ASV users: the everything ASV thread.

[no-hardmask]

...research shows ASV machines are not just good for CA, but better at controlling OSA.

Do you have the reference(s) for that?
Thanks.

You might do a search using your favorite online search for ASV efficacy CSA, OSA . I've been on an S9 ADAPT for about a week and am working through the different 'mannerisms' of it. I'm thinking the Adapt is doing a better job reducing the intensity of all events, but then, too, i've had to add a new FFM into the mix. Still learning; Good luck to us both.

[mollete]

...research shows ASV machines are not just good for CA, but better at controlling OSA.

Do you have the reference(s) for that?
Thanks.

You might do a search using your favorite online search...

Thanks, but if patrissimo has strong evidence I'd like to take a look at that first.

[-SWS]

I would also like to see evidence or references that ASV is superior OSA treatment. That would be welcome yet surprising news.

[patrissimo]

...research shows ASV machines are not just good for CA, but better at controlling OSA.

Do you have the reference(s) for that?

Thanks.

The studies are all for patients with centrals, like congestive heart failure patients, and those with CSR:

Teschler H et. al. Adaptive Pressure Support Servo-Ventilation. A Novel Treatment for Cheyne-Stokes Respiration in Heart Failure. Am J Resp & Crit Care Med 16: 614-619, 2001, cited by Dr. Krakow here: http://thesleepsite.com/content/view/76/91/

In this study on opioid users, ASV decreased AHI as well as CAI (Central Apnea Index): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2542500/. Same with this study on people with central, CSR, or CPAP-produced centrals: http://narvalwebtv.com/us/documents/Mor ... ilevel.pdf. For example, CPAP had a residual 6.2 AHI, primarily hypnopneas, while ASV had 0.8. Though sleep stage %ages didn't change much.

While I haven't found any studies on CPAP vs. ASV for OSA-only (no centrals) patients, if we believe the scoring these three studies used to classify obstructive apneas, hypnopneas, and centrals, it seems quite telling that ASV decreases flow-limited events much better than CPAP. It doesn't just eliminate centrals.

BTW, here's a nice detailed technical review of ASV, and historical context: http://www.mdconsult.com/das/article/bo ... =1556-407X, it includes cites of the papers above and many more. It looks like "volume assured pressure support" is something similar to ASV which has been tested more often on non-central populations.

[-SWS]

While I haven't found any studies on CPAP vs. ASV for OSA-only (no centrals) patients..

Bear in mind ASV is off-label for OSA and UARS. I think that's why you haven't encountered CPAP vs. ASV studies for OSA. The adaptive part of ASV is what distinguishes ASV from CPAP. That adaptive part bolsters flow during central undershoot. By contrast CPAP stents the airway with static pressure to address obstruction. So ASV adaptively fluctuates PS to help ventilate during central undershoot, while also stenting with static pressure to address any incidental obstructive component.

...if we believe the scoring these three studies used to classify obstructive apneas, hypnopneas, and centrals, it seems quite telling that ASV decreases flow-limited events much better than CPAP.

I'm sorry, but I don't follow that line of reason. I have yet to see peer-reviewed literature that suggests ASV provides superior OSA treatment or superior UARS treatment. ASV is presently targeted for central-only patients or central patients also presenting obstruction.

This study documents that unnecessarily high PS can induce glottis narrowing---and thus flow-limited type obstruction in normal subjects:
http://www.ncbi.nlm.nih.gov/pubmed/8630611

Rather than viewing ASV as providing superior treatment for UARS, I think there's some theoretical room to suspect ASV can induce iatrogenic flow limitation in some cases.

[4betterO2]

seeing a few ASV users reply above, can you please help with my problem? I first wrote about in a prior post subtitled "HELP! - ASV drops IPAP pressure prematurely" .I'm mostly recopying it here below. I really need to explore this subject before my next visit to the DME provider and to my neurologist. I'm really concerned about avoiding hypopnea...

I have a big problem using the PR Advanced ASV model 950, I'm not sure if I'm really getting the oxygen I need, because much too often, my machine drops the IPAP pressure on me while I'm still inhaling... Very uncomfortable!!!
Makes me feel smothered over... I need the higher pressure of IPAP to inhale. If it drops it's like my breathing goes over a cliff, I stop inhaling. The pressure settings I'm getting from my prescription are OK, it's the TIMING OF THE SHIFT from IPAP to EPAP pressure that is the problem. Right now I can't take it back to the DME provider, so I'm trying to accomodate it, by letting my breathing go down as if I'm very tired, and then the machine ends up with a sort of rhythm of short breaths, which I fear, cannot at all deliver the optimal oxygen I need. It would help me if I can refer to info from others when I do get to talk about this to my DME, so they won't just tell me "you just need to get used to the machine"...
Is my machine working normally? Is any other ASV user having this problem?
Isn't the ASV machine supposed to LET YOU INHALE with your indicated IPAP pressure UNTIL YOU ARE FINISHED INHALING, and not drop to the EPAP pressure until it SENSES you are exhaling?
Please help, in as much detail as you can...

[mollete]

It looks like "volume assured pressure support" is something similar to ASV which has been tested more often on non-central populations.

AVAPS is pretty much limited to respiratory failure (COPD, NMD, etc.). The response time of AVAPS is incredibly slow (relatively speaking) so it is not a modality that lends itself to the the treatment of SDB (see -SWS points in viewtopic.php?f=1&t=30417&p=282502&hilit=+avaps#p282502).

[-SWS]

...much too often, my machine drops the IPAP pressure on me while I'm still inhaling... Very uncomfortable!!!

It sounds as if your machine is cycling to EPAP prematurely. Excessive leaks commonly cause that problem.

