment about having only "a" solenoid valve venting "the" control pressure sensor (as opposed to multiple solenoids) to atmosphere prophetic:

Guest wrote:Solenoid Valve - The sensor board uses a solenoid valve to auto null/vent the control pressure sensor to atmosphere periodically via port 1 of the plastic manifold.

Looking at the waveforms in highly magnified view, it is apparent that the control pressure sensor has been vented to ambient at the start of machine breath, but as there is no effect on the flow waveform, the pressure to the patient is not affected by the zeroing procedure:

One solenoid---periodically connecting the PCA manifold to ambient pressure---nicely "nulls" static pressure buildup on all tubes connected to that manifold. Nice.

-SWS wrote:

Madalot wrote:Another night, another morning. Uneventful again. As has been typical in the last few days, I stayed on my side until about the last hour... The max EPAP was set to 12, but last night it barely hit 11 with the average being just above 9. Mollete's opinion that it isn't seeing much to change seems very likely, although only being supine for an hour doesn't give it a lot of time to worry about it.

True. You'll have plenty of time to test supine sleep. Congratulations on making it to the final setting of your auto-EPAP 9cm through 12cm exploration! If this final setting doesn't feel adverse, consider taking plenty of time to accumulate data (DirectView & oximetry) as well as your own subjective assessment. Then I'd suggest reverting back to your former AVAPS settings (fixed 9cm EPAP) for at least 3 or 4 days as you perform a side-by-side comparison. You might attempt to answer questions like these:

1) Which setting yields better DirectView efficacy?
2) Which setting yields better oximetry?
3) Which setting yields a better overall sleep experience?
4) Which setting yields better following-day symptoms?

Madalot wrote: I am uploading the data every day and occasionally putting files in Dropbox, if anyone is interested in looking at it from time to time. If a new link to it is necessary, drop me a PM or ask here and I'll provide it.

Are you periodically uploading to this Dropbox link or a different link: https://www.dropbox.com/sh/pnm43shsca1ggy8/Rxj81YMaji ?

I am still learning the "ins" and "outs" of dropbox. When I access the link for the file I created today, the link is DIFFERENT:

https://www.dropbox.com/s/00f2t15uts0pu ... 082013.zip

To everything else you suggested above, many thanks for all this input. I think you have fabulous insight into this and give excellent ideas & suggestions.

I plan to attempt to charge my pulse ox monitor, but admittedly without my desktop computer, it's not quite as easy as I would like. When I charge the netbook later today, I'll hook the monitor up to it and hope it charges okay.

I still have a few things to consider and/or take care of. Leaks while supine is a problem and one that I'm not positive is going to be easily solved. My mask is fine on my side, but man those leaks start pretty fast after getting supine.

I also do not know if I should try the Auto BMP feature and see where that gets me. I'm not sure it's really necessary.

I think your suggestion to get the AE settings where they seem good, then go back to regular AVAPS a few nights and look at the data to see which is better -- very smart idea. I will plan on doing that.

Maybe when I do, some of you experts wouldn't mind looking at the data to see what YOU see & think compared to my novice eyes.