Back from the Sleep Doc - VPAP Adapt SV

I believe some folk have tried USB serial replacements but I steer clear of them as if they don't work as hoped they are massive time wasters. They really are a case of suck-it-and-see testing.

Re ResLink, it records more data than tha base machine so yes you can do without it but the data is nowjhere near as granular as what comes off the ResLink SM card.

DSM

dsm wrote: If you can locate a ResLink, they used to go for about $200 if you knew where to get one. ...

BUT, both of these Reslinks use a stock standard SM card (Smart Media) which can be read by any el cheapo ($10 from Amazon),reader.

Thanks DSM! I may have a line on a ResLink, I will know more about that after Saturday.

It is **great** that they went with a standard card and reader! That brings the total cost down. I hate all of the proprietary stuff!

Thanks too for the heads up on the oximeter. I was looking at that right away. Too bad they only support that one $600 unit, which isn't as good as a $120 one ... it would be nice to have all of the data together in one place! Open architecture folks ....

It sure is confusing to try to piece all of this together on the ResMed web site. Once the machine is here I am sure it will all make more sense. But first - who cares about the data - maybe I can sleep! Yeah!

Looks like I will probably get a Respironics ASV through insurance eventually.

This is an odd question, but ... Will using the ResMed, and having a few good nights sleep, and getting my pain levels down, interfere with the results of my ASV titration sleep study in a few days?

I'd hate to sleep so much better that it doesn't look like I need an ASV, only because I have already paid for one myself, and then not have my insurance cover it! Does that make sense? I think some of my centrals are from my chronic pain, which leads to more arousals. And the pain is partly from my Complex sleep apnea. Viscous circle!

Not that I could make myself suffer with the machine sitting here, even for a few more days!

Best, Michael

unadog wrote:

dsm wrote: If you can locate a ResLink, they used to go for about $200 if you knew where to get one. ...

BUT, both of these Reslinks use a stock standard SM card (Smart Media) which can be read by any el cheapo ($10 from Amazon),reader.

Thanks DSM! I may have a line on a ResLink, I will know more about that after Saturday.

It is **great** that they went with a standard card and reader! That brings the total cost down. I hate all of the proprietary stuff!

Thanks too for the heads up on the oximeter. I was looking at that right away. Too bad they only support that one $600 unit, which isn't as good as a $120 one ... it would be nice to have all of the data together in one place! Open architecture folks ....

It sure is confusing to try to piece all of this together on the ResMed web site. Once the machine is here I am sure it will all make more sense. But first - who cares about the data - maybe I can sleep! Yeah!

Looks like I will probably get a Respironics ASV through insurance eventually.

This is an odd question, but ... Will using the ResMed, and having a few good nights sleep, and getting my pain levels down, interfere with the results of my ASV titration sleep study in a few days?

I'd hate to sleep so much better that it doesn't look like I need an ASV, only because I have already paid for one myself, and then not have my insurance cover it! Does that make sense? I think some of my centrals are from my chronic pain, which leads to more arousals. And the pain is partly from my Complex sleep apnea. Viscous circle!

Not that I could make myself suffer with the machine sitting here, even for a few more days!

Best, Michael

Michael,
As best as I can tell, if the sleep clinic does a really good in depth eval, the way you breathe will be consistent.

But, I also say that in 3 sleep studies that I did, not one, (any) I did said anything other than OSA at 40 events per hr yet cpap & auto do very little for me whereas Vpap Adapt SV changes things significantly (providing I have a good f/f mask with a new seal & new straps). So I kind of think that the clinic (back in 2007) was not as up to date as they may be now in regard to CompSA. I know I have centrals when on therapy.

Cheers

DSM

Still a little confused about SV.
Neither of the current machines out actually detects centrals, right? So does the machine automatically assume they are all centrals? Does the 10cm H2O rule still hold for treating apneas on the SV-style machines?

What makes this type of machine better than using a rebreather mask with, say, the S9?

dsm wrote: As best as I can tell, if the sleep clinic does a really good in depth eval, the way you breathe will be consistent.

