Resmed vs. Respironics - Help

[dsm]

Velbor,

R U in Oz or Uk ?

When I saw that 'I am not a number ...' thought here is someone who enjoys good English sci-fi every time I see someone in a striped coat in a golf cart - that show comes to mind.

DSM

[NightHawkeye]

Have I mentioned that I dislike cocktail parties?? All the meaningless, undirected, random chatter ....

Like entropy, it is ...

entropy (ntr-p)
"A measure of the amount of energy in a physical system not available to do work."
from: http://www.thefreedictionary.com/entropy

You were wise to prod the discussion in your preferred direction, Velbor, to harness the energy, and harvest that useful to you.

I particularly want to thank NightHawkeye for the diagram posted on Page 22.

You're entirely welcome. I'd hoped it would be useful to you.

It portrays, more effectively than any other I've seen, how a "radial" pressure differential from CPAP can exist between the airway and the outside, which could indeed involve the movement of "craniofacial structures". So I retract my ill-advised suggestion that the airway is radially rigid.

And, so we all have learned from the discourse (if I may be so presumptuous), despite our predilections and scattered thought processes.

Regards,
Bill

[split_city]

PS S-C - wife & I were in Rowland Flat near Tanunda early last week as part of a national car rally great week - Barossa towns are more magical than ever.

Hope the weather there has settled

I love the Barossa! I just don't get a chance to ventue up there much

Weather has settled but we desperately need some rain!

Adelaide recently (March) had the longest ever recorded heatwave for any Australian capital city. We had 15 consecutive days above 35 degrees celsius (that 95 degrees Fahrenheit for you Americans). That may not sound much to people that live inland, but Adelaide is right on the coast. This was apparently a 1 in 3000 year event

[dsm]

I would like to throw in another topic while we have such esteemed minds gathered at this one big international cocktail party ...

Does anyone know of any studies or evidence that people become immune to the benefits of their xPAP therapy over time.

The idea I am exploring is based on my own experience where CPAP was very effective for about 3 months then a 'dullness/heavyness' returned, then went on APAP & after 3 months of apparent improvement same slide started then went on Bilevel but got a good 12 months then the slide again but to a much lesser extent than before - now am on an SV machine & am watching to see if this provides a jump as has happened with other new devices.

After reading many other posts by people here over the past 3 years have been wondering if there is such an effect as 'xPAP fade' where the therapy starts to lose its effect.


DSM

As an added qualifier - when I 1st went on CPAP it seemed like magic - was up early full of energy ready to take on the world - then the fade started & at the same time wife began saying that I seemed to be stopping breathing just like before going on CPAP - this got worse in proportion to the slide. The Auto reversed that for a short while - the Bilevel provided the longest improvement but even that was starting to fade.

[NightHawkeye]

Grudgingly, I began investigating ResMed patent, no. 6,138,675. Although I don't own a ResMed machine, it seemed an egregious oversight to ignore ResMed further. (Newcomers to the board for instance when opening this thread, because of the thread name, just might expect to see some evaluation of ResMed machines here.)

Without any preconceived notions, other than perhaps that ResMed products were inferior in all respects to Puritan-Bennett and Respironics products, I began looking through the patent expecting to see little more than boring charts and a few flow diagrams drawn simply for the purpose of hoodwinking the patent examiners. Before finishing two pages though, I discovered that the algorithm not only identifies Central Apnea (via cardiac rhythm), it also initiates a sonic burst to determine patency (i.e., windpipe open).

Wow! Now, that's intriguing stuff. The boring Respironics algorithm certainly doesn't do either of those things (despite all of those vaunted layers). The 420E does identify Central Apnea, but I don't recall anything about using a sonic burst with the 420E.

The ResMed patent even includes lots of timing details, such as the following:

Approximately 5 seconds into the apnea a 2 Hz, 1 cm H2O pressure oscillation is induced (applied) for 6 seconds (i.e., between t=14 s to t=20.5 s). It can be seen that this pressure modulation induces a corresponding 2 Hz modulation in the respiratory air flow signal. ...
... As further shown in Figure 14, the air flow induced by the pressure modulation is separated from air flow induced by other factors (such as heartbeat), by demodulating the measured air flow signal, fn, by a demodulator ...
... Apneas are classified as "airway open" if the mean induced signal is more than 0.03 l/sec, and "airway closed" if the mean induced signal is less than 0.03 l/sec. ...

The most interesting part though is that the ResMed algorithm does the very thing I/we've been saying APAPs do not do!

In the case of either methodology utilised to determine patency, if the result of that determination (step 20) is "No", then as was the case for a partial obstruction, the CPAP treatment pressure is increased. If the result is "Yes", then a central apnea with an open airway is occurring, and it is inappropriate to increase CPAP pressure. Instead the event is only logged, and step 17 follows, whereby CPAP pressure is reduced, as has previously been discussed.

