Is absence of snoring a good indicator of xPAP efficacy?

KLM wrote:I agree there are a few individuals who may find the algorithms used by one manufacturer are better suited to their breathing patterns than another. But I also want to emphasize the majority will receive effective treatment from any apap. Apap event detection and the reporting software is not the gospel. But it's the best method currently available. We know clinically defined hypopneas cannot be detected without an oximeter and clinically defined centrals cannot be detected without a respiratory effort belt, but we also know the algorithms currently used employ highly complex techniques for discerning these events to the best of their programmed ability.

KLM has it exactly right.

The stated, designed function of an APAP machine to reduce apnea and hypopnea (by which I mean according to their clinical definitions) and the current machines do that very well for most people. Then again a CPAP machine can do that quite well for most people but APAP has other advantages. The fact that you can download an event log from the APAP is a good feature but must not be reified into a belief that those downloaded numbers add up to a little sleep study every night. Far from it, the definitions of apnea and hypopnea require information not available to the APAP machine at all. If you consider the data downloaded from an APAP machine to be a sleep study, then it's a sleep study with very poor validity and with unknown sensitivity and specificity.

So the fact of the matter is that with or without downloaded data from the APAP machine, you don't truly know how well your OSA has been treated. Fortunately, you don't need an absolute standard of evaluation every night of your life. What is true of the numbers you can download is that almost always lower numbers correspond to better treatment (unless there's something very unusual about your sleep disorder). So if APAP under a certain setting and conditions gives you a "9" on its scale and under a different setting and conditions gives you a "2" then you're pretty sure that the latter is the way to go, notwithstanding the fact that your downloaded "2" may or may not correspond to any number "2" that a sleep study would show.

APAP is a treatment device. Just like CPAP its purpose is to splint your airway open while you sleep. To the extent that an APAP can be used as a "diagnostic" tool, it is valid only for diagnosing the effective pressure or range of pressures that you require. The commonly-used APAP machines have not been validated for diagnosing the presence of severity of obstructive sleep apnea.

Hey gang, APAPS and their detection capabilities may not be perfect, but they are still pretty darn good!

Some informative links to click on:

Nonattended home automated continuous positive airway
pressure titration: Comparison with polysomnography

Nasal APAP titration in this study correctly identified residual apnea equivalent to the use of PSG. This correct identification allows the physician to accurately access the efficacy of treatment.

and:

Not Every Patient Needs to Go to the Sleep Lab (A powerpoint presentation by a well respected board certified sleep doctor/pulmonologist, Dr. Barbara Phillips, at a meeting of the American Lung Association of the Central Coast - November 2004)

and:

Use of Conventional and Self-Adjusting Nasal Continuous Positive Airway Pressure for Treatment of Severe Obstructive Sleep Apnea Syndrome

Conclusion: Self-adjusting nCPAP demonstrates the same reliability in suppression of respiratory disturbances as fixed-mask pressure therapy. Sleep quality is slightly superior, patient compliance is highly significantly better.

and:

Can Patients with Obstructive Sleep Apnea Titrate Their Own Continuous Positive Airway Pressure?

In summary, this study demonstrates that self-titration of patients with OSA is as efficacious as manual titration in a sleep laboratory

KLM wrote:

klm wrote:
Stopping breathing, on the other hand, is not normal. I agree with ehusen, it is disappointing to hear dsm's machines did not sense he had stopped breathing -as reported by his wife. But how do we know the machine did not sense it and correct it (as it would in a perceived obstructive event), or sense it and attempt to correct it but then stop (as it would in a perceived central event)?

Some simple questions re this ...

What CPAP or AUTO machine do you have that can detect that you have stopped breathing and correct it ?

How does 'this' CPAP or AUTO machine correct stopped breathing ?

What CPAP or AUTO machine can correct centrals ?, how ?

Cheers

DSM

(It is very easy to assume some machines do more than they are capable of )

_________________

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

dsm wrote:What CPAP or AUTO machine do you have that can detect that you have stopped breathing and correct it ?

How does 'this' CPAP or AUTO machine correct stopped breathing ?

What CPAP or AUTO machine can correct centrals ?, how ?

I'm not %100 certain, so it's important to confirm with ones provider, but the BiPAP ST is one of the few that's actually used for Central Sleep Apnea.

