Philips Respironics Launches BiPAP autoSV Advanced Sleep Sys

[dsm]

It works as I always understood it did but the point I was making is that that mode of working raises in my mind issues as to the value of shifting the whole SV pressure range up and down with epap.

Epap is addressing OSA events by stenting the airway. To hang both bilevel pressure variance and SV pressure variance off a fluctuating epap just looks like it will create problems for anyone who gets used to particular pressure ranges.

Here's how I understand the system:
It is called BIPAP because it is capable of supplying 2 kinds of pressure, one for inhale (IPAP) one for exhale (EPAP).
It varies EPAP automatically based on the improved auto algorithm (used in the PR1) and its aim is to keep the airway patent -- avoid obstructions (As though a person were using an APAP).
The machine also varies IPAP -- however it uses only the SV algorith to do that, not the Auto algorithm.
No matter what the EPAP a person needs, SV will be taking care of the inhale pressure. There can be a minimal SV response, and it has a range up to a maximal SV response. There is no "non-SV" IPAP variablilty. All inhale pressure changes are a result of the SV algorithm.

http://bipapautosvadvanced.respironics.com/

A smart blend of advanced technologies
BiPAP autoSV Advanced has at its core the clinically-proven 1, 2 REMstar Auto algorithm. Utilizing a blend of advanced Respironics technologies (Digital Auto-Trak and REMstar Auto titration algorithm plus auto EPAP) the device is uniquely able to continually and effectively manage the patient's airway. Our proven servo ventilation algorithm then works to assure that with each and every breath, the patient is appropriately ventilated.

If you look at the Prescripton Conversion Guide you'll find that the new machine doesn't even seem to have an IPAP definition at all. Everything is defined in PS terminology - how inhale pressure is supported after obsturctions have been solved by the auto.

Ozij,

Am not really sure what your point is - You are agreeing that the whole SV box & dice 'floats' with the 'floating' epap (aren't you ?).

I was saying that if someone sets EpapMin to say 4 CMs and EpapMax to say 10 CMs and also has PSMin=3 (which adds 3 CMs on top of the active Epap to deliver Ipap (initially at 7 Cms) and has SV activated say PSMax=12) which adds further potential SV pressure on to Ipap (t max 16 CMs) which is a range of 9 CMs to respond to SV events, BUT SAY THIS PERSON NORMALLY NEEDS Epap=10 because of their OSA, then this scenario will be a recipe for trouble just as setting a CpapAuto to min=4 max=20. At least in a CpapAuto there is only the one pressure. But with a Bipap Auto SV advanced there are now 3 fluctuating pressure ranges & 2 of them (the bilevel component & the SV component) float (tied by PSMin) with the third one which is epap.

We have been through the mess with CpapAuto that 4-20 'open' settings created. Now we are seeing that same mess emerging when someone naivly believes that setting their Bipap Auto SV Adv to EpapMin=4 or 5 or therabouts, will solve all their problems because the 'auto' will adjust as needed.

I now fear that the settings on this machine are so variable and so complex that no one really understands them, or the repercussions anymore. I postulate that this thread is a reasonable proof of this.

It is a worry.

Cheers

DSM

[-SWS]

the point I was making is that that mode of working raises in my mind issues as to the value of shifting the whole SV pressure range up and down with epap.

Well, in theory the entire static-pressure shift up or shift down is required to offset increases and decreases in airway resistance. If the algorithm does that well, then it's basically a zero-sum game that nicely balances.

Epap is addressing OSA events by stenting the airway. To hang both bilevel pressure variance and SV pressure variance off a fluctuating epap just looks like it will create problems for anyone who gets used to particular pressure ranges.

Intuitive reasoning that just might be right or just might be wrong IMO. However, intuitive reasoning can easily be deceptive for all of us when we analyze new technology. Recall what you thought about CPAP+SV modality when Respironics first introduced it. That also looked like it should create problems. And to this day, CPAP mode is the Respironics recommended base modality for their SV machines. Extremely counter-intuitive... and this reasoned assumption might be equally counter-intuitive.

