Using a Bipap Auto SV and using a Vpap Adapt SV

[-SWS]

what else might be getting "tidied up" for a guy who's wife claims he breathes way too slowly? Could it be the respiratory controller is getting compensated since that's what the machine design was optimized to do and since that's what the medical studies about SV tend to support?

That makes sense to me.

I'm thinking if there's a machine that compensates respiratory controller gain by design, and if a person feels a lot better on that machine---then they may have had "tidied up" respiratory controller issues

Exactly!

Well, I think it's entirely possible that DSM's obstructive events are getting "tidied up" by a design that has been optimized for respiratory controller gain problems.

Doug was diagnosed as having vanilla OSA in a typical best-practices sleep study. A question in my mind about that sleep study echoes ozij's comments as well as yours: Was DSM's OSA really vanilla? Or rather was it the sleep study that was woefully vanilla (meaning an excellent study by today's standards)?

Because today's typical vanilla sleep study is virtually guaranteed to miss night-to-night variations---those occasional disruptive raspberry swirls thrown in by a presumably less-than-perfect respiratory controller, or twitchy neuromuscular defensive closures that may be inherently episodic and highly variable. Theoretically there should be a veritable slew of factors in pathophysiology resulting in night-to-night variability frequently reported here---and more importantly reported in the medical literature.

IMHO today's vanilla sleep studies tend to show obstructive, central, and mixed events that were lucky enough to be frankly manifested that night. So where does that leave the predominately transient, longitudinally transitional, or inherently episodic SDB manifestations during that one-night vanilla-PSG snap shot?

Answer: quite often undetected and therefore "complexity under-diagnosed" I would boldly presume.

I'm wondering how many of us are really "purely obstructive".

My radical suspicions have complex breathing problems---albeit often symptomatically subtle and just as diagnostically elusive---at more than 15%. I'm only a layperson, but I think there's more etiological discovery and complex SDB phenotyping ahead...

[-SWS]

From tomorrow I'll be back on the S8 vantage (am traveling to NZ to do some very welcome babysitting

DSM is visiting with his daughter in the hospital this week. I realize this thread is going to have to take a back-seat regarding priority for a while. Doug, please give Anne our very best!

In the mean time a little stalling or holding pattern on my part, until DSM has a chance to share more of his thoughts...

Add FOT capability to the SV and just at the beginning of each inspiration cycle and before deciding if the sleeper will hit the target flow, FOT the airway & analyze the signal to determine if the airway is open to a tracked target. If yes then proceed with the mid-point decision process & act according to flow target being met.

My guess is the manufacturers would love to come up with a sure-fire way to differentiate central from obstructive from mixed events. Interestingly, Forced Oscillation Technique (FOT) hasn't taken off like wildfire. I think SAG and NightHawkeye both pointed out concerns that were documented in at least one patent description about FOT's tendency to cause at least some sleep arousals.

On that note, I believe that Proportional Assist Ventilation or SV (also dubbed "trilevel" in this thread) may suffer that same shortcoming relative to extremely quick elimination of obstructions: inducing sleep-related arousals from rapid airway stretch (regarding sensory stimuli and quite possibly homeostatic disturbances). However, applied to an open airway PAV or SV should be able to quickly and proportionately ventilate without all that highly dynamic and potentially disruptive upper airway stretch.

Regarding why the Resmed machine didn't seem as smooth to you. Whether that can be attributed to your nasal congestion or leaks, I will soon post the part of the VPAP Adapt SV algorithm that I think is getting thrown off.

Before I post those fuzzy logic association rules from the Resmed algorithm, let's first look at the pressure waveform template that Resmed uses:

Click Here to See ASV Pressure Template From Resmed Patent 6951217

Note the above template is the targeted pressure output wave at the flow generator, and not the measured patient flow wave. At 0 phase we have the pressure output at the beginning of inspiration. At 0.5 phase we have the pressure output changing from inspiratory pressure support to expiratory pressure support. At 1 (the completion point of one respiratory phase-related cycle) we have the pressure output wave immediately after expiration. The pressure does not drop all the way to 0 cm H2O at the end of expiration. That is a static-pressure baseline value called EEP or Expiratory End Pressure (manually set anywhere between 5 and 10 cm H2O).

