CPAPtalk.com

FYI,

Here is a reply to SleepyDave from the SleepStrip folks:

Dave,

My name is Noam Hadas and I’m the engineer who headed the team inventing and developing the SleepStrip at SLP, in collaboration with the Technion Sleep Medicine Center. Your arguments against the usage of the “SleepStrip” all target the “accuracy” of the device in the diagnosis of sleep apnea, which in our opinion completely misses the whole point of the device.

From your post I understand that you take your children to the hospital for a CT before you take their temperature at home. In your world there is only room for the best, and most expensive answers. Well, millions of undiagnosed apnea patients stand to show this approach in sleep medicine is very problematic.

We agree that a full night in a properly equipped sleep lab, with a well trained and attentive technician scoring the data, and an expert physician writing the report is the best way to diagnose SDB, but how many of the people who suffer from sleep apnea are studied in sleep clinics?

Based on the Wisconsin Cohort data, Dr. Terry Young estimated that no more than 15% of the patients “out there” were actually studied for sleep disorders. Thus, there are millions of people who are not aware of their sleep breathing disorders, and suffer cardiovascular damage night after night. There are many reasons for the disparity between the number of people with SDB and the number of studies actually performed. These include the limited number of available beds, the relatively small number of sleep specialists, the lack of awareness of the medical community and of the public at large of the clinical significance of breathing disorders in sleep and so on.

The purpose of the SleepStrip is NOT to provide a diagnosis of sleep apnea syndrome. Its purpose is to provide a simple, cost-effective screening of large numbers of people. A positive SleepStrip finding should be viewed as a ‘red flag’ signaling a high likelihood of breathing disorders in sleep that should be followed by a diagnostic test. We believe that the SleepStrip is an important tool particularly in younger people who, even if they have severe apneic events, are less symptomatic and “hate” the idea to spend a night in the sleep laboratory connected to electrodes. For them, a positive SleepStrip finding should be a powerful incentive to seek a professional help and diagnostic sleep study.

The SleepStrip is the only tool available that can allow these undiagnosed millions to test their likelihood of having sleep apnea. There is no way the health system can afford in-lab testing for all of them without some kind of proper screening, and there is no chance they will suddenly realize they need a study on their own. The SleepStrip is intended for screening the masses, identifying the moderate and severe patients (at least) at a very reasonable cost, and bringing them into the labs so people like you can help them.

During these years of marketing the SleepStrip I personally gave it to many people who were not happy about their sleep, but never thought of complaining to their physicians or getting tested. Following positive Strip findings many were later diagnosed and put on therapy. Are you so sure this is wrong?

Noam

NightHawkeye wrote:The Sleep Strips look to me like a complete waste of time. Funny thing is normally I'm all in favor of cheap diagnostics, so I'll attempt to outline why I would recommend against them to anybody that asked my opinion.

Characteristics of a good diagnostic test:
1) Provide unequivocal results, accurately diagnose and never fail to diagnose
2) Convenient and easy to use
3) Low cost

For a myriad of reasons it appears that the sleep strip fails to meet desired characteristic 1) above. Sleep Dave pretty well detailed this in the reference provided earlier. Additionally, it strikes me that the sleep strip falls in the category of voodoo medicine - a magical device with inner workings largely concealed from the world. In this respect, rather than enabling patients to take charge of their health concerns, it actually plays into the current system with the physician being totally in charge and forces the patient to accept whatever arbitrary diagnosis the strip provides.

The real reason I'm opposed to the sleep strip is that a cheaper, easier, and much more accurate diagnostic tool is available - an oximeter study. If sleep apnea is a problem, then desaturations will be present in the oximeter data, no question about. An oximeter will not fail to diagnose sleep apnea. In comparison, the sleep strip, according to Sleep Dave, is highly prone to misdiagnosis.

I'd suggest that CPAP.com would provide much better service to their customers if they simply made oximeters available for rent.