The other question in my mind is why does Ipap & SV pressure ranging have to depend on a floating epap ?.

I think in theory it has to do with floating EPAP used to offset variable airway resistance----leaving the IPAP/EPAP transition itself for ventilatory assistance, based on that pressure wave's leading edge even more than the peak magnitude (which is only relative to the magnitude of the EPAP static-pressure bias anyway).

I believe the SOMMNOVent CR isolates the SV support from the floating epap by introducing an eepap & IIRC it is the eepap that deals with OSA while the normal epap/ipap respond as bilevel (if activated) & SV (when activated) and this ranging does not 'float' with eepap on that machine.

Different machine, different algorithm, different patent protection, and even different physics with that tail-end eepap.

I would suspect that 'floating' bilevel & SV ranging is not a good idea ? - leaving epap to float on its own seems like the smarter & safer choice.

You know "reasoning's" track record on this message board: many times right and many times wrong.

What triggered this line of thinking was when banned suggested setting MinEpap to 5 & that kind of horrified me because it meant all the above pressures would be (in that example) 4 CMs below where they previously were. Then when I thought about the consequences, it reminded me of the battle we went through to alert people to NOT set their Autos to 4 CMs & 20 CMs in the naive belief the Auto algorithm would always zap in and fix things.

I fear we are heading down that path again with that floating epap & people suggesting it be set around the 4-5 mark. !

I agree this is a caveat to be on the lookout for. We don't yet know how well or how poorly this new algorithm will automatically adjust EPAP to address varying airway resistance (obstructive FL/H/A). On the flip side, setting too high of an EPAP min will exacerbate CompSAS/CSDB in some patients. There is plenty of room for error in either direction IMHO.

Caution is warranted. So is working with a knowledgeable clinician.

[dsm]

the point I was making is that that mode of working raises in my mind issues as to the value of shifting the whole SV pressure range up and down with epap.

Well, in theory the entire static-pressure shift up or shift down is required to offset increases and decreases in airway resistance. If the algorithm does that well, then it's basically a zero-sum game that nicely balances.

Epap is addressing OSA events by stenting the airway. To hang both bilevel pressure variance and SV pressure variance off a fluctuating epap just looks like it will create problems for anyone who gets used to particular pressure ranges.

Intuitive reasoning that just might be right or just might be wrong IMO. However, intuitive reasoning can easily be deceptive for all of us when we analyze new technology. Recall what you thought about CPAP+SV modality when Respironics first introduced it. That also looked like it should create problems. And to this day, CPAP mode is the Respironics recommended base modality for their SV machines. Extremely counter-intuitive... and this reasoned assumption might be equally counter-intuitive.

The other question in my mind is why does Ipap & SV pressure ranging have to depend on a floating epap ?.

I think in theory it has to do with floating EPAP used to offset and variable airway resistance----leaving the IPAP/EPAP transition itself for ventilation assistance, based on the pressure wave's leading edge more than the peak magnitude (which is only relative to the magnitude of the EPAP static-pressure bias anyway).

I believe the SOMMNOVent CR isolates the SV support from the floating epap by introducing an eepap & IIRC it is the eepap that deals with OSA while the normal epap/ipap respond as bilevel (if activated) & SV (when activated) and this ranging does not 'float' with eepap on that machine.

Different machine, different algorithm, different patent protection, and even different physics with the eepap.

I would suspect that 'floating' bilevel & SV ranging is not a good idea ? - leaving epap to float on its own seems like the smarter & safer choice.

You know "reasoning's" track record on this message board: many times right and many times wrong.

What triggered this line of thinking was when banned suggested setting MinEpap to 5 & that kind of horrified me because it meant all the above pressures would be (in that example) 4 CMs below where they previously were. Then when I thought about the consequences, it reminded me of the battle we went through to alert people to NOT set their Autos to 4 CMs & 20 CMs in the naive belief the Auto algorithm would always zap in and fix things.