In the next post I'll list the fuzzy logic association rules relative to determining the patient's respiratory phase. The purpose of those fuzzy logic rules is to determine where in the above pressure-output template the machine's pressure delivery needs to be. If the machine gets confused by the measured instantaneous patient flow the algorithm can get thrown off (think sudden leaks, extremely sharp inspiratory effort to compensate for nasal congestion, etc.). The result is that the machine's delivery phase can get very out-of-sync with the patient's own respiratory phase. And for at least some SDB patients that can be disconcerting...

[-SWS]

Still in a slow holding pattern until DSM rejoins us.

In the next post I'll list the fuzzy logic association rules relative to determining the patient's respiratory phase. The purpose of those fuzzy logic rules is to determine where in the above pressure-output template the machine's pressure delivery needs to be.

# 1. If the airflow is zero and increasing fast then the phase is 0 revolutions.
# 2. If the airflow is large positive and steady then the phase is 0.25 revolutions.
# 3. If the airflow is zero and falling fast, then the phase is 0.5 revolutions.
# 4. If the airflow is large negative and steady then the phase is 0.75 revolutions.

These are the four most basic fuzzy-logic (membership) association rules the Resmed VPAP Adapt uses to determine where in the patient's respiratory phase the machine's own delivery needs to be (i.e. phase-match using the above referenced pressure-delivery template). Note that the marketing literature shows more than the above four phase-related reference points are currently used. Regardless, we can use the above description to get a feel for how fuzzy logic is employed to differentiate respiratory phase.


Fuzzy association rule # 1 says that if the instantaneous airflow is very quickly increasing from zero, then the patient must have just commenced inspiration. Both here and below, slope (or rate of change) is important as well as instantaneous magnitude of flow. Yet the precise values are not important: just the "fuzzy" or imprecise category/membership recognitions (called "fuzzy associations") suffice with this well-respected type of algorithmic logic.

Fuzzy association rule # 2 says that if instantaneous flow is significantly greater than zero and the rate of change is not so steep, then the patient must be right around that top peak of inspiratory flow.

Fuzzy association rule # 3 says that if the instantaneous airflow is very quickly decreasing from zero, then the patient must have just commenced expiration.

Fuzzy association rule # 4 says that if the instantaneous airflow is less than zero and the rate of change is not so steep, then the patient must be right around the bottom peak of expiratory flow.


There are five more fuzzy association rules that I'll post next. And again bear in mind that the current model employs more than just the above four phase-related reference points (or more accurately zone-segmented fuzzy memberships). But you can see how sudden leaks can skew instantaneous flow measurements toward zero flow. And with more reference points or membership zones, sudden leaks will potentially skew phase-related recognition one or several fuzzy-based increments toward zero.

Sometimes people compensate for high nasal impedance with sudden, sharp inspiratory effort---until their compensating respiratory controller reaches a biologically targeted volume. You wouldn't expect that type of respiratory-controller driven compensation to manifest uniformly across the SDB patient population would you? Those sharp and often irregular increases can conceivably skew both SV recent-average or target baselining as well as fuzzy association regarding reference-point or fuzzy membership-zone differentiation.

As a general rule finer reference-point gradations or granularity tend to suffer more reference-point association skew from anomalous measurements. Sudden leaks and/or extreme breathing irregularities will impose significant fuzzy-based association skew. The upcoming fuzzy logic association rules are designed to cope with some of those breathing signal irregularities...

[dsm]

SWS,

Many thanks - appreciate the kind words re Anne, have lots to tell in that story but bottom line is I would (seriously) not be surprised if they discharge her within in 2 weeks !!!. She is a champion.May take a few days to update blog.

While in NZ used the S8 Vantage in EPR mode but upped CMS to 14 (based on how high Bipap SV was averaging- 16 CMS).