I did not find any real time qualifiers on the pressure increase. I only spent about an hour looking through the patent though, so I'm sure there's more.

Regards,
Bill ( ... wondering if this difference between machines is part of the reason some folks swear one brand works so much better for them ... )

[Snoredog]

Grudgingly, I began investigating ResMed patent, no. 6,138,675. Although I don't own a ResMed machine, it seemed an egregious oversight to ignore ResMed further. (Newcomers to the board for instance when opening this thread, because of the thread name, just might expect to see some evaluation of ResMed machines here.)

Without any preconceived notions, other than perhaps that ResMed products were inferior in all respects to Puritan-Bennett and Respironics products, I began looking through the patent expecting to see little more than boring charts and a few flow diagrams drawn simply for the purpose of hoodwinking the patent examiners. Before finishing two pages though, I discovered that the algorithm not only identifies Central Apnea (via cardiac rhythm), it also initiates a sonic burst to determine patency (i.e., windpipe open).

Wow! Now, that's intriguing stuff. The boring Respironics algorithm certainly doesn't do either of those things (despite all of those vaunted layers). The 420E does identify Central Apnea, but I don't recall anything about using a sonic burst with the 420E.

The ResMed patent even includes lots of timing details, such as the following:

Approximately 5 seconds into the apnea a 2 Hz, 1 cm H2O pressure oscillation is induced (applied) for 6 seconds (i.e., between t=14 s to t=20.5 s). It can be seen that this pressure modulation induces a corresponding 2 Hz modulation in the respiratory air flow signal. ...
... As further shown in Figure 14, the air flow induced by the pressure modulation is separated from air flow induced by other factors (such as heartbeat), by demodulating the measured air flow signal, fn, by a demodulator ...
... Apneas are classified as "airway open" if the mean induced signal is more than 0.03 l/sec, and "airway closed" if the mean induced signal is less than 0.03 l/sec. ...

The most interesting part though is that the ResMed algorithm does the very thing I/we've been saying APAPs do not do!

In the case of either methodology utilised to determine patency, if the result of that determination (step 20) is "No", then as was the case for a partial obstruction, the CPAP treatment pressure is increased. If the result is "Yes", then a central apnea with an open airway is occurring, and it is inappropriate to increase CPAP pressure. Instead the event is only logged, and step 17 follows, whereby CPAP pressure is reduced, as has previously been discussed.

I did not find any real time qualifiers on the pressure increase. I only spent about an hour looking through the patent though, so I'm sure there's more.

Regards,
Bill ( ... wondering if this difference between machines is part of the reason some folks swear one brand works so much better for them ... )

[-SWS]

Diminishing xPAP Returns- Doug, I know exactly what you mean about perceived "diminished returns" gradually following xPAP changes. I am unaware of any published literature addressing that effect as either real or perceived. But I have experienced it myself and have read plenty of similar anecdotes.

I tentatively have that phenomenon attributed more as an affect of human psychology rather than physiology. But I haven't completely ruled out the possibility of acclimation somehow factoring in (perhaps neural adaptive plasticity at work).


Forced Oscillation Technique- Bill, I noticed that Resmed patent is listed as one of several patents employed in the current S8 AutoSet. When SAG first mentioned that patent I was very surprised (and still am) that there's absolutely no mention of this forced oscillation technique (FOT) anywhere in Resmed's marketing literature.

That patented technique seems basic compared to some forced oscillation techniques employed in respiratory medicine. Regardless I would have expected Resmed to capitalize with a flattering spin in their marketing literature.

[NightHawkeye]

Only problem is back in 2000 when the patent was granted, they didn't have a machine with a sensor installed that could detect cardiac oscillations.

This particular patent was filed in 1997, but is a continuation of a 1994 application. Seems like a long time ago.

Not that that matters too much now. I took a peek at ResMed patent 7,320,320, dated January 22, 2008. Brand spanking fresh new patent, except that it's got the same stuff as the 2000 patent, including the exact same 20 pages of charts and flow graphs. Guess if you've seen one, you've seen 'em all. I'm sure they musta changed something. It describes sonic bursting as well as the cardiac sensing. Sure seems about the same as what I read last night.

Now I see what changed ... they gave the the sonic burst technique a name. They now call it Forced Oscillation Technique (just like ya said, -SWS). Funny, they didn't call it FOT earlier. But, hey, the name's almost novel enough to warrant a patent all by itself.

That patented technique seems basic compared to some forced oscillation techniques employed in respiratory medicine. Regardless I would have expected Resmed to capitalize with a flattering spin in their marketing literature.