But, I also say that in 3 sleep studies that I did, not one, (any) I did said anything other than OSA at 40 events per hr yet cpap & auto do very little for me whereas Vpap Adapt SV changes things significantly (providing I have a good f/f mask with a new seal & new straps). So I kind of think that the clinic (back in 2007) was not as up to date as they may be now in regard to CompSA. I know I have centrals when on therapy.

I had mostly centrals on my titration study (below.) Because I was on pain meds, the doctors were unsure whether it was from the meds, or were classic CompSA. And if the latter, of course, the question was whether it was transitory and would clear up with time. Hence the 4 month wait ....

I guess now that I have this machine it doesn't matter as much whether it shows up on the sleep study. But I would like to get a Bipap Auto SV, and I would like insurance company and doctor support and understanding of what is really going on.

I could tell just from how I felt over the past few months that I still had **major** sleeping issues. I spent 3 months on CPAP and had some improvement in memory, etc., which I would estimate now at about 15%. After starting Bipap, I had more improvement, which I would put at 40%. Closer to being a **real** human!

I slept 10 hours last night, which is great! So I am very hopeful. I could feel teh tightness in my head, troat, and chest unwinding a bit during teh night. But I also had bad leaks from the mask during the night, which makes the data hard to read. (I have the machine hooked up via serial cable. I stil have to find a ResLink.) The mask is a Quattro Mirage Full Face. Unfortunately, the cushions are a couple of moths old, the mask and headstrap are 4 months old.

I just got a new Activa LT, any hope that that would work better? I did have soem mouth breathing, woke up during the night with my mouth very dry! I never had that problem at all on my Respironics. I will have to find my chin strap.

Pressures were up to 25 at times. My base EEP is set at 9.4, that is about where my Bipap averaged for EPAP. I left the defaults on for PS, minimum 3.0 and maximum 15.0 No apneas, hypopneas were about 3.5 if the data is to be trusted.

Thx! Michael

DreamDiver wrote:... Still a little confused about SV. ... Neither of the current machines out actually detects centrals, right? ...

I think the Respironics does now detect at least non-responsive apneas.

DreamDiver wrote:... So does the machine automatically assume they are all centrals? Does the 10cm H2O rule still hold for treating apneas on the SV-style machines? ...

Remember, the primary market was for those patients with periodic breathnig and central apneas. It turns out that ComplexSA also includes a central apnea component. So, that part of the complex sleep apnea it treats as a central apnea.

In essence the machine helps breathe for you when you are not. It's not full ventilation. But it's a lot closer that CPAP or BiPAP. In short, what researchers found is that if they support the breathing when the body does not, it returns to normal respiration after that.

DreamDiver wrote:... What makes this type of machine better than using a rebreather mask with, say, the S9? ...

The actual ventilation support it provides.

DreamDiver wrote:Still a little confused about SV.
Neither of the current machines out actually detects centrals, right? So does the machine automatically assume they are all centrals? Does the 10cm H2O rule still hold for treating apneas on the SV-style machines?

What makes this type of machine better than using a rebreather mask with, say, the S9?

The brands of SV that do detect centrals do so for different reasons.

1) The Weinmann SOMMNOvent CR detects the difference between obstructions & centrals but it is not for sale in the US (it can raise its eepap pressure in response to OSA & uses a unique pressure support approach to apply SV pressure support.

2) The enhanced Bipap Auto SV detects obstructions and can raise the epap pressure in response, it can also detetct open airway apneas

3) The Vpap Adapt SV assumes the EEP (epap) pressure has been set to deal with obstructive apneas & it treats all others as centrals but because it tracks volume, it responds to centrals well before they get a hold so it becomes moot.

DSM

unadog wrote:... But, I also say that in 3 sleep studies that I did, not one, (any) I did said anything other than OSA ... I had mostly centrals on my titration study (below.) ...

They may not have focused on it, but it appears (at least from the numbers you posted, you had plenty of central apneas. Typically doctors will try to see if it clears up on its own without intervention. It sometimes does.