S8 data typically 4-6 AHI each night vs Bipap SV at AI of 1.0-2.0. And as I have experienced many times before when comparing resp to resm, one scores AIs, the other scores HIs - if the S8can be taken as gospel then AIs are usually 0.6 or less and HIs 2.0-4.0 - if BipapSV, then AIs = >1 to 2.0 while HIs barely show at all (one or 2 for a whole night). Sleep with S8 is notas deep or as consistent as with bipap sv.

BipapSV still looking pretty durned good.


dsm

PS the last 5 nights data from S8-Vantage in EPR mode is in a single file
here

http://www.internetage.com/cpapdata/ choose menu item 3 then the file called 02-dsm-s8-19jun08-23jun08.pdf
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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, AHI

[-SWS]

...re Anne, have lots to tell in that story but bottom line is I would (seriously) not be surprised if they discharge her within in 2 weeks !!!. She is a champion.May take a few days to update blog.

That is great, GREAT news, Doug!!!

S8 data typically 4-6 AHI each night vs Bipap SV at AI of 1.0-2.0.

So on many nights the Bipap SV has me at AHI 1.0 if I ignore the glitch... By contrast the S8 Vantage has me at AHI of 4 to 6. I guess that is not a big variance but on the S8 as is normal, it shows lots of HI - in fact it rates my HI always higher than my AI. I suspect that to be probably true.

Well, Resmed's purely OSA-targeted AutoSets will have completely different hypopnea treatment strategies than Respironics' or even Resmed's central/mixed/OSA-targeted SV machines. We've already discussed that both SV manufacturers emphasize that the obstructive component of SDB should first be manually addressed---so that fluctuating PS and backup rate can be reserved for treatment of central issues (including central hypopneas). That latter non-OSA objective is the essence of SV's automated or adaptive treatment strategy regarding design intent.

But what we haven't discussed is that machines targeted for pure OSA, such as the S8 AutoSet Vantage, can very intentionally leave hypopneas untreated. Here is a very old Resmed newsletter that reflects the hypopnea views of Dr. Michael Berthon-Jones way back in April of 2002. He is the inventor of both AutoSet technology and the Resmed VPAP AdaptSV.

Click Here for a Link To ResMedica Clinical Newsletters--See Edition One for Dr. Berthon-Jones' April 2002 Interview

Now for some interesting excerpts about AutoSet hypopnea treatment for pure cases of OSA:

Why doesn’t ResMed's AutoSet respond to
hypopnoea?

When you are lying quietly awake, or when you
first go to sleep, or when you are dreaming, you
can have hypopneas (reductions in the depth of
breathing) which are nothing to do with the state of
the airway. For example if you sigh, which you do
every few minutes, you usually have a hypopnea
immediately afterwards. This can also happen if
you have just rolled over and are getting settled, or
if you are dreaming. And the annoying thing is that
when you are on CPAP, this tendency to have what
are called central hypopneas - hypopneas that are
nothing to do with the state of the airway - is
increased. If you make an automatic CPAP device
that responds to hypopneas, you will put the
pressure up to the maximum while the patient is
awake.

Do you think there is a misconception clinically that all
hypopneas should be treated ?

For simple obstructive sleep apnea, central hypopneas
should not be treated. They are not a disease. Everyone
has them. And they don’t go away with CPAP. There is a
rare and important exception: central hypopneas due to
heart disease. This is called Cheyne-Stokes breathing.
CPAP does help with that.

Why doesn’t ResMed's AutoSet respond to
apnea above 10 cm H2O in pressure?

I mentioned before that the higher the pressure,
the more central hypopneas you will have. At a
pressure somewhere around 10 cmH2O, the central
hypopneas become central apneas. On the other
hand, the vast majority of obstructive apneas are
already well controlled by 10 cmH2O, and we are only
fine tuning using snoring and flattening. So it
is a pretty good bet that if the pressure is already
above 10 cmH2O, any apneas are most likely
central, and you should leave them alone (except
in patients with central apneas due to heart failure).
But if the pressure is below 10 cmH2O, most
apneas will be obstructive and you should put the
pressure up. There’s nothing magical about 10
cmH2O, it’s just a good place to put the line in the
sand

Likewise can a device that responds to
hypopnea over-treat it ?