I don't think that CPAP or APAP is perscribed for a sufferer of CSA at this time.

RestInSeattle wrote:

dsm wrote:What CPAP or AUTO machine do you have that can detect that you have stopped breathing and correct it ?

How does 'this' CPAP or AUTO machine correct stopped breathing ?

What CPAP or AUTO machine can correct centrals ?, how ?

I'm not %100 certain, so it's important to confirm with ones provider, but the BiPAP ST is one of the few that's actually used for Central Sleep Apnea.

I don't think that CPAP or APAP is perscribed for a sufferer of CSA at this time.

dsm wrote:What CPAP or AUTO machine do you have that can detect that you have stopped breathing and correct it ?

All modern apaps with flow sensors. That's why so many on this board are such strong proponents of apap therapy. Apaps are able to detect obstructive apneas.

dsm wrote:How does 'this' CPAP or AUTO machine correct stopped breathing ?

An apap increases the pressure to open the airway. Again, this is one of the main reasons we advocate for apaps. In addition, not only are apaps able to react to and clear our obstructive apneas, they are able to prevent them quite successfully too.

dsm wrote:What CPAP or AUTO machine can correct centrals ?, how ?

I did not say a CPAP or AUTO could correct centrals. I said it would stop the attempt to correct a perceived central:

Stopping breathing, on the other hand, is not normal. I agree with ehusen, it is disappointing to hear dsm's machines did not sense he had stopped breathing -as reported by his wife. But how do we know the machine did not sense it and correct it (as it would in a perceived obstructive event), or sense it and attempt to correct it but then stop (as it would in a perceived central event)?

Prior to receiving treatment, many of us diagnosed with OSA experienced the classic sign of stopping breathing throughout the night, which was of great concern to our sleep partners. With apap treatment, if an obstructive event is perceived, the pressure is raised to open the airway. This is why we are now able to breathe again. Our obstructive apnea is being treated.

If the raised pressure does not succeed in opening the airway, a series of additional attempts are made until it is determined this is a perceived central event, at which point the attempt stops.

In the interview with Respironics Product Managers: Jeff Maglin, Product Manager, CPAP, C-Flex and Humidification and Shawn Trautman, Product Manager, REMstar Auto and Encore Pro wrote: The REMstar Auto algorithm looks for apnea’s that are non-responsive to treatment which could indicate that these are central events. At any pressure 8 cm H2O or higher we will make three pressure increases in response to a sustained string of events. If there is no improvement after the third increase, indicated by the persistence of events, the pressure is dropped 2 cm and a constant pressure is held for several minutes. If there is snoring noted during this period of constant pressure, which would indicate obstruction, we will increase pressure and reset the non-responsive treatment, thus allowing for three more pressure increases. Apneas can potentially be treated up to the device's maximum pressure setting (20 cm H2O).

I hope this has adequately answered your questions. I believe it points to the fact that apap therapy is quite effective at treating OSA.

KLM,

This is no big deal. No AUTO or CPAP can make you breath again if you stop breathing & that was where this thread started and what I was trying to bring home to you. We all know that AUTOs & CPAP address OSA.

Just try this simple experiment - stop breathing while on your xPAP & see what happens. - Nothing. But if you had a BiPap with T it should, after a short period of time switch from EPAP to IPAP and that has the effect in most cases of kicking off breathing again.

Go back and read the original posts and my post where I highlight your words. I was just pointing out that my Remstar AUTO & Resmed AUTO could not fix me stopping breathing. They can up the pressure as much as they like. It is the kick from a BiLevel that has the required mechanism to get people breathing again.

Cheers

Doug

dsm, when you said "stopped breathing", did you perhaps have in mind, "was making no effort to breathe"? Just wondered, because either situation - obstructive apnea or central apnea - could make a person stop breathing.

An obstructive apnea can certainly make a person stop breathing even though he or she is still making an effort to breathe. The effort wouldn't have to be massive heaving and thrashing. The effort could be so subtle that even an astute observer could have difficulty seeing it. That's why they use belts around the chest and abdomen during PSG sleep studies to track respiratory effort. And even the belts can be fallible if they loosen too much or slip.

dsm, in your PSG sleep study, do you recall what the breakdown was in your diagnostic results? The separate index for central apneas vs obstructive apneas?

dsm wrote:KLM,

This is no big deal. No AUTO or CPAP can make you breath again if you stop breathing & that was where this thread started and what I was trying to bring home to you.