But this time around, it will NOT make any difference if you use an ASV unit prior to the study or not. They just want to get the right pressure for you. So, it will be a titration to the ASV unit, not to CPAP or BiPAP.

Better sleep a few days before might mean you won't have as many central apneas. No sweat. They want to titrate you for the obstruction. The ASV mode will handle the central events. They want to be certain the highest pressure is not a problem and that the low pressure clears your obstructions.

And as I just noted to DreamDiver, the ASV units do take some adjustment. They take over breathing when you don't breathe. It takes a while to get used to the machine doing that. You will feel "out of synch" with the unit for a while. Give it time. The good sleep can be wonderful.

Hope it goes well for you!

dsm wrote:The brands of SV that do detect centrals do so for different reasons.

1) The Weinmann SOMMNOvent CR detects the difference between obstructions & centrals but it is not for sale in the US (it can raise its eepap pressure in response to OSA & uses a unique pressure support approach to apply SV pressure support.

2) The enhanced Bipap Auto SV detects obstructions and can raise the epap pressure in response, it can also detetct open airway apneas

3) The Vpap Adapt SV assumes the EEP (epap) pressure has been set to deal with obstructive apneas & it treats all others as centrals but because it tracks volume, it responds to centrals well before they get a hold so it becomes moot.

DSM

JohnBFisher wrote:They take over breathing when you don't breathe. It takes a while to get used to the machine doing that.

But this is what makes me confused: The need for servo ventillation provides muscular assistance for something that is for me an entirely neurological disorder. If the neurological disorder is better cured with a rebreather mask, it seems to me like SV is the wrong method. In fact, it sounds counterproductive. Instead of introducing the proper balance of O2 and CO2 that will make me breathe for myself, we're forcing more O2 into the system. Technically, all this should do is cause further CO2 retention, causing further depression of the nervous system. All it will do is make me more dependent on servo ventillation. I don't get it. Am I wrong here? I just don't get it.

I think the assumption that all centrals are caused by CO2 levels may not be correct. Based on my reading, I think the cause of centrals is very much up in the air. Some may be caused by delayed CO2 readings, some by arousal, etc.

But if the CO2 reading is delayed, it doesn't reflect what the body needs right now either. And that is going to lead to a crisis - a startled arousal followed by a deep breath - further down the line, as the body reacts (overreacts) to something it failed to catch earlier becauser it was behind - the need to breath! And that crisis can be avoided by getting the body to breath now even though it hasn't recognized that it is needed yet. Dampening out the pendulum swings before they propagate ...

So there may be a few cases of accurate CO2 readings, where the body really doesn't need to breathe, that don't require a machine response. But what proportion is that? Hard for the machine to tell. And what are the negative consequences of the machine initiating a breath, versus what we already have - no breath, and fragmented sleep? So all you really need to know to start is that making the body breath - on about the same schedule (BPM) and same volume - prevents bad things (arousals and desats.)

So then the machines are trying to deal with two side effects of centrals, without worrying about causation. One is arousals that fragment sleep and prevent you from reaching deeper stages of sleep, which has profound negative consequences. The other is desats, which may also be part of the problem with arousals, but also can lead to damage in their own right (peripheral nerve damage, etc.)

And the machines are looking at what your body is doing on a breath by breath basis. Then they are pumping in oxygen to keep the body on an "even keel", so that sleep can continue through these events that would otherwise shock you awake.

The algorythms that detect centrals were apparently developed as part of what they learned through developing the SV machines. They are going beyond what the usual CPAP machines did in the past to incorporate SV-type observation of multiple parameters - volumes, waveforms, etc.

The implementation in those units, like the S9, seems to be more a function of when the machines were refreshed. The new SV machines are sure to incorporate the updated algorythms that are already released in the S9, etc. But monitoring and treating on a per breath basis was in place in the SV's before everything was fully named and documented in the reporting software.

Anyway, that is my partial take on this. My logic used to be steller years ago. Now it takes me days to think through all the details, and I often find mistakes. Finally realized recently why something happened 3-4 years ago - so I'll get back to you on this!

DreamDiver wrote:... If the neurological disorder is better cured with a rebreather mask, it seems to me like SV is the wrong method. In fact, it sounds counterproductive. ...