I fear we are heading down that path again with that floating epap & people suggesting it be set around the 4-5 mark. !

I agree this is a caveat to be on the lookout for. We don't yet know how well or how poorly this new algorithm will automatically adjust EPAP to address varying airway resistance (obstructive FL/H/A). On the flip side, setting too high of an EPAP min will exacerbate CompSAS/CSDB in some patients. There is plenty of room for error in either direction IMHO.

Caution is warranted. So is working with a knowledgeable clinician.

SWS apart from this "Recall what you thought about CPAP+SV modality when Respironics first introduced it. That also looked like it should create problems. And to this day, CPAP mode is the Respironics recommended base modality for their SV machines. Extremely counter-intuitive... and this reasoned assumption might be equally counter-intuitive. "

I don't recall it quite that way ? - can you point me to the thread ? (no big deal, just want to review what was said)

On your other thoughts, I agree.

Cheers

DSM

[ozij]

But with a Bipap Auto SV advanced there are now 3 fluctuating pressure ranges & 2 of them (the bilevel component & the SV component) float (tied by PSMin) with the third one which is epap.

My understanding is different. I see only 2 ways being used here to ensure proper breathing: one used for exhale, the other for inahle.
I don't see what you call a "bilevel component" separated from an SV component.

The following, taken from the manual, describes two different levels of pressure -- not the technologies behind them.

Bi-level ventilation with the device helps you to breathe by supplying two levels of air pressure. The device
provides a higher pressure—known as IPAP (Inspiratory Positive Airway Pressure)—when you inhale, and
a lower pressure—known as EPAP (Expiratory Positive Airway Pressure)—when you exhale.

The BIPAP Auto Enhanced SV attempts to supply these two levels by using separate technologies to gauge the correct pressure necessary for each phase of breathing.
The pressure needed when a person exhales is assessed (and controlled) using the EPAP-Auto algorithm - an enhancement of the familiar Auto.
The pressure needed when a person inhales is assessed (and controlled) using the SV algorithm.

Only those two technologies. The SV is given a range between a max and a min -- but it is the SV algorithm at work, not the Auto Algorithm. Think of a ship, floating in a lock: - the deck will always be that high above the water, and the chimney that high + x). Rising or dropping water level will not change anything in the way the ship functions.

If a person needs fluctuating higher pressure for inhalation, and lower pressure for exhalation, this fluctuating higher inhalation pressure will be dealt with only with Servo Ventilation (The ship's captain will decide where in the ship his presence is necessary - engine room? bridge? chimney? The lockmaster meanwhile is changing the water level in the lock independently).

If a person's airway needs varying pressure to keep it patent during exhalation, it will be dealt with using the EPAP-Auto algorithm.

"Pressure Support" is a term used to define the difference in cms between the exhale pressure and the inahle pressure. It does not indicate the technology used for supplying pressure.

Simply put, the machine in auto mode is instructed to find the proper EPAP pressure automatically.

In BIPAP mode, it is instructed to use Servo Ventilation for fluctuating inhalation pressure, starting at a minimal difference from EPAP, and going no higher than a maximum defined.

We have been through the mess with CpapAuto that 4-20 'open' settings created. Now we are seeing that same mess emerging when someone naivly believes that setting their Bipap Auto SV Adv to EpapMin=4 or 5 or therabouts, will solve all their problems because the 'auto' will adjust as needed.

Your above point, a valid one, is one I would phrase like this: Can the auto component used for EPAP be trusted to keep the airway stented under all conditions? Previous previous experience leaves place for doubt.
However, I would like to add a caveat: previous experience is based on the auto functioning for both inhale and exhale. Now we the auto demoted to EPAP only, and and SV component solving fluctuation inhalation needs. I have no idea how the new combination will work - it rather depend in the reasons simple Auto- and even BIPAP auto failed. For starters, neither of those attempts had an SV component.

