respironics autoSV & new software - why AHI so high?

dsm wrote:If we look at the VpapSV vs the BipapSV I would say that the VpapSV can do the boost in less than one cycle whereas the BipapSV takes maybe one or more cycles & for me that difference in acceleration makes all the difference.

The upper airway stretch I feel when on the VpapSV bothers me. But on the BipapSV I don't feel it even though both machines are set to approximately the same tri-level settings.

Looking at that graph recently inserted by Snoredog: that first periodic breathing occurrence takes three inspiratory cycles before IPAP reaches that segment's maximum.

Must be a very good match for you, DSM!





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Anonymous wrote:

dsm wrote:If we look at the VpapSV vs the BipapSV I would say that the VpapSV can do the boost in less than one cycle whereas the BipapSV takes maybe one or more cycles & for me that difference in acceleration makes all the difference.

The upper airway stretch I feel when on the VpapSV bothers me. But on the BipapSV I don't feel it even though both machines are set to approximately the same tri-level settings.

Looking at that graph recently inserted by Snoredog: that first periodic breathing occurrence takes three inspiratory cycles before IPAP reaches that segment's maximum.

Must be a very good match for you, DSM!

That was me.

Looking at the Resmed graph, I see where that machine is also portrayed as taking three or four inspiratory cycles to reach peak IPAP:
http://www.resmed.com/en-us/assets/docu ... -sheet.pdf

It could be that Resmed's algorithm is responsively hitting an IPAP peak earlier than Respironics for DSM's breathing patterns.

One other possible comfort difference perceived may be the shape of the inspiratory pressure curve: a rounded-off square wave for Respironics and a sawtooth pressure wave for Resmed.

-SWS wrote:
Take a peak at Laryssa's BiPAP autoSV report very kindly provided by Nelson:
http://www.baumgratz.eng.br/laryssa/rep ... 080628.htm

You can see there is no tracking or reporting of FL or VS. The tracked/reported parameters are PB, AP, and H. And all of those are presumed central since obstruction is already titered away with fixed BiLevel or fixed CPAP.

Regardless, when residual obstruction-based flow reduction does occur, SV mode is going to very quickly drive IPAP in the general direction of IPAP max, based on recent-average targeting. That may be good and mitigating or that may be bad, depending on whether say 10 cm of very quick upper airway stretch also happens to disturb one's sleep architecture or state.

Thus the concept of preventing obstruction via either fixed CPAP or EPAP inflation becomes preferable IMO. And that is the premise of those preliminary obstruction-addressing steps of either manufacturer's SV titration protocol.

thanks SWS I see that now, that is the first report I've seen from the SV, not even remotely similar to the BP Auto's,

that report shows a AHI=81-93?? is that an improvement over prior therapy?

that poor thing, only part of that report where I see she had an improvement is on 6/26 after therapy hour 7 where apnea STOPPED??

it appears to me that she did the best when IPAP was at Minimum setting. The IPAP Max=16 doesn't appear to be doing her any good (only my opinion, maybe I'm missing something). Her AHI for that night was only 39 compared to 80's-90's on other nights, SOMETHING has to be going on there, if they could only duplicate those conditions.

What do you see on 6/26 after therapy hour 7?

Apart from silent GERD, I like to think I am pretty normal

So, I extrapolate that many others would get great benefit from the same PS feature. I think Respironics hit on a winner.

Now wouldn't it be funny if the only reason they added it was because one of their researchers stumbled on an enhancement to the software on a Bipap S/T to boost pressure in 2-4 cycles in a safe way. Hmmm how can we sell this, Errrrr that boost would be useful if someone is breathing a bit wobbly, Yeahhh, lets sell it as a solution for periodic breathing ! (truly, I am joking )

DSM

Hi gentlemen
I haven't had a chance to review the new posts since yesterday but I will tonight and really appreciate all your insight.
Since I only have a few moments this morning I wanted to say thank you because I'm thrilled to report my AHI droped to ~ 5. The first night after changing the EPAP to 7 & max IPAP to 20 and downloading the reports I didn't realize the date in encoreviewer hadn't changed. Today I discovered those changes actually droped my nummbers considerably. Thinking those minor tweaks hadn't helped, last night I increased EPAP to 9 and IPAP to 11 and numbers remained the same. Now I can scale back to 7 & 10 and fine tune everything else but at least I'm with in a normal AHI range.
I still need to spend more time trying to understand the leak & avg patient breaths data relationship, among other things. Hopefully being more well rested will raise my IQ enough to comprehend everything.
Thanks again!