The funny thing is that it can both over-treat and
under-treat. It will put the pressure up through the
roof in some subjects, who have lots of central
hypopneas. And it can completely miss repetitive
severe silent inspiratory flow limitation that is totally
disturbing the patient’s sleep without there being
any hypopneas. If this occurs without CPAP, it is
called upper airway resistance syndrome. It is just
as bad for you as obstructive sleep apnea. But a
CPAP machine that responds only to hypopneas
will treat your obstructive sleep apnea, and give
you upper airway resistance syndrome instead.

What an icon and what a veritable pioneer in the field of SDB treatment! But please bear in mind that Dr. Michael Berthon-Jones' views regarding hypopnea treatment strategies---or prevalence of mixed/irregular SDB patterns and distributions in the patient population--- may have changed since early 2002, with additional SDB research having occurred since. The main point to my post being that the S8 AutoSet Vantage (targeted for pure cases of OSA) and adaptive SV treatment platforms (not intended for pure cases of OSA) will very intentionally have different treatment strategies regarding those hypopneas. And those fundamental differences in treatment strategies are based largely on present-day understanding of SDB etiologies and statistically-based epidemiology.

And if it turns out that either SV machine genuinely works better for you than your past machines that were targeted for simple OSA, then you are very fortunate for having made that discovery IMO! The test of time itself will undoubtedly be one of your factors in judging BiPAP autoSV efficacy. I also have high hopes for you and that machine! .

[feeling_better]

This is a very high level discussion with a lot of useful info for me. _SWS, and others, thank you very much for bringing this here.

I am very new, just about 4 weeks into CPAP. I was getting concerned about my AHI being in the 5-8 range. My screen (M series, running in fixed 6.5 now), only shows the total AHI. The very few days' data I saw when taken to the doctors office had the AI at 1-2 and the rest was HI. The posting above is beginning to put my mind at ease. When I had it for about 10 days on auto 4-15, I was miserable all night with the pressure going all the way to 15; even limiting to 10 did not give as good a condition as the current fixed at 6.5. I will be slowly searching for my optimal pressure around this number in steps of 0.5 in the coming weeks. BTW, I have a habit, when I am awake at night of taking a few very deep slow breaths, and mostly likely following that the machine may be detecting my false H's?

I have tried to read thru most of this very long thread, but might have missed them. And also for others who might stumble on this thread at this stage, would you kindly give (repeat) some definitions or references to the commonly used terms in this thread: AutoSet, SV, PS, SDB, ... ? Thank you.
If not already done, this thread needs to be permanently saved, or pinned.

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

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

[dsm]

Feeling better,

I agree, the data SWS is able to come up with plus his intricate insights, are great material and I am sure that the way the discussions have evolved has offered people an opportunity to gain their own insights to aspects of cpap therapy.

Here are some simple definitions

******************
'Sullivan Autoset CS' was a machine developed by Resmed in the early 2000s that applies a special way of controlling breathing. It was originally targeted at people with CHF (Chronic Heart Failure) who often exhibit CSR (Cheynes-Stokes Respiration http://www.chestjournal.org/cgi/content/full/124/5/1627 ) also referred to as cyclic or irregular breathing.

The modern version of this machine was made generally available in 2007 and called the Resmed Autoset CS2 (outside USA) and the Vpap Adapt SV (inside the USA).

Respironics have a similar machine but it uses a markedly different design and approach to 'Irregulr Breathing' from the Resmed machine.

The two machines overlap but in general they target slightly different breathing disorder groups. This thread compares them and much discussion centered on the validity of a normal vanilla OSA sufferer using these specialized machines instead of a regular OSA cpap machine.

(OSA = Obstructrive Sleep Apnea - what most of us here have)
*********************


SV = Servo Ventilation. This in very simple terms means the machine can act as a passive ventilator (it follows the breather's pace) but when it believes it needs to, and based on monitoring the sleeper, can switch to active ventilation where it 'drives' the sleepers' breathing to keep it regular and to ensure the sleeper breathes in an adequate volume of air on a breath-by-breath (b-by-b) basis. The b-by-b really means that these machines monitor every individual breath and can rapidly raise pressure within a single breath, in order to bring rate & volume back in line with a tracked target. The Respironics Bipap SV tracks 'peak-flow' and 'rate' within a 4min window. The Vpap Adapt SV tracks volume and rate withing a 3min window.