Here are links to some of the studies on Adaptive Servo-Ventilation. Following the links, I also include the appropriate excerpts.

Here's some Adaptive Servo-Ventilation articles:

Efficacy of Adaptive Servoventilation in Treatment of Complex and Central Sleep Apnea Syndromes
http://chestjournal.chestpubs.org/conte ... l.pdf+html

Adaptive Servoventilation (ASV) in Patients with Sleep Disordered Breathing Associated with Chronic Opioid Medications for Non-Malignant Pain
http://www.ncbi.nlm.nih.gov/pmc/article ... .4.311.pdf

There are numerous factors which may induce periodic breathing (CSR), but the critical factor leading to central apnea is the gap between eucapnia and the hypocapnic threshold. Depending upon the position and slope of the individual’s ventilatory response to CO2 and his or her set point for apnea, relatively modest changes in ventilation can reduce the PaCO2 below the apneic threshold, thereby inhibiting ventilation until the accumulation of CO2 is sufficient to stimulate respiratory neurons. That is, a narrow difference or gap between the prevailing CO2 during normal ventilation and the apneic threshold increases ones susceptibility to central apneas. It is possible to widen the gap either by manipulating the hypocapnic threshold itself or by increasing the PaCO2. Adaptive servoventilation machines track the patient’s breathing pattern and, using an internal algorithm, adjust breath-by-breath inspiratory pressure
support to maintain a slightly reduced minute ventilation to prevent periodic hyperventilation and episodic hypocapnia. Thus, the breathing pattern is stabilized and central apneas are prevented. It seems that ASV might function optimally when there is a more or less regular “predictable” respiratory pattern
which can be used by the machine to track ventilation and then to drive the bilevel device.

Adaptive servo-ventilation and deadspace: effects on central sleep apnoea
http://www.sciencesleep.org/ziliao/Adap ... apnoea.pdf

Work by Teschler et al. (2001) has shown adaptive pressure support servo-ventilation (ASV) to be more effective in treating CSA than CPAP, bi-level positive pressure support and supplemental O2 in a group of patients with CHF. ASV provides a varying amount of ventilatory support that acts directly to stabilise ventilation with the aim of improving sleep architecture and sleep quality. It provides a background level of expiratory positive airway pressure (EPAP) to which a variable amount of inspiratory pressure support (IPAP) is added. The pressure support (IPAP-EPAP) applied varies from 4 to 10 cmH2O depending on the subjects ventilatory effort. If effort is reduced, ventilatory support is increased and when effort is increased, ventilatory support is reduced. It is the only form of ventilatory support that is specifically designed to maintain ventilation at 90% of the patient’s own long-term average ventilation and hence decrease the likelihood of hyperventilation (Teschler et al., 2001).
:
It is thought that raising FiCO2 stabilizes ventilation by keeping PaCO2 above the apnoeic threshold leading to improvements in sleep quality. However, Andreas et al. (1998) reported that despite reductions in AHI using both supplemental O2 and CO2, sleep quality remained poor and sympathetic activation as measured by plasma noradrenalin was high. Indeed, increasing CO2 has been shown to cause arousal through its effect on increasing ventilatory effort
(Gleeson et al., 1990). Ayas et al. (2000) have demonstrated that hypercapnia alone can induce arousal from sleep in the absence of changes in mechanoreceptor activity. Based on these observations, the effect of increasing the level of inspired CO2 on sleep architecture remains unclear.

A Randomised Controlled Trial of Adaptive Ventilation for Cheyne-Stokes Breathing in Heart Failure
http://ajrccm.atsjournals.org/cgi/repri ... 2-1476OCv1

Adaptive Servo-Ventilation in Patients With Idiopathic Cheyne-Stokes Breathing
http://www.aasmnet.org/JCSM/Articles/020212.pdf

Adaptive Servoventilation Versus Noninvasive Positive Pressure Ventilation For Central, Mixed, And Complex Sleep Apnea Syndromes
http://www.resmed.net/us/documents/Morg ... ilevel.pdf

unadog wrote:... I think the assumption that all centrals are caused by CO2 levels may not be correct. ...