[JohnBFisher]

... One overriding concern IMHO is that many readers here DO NOT check with their doctors or RTs when reading threads and attempting machine changes. ...

-SWS, I definitely agree with your concern. Let me be very, very clear why I am so concerned for anyone using an ASV unit. If you are on an ASV unit, then you were most probably diagnosed with one of the following conditions:

• Central Sleep Apnea (CSA)
• Complex Sleep Apnea Syndrome (ComplexSAS)
• Cheyne-Stokes Respiration (CSR)

If you have central sleep apnea ONLY - and that is EXTREMELY rare - then you might not introduce problems by making changes. Of course, without any other measurement tool you won't know for certain things are still stable.

If you have a obstructive with CSA, then you need to be certain that changing one does not adversely impact the other.

If you have ComplexSAS, then you need to be VERY, VERY careful that changing a setting does not cause the max pressure to rise and suddenly introduce lots of central apneas. At the same time, you need to be certain the "lower end" settings don't introduce problems with the obstructive problems the machine addresses.

But if you have CSR, then changing settings - without the input from your medical team - can be a very bad idea. You don't want to add any more strain on the heart than already exists.

I'm not saynig don't do it. I'm just saying, do what I do.

I brought my data with me for my visit with my neurologist / sleep specialist. We talked about the settings. He was surprised the DME had not properly set the unit (they had not set the EEP, thinking it was an Auto-Titrating unit). I explained that I felt it had been too low and was bumping up the EEP using my pulse oximeter to track my progress. He was VERY frustrated with the DME and he was VERY pleased that I was using the pulse oximeter to cross check my progress. He actually got excited that I was trying to use it to sort out my latest issue with mask leaks.

Remember, the settings on these units were done after you had LOTS of measurements during a sleep study. If you make those measurements without any intedependant confirmation of their impact, you might make things better. But you might just as easily make things worse.

So, please do involve your medical team.

[Banned]

Remember that if you were to drop EpapMin to say 5 as banned as suggested,

You keep bringing this up and I don't recall suggesting that.

What I do recall suggesting is Mboze change to PS Min: 5.

Which Mboze did and seems to be giving him some success.

Please, I don't want you to ruin my credibility with RG!

Banned

[nghy]

nghy owns a "BiPAP autoSV Advanced"
but has a Provider Manual for the "BiPAP autoSV"
not the "BiPAP autoSV Advanced"

Hence the mix up.

Well, that BPM=off, auto, fixed feature should be in both of those manuals. And it's important to understand both features using the word "auto" since we have so many new dial-wingers reading these threads.

The URL that nghy linked to describes the "auto algorithm" that is enabled or limited by the EPAP min and EPAP max settings---and not the BPM settings he might have pulled out of either manual. By contrast those BPM settings deal ONLY with backup rate---which can be automatically calculated on-the-fly.

You are correct about the Breath per minute backup settingd being similar on both machines. Before I went to sleep, I changed the backup setting from 12 to auto. There were no remarkable changes in the measurements reported by Encore Pro software this morning. Subjectively, I felt more comfortable and was less aware of the breathing assists. I remember less about my sleep than I do typically. My diaphram seemed less excercised. My mask did not bother me nor did I have any large leaks. Other observations will need to be tracked over time. I use a CMS50E pulse oximeter to record pulse and SPO2 levels while I sleep. This morning my SPO2 levels were significantly higher than other nights. 98-99 versus 94-95. My wife and I both sensed that the machine seemed quieter. The bottom line is that changing this setting did not seem to have any obvious negatives while any positives were subtle and subjective. Also one of my concerns has to do with my stopping breathing as I fall into deep sleep. I used to sense a time lag before the assist would kick in. Last night the assist was very comfortable, gentle and not so detectible. I did not change any other settings. I will discuss these with my doctor shortly.