On this point, we shall have to agree to disagree.


I would reiterate,

Prior to receiving treatment, many of us diagnosed with OSA experienced the classic sign of stopping breathing throughout the night, which was of great concern to our sleep partners. With apap treatment, if an obstructive event is perceived, the pressure is raised to open the airway. This is why we are now able to breathe again. Our obstructive apnea is being treated.

In your post, to which I originally responded, you wrote:

dsm wrote:Some of us appear to be luckier than other in regard to what our partner observes. It may be that some of us just have more astute partners.

Mine will tell me if my breathing patterns change markedly (she is a light sleeper).

She will tell me if I stop or slow my breathing. It was her feedback that I was able to map against the data from my Remstar AUTO and my ResMed spirit AUTO that prompted me to move to a BiLevel. - When I had my AUTOs she commented that after a the initial few months she was observing me slowing & stopping my breathing again. I only got the corroborative evidence from one of these machines.

I attribute my wife's observations as the reason I learned not to trust the snore index of one brand and also to question the veracity of other data it reported. Not many people actually get the opportunity to compare the results from different machines in similar periods & thus can be lulled into thinking the data from their machine is scientific when it is nowhere near so.

There has been a tendency here for some folk to regard the data from their particular machine as a new gospel written by a higher authority and ready to be added to the good book when in fact there is very strong evidence that what some machines report is unique to those machines & that in fact other machine may tell an entirely different story.

My interpretation of your words was that you were issuing a general warning of sorts; implying certain apaps are ineffective at treating OSA, the data supplied by certain apaps is inaccurate, and even that visual observations were more accurate than software data. Ehusen's response indicated he made that same interpretation:

ehusen wrote:Hmmm, I dont' like hearing that the detections algorithms for APAP machines may "not be that great". It concerns me to hear that. For many of us, we only get one machine to use and we have to hope that it is effective in doing its job.

My original response was based upon that interpretation.

Now, however, if I am understanding you correctly, I believe what you are now saying is you do not have OSA, but Central Sleep Apnea. I'm not familiar with your history and PSG results. Did you exhibit centrals and receive a diagnosis of CSA? It is my understanding a bi-level machine is more appropriately prescribed for CSA, so it is not at all surprising you find your current machine more to your liking.

But I think it is very important to make the distinction that your case is not OSA, but rather CSA. Apaps are not necessarily effective in treating CSA (as they have proven to be in treating OSA). So I would caution anyone against worrying the different apaps' algorithms may not be that great. The more correct statement would be that apaps aren't that great for treating DSM's Central Sleep Apnea.

rested gal wrote:dsm, when you said "stopped breathing", did you perhaps have in mind, "was making no effort to breathe"? Just wondered, because either situation - obstructive apnea or central apnea - could make a person stop breathing.

An obstructive apnea can certainly make a person stop breathing even though he or she is still making an effort to breathe. The effort wouldn't have to be massive heaving and thrashing. The effort could be so subtle that even an astute observer could have difficulty seeing it. That's why they use belts around the chest and abdomen during PSG sleep studies to track respiratory effort. And even the belts can be fallible if they loosen too much or slip.

dsm, in your PSG sleep study, do you recall what the breakdown was in your diagnostic results? The separate index for central apneas vs obstructive apneas?

RG,

My study showed *no* centrals. This was a topic I took up with my contact at the sleep clinic and one I still plan to review with my original sleep specialist.

I now believe that sleep studies are merely a guide to SA OSA problems & may not expose all conditions such as those among us who may have mixed SA (centrals & obstuctive).

Cheers

DSM

KLM wrote: <snip>
On this point, we shall have to agree to disagree.
<snip>

I agree.

Cheers

DSM

dsm wrote:I now believe that sleep studies are merely a guide to SA OSA problems . . .

Amen, a point sorely missed by most of the medical community. They act on the results of a single sleep study as if it were gospel come down from the mountain and written in stone.

I feel the need for a new thread on this topic. Just wish I had time to start it now.

Regards,
Bill

Just try this simple experiment - stop breathing while on your xPAP & see what happens. - Nothing.