Regards,
Bill

Wouldn't an oximeter by itself fail for someone with hypotension, cardiac arythmia, and other vascular disorders? I have also read that carbon monoxide in the blood can fool an oximeter into thinking it is oxygen (could happen while using CPAP if exhaust ventilation is too low when used to evaluate efficacy of treatment) ... also heard that nail varnish can give inaccurate oximeter readings.

Perhaps using the srtip test in conjunction with an oximeter would improve the accuracy of OSA diagnosis?

Just my $0.02 ...

- roberto

All those who think its free, just because part of the cost is covered by insurance, please raise your hand.

INSURANCE IS NOT FREE. Most insurance companies make a profit.
Therefore, somebody must be paying..

Hat's off to cpap dot com...

Noam.....I applaud you for working hard to innovate and present a new product....and I wish you success. If your product (SleepStrip) offers more value than the alternatives, the world will slowly....but relentlessly....beat a path to your door.

Price is only one component of value....and time will tell if you're able to help people with your product. A few of us understand the struggles connected with innovation and the education of the public (as to the value of a new product).

DreamStalker wrote:Wouldn't an oximeter by itself fail for someone with hypotension, cardiac arythmia, and other vascular disorders?

There are other disorders that could also be indicated in the oximeter results. Remember though that CPAP.com has a physician on staff to interpret results, as well as to write prescriptions. The distinctive gradual desaturations associated with sleep apnea are different from the low oxygen levels indicative of COPD problems and cardiac disturbances for instance. As a technical matter, it also appears that the oximeter data is much easier to interpret than the results with the sleep strip, which may or may not detect a particular individual's apnea.

Remember also that with any medical diagnostic test the primary objective is to first detect if a patient has a problem, not just to diagnose apnea. In that regard the oximeter is essentially an ideal tool, as it detects all apneas. It cares not a whit whether the apnea is obstructive or central, and it cares not a whit whether one is mouth-breathing or not. The fact that an oximeter also detects other problems is a good thing from the patient's perspective.

DreamStalker wrote:I have also read that carbon monoxide in the blood can fool an oximeter into thinking it is oxygen (could happen while using CPAP if exhaust ventilation is too low when used to evaluate efficacy of treatment)

Sounds like you're confusing carbon monoxide with carbon dioxide, DreamStalker. Carbon dioxide in our exhalation can cause us to hyperventilate, but oximeters are not confused by carbon dioxide. As for carbon monoxide, I doubt that any apnea diagnostic tool will identify that and, if carbon monoxide is present, then whether or not one gets the apnea diagnosis right probably doesn't matter much as death is likely to set in prior to morning anyway.

DreamStalker wrote: ... also heard that nail varnish can give inaccurate oximeter readings.

If a patient is deliberately using inhalants then sleep apnea should probably not be their biggest immediate concern.

Regards,
Bill

My apologies for my mistake rearding CO2 vs CO. As for the nail varnish I was not referring to inhalation but rather the effect on the finger type sensor connected to the oximeter.

I'm not disagreeing with you that oximeter data is not good to use ... I was just thinking that it may be better to have multiple sources of data if possible. However, I'll be the first to admit that this is not my area of expertise.

- r

Wader posted Noam's reply to sleepydave's objections to relying on the SleepStrip's method of screening for sleep apnea.

StillAnotherGuest posted a clickable link to the entire discussion at http://apneasupport.org/viewtopic.php?t=673

Here is sleepydave's original post about the SleepStrip -- these are the objections (valid, imho) that prompted the response by Noam Hadas, the engineer who headed the team inventing and developing the SleepStrip:

__________________________________

sleepydave
Moderator
Joined: 05 Jul 2005
Posts: 890
Location: In the Sleep Laboratory

Sleep Strips

Hello Everybody!

I'd like to start a discussion about Sleep Strips, cause I see them tossed around a lot. Never used them, never even seen one. But I know a little bit about these types of devices and have some concerns. I may be wrong, but invite enlightened debate here. If I'm right, then people who use these things need to know these things too.

OK, so it's a stand alone device that monitors breathing during sleep. You can find a picture of it if you surf, but I won't put up the link. And it has an algorithm that quantifies the severity of SA you have. Not OSA, just SA. It can't tell a central from an obstructive, but that's picky.