Assuming that they're even using FOT. They might not be. They don't have to use it. Maybe they don't. I also ran across a hose-cleaning patent of ResMed's which includes a patient warning mechanism to make sure the patient isn't hooked up to the machine when the cleaning technique fires up. Great stuff! I can hardly wait to spend my money on one of those.

Regards,
Bill

[NightHawkeye]

I'll once again quote Snoredog:

Only problem is back in 2000 when the patent was granted, they didn't have a machine with a sensor installed that could detect cardiac oscillations.

Yep, and that's the difference between patents 6,138,675 stemming from 1994 and 7,320,320 granted in Jan 2008. Patent 7,320,320 contains ten claims relating to "cardiogenic" activity (and only ten claims altogether, I might add).

As I mentioned in my previous post, the two patents are verbatim identical, all 30+ pages, except for the first page which contains a slightly different drawing, and the claims section at the end with its "cardiogenic" stuff.

Also interestingly, this latest patent is listed as stemming from the same 1994 patent, no. 5,704,345 (edit: more correctly stated as stemming from the same patent application, No. 08/335,118, of which patent 5,704,345 was the first granted). For whatever reason (either sensor related like Snoredog said, or possibly legal issues) ResMed was unable to get the cardiogenic related parts of the 1994 patent application approved until 2008 although the cardiogenic detection technique was described in detail in the earlier applications.

OK - Bottom line: It appears that current ResMed S8 APAPs have fast response and the ability to definitively detect Central Apneas. The patent indicates that the machine will hold/reduce pressure when central apnea is detected. That could be of importance to some folks. According to the patent, the ResMed machine is also likely to increase pressure when an obstructive apnea is detected, rather than wait. (Personally, that doesn't sound so good.)

Regards,
Bill ( ... who suspects that a few other ResMed patents are verbatim identical with these two ... )

[dsm]

NightHawkEye

Thanks muchly for the research you are doing here - I am finding it very informative.

Thanks

DSM

[Wulfman]

Don't companies need to re-file patents every "so many" years so they don't expire? I was thinking it was a multiple of 7 years......like 14?.....which would be the timeframe from 1994 to 2008.
By listing the bulk of their previous patent and adding a few more "features" they would be able to protect their previous and newer technologies.


Den

[NightHawkeye]

Don't companies need to re-file patents every "so many" years so they don't expire? I was thinking it was a multiple of 7 years......like 14?.....which would be the timeframe from 1994 to 2008.
By listing the bulk of their previous patent and adding a few more "features" they would be able to protect their previous and newer technologies.

Great question, Den. Companies would like to be able to extend their patents forever, but the patent system was never set up to allow that. Maximum patent protection duration is 20 years (I think). Notably, I've read that some software companies and biotech companies have attempted to extend their patents as you suggest by making minor changes to their patented "technique" so that they can then request a new patent for another 20 years of protection. I'm not sure how successfully this has worked out for anyone though. I believe that the US Patent and Trademark Office (USPTO) has actively sought to deny such claims and even overturn them when necessary.

The reasoning behind patents is to encourage innovative ideas by providing protection to the original inventor for a period of years. In return, the inventor must disclose all relevant details necessary for one "skilled in the art" to be able to produce a competing product. Sometimes companies file for patent protection. Sometimes, deliberately, they do not file for patent protection, judging they can keep their secret longer than the patent system would protect them.

Here's what ehow.com says about patent duration and protection:
http://www.ehow.com/how_2039495_determi ... ation.html

Determine the Duration of Your Patent
Step1
Apply for a utility patent if you have a specific invention, machine, new process, article of manufacture or composition of matter. These patents are protected for 20 years after the patent application is filed.
Step2
Seek a design patent for design improvements, modifications and ornaments to existing products. A design patent generally lasts for 14 years.
Step3
Obtain a plant patent if you seek to protect the asexual creation of a new plant species for 20 years. Asexual plant reproduction is defined by new species that are not created through the use of seeds, but rather by cutting, grafting or budding.

Protect Your Patent Duration
Step1
Pay all maintenance fees for your patent 3 1/2, 7 1/2 and 11 1/2 years after the date your patent was granted. It is important to determine these due dates in advance, since the USPTO will not notify you. There is a six-month window where you can pay these fees. Failure to comply may result in forfeit of your patent.
Step2
Renew your patent before its expiration date by filing a patent extension with the USPTO. Failure to do so will result in forfeit of the patent, and the invention or design will become part of the public domain.
Step3
Will your patent to friends or loved ones after you die by filing the appropriate paperwork. All forms and applications are available on the USPTO Web site, or at any USPTO office

Regards,
Bill

[Velbor]

OK - Bottom line: It appears that current ResMed S8 APAPs have fast response and the ability to definitively detect Central Apneas. The patent indicates that the machine will hold/reduce pressure when central apnea is detected.