[nghy]

The Rain is Spain........ I think I've got it.....

After reading all the comments posted (for which I am very grateful) I understand the BiPAP Auto SV Advanced has the potential to manage three important aspects of the sleep disorder problem independently of one another.

First, it can manage the EPAP to keep the airway open under varying conditions.

Second, it can manage the Support Pressure to ventilate the patient adequately

Third, it can calculate the breathing rate on the fly and detect just when an assist is necessary.

By setting EPAPmax and EPAPmin equal to each other, the machine's ability to manage the EPAP is disabled.

By setting PRESSURE_SUPPORTmin and PRESSURE_SUPPORTmax two units apart, the machine's ability to manage my ventilation needs is severely limited.

By setting the Breaths per minute to a fixed value far below my normal breathing rate, the machine's ability to detect when I needed a breathing assist is disabled, causing a fixed delay of ten seconds before that assist was available.

If my understanding is correct, I now have a simple framework to discuss the settings for my machine with my doctor.

Somewhere along the line whoever dictated the current settings settled for what they knew and gave very little consideration to capabilities of this very sophisticated machine. (IMHO)

[DoninOrlando]

I hope you do not mind me writing in this thread. I cannot contribute to this discussion, but this appears to be the group I need to address to ask a few questions. My apologies in advance for the intrusion but it just seems like the right experts were in this thread and a new thread might not attract the same ones.

Although I am currently on just Cpap, I have a large number of centrals and expect to be switched to something else. I have an appointment with my sleep doc soon. I only recently obtained the sleep study results from 4 months ago when I was first diagnosed and started Cpap. My AHI was 69. During the titration, my AHI was 18, and all centrals. The doctor did not discuss this with me and prescribed a Cpap. Luckily I insisted on a data capable machine. For 4 months I have bought numerous masks, tried numerous fixes, changed pillows, bedding, medications, seen an allergist to treat sinus issues, etc. Since my AI seems to rarely improve from around 15-20 I contacted the DME I bought the Cpap from to see if they had my sleep study results and they sent it to me. My sleep doctor was reluctant to provide them at my 30 day followup. That is how I found out the centrals exist. It explains why nothing I tried would get my AHI below 10 consistently. I had a few nights eary on around 5 with pillows masks, but it required Afrin, taping, chinstraps, and much effort. I could not do it for long. With a FFM (Quattro), I have only had one night AHI below 5 in 3 months and a handful around 10-12. Nothing special those nights to tell me why and I log every tiny detail to look for explanations of changes.

I guess my questions are: Where do I go from here ? Should I give my sleep doctor a hard time about only prescribing CPAP when he knew I had Centrals ? Does a Cpap sometimes work with centrals or was he doing insurance compliance measures out of habit. ( I do not have insurance to speak of and all this has been out of pocket) The $700 I spent on the CPap could have gone towards a BPAP or VPAP or whatever is required. I know $700 was high but that was before I knew of any other options than the DME he sent me to.

I also want to know, do you strive for the same <5 AHI with this condition as simple OSA and do you get it?
Any idea why I did have a few nights under 5 ?
What machine should I go for next ?
Thank You,
Don

[nghy]

I hope you do not mind me writing in this thread. I cannot contribute to this discussion, but this appears to be the group I need to address to ask a few questions. My apologies in advance for the intrusion but it just seems like the right experts were in this thread and a new thread might not attract the same ones.