And for that matter, it counts hypopneas as well as apneas:

"An apnea event is counted when respiration amplitude drops to under 12% of the average for more than 10 seconds. A hyponea event is counted if respiration amplitude drops to less than 50%, but more than 12%, of the average for more than 10 seconds. Respiratory events (apneas and hypopneas) are counted for the duration of the study. These values were selected for maximum correlation with polysomnographic results."

Which is odd, because you can't call a hypopnea as such unless there's also a desaturation and/or an arousal. Or if you're using Medicare criteria, then a desaturation only. Well that's a problem, cause without an oximeter or EEG leads, you can't tell that. OK, it's me being picky again.

Anyway, the algorithm calculates the severity of your SA:

"The final score represents five possible test outcomes based on sleep apnea severity level:

0 - no apnea: comparable to a sleep lab AHI of less than 14

1 – Mild: comparable to a sleep lab AHI between 15 and 24

2 – Moderate: comparable to a sleep lab AHI between 25 and 39

3 – Severe: comparable to a sleep lab AHI of more than 40

E – Error in measurement"

Now where did these values come from. Even Medicare, with strict requirements, allow CPAP if your AHI is from 5 to 15 if you have symptoms. And everybody I know says AHI 5-15 is mild sleep apnea. And there's plenty of data that says even mild sleep apnea can cause all the same problems, including hypertension, that moderate to severe apnea can, so you should be treated.

But here's where I have real issues. There are plenty of scenarios where the algorithm will give absolutely erroneous results. For instance:

SA is usually more severe where you're on your back or in REM. But one usually only spends 20% of the time in REM, and most people shift positions during the night. But if they have severe SA in REM, or when supine, and are relatively normal in the other positions, and that sleep segment is say 20% of the night, you could have an AHI of 75 during those periods and this algorithm will say you have NO APNEA. Not mild, not get a sleep study, NO APNEA.

OK, the desaturations. We're very concerned about those, severe desaturations bump up your severity to moderate or severe. For instance, AHI of 14 with desats to 40% would be very severe SA. Normal again with the SS, and that's just dangerous.

PLMs occur in 10% of patients and can contribute to daytime sleepiness, and overall daytime sleepiness is caused by arousals, sleep stage changes and reduced levels of quality sleep. You're still going to need PSG to evaluate these, and you're undoubtedly going to need it if you intend to have CPAP covered by insurance.

So here's the most important point:
A score of 0 can and will be misinterpreted. It in no way can mean you have no apnea, it doesn't mean you don't have OSA and it absolutely cannot mean you don't have a problem. Because if you have been have been screened properly, at least enough to get a SS, then you have some signs and symptoms of a sleep-related breathing disorder (SBD). And after this test is done, you know what? You still do. And if a person unversed in the study of sleep is interpreting the results for you, that could very well be the end of the line in finding and treating your problems.

The medical support of this device is anecdotal at best, and only correlate AHI in the mild to moderate range. With a 5 year history of its use, though, it's actually quite sparse. Circumstantial arguement? Maybe.

But until a see a study that looks at people who had complaints of SBD, used the SS, were rated 0, no apnea and then had follow-up studies to determine what their problems and their severity were, I would not even recommend using it. Because I think that would really bring to light the dangers and limitations of this device, and consequently really educate potential users.

So what happened to the people with SS results? There's 4 possibilities:

You had a positive result and had a PSG and/or now on CPAP. OK, not bad. Who had a positive SS and got a PSG anyway? Did the SS really cost $40, or did you need 2 physician visits as well?

You had a positive result and did nothing about it. Nuff said.

You had a negative result, but continued to follow-up and solve your problem. Great.

You had a negative result and did nothing further. What made you get a SS in the first place? And knowing what you do now, are you still satisfied with the results?

My recommendation would be that a PSG is necessary in all of these situations. Data from SS ranges from inaccurate to erroneous. I believe many people are dangerously falling through the cracks when this device is used. The information from the SS only has a remote chance of being accurately interpreted unless it is in the hands of a qualified sleep specialist, and I just don't see it becoming a part of their repertoire. It just leaves too many questions unanswered.