Even when it is correct, there is a growing body of evidence that the ASV mode of treatement is more effective than use of increased CO2. Studies show that the use of CO2 tends to lead to less effective sleep than an ASV unit.

To some extent we can compare this to quantum mechanics. It's not really clear WHY it works this way, but it IS CLEAR that it DOES work. Of course, in this case, I think researchers are much closer to a deeper and complete understanding of the mechanisms involved.

Regardless, the evidence shows that ASV is more effective. So, when in doubt, go with what has been shown to work.

Hope that helps.

JohnBFisher wrote:

unadog wrote:... I think the assumption that all centrals are caused by CO2 levels may not be correct. ...

Even when it is correct, there is a growing body of evidence that the ASV mode of treatement is more effective than use of increased CO2. Studies show that the use of CO2 tends to lead to less effective sleep than an ASV unit.

To some extent we can compare this to quantum mechanics. It's not really clear WHY it works this way, but it IS CLEAR that it DOES work. Of course, in this case, I think researchers are much closer to a deeper and complete understanding of the mechanisms involved.

Regardless, the evidence shows that ASV is more effective. So, when in doubt, go with what has been shown to work.

Hope that helps.

A-men

I believe John has covered all aspects very well with those links. The last one is probably most specific to the discussion here.

As I understand it, part of what the ASV algorithm seeks to achieve is a balance between hyopventilation & hyperventilation. If it can smooth those aspects of breathing out then the PaCO2 tends to remain in acceptable range. (Muffy posted a very simple but very accurate chart that shows this balancing act (see below)). With out ASV to regulate flow, there is the tendency for some people with CO2 imbalance complications, to overshoot and then bounce, then overshoot then bounce etc: etc: .

viewtopic.php?f=1&t=46945&p=442237&hili ... in#p442237

DSM

PS, As best as I understand, the bulk of people suitable for using xPAP therapy can be impacted by PaCO2 being at incorrect levels. Someone who isn't may be a case for other therapy or a mix of xPAP & other. A yawn triggers a very quick PaCO2 imbalance that gets corrected immediately by a hypopnea or central apnea (which is the body's mechanism for quickly lifting the PaCO2 level back to normal).

Turning over in sleep - same. Going back to sleep after an arousal from sleep - same.

What gets interesting though, is in REM sleep that some people are otherwise in balance can get out of whack (PaCO2) whereas some other folk who have Periodic Breathing get into REM & the PB goes away ?. Very tricky.

D

JohnB, unadog, DSM

You guys are the tops. Thank you. Along with the articles (where I could understand them) and the chart explanation by Muffy, I think I'm beginning to get it. There are so very many variables with Periodic Breathing and Central Apnea and how they might each be best controlled under such variable circumstances that it's just smoother and easier to regulate the physical systems than the neurological systems. In the end, a better night's sleep is achieved. Brain, kidneys, hearts and lungs are spared further injury. Am I getting the gist?

DreamDiver wrote:JohnB, unadog, DSM

You guys are the tops. Thank you. Along with the articles (where I could understand them) and the chart explanation by Muffy, I think I'm beginning to get it. There are so very many variables with Periodic Breathing and Central Apnea and how they might each be best controlled under such variable circumstances that it's just smoother and easier to regulate the physical systems than the neurological systems. In the end, a better night's sleep is achieved. Brain, kidneys, hearts and lungs are spared further injury. Am I getting the gist?

DreamDiver - I sure hope so - took me years & years to kind of hang the core parts together & I only hope, enough to make sense

Cheers

DSM

PS that label PcrCO2 = (IIRC) Patient ChemoReceptor CO2 (as distict from PaCO2 = Patient Arterial CO2) - the Muffy chart highlights the potential
for overshoot should the PaCO2 level be delayed (slow blood flow etc: ) which creates a delay in letting the ChemoReceptors in the brain area know that
CO2 is ok or too high or too low, but if there is that lag, then the brain is already ramping up an overreaction one way or the other).