Although I am currently on just Cpap, I have a large number of centrals and expect to be switched to something else. I have an appointment with my sleep doc soon. I only recently obtained the sleep study results from 4 months ago when I was first diagnosed and started Cpap. My AHI was 69. During the titration, my AHI was 18, and all centrals. The doctor did not discuss this with me and prescribed a Cpap. Luckily I insisted on a data capable machine. For 4 months I have bought numerous masks, tried numerous fixes, changed pillows, bedding, medications, seen an allergist to treat sinus issues, etc. Since my AI seems to rarely improve from around 15-20 I contacted the DME I bought the Cpap from to see if they had my sleep study results and they sent it to me. My sleep doctor was reluctant to provide them at my 30 day followup. That is how I found out the centrals exist. It explains why nothing I tried would get my AHI below 10 consistently. I had a few nights eary on around 5 with pillows masks, but it required Afrin, taping, chinstraps, and much effort. I could not do it for long. With a FFM (Quattro), I have only had one night AHI below 5 in 3 months and a handful around 10-12. Nothing special those nights to tell me why and I log every tiny detail to look for explanations of changes.

I guess my questions are: Where do I go from here ? Should I give my sleep doctor a hard time about only prescribing CPAP when he knew I had Centrals ? Does a Cpap sometimes work with centrals or was he doing insurance compliance measures out of habit. ( I do not have insurance to speak of and all this has been out of pocket) The $700 I spent on the CPap could have gone towards a BPAP or VPAP or whatever is required. I know $700 was high but that was before I knew of any other options than the DME he sent me to.

I also want to know, do you strive for the same <5 AHI with this condition as simple OSA and do you get it?

Any idea why I did have a few nights under 5 ?
What machine should I go for next ?
Thank You,
Don

This is a good place to start because the BiPAP AutoSV Advanced was designed for your problem. The issue is that this is a costly machine. Insurance coverage and payment is a issue for some.
This is the URL for info about this machine http://bipapautosvadvanced.respironics.com/

[JohnBFisher]

BLAST! My computer ate my response to you. Don, Here's a quick recap.

But the basic answer is that your doctor was not just following insurance procedures. There is strong clinical evidence that clearing OSA can lesson the stress on the central nervous system. As a result, fairly often central sleep apneas can diminish and clear up - at least for a time - with just CPAP.

However, it all depends on what is causing the problem.

Additionally, if someone has just OSA, they certainly can achieve an AHI values that is less than 5. It takes time for the body to adjust and to get things "just right". And as I noted, as the stress on your body decreases, it can then lessen the CSA events.

IF that happened for you, it would be the cheapest option. So, your doctor provided a good medical path forward. Unfortunately, you now need to head to the next step.

You should consider an ASV machine. Unfortunately, there are two new costs with it. You will need another sleep study and they units are VERY expensive. Though you can often find them for much less on the CPAPauction.com site. Of course, you can also sell your existing unit there. Or you can keep it as an emergency backup.

Hope that helps.

[DoninOrlando]

BLAST! My computer ate my response to you. Don, Here's a quick recap.
You should consider an ASV machine. Unfortunately, there are two new costs with it. You will need another sleep study and they units are VERY expensive. Though you can often find them for much less on the CPAPauction.com site. Of course, you can also sell your existing unit there. Or you can keep it as an emergency backup.

Hope that helps.

Wow, Another sleep study. That is almost as much as the new machine. My DME said the machine I need to treet my condition is around $4000. That sound about right ? They did not say what unit. I doubt it is that newest model.
Do you strive for and achieve AHI under 5 with Central APneas and an ASV machine? Is that expected ?
I just don't want to borrow and spend $6-8,000 I do not have for marginal results.

I have had considerable improvements from pre cpap such as no more night pee trips, no more falling asleep watching tv or driving, my BP has gone down from around 135/90 to 120/80 avg and 110/75 at last dr visit. That's with a little dieting and almost 0 excercise as I had a knee injury preventing excercise until now.
I feel much better than before. My snoring is about 90-95% gone and wife is back in same bed.
Now she snores more than me and falls asleep watching TV far more...but that's another story.........
I am just wondering if any improvements from this stage will justify the cost if there are no gurantees.
I have a recording Oximeter on order so I will soon know if Ox sats are good. I was down to as low as 50% precpap.
I am thinking with my results it may be ok now. Not the deciding factor but a big one.
Would a new sleep study be with an ASV and show if it reduces Centrals ? So I would not buy the machine for nothing ?
Your Thoughts ?
Thanks,
Don

