CPAPtalk.com

StillAnotherGuest wrote:

-SWS wrote:I thought the original Somnosmart exclusively employed FOT detection---and that the current Somnosmart 2 now additionally employs traditional flow-based sensors common to traditional APAPs

And we'll also have to see if it constantly FOTs or only occasionally FOTs. I mean, just about everybody FOTs occasionally, but continuous FOT-ing...(sorry, too much caffeine already).

AHEM!

The only thing I can find out about the ResMed approach to FOT-ing in the above reference is that

The Autoset II Plus (Resmed) generated a small pressure oscillation (5 Hz) when no breathing flow was detected in the course of 8 s. This capability allowed the device to detect obstructions only during apneas.

and I would wonder if generating an impulse in that fashion would be like the "spoon-pot effect" and create an arousal. Or would that be academic, would you have an arousal anyway. But, in the case of CSR, a lot of folks just sleep right through centrals. Or if you're having that many centrals, you shouldn't be on an APAP anyway. But occasional centrals don't create a tear in the universe. And if they're post-arousal, there's REALLY nothing you can do, you don't even count those. Except if they were caused by a burst of FOT...

Hmm, I wonder if there was a point in there.
SAG

As probe is concerned-- my dad is now having a 2-week test on a Somnosmart, and I see there's a tube in the factory-supplied hose a la P-B 420E.

Sam,

It is interesting that most of the newer machines are resorting to the added pressure sensor line. We had a debate here on cpaptalk about this issue just under a year back. The opposing view regarded them as quite unneccesary & serving no purpose in modern machines, I believe that subsequent releases of new advanced models with added pressure sensing lines proved categorically the opposite. Needless to say the two sides of that debate could not agree

I believe that it is the only way they can achieve the level of accuracy required to report accurate data with these faster responding machines & esp those that can detect centrals accurately.

I believe PB still use added pressure asensor lines as well as the new Vpap Adapts - will be interested to see if the Autoset CS2 has one but the parents of this new model were pretty good at accurately assessing AI & HI numbers all along. Maybe they don't really need one of that application (auto varying CPAP)

DSM

SamCurt wrote:As probe is concerned-- my dad is now having a 2-week test on a Somnosmart...

Y'know, I was thinking that there might be a problem with doing diagnostic studies with SomnoSmart2. If we think that SomnoSmart2 tends to give a number (P95) that is lower than if you were just setting up a fixed pressure to cover the sum of the night's events (which it does), then you might have to be a little careful if you then get a fixed CPAP and base the setting on the SomnoSmart2 analysis.

From ERS

• P4608
  Automatic nCPAP-Therapy is not equivalent to autotitration in the treatment of OSAS
  
  Wolfgang Galetke, Kerstin Richter, Norbert Anduleit, Winfried Randerath. Bethanien Hospital, Institute for Pneumology, University Witten/Herdecke, Solingen, Germany
  
  Introduction:
  Automatic Positive Airway Pressure (APAP) can be used in two different ways. APAP-therapy is an effective treatment for OSAS patients by varying pressure according to sleep stages and body position. Autotitration can be used to determine an optimal fixed level of CPAP for long-term treatment with conventional CPAP. We asked, whether the pressure profile of an APAP-therapy device can also identify a sufficient constant pressure.
  Methods:
  28 patients (8 female, 20 male; age 60.8±10,5 years; BMI 31.3±6,1 kg/m2) with OSAS were enrolled with a diagnostic polysomnography (PSG) followed by CPAP titration and a PSG under APAP-therapy in random order. For APAP-therapy we used a new device based on Forced Oscillation Technique (FOT), snore and flow signals (SOMNOsmart2®, Weinmann, Germany).
  Results:
  APAP-therapy lowered the Apnea-Hypopnea-Index (AHI) from 40.1±24.7 h-1 to 7.7±3.0 h-1 (p<0,001). Mean APAP pressure was 6.6±2,2 and P95% 8.7±3,1 cm H2O, respectively. Mean pressure during conventional CPAP night was 8.2±1,8 cm H2O. Correlation between P95% and mean CPAP in the whole study group was high (r2=0.423), but comparison of fixed CPAP and difference P95% to fixed CPAP for each individual showed correspondence of±1cm H2O in only 8 of 28 patients.
  Conclusions:
  APAP therapy based on FOT, snore and flow signals is an effective treatment in OSAS patients. An APAP device using this distinct algorithm does not provide treatment equivalent to autotitration; we conclude, that it should use for its intended purpose.