Forgive me; I'm getting all confused (again). Sounds like the conclusion is being drawn that, simply because a technology is included in a patent, and a device is "covered" by that patent, that all of the patented technology is therefore present in the "covered" product.

My understanding of a patent is that it protects an idea. The patent applicant for a device is required to demonstrate that the idea is original, non-trivial, and buildable. However, I'm aware of no requirement that, having been granted a patent, an applicant MUST build the described machine. I further understand that a patent grantee MAY utilize SOME of the patented ideas, without being required to implement ALL of the technologies covered by the patent.

A patent "enables" the "protected" marketing of an innovative technology, but does not become a "required blueprint" for a marketed product. A patent is not the same as a "description" of a medical device for regulatory approval.

[NightHawkeye]

OK - Bottom line: It appears that current ResMed S8 APAPs have fast response and the ability to definitively detect Central Apneas. The patent indicates that the machine will hold/reduce pressure when central apnea is detected.

Forgive me; I'm getting all confused (again). Sounds like the conclusion is being drawn that, simply because a technology is included in a patent, and a device is "covered" by that patent, that all of the patented technology is therefore present in the "covered" product.

You are absolutely correct, Velbor, which is why I qualified the first sentence you quoted:

OK - Bottom line: It appears that current ResMed S8 APAPs have fast response and the ability to definitively detect Central Apneas.

I confess to committing a grievous editorial blunder, however, in regard to the second sentence:

Judging from the patent, it appears that the machine will either hold or reduce pressure when central apnea is detected.

One thing about patents though is that they are relatively expensive. The amount of time (translation: $$$) required to get one is significant. For that reason many companies (the one I work for, for instance) will only pursue patent protection when a very strong business case to do so exists.

As with Snoredog's posting above about the S7 not being able to detect central apneas and -SWS's observation that FOT may not be included at all (since that hasn't shown up in product promotional materials), additional info from other sources would further the discussion.

I kinda view patents as a starting point for discussion here. ResMed might be (and likely is, in some respects) deviating from their patent description, but in general I expect the ResMed patent offers considerable insight into how their APAP operates, and also why it operates the way that it does. Just my opinion, of course.

Regards,
Bill ( ... vaguely remembering pointing out the limitations of patents just a few pages back ... )

[NightHawkeye]

I stumbled across a quad of ResMed patents this morning, titled:
ADMINISTRATION OF CPAP TREATMENT PRESSURE IN PRESENCE OF APNEA

Automatic detection of partial upper airway obstruction and pre-emptive adjustment of nasal CPAP pressure works to prevent frank obstructive apneas in the majority of subjects with obstructive sleep apnea syndrome. However, some subjects with severe disease progress directly from a stable open upper airway to a closed airway apnea with complete airway closure, with little or no intervening period of partial obstruction. Therefore it is useful for an automatically adjusting CPAP system to also respond to a closed airway apnea by an increase in CPAP pressure. However, it is not desirable to increase CPAP pressure in response to open airway apneas, firstly because this leads to an unnecessarily high pressure, and secondly because the high pressure can reflexly cause yet further open airway apneas, leading to a vicious circle of pressure increase.

It again appears that ResMed, presumably on the basis of research, favors immediate pressure increase when obstructive apnea has been detected. The reason ResMed states for doing this is that pre-emptive pressure increases do not work for some patients. The issue of how good or bad that immediate pressure increase might be for most patients is simply not addressed. There also is a hard upper limit of 10 cm for the pressure increases, with a softer limit starting at 8 cm. Central apneas, however, do not warrant any pressure increase.

The deliberateness of this immediate pressure building technique is underscored by the fact that with this "patented technique" pressure continues to build higher the longer the apnea persists, as indicated in figure 3 and figure 4 shown in the patent.

These four patents also shed insight on why the Forced Oscillation Technique (FOT) may not be included in the ResMed APAP products:

This 'forced oscillation method' requires the ability to modulate the mask pressure at 4 Hz, which increases the cost of the device. Furthermore, the method does not work in the presence of high leak, and can falsely report that the airway is closed if the subject has a high nasal or intrapulmonary resistance.
The present invention is directed to overcoming or at least ameliorating one or more of the foregoing disadvantages in the prior art.

Perhaps even though they patented FOT, they never got it to work satisfactorily and so never included it in their products. (Speculation on my part, of course.)

It's also worth mentioning that these four patents, stemming from an application in 1998, contain a large amount of pseudo-code, thereby allowing for a very precise understanding of exactly how the "algorithms" function.

Regards,
Bill (hoping someone besides me finds this interesting ... )