Any and all responses are invited, especially those who had "normal" results and how their problem was finally solved or if it's still ongoing.
sleepydave

------Excerpt from follow-up post by sleepydave------

sleepydave
Moderator
Joined: 05 Jul 2005
Posts: 890
Location: In the Sleep Laboratory

For example...

And lest anybody even think of using an SS on a child, don't-- no, non, nein, nyet.
Here's the range of abnormal values for OSA in children:

There aren't any.

There is general agreement among the pediatric community that anything over AHI 1.0 is abnormal, but after that, there's nothing concrete, but here's what we use, just to attach a name that puts the value into context:

AHI<1.0 Normal
AHI 1.0-5.0 Mild OSA
AHI 5.0-10.0 Moderate OSA
AHI >10.0 Severe OSA

At AHI 3.0, they're serious candidates for surgery, and adding in desaturations at any level is pretty much a trump.

And the SS didn't even report anything yet.

_________________________________________

Just to through this in the mix.

One local children's hospital was saying on the radio that they you oximetry to check out children.

I found it odd that that is what they do.

Thanks for the the links/posts.

I agree with NightHawkeye that overnight recording pulse oximetry is a better first line action screening test. So, I'm not too surprised that a hospital would be encouraging parents to have at least that (recording SpO2 oximetry test -- not a SleepStrip) as a screening for children suspected of sleep disordered breathing.

Would be hard to advertise to bring 'em in for a PSG, but parents might think about something that sounds simpler and more familiar...the idea of a screening by recording O2 levels overnight at home. Again, it would only be as good as the pediatric OSA knowledge of the doctors looking at the SpO2 data, since the threshold for diagnosis in children is sooo different than for adults.

Rested Gal, I agree that O2 is good info for sleep apnea.

I was surprised they do not hook up children to wires for other indicators.

The adult hospitals hook up adults at home, because of the long waiting times for sleep labs, to some machine, I will edit and add name. If a child has other sleep issues they will not be picked up.

rested gal wrote:I agree with NightHawkeye that overnight recording pulse oximetry is a better first line action screening test. So, I'm not too surprised that a hospital would be encouraging parents to have at least that (recording SpO2 oximetry test -- not a SleepStrip) as a screening for children.

SelfSeeker wrote:I was surprised they do not hook up children to wires for other indicators.

Maybe 'cause they are squirmy little creatures?

The simpler a screening can be yet be able to indicate a possible problem, the more likely the parent could actually get the child through it at home. Might have to sneak into the bedroom to put the pulse oxi sensor on them anyway.

After the screening (but not a SleepStrip where kids are concerned!) they could go to the next step if indicated -- PSG with ALL the wires.

Johnny,

My problem is that during the last third of the sleep cycle my sleep apnea is so bad that I have dreams of suffocation. I was once even shown the happy times of my life in shades of white and gray with a door and light at the end of the sequence and was asked if I wanted to pass thru. I can feel that my heart is going in to pretty bad AFIB (atrial fibrillation) during this time. Note that if I take a Tramadol (minor pain killer usually used for arthritis) I can avoid the sleep apnea altogether. I am wondering if this means I have central nervous system sleep apnea rather than the more common obstructive sleep apnea and a simple prescription might fix it. Anyway, my cardiologist says he can fix the AFIB only after I get rid of the sleep apnea. I am happy to hear about your group and welcome any advice.

Please tell me how to get started with your group and how to sign up for the testing. I, like you, don't believe these tests should be that expensive. I have to admit that your group sounds too good to be true.

THX- Steve

Hi - you responded to an 8 yr old post here, and while Johhny owns the site, he doesn't correspond here on the forum. And testing for apnea is done through your own doctor who hopefully refers you to the right place(s) to get it done. It would be much better if you have other questions to start a new thread, but please register as a member and then you'll see lots of people just waiting to help. This forum is self help for all of us, but none are doctors, or other pros (except on rare occasions when someone incidentally is), but there are people with lots of knowledge and experience to help you.

Wow! 8 year necro thread - that might be a record!!!