[timbalionguy]

By setting the Breaths per minute to a fixed value far below my normal breathing rate, the machine's ability to detect when I needed a breathing assist is disabled, causing a fixed delay of ten seconds before that assist was available.

nghy,
I think the BPM setting doesn't disable the sensing of when you need a breath. It sets what the breathing rate should be if you do indeed need SV support. Auto lets the machine choose the right rate, based on you recent breathing history over the past (I think 4) minutes. Manual BPM sets a fixed breathing rate, and also allows some other peramaters related to breathing rate be set. This, I think, is for patients where CO2 saturation control is imporetant in managing their therapy. By managing breathing rate, and the ratio of inpiratory to expiratory time, the veltilation level can be set such that not too much CO2 gets washed out of the bloodstream. This is the usual cause of CSRs.
The one thing missing in your analysis of the BiPAP SV Advanced algorithm is the SV part. The machine manages IPAP in such a way that if there is an event the machine suspects is a central (or CSR), it will boost the IPAP while also cycling between IPAP and EPAP to encourage the patient to breathe. Note that the IPAP value changes above the sum of EPAP and PS. Normally, IPAP is at IPAP min unless the SV support is needed. Then, the pressure can increase-- quite rapidly if need be-- to IPAP max or PRES max, whichever is lower. Note that with an auto BiPAP modality set, IPAP tracks EPAP by the difference of PS. But IPAP can only vary in a range between EPAPmin + PS and EPAPmax + PS. The SV IPAP variation happens on top of this. So, this machine can make some fairly complex manipulations of pressure.

On a completely different note, but related to the BiPAP SV advanced, I wonder if many patients who do not have CSA, CompSAS or CSR, etc. wouldnb't benifit every now and then from a machine with an SV algorithm. Like DoninOrlando, my original sleep study showed a lot of centrals, and in fact, they limited the titration that could be performed. But because I had never experienced xPAP before, my doctor thought it best to start out with an autoadjusting CPPAP machine. She was right in that the centrals disappeared very quickly, and now I only seem to experience a 'baseline few' of them, which most CPAPers do. However, there is something about my OSA that causes me to have nights where the AHI fluctuates significantly. I started out with an IntelliPAP autoadjust (my choice), which tended to not respond fast enough, and then overcorrect (otherwise, a fine machine). So, I switched to a machine with a much faster response, the ResMed VPAP auto 25. This machine has helped significantly, in that it is much more comfortable to breathe against (and I am using it as a straight auto with no bilevel modality at this point). I also don't really notice the pressure changes, nor do they tend to overshoot. My average AHI dropped from about 7 to just above 5. But I still have nights where my AHI is above 10. What is interesting about those nights is that AI is often much higher than typical. Typical AI for me is .1 to .2. The AI when my overall AHI is higher is typically .4 to .6. This suggests that 1.) The A10 algorithm in these machines is limiting the ability of the machine to catch all obstructive apneas, or 2, some of these might really be centrals. I will know more when my card reader finally shows up. (I was shipped late last week). Still though, I think I made the right decision to switch machines.

But to get back to the point I was trying to make. An occasional shot of high IPAP might clear some of these residual events, even though I have not been officially diagnosed with any of the more complex SDB disorders. And I think this is where Respironics was going when they said that SV style machines are the future of sleep apnea therapy some years back.

[dsm]

But with a Bipap Auto SV advanced there are now 3 fluctuating pressure ranges & 2 of them (the bilevel component & the SV component) float (tied by PSMin) with the third one which is epap.

My understanding is different. I see only 2 ways being used here to ensure proper breathing: one used for exhale, the other for inahle.
I don't see what you call a "bilevel component" separated from an SV component.

The following, taken from the manual, describes two different levels of pressure -- not the technologies behind them.