...the TIMING OF THE SHIFT from IPAP to EPAP pressure that is the problem.

Does your prescription use an automatic backup rate or fixed rate? If you're sure leaks are not the culprit, then ask your doctor or DME to look at backup rate and the Ti setting to avoid that problem. But first be sure leaks aren't the culprit.

[mollete]

...it seems quite telling that ASV decreases flow-limited events much better than CPAP.

Actually, I see no evidence to support that whatsoever.

By its very nature, even if it sees an event, ASV only attacks to the extent of 95% based on flow (PR) or 90% based on volume (RM). Is this enough to do anything (or everything)? It seems to me that an obstructive-based algorithm would be far more capable of dealing with obstructive-based events.

Further, while ASV could theoretically attack an acute obstructive event (although if the baseline parameters are set up correctly, why would there be a heap of residual obstructive events)(and anyway, instead of being proactive, it would be reactive, with events continuing to occur) it would not address a baseline pattern of flow limitation because it would think that is (by definition) the baseline.

IMHO, this is an important discussion because I really don't want people spending a lot of time and money on a modality that is not appropriate for them.

BTW -SWS, finally got a hold of a PAV machine. In looking at the old Loop Graphics, I can certainly see how someone could get "overshoot".

[Taringa542]

...research shows ASV machines are not just good for CA, but better at controlling OSA.

Do you have the reference(s) for that?

Thanks.

The studies are all for patients with centrals, like congestive heart failure patients, and those with CSR:

Teschler H et. al. Adaptive Pressure Support Servo-Ventilation. A Novel Treatment for Cheyne-Stokes Respiration in Heart Failure. Am J Resp & Crit Care Med 16: 614-619, 2001, cited by Dr. Krakow here: http://thesleepsite.com/content/view/76/91/

In this study on opioid users, ASV decreased AHI as well as CAI (Central Apnea Index): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2542500/. Same with this study on people with central, CSR, or CPAP-produced centrals: http://narvalwebtv.com/us/documents/Mor ... ilevel.pdf. For example, CPAP had a residual 6.2 AHI, primarily hypnopneas, while ASV had 0.8. Though sleep stage %ages didn't change much.

While I haven't found any studies on CPAP vs. ASV for OSA-only (no centrals) patients, if we believe the scoring these three studies used to classify obstructive apneas, hypnopneas, and centrals, it seems quite telling that ASV decreases flow-limited events much better than CPAP. It doesn't just eliminate centrals.

BTW, here's a nice detailed technical review of ASV, and historical context: http://www.mdconsult.com/das/article/bo ... =1556-407X, it includes cites of the papers above and many more. It looks like "volume assured pressure support" is something similar to ASV which has been tested more often on non-central populations.

My pressure on the S9 Autoset was maxing out every night, now on the ASV has settled to 16-17, AHI's most days are 0,

It took about a month to get use to the machine, but I wouldn't be without it now, it was a very long month tho

On CPAP I had very few centrals

EPAP= 10 all other settings set at default

patrissimo, an ASV can be bought quite cheaply off this forum from time to time, just gotta keep your eyes open

[avi123]

patrissimo, wouldn't it be a waste of money to use an ASV machine for plain OSA?

S9 Autoset goes for less than $1,000 while a latest ASV goes above $3,000.

Also, Medicare and other insurers would not cover an ASV machine unless for:


Central sleep apnea, defined as:

1. Study showing AHI > 5 events/hr. and
2. Central apneas/hypopneas greater than > 50% of the total apneas/hypopneas, and
3. Central apneas or hypopneas >=5/hr., and
4. Symptoms of either excessive sleepiness or disrupted sleep.

Complex sleep apnea

CompSA is a form of central sleep apnea specifically identified by the persistence or emergence of central apneas or hypopneas upon exposure to CPAP or an EO470 [Bi-level] device when obstructive events have disappeared. These patients have predominantly obstructive or mixed apenas during the diagnostic sleep study occurring at >= 5 times per hour. With use of a CPAP or EO470 [Bi-level], they show a pattern of apneas and hypopneas that meets the definition of CSA described above.

[4betterO2]

for ASVs you should probably be using the software native to your machine for best results.

I can't afford to buy the Encore Viewer software, but I've read that the Encore Pro version is downloadable for free from Respironics, though it is difficult to get to that link. How could I download it?

[SleepingUgly]

Mollete, you need a project. How about taking Patrissimo on? If RobySue has left the forum, I think this guy is going to take her place among the "top 3 smartest people on this board". You need a Blizzard Boy. Sadly, I've never been your Blizzard Boy. So take him. What say you?

[4betterO2]

...what is the Pressure Pulse measurement, in this context?

"One or more test pulses delivered by the device during an apnea to determine if the event is a clear airway apnea or an obstructed airway apnea."

By "clear airway apnea" do you mean a CNS event?
Does these test pulses apply to the PR (Respironics) ASV machine, or only to the ResMed?
I saw those terms in SleepyHead, but I did not think that the PR ASV machine sent those pulses?
I thought the PR ASV machine determines central apnea events by the length of time a patient waits before triggering a breath?

[4betterO2]

Does your prescription use an automatic backup rate or fixed rate?

I have a fixed backup rate. How does that impact the premature cycling from IPAP to EPAP, and how would this be different if the backup rate was set to auto?

ask your doctor or DME to look at backup rate and the Ti setting to avoid that problem.

what is the Ti setting, in words? what are the min and max range limits, and is it possible to set it to a fixed value?

...And how do the backup rate and the Ti interface?

Thanks for your attention, I 'm more hopeful now about working out a solution!
The DME should not have put me in this position to start, so I need to find my own solution, then ask them to apply it.