[quote="kolchak"]Hi gentlemen
I haven't had a chance to review the new posts since yesterday but I will tonight and really appreciate all your insight.
Since I only have a few moments this morning I wanted to say thank you because I'm thrilled to report my AHI droped to ~ 5. The first night after changing the EPAP to 7 & max IPAP to 20 and downloading the reports I didn't realize the date in encoreviewer hadn't changed. Today I discovered those changes actually droped my nummbers considerably. Thinking those minor tweaks hadn't helped, last night I increased EPAP to 9 and IPAP to 11 and numbers remained the same. Now I can scale back to 7 & 10 and fine tune everything else but at least I'm with in a normal AHI range.
I still need to spend more time trying to understand the leak & avg patient breaths data relationship, among other things. Hopefully being more well rested will raise my IQ enough to comprehend everything.
Thanks again!

kolchak wrote:I wanted to say thank you because I'm thrilled to report my AHI droped to ~ 5.

Hey, that's alright! Sounds like you're on the road to getting that AHI even lower.

snoredog wrote:that report shows a AHI=81-93?? is that an improvement over prior therapy?

No, I think that report shows what happens when high tech is not the correct tech for the job.

That SV algorithm is without doubt great for what it was designed to do. However, it was not designed for pediatric applications. Nor is it suitable for sustained hypoventilation, frank respiratory failure, COPD, and a few other problems in physiology.

snoredog wrote:What do you see on 6/26 after therapy hour 7?

Virtually all machine-initiated breaths. The algorithm has trouble recent-average scoring and baselining her pediatric volumes. Also an improved tidal volume well into that hour-long segment of machine initiated breaths---yet more than a third of that same segment manifesting significant volume problems. Again, adult-targeted SV is definitely the wrong machine for this pediatric task IMO.

Dr. Vergara mentioned better results after placing her on BiLevel ST. That's encouraging to hear.

In another thread dsm wrote:Anne is being discharged from hospital today!. They say there is nothing more they can do for her since she can do everything herself.

That's wonderful news, Doug! Congratulations!!!

Thanks DSM & SWS
It feels good to know I'm finally going to get some good sleep! I really hope my energy continues to improves as I noticed a huge difference getting my AHI down to the ~15 for the last ~ 6 months. I actually excited about going to sleep tonight
I "think" my rise time is set at 5 but that number was probably picked from a hat. I know my BPM is set for auto. If I'm averaging ~ 13 BPM would their be a benifit in changing the BPM?
have a good night

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CPAPopedia Keywords Contained In This Post (Click For Definition): AHI, auto

[quote="kolchak"]Thanks DSM & SWS
It feels good to know I'm finally going to get some good sleep! I really hope my energy continues to improves as I noticed a huge difference getting my AHI down to the ~15 for the last ~ 6 months. I actually excited about going to sleep tonight
I "think" my rise time is set at 5 but that number was probably picked from a hat. I know my BPM is set for auto. If I'm averaging ~ 13 BPM would their be a benifit in changing the BPM?
have a good night

FYI - after changing the rise time to 3 my AHI droped down to 2! Think I'm set up perfectly now.

Last question (for now) to any people using the autoSV - have you found specific masks work best with this machine?

I prefer the swift 2, but being a mouth breather I get tired of taping my mouth some nights. I have an FP 431 but my previous numbers were worse with this mask. I'm going to try it again now that I've found correct settings, but I'm eligable for a new mask from my insurance and not sure what to get.
thanks for any 's

kolchak wrote:FYI - after changing the rise time to 3 my AHI droped down to 2! Think I'm set up perfectly now.

That's nice! I'd still keep an eye out for night-to-night variation. We would absolutely love to hear that your improved results are sustained over the long-term!





[on edit: remainder of original post containing irrelevant question deleted]

[quote="kolchak"]FYI - after changing the rise time to 3 my AHI droped down to 2! Think I'm set up perfectly now.

Last question (for now) to any people using the autoSV - have you found specific masks work best with this machine?

I prefer the swift 2, but being a mouth breather I get tired of taping my mouth some nights. I have an FP 431 but my previous numbers were worse with this mask. I'm going to try it again now that I've found correct settings, but I'm eligable for a new mask from my insurance and not sure what to get.
thanks for any 's