These machines are intended to go beyond just OSA. In fact the Vpap Adapt SV is not really ideal for someone who is predominantly an OSA patient (ref Resmed web site) whereas the Respironics Bipap SV treats OSA (using a bilevel approach) and as its secondary goal, targets irregular breathing and central apnea (as stated by Respironics).

*********************

SDB is a blanket term meaning Sleep Disordered Breathing. The term covers OSA, Centrals, Mixed Apnea, Complex Apnea, CSR etc:

OSA Obstructive Sleep Apnea - sleeper experiences blocking & partial-blocking of airway while trying to breathing (plumbing problem)

Central - sleeper stops breathing but not because of a block. Body fails to send breathe signal - eventually brain gets message that Co2 levels in blood are rising & arouses the sleeper who will usually start breathing again (signals problem). http://sleepdisorders.about.com/od/slee ... entral.htm

Mixed Apnea - sleeper experiencing both OSA & Central Apnea
http://kidshealth.org/parent/general/sleep/apnea.html

Complex Apnea - Complex sleep apnea is a specific type of sleep apnea where patients exhibit obstructive sleep apnea events, but also demonstrate persistent central sleep apnea events. This central apnea is most commonly noted while on CPAP therapy, after the obstructive component has been eliminated.

CSR - Cheynes-Stokes Respiration. A cyclic breathing pattern - waxing and waning in strength. http://www.scholarpedia.org/article/User:Trinder

*********************

PS (Pressure Support) is a newish term in cpap discussions. It is used in some types of machine to name the setting of how much pressure support is to be allowed. This means applying more air pressure to try to resolve some issues. There are two contexts for PS (1) to do with SV machines & (2) to do with OSA machines that auto adjust the delivered pressure and also are bilevels at the same time.

The SV machines all use PS to achieve their SV capability (this means they will bump up pressure within a single breath if they need to push or control the patients breathing). The PS settings are Min & Max and mean the minimum gap between epap & ipap (min ps) and the maximum gap between epap & ipap (max ps). (epap = exhale pressure & ipap = inhale pressure).

As a contrast, the Respironics Bipap Auto (with Biflex) is a machine designed to deal with OSA (along with the Vpap Auto from Resmed). Both these machines have a PS setting but in their case the PS is applied slowly. PS means raising the pressure in response to detected snores, hypopneas and flow-limitations.

It is very easy to get confused with these acronyms (i.e. PS) as they tend to get used differently between brands and types of machine.

***************************

dsm

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[feeling_better]

dsm, Thank you very much for that detailed summary and definitions!
I am adding an article reference to complex apnea: http://www.mayoclinic.org/news2006-rst/3608.html

[Gregg]

With little else to add, aside from adding to the length of this thread, I would also like to state how enthused I am about the discussion here. It goes well beyond any I've seen.

I am on day four of my new bipap. Which is going rather well. And after years of observing breathing, and not having any support, I now see so much being revealed here that I already suspected.

In fact, SWS's post just above states in a way that I was unable to, just exactly why I did not have a sleep study before getting into 'pap. I used to call it subclinical diagnosis.

It's funny how something so simple can be so complex to observe and manipulate.

So thank you folks.

[dsm]

Quote from SWS - "On that note, I believe that Proportional Assist Ventilation or SV (also dubbed "trilevel" in this thread) may suffer that same shortcoming relative to extremely quick elimination of obstructions: inducing sleep-related arousals from rapid airway stretch (regarding sensory stimuli and quite possibly homeostatic disturbances). However, applied to an open airway PAV or SV should be able to quickly and proportionately ventilate without all that highly dynamic and potentially disruptive upper airway stretch. "

SWS,

Having again returned to the Bipap SV from the S8, I am delighted at the return to the depth and soundness of sleep. The dream machine is working for me again.