For an AutoPAP the "settling period" must have already expired before it will respond to absence of inspiration. By contrast the BiLevel has no settling period by design and will immediately cycle. It's a valid experiment for any BiLevel yet it's an invalid experiment for any and all AutoPAP machines unless the "settling period" criteria has been met. For some AutoPAP machines time alone defines settling period, for others the number of sequential breaths factor in.

Hope this helps.

DSM,
Now that all the pieces of the puzzle have been presented, I believe I understand your thinking regarding Mixed Apnea. However, since we've learned you weren't diagnosed with CSA or Mixed Apnea and, in fact, did not have a single central apnea event during your PSG, wouldn't it be logical to assume the stopped breathing your wife observes is caused by obstructive apnea, not central apnea? Both OSA and CSA cause your body to stop breathing during sleep, but for different reasons. I don't understand your assumption that, in your case, this is the result of CSA or Mixed Apnea and not the result of your clinically diagnosed OSA.

It is possible your self-diagnosis of Mixed Apnea may have missed the mark. As the previous post explains, the experiment you performed with your apap was invalid. Also, relying on your wife's observations as evidence of central apnea is invalid, since it is not always humanly possible to visually differentiate between stopped breathing which results from obstructive apnea vs. central apnea. In addition, your assertion the apap data was inaccurate because it did not corroborate your hypothesis of central or mixed apnea is problematic because, in fact, all evidence points to the likelihood it is your hypothesis which may be inaccurate. It reminds me of the old saying: if it looks like a duck, walks like a duck and quacks like a duck; it's a duck.

A new PSG is paramount. If indeed you have Mixed Apnea to the degree that you require a bi-level machine with timed backup in order to continue breathing throughout the night, you should also schedule a complete neurological workup as soon as possible. This is serious business. Do not wait.

Just as it is important to educate readers that OSA and CSA are different in their etiologies and treatments, it is equally important to educate readers that having central apnea events is not synonymous with having Central Sleep Apnea or Mixed Apnea.

There are a number of reasons that a person may have a “central apnea” during sleep. Central apneas occur when there is no effort to breathe (no movement of the chest or abdomen). Most of the time these central apneas—not to be confused with central sleep apnea—are normal hysiologic events.They often occur after we sigh or when we take a larger than normal breath and lower the level of carbon dioxide in our blood.They are more apparent when we are sleeping because there are fewer overriding factors controlling breathing when we sleep.We frequently see central apneas in the period of transition between being awake and being asleep, either when you first fall asleep or after any awakening during the night. It would not be unusual for you or your wife to notice apneas at these times. In central sleep apnea, an uncommon form of sleep apnea most often seen in individuals with heart failure or stroke, the central apneas occur frequently throughout the night. In addition, there are some individuals who have what is termed “idiopathic central sleep apnea” because their breathing center is overly sensitive to slight changes in carbon dioxide in their blood.
If you are sleeping well and are not sleepy during the day, and if your “apneas” occur only occasionally, it is unlikely that you have anything to worry about. If you have any concerns, however, you should follow up with your sleep specialist.

Kathe Henke, Ph.D.,A.B.S.M.,
Sleep Disorders Center of Virginia,
Richmond,Virginia

Anonymous wrote:

Just try this simple experiment - stop breathing while on your xPAP & see what happens. - Nothing.

For an AutoPAP the "settling period" must have already expired before it will respond to absence of inspiration. By contrast the BiLevel has no settling period by design and will immediately cycle. It's a valid experiment for any BiLevel yet it's an invalid experiment for any and all AutoPAP machines unless the "settling period" criteria has been met. For some AutoPAP machines time alone defines settling period, for others the number of sequential breaths factor in.

Hope this helps.

I have a BiLevel that does nothing if I exhale slowly & hold, in fact all the BiLevels I have will behave this way in S mode.

Bilevels operating in T mode are the only xPAPs I am aware of that have a mechanism that having detected stopped flow (and after a short period - 4 secs on my PB330) will kick over to IPAP and use that flip to try and get the user breathing again.

An AUTO does not have that 'kick' capability !. The best an AUTO can do is to try to prevent the situation occuring but all it can prevent from occuring is a blockage not a central.

DSM

_________________

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

_________________

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

_________________

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