OK, the translation is a little choppy, but I think you get the idea. One would imagine if you test on SomnoSmart2, you stay on Somnosmart2.
SAG

Eh, SAG, My dad's not titrating. He is testing around for APAPs. 1.5 weeks later he'd be on a Remstar w/C-Plus Auto.

SamCurt wrote:Eh, SAG, My dad's not titrating. He is testing around for APAPs. 1.5 weeks later he'd be on a Remstar w/C-Plus Auto.

Ooh, great opportunity then. It will be interesting to see if the P95 variation occurs, and if so, how much, if it's close to the 3.0 cmH2O mark.

Hmmm, the SAG Awards are on TV tonite. Wonder if I'll win anything.

Or maybe I'm supposed to be handing them out. Guess I better check.
SAG

dsm wrote:

SamCurt wrote:Hey all, I wonder if I should summarize that other test, in which I think is more sophisticated (but still iron lung ) than this, and if yes, post in this thread or a new one.

Sam,

Can you provide any more detailed info from this report ?
http://www.chestjournal.org/cgi/content/full/130/2/312

Many thanks if you can


DSM

Sorry, sorry, for being very very late.

This article is an editorial of that issue of Chest that carried the Lofaso article (The article that I posted as OP) and the Rigau article (The Barcelona article), and is on APAPs.

First, the editor stated that medical devices are getting more complex, while market competition has prevented manufacturer to provide how their products really work.

However, devices "that collect, filter and analyze data, providing only the processed version to the clinician, or interpose their own judgment in diagnozing a condition or treating a patient" has to be investigated by outsiders so that they can trust them, since doctors can only believe technology under conditions.

Then it gave out examples of why such things should not be automatically trusted: a computer-controlled radiotherapy device overdosed a patient due to unexpected algorithm flaw; and differences between brands of pulse oximeter is enough to determine if a person is having hyponea.

APAP is a classic "black box" in that it contains things that outsiders don't know. Because it has been proven equivalence to CPAPs it got approved by FDA-- but as algorithms is concerned, there were only quite outdated publications that are over 10 years old and would not be representative of the technology of today.

"In the absence of detailed information on the algorithms used by these devices to control therapy, they are fair game for studies that evaluate their operation under simulated or real-world situations."

[Summaries of the two articles skipped]

Lofaso's article concluded that manufacturers should publicize the technical details and algorithms employed by their APAPs so that doctors can choose, but since this is not the case, the editors proposed five ways they "respond to this situation as a community of sleep medicine physicians"

1. Following the symptomatic response of patients on APAPs, assuming a complaint is present in the first case. But: in well-randomized trials of CPAPs a noticeable placebo effect can be found, and lack of strong correlation between the severity of apnea and any given symptom.
2. Doing PSM on people who are on APAPs. The editor says he applies sometimes on complex cases to ensure it is responding adequately-- even he don't know why it is such.
3. Depend on the quantification of events by the devices themselves. But: Circular reasoning.
4. (As Rigau et al proposed) Consensus between manufacturers to standardize the signals to be measured and the algorithms. But: Stifle further research and development and given the market is so competitive, there would be no consensus.
5. (As the Editor proposed) Independent, Standardized, verifiable testing a la Consumer Reports.

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): APAP

Or....

As I've so frequently stated, given the apparent clinically significant differences between the algorithms developed by the competing manufacturers, urge SDB patients to abandon their tragic and potentially catastrophic passivity and demand that they be given the opportunity to try as many auto-titrating PAPs as possible to determine which renders the most effective treatment FOR THEM! In so doing, the standard of care would change to the benefit of patients who's very lives depend on receiving the most effective care for them.

Put simply, TRY BEFORE YOU BUY!!! Your lives depend on it!

Chuck

GoofyUT wrote:Or....

As I've so frequently stated, given the apparent clinically significant differences between the algorithms developed by the competing manufacturers, urge SDB patients to abandon their tragic and potentially catastrophic passivity and demand that they be given the opportunity to try as many auto-titrating PAPs as possible to determine which renders the most effective treatment FOR THEM! In so doing, the standard of care would change to the benefit of patients who's very lives depend on receiving the most effective care for them.

Put simply, TRY BEFORE YOU BUY!!! Your lives depend on it!

Chuck

Not the most practical thing to do, IMO.

Put an analogy: Would your doctor agree to prescribe "SSRI antidepressent 1 month" and ask you to be the white rabbit for Prozac, Lexapro, Paxil, and Zoloft?

SamCurt wrote:

GoofyUT wrote:Or....