Bi-level ventilation with the device helps you to breathe by supplying two levels of air pressure. The device
provides a higher pressure—known as IPAP (Inspiratory Positive Airway Pressure)—when you inhale, and
a lower pressure—known as EPAP (Expiratory Positive Airway Pressure)—when you exhale.

The BIPAP Auto Enhanced SV attempts to supply these two levels by using separate technologies to gauge the correct pressure necessary for each phase of breathing.
The pressure needed when a person exhales is assessed (and controlled) using the EPAP-Auto algorithm - an enhancement of the familiar Auto.
The pressure needed when a person inhales is assessed (and controlled) using the SV algorithm.

Only those two technologies. The SV is given a range between a max and a min -- but it is the SV algorithm at work, not the Auto Algorithm. Think of a ship, floating in a lock: - the deck will always be that high above the water, and the chimney that high + x). Rising or dropping water level will not change anything in the way the ship functions.

If a person needs fluctuating higher pressure for inhalation, and lower pressure for exhalation, this fluctuating higher inhalation pressure will be dealt with only with Servo Ventilation (The ship's captain will decide where in the ship his presence is necessary - engine room? bridge? chimney? The lockmaster meanwhile is changing the water level in the lock independently).

If a person's airway needs varying pressure to keep it patent during exhalation, it will be dealt with using the EPAP-Auto algorithm.

"Pressure Support" is a term used to define the difference in cms between the exhale pressure and the inahle pressure. It does not indicate the technology used for supplying pressure.

Simply put, the machine in auto mode is instructed to find the proper EPAP pressure automatically.

In BIPAP mode, it is instructed to use Servo Ventilation for fluctuating inhalation pressure, starting at a minimal difference from EPAP, and going no higher than a maximum defined.

We have been through the mess with CpapAuto that 4-20 'open' settings created. Now we are seeing that same mess emerging when someone naivly believes that setting their Bipap Auto SV Adv to EpapMin=4 or 5 or therabouts, will solve all their problems because the 'auto' will adjust as needed.

Your above point, a valid one, is one I would phrase like this: Can the auto component used for EPAP be trusted to keep the airway stented under all conditions? Previous previous experience leaves place for doubt.
However, I would like to add a caveat: previous experience is based on the auto functioning for both inhale and exhale. Now we the auto demoted to EPAP only, and and SV component solving fluctuation inhalation needs. I have no idea how the new combination will work - it rather depend in the reasons simple Auto- and even BIPAP auto failed. For starters, neither of those attempts had an SV component.

1 = Epap floating between EpaMin & EpapMax (slowly & in response to OSA events).

2 = (if activated) a regular pattern of 2 pressures being epap & ipap (Bilevel modality).

3 = (if activated) an occasional burst of pressure added to iPap that can go as high as 10 CMs above Ipap in 3 breaths in support of av peak flow targetting

Ozij, they are the 3 patterns (fluctuating ranges).

Cheers DSM

#2 Also, the other matter is that 2 & 3 above get shifted (floated) up and down with the floating epap & that is where my worry lies. As mentioned, another vendor allows epap (in the form of a 2nd epap called eepap) to respond to OSA events without shifting the bilevel modality pressures and the SV modality pressures up and down with the floating eepap. The potential for this to give problems increases with how low someone decides to set EpapMin below what best clears a persons OSA events.

D

[dsm]

Remember that if you were to drop EpapMin to say 5 as banned as suggested,

You keep bringing this up and I don't recall suggesting that.

What I do recall suggesting is Mboze change to PS Min: 5.

Which Mboze did and seems to be giving him some success.

Please, I don't want you to ruin my credibility with RG!

Banned

Banned, my appologies

Yes invoking the ire of RestedGal was not my intention & I humbly beg your forgiveness for dropping you in the dog doo

I am promoting RestedGal from being the PollyAnna of cpaptalk to being the Sara Palin of cpaptalk. When the topic is too
complex she still says her piece which is to deliver a backhanded compliment. A practiced art by an over controller.

D