As I've so frequently stated, given the apparent clinically significant differences between the algorithms developed by the competing manufacturers, urge SDB patients to abandon their tragic and potentially catastrophic passivity and demand that they be given the opportunity to try as many auto-titrating PAPs as possible to determine which renders the most effective treatment FOR THEM! In so doing, the standard of care would change to the benefit of patients who's very lives depend on receiving the most effective care for them.

Put simply, TRY BEFORE YOU BUY!!! Your lives depend on it!

Chuck

Not the most practical thing to do, IMO.

Put an analogy: Would your doctor agree to prescribe "SSRI antidepressent 1 month" and ask you to be the white rabbit for Prozac, Lexapro, Paxil, and Zoloft?

That's the way my wife and her doc approached it and they eventually decided that Paxil worked best for her condition ... I think she tried a couple of others too but I can't remember which.

SamCurt wrote:

GoofyUT wrote:Or....

As I've so frequently stated, given the apparent clinically significant differences between the algorithms developed by the competing manufacturers, urge SDB patients to abandon their tragic and potentially catastrophic passivity and demand that they be given the opportunity to try as many auto-titrating PAPs as possible to determine which renders the most effective treatment FOR THEM! In so doing, the standard of care would change to the benefit of patients who's very lives depend on receiving the most effective care for them.

Put simply, TRY BEFORE YOU BUY!!! Your lives depend on it!

Chuck

Not the most practical thing to do, IMO.

Put an analogy: Would your doctor agree to prescribe "SSRI antidepressent 1 month" and ask you to be the white rabbit for Prozac, Lexapro, Paxil, and Zoloft?

I think Sam's point is that trialling multiple Autos is impractical because of cost.

Also, are you going to accept a machine that someone else has 'trialled' & rejected ?

Who will pay for the trialling & who gets to determine if the patient's subjective assesment is right when they do choose.

This is the impractical problem of trialling expensive medical equipment at someone's expense & few patients will be willing to put the money up. Health insurance organizations if they were to adopt such an approach, would have to pass on the cost of restocking & cleaning machines, on to insurers. So which company steps forward to be first ? - methinks not many.

Trialling Autos by hit and miss, is a poor approach to therapy and financially unsustainable.



DSM

Are you kidding???

Because of the expense to the insurance companies and consumers of being afforded the opportunity we deserve to arrive at the BEST treatment, we should accept the current "hit or miss" approach of taking whatever APAP that the DME favors, without question??? My health is worth FAR more to me than that.

APAPs ain't THAT expensive. And, if it was the "standard of care" that folks be trialed on different algorithms to determine which provides the best individualized response, insurers wouldn't have any other choice. I'm afraid that it will become the standard of care only after some expensive judgements are awarded as a result of litigation that will eventually come about from the survivors of those that succumb to their SDB and claim that their deaths were wrongful because their doctors allowed sub-optimal auto-titration. Or else, the medical community will remain steadfast in opposing auto-titration as a way of managing risk.

Tell ya what Doug: I'm not computer-literate enough to figure out how to set up a poll here. Why not take the step of creating a poll to find out how many of us would be willing to bear some expense for being given the opportunity to try different APAPs until they found the one that would work the best for them?

Chuck

_________________

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

[quote="GoofyUT"]Are you kidding???

Because of the expense to the insurance companies and consumers of being afforded the opportunity we deserve to arrive at the BEST treatment, we should accept the current "hit or miss" approach of taking whatever APAP that the DME favors, without question??? My health is worth FAR more to me than that.

APAPs ain't THAT expensive. And, if it was the "standard of care" that folks be trialed on different algorithms to determine which provides the best individualized response, insurers wouldn't have any other choice. I'm afraid that it will become the standard of care only after some expensive judgements are awarded as a result of litigation that will eventually come about from the survivors of those that succumb to their SDB and claim that their deaths were wrongful because their doctors allowed sub-optimal auto-titration. Or else, the medical community will remain steadfast in opposing auto-titration as a way of managing risk.

Tell ya what Doug: I'm not computer-literate enough to figure out how to set up a poll here. Why not take the step of creating a poll to find out how many of us would be willing to bear some expense for being given the opportunity to try different APAPs until they found the one that would work the best for them?

Chuck

Are YOU kidding, Chuck?

Sam and Doug finally said what I've been thinking throughout the course of this whole thread.
The cost of our healthcare is ridiculous now.....something like having everybody being able to trial several different brands of machines would make it astronomical.
SOMEBODY'S going to pay for it.....and guess who that would be?!?!

Den