Last week the S8 was ok, but I did notice during the day an ever so slight (but familiar) dizzyness that I have come to associate with straight cpap machines.

If anything, I find ordinary cpap & even bilevel will cause regular arousals. The Bipap SV is doing the opposite - letting me enjoy a deep restful sleep.

What I would like to see is if someone else diagnosed with vanilla OSA gets one of these machines and is able to provide complimentary or contrary feedback. I know banned has his Vpap Adapt SV, but we don't (AFAICT) have a PSG to look at for banned ?. That leaves his therapy requirements open to speculation.

dsm

[-SWS]

If anything, I find ordinary cpap & even bilevel will cause regular arousals. The Bipap SV is doing the opposite - letting me enjoy a deep restful sleep.

So in essence the vanilla-OSA treatment machines don't treat your diagnosed "vanilla OSA" as well as the non-vanilla BiPAP autoSV platform. We do hear your above anecdote from non-OSA patients, of course---that they receive arousals from the "vanilla OSA" treatment platforms.

What I would like to see is if someone else diagnosed with vanilla OSA gets one of these machines and is able to provide complimentary or contrary feedback. I know banned has his Vpap Adapt SV, but we don't (AFAICT) have a PSG to look at for banned ?. That leaves his therapy requirements open to speculation.

Banned was diagnosed "with only mild OSA".

I was diagnosed with only mild SA.

So your vanilla OSA doesn't appear to resolve anywhere near as nicely on the Resmed Adapt ASV as Banned's vanilla OSA.

But at least we know that both of your vanilla OSA cases don't nicely resolve on the platforms that were designed to treat vanilla OSA. They only seem to satisfactorily resolve on the treatment platforms that medicine uses to treat mixed and central SDB.

Fortunately we have our own medical vanilla analysis---which I propose that we hereby dub message board "vanillaology". With enough careful comparisons we'll have vanillaology-based epidemiology in no time flat.

.

[-SWS]

Not to let all the above vanilla humor detract from DSM's extremely valid inquiry:

What I would like to see is if someone else diagnosed with vanilla OSA gets one of these machines and is able to provide complimentary or contrary feedback.

Placing all whimsical humor aside, Doug's is an extremely key question IMHO.

Will there be many or perhaps few diagnosed with vanilla OSA who are better treated on SV machines? And will those be genuine cases of simple/vanilla OSA or will they be subtle yet complex (or otherwise confounded) cases of SDB---despite those initial vanilla OSA diagnoses?

And to extend that same manner of analysis: Should most vanilla OSA cases respond better to SV? If not, which ones will and which ones won't? What might any treatment discrepancies among the vanilla OSA crowd say about the various treatment platforms? What might it say about diagnostic methods? About SDB confounding factors in pathophysiology? About contemporary SDB epidemiology?

What challenging questions to ponder IMO... Thanks, Doug!

Also, I noted some interesting data-returns in DSM's BiPAP autoSV charts. I'll comment on those as soon as I catch up on the Resmed ASV fuzzy-logic membership association rules. Then eventually I'll pull the Respironics BiPAP autoSV patent up for a comparative look---if no else pulls it up first that is. And it's perfectly A-OK if anyone would like to! .

[dsm]

SWS,

I am not happy about all this vanilla flowing around without some chocolate.

But, humor aside, if my 2 PSGs done at the country's foremost sleep lab, are not telling a proper story, then lord help anyone going in for a study there or anywhere.

I now think a lot of folk do have extra issues to do with breathing at night that are not being picked up in sleep labs. It seems to me the issue clarified elsewhere by Ozij of 'positional apneas' is significant.

Also coming back to the post I made the day I went oseas re a 'post arousal central' - even if the Bipap SV hits me with an air boost to bring me on target, I can't see that being any sort of a problem as the target it is aiming for is the one set in the prior 4 mins of tracking & thus the 'boost' should not be that big nor any problem.


Re the Vpap Adapt SV.

I now have a Reslink for the Vpap Adapt SV so will do another couple of nights on it and collect the data. I may also have the integrated SpO2 working by this w/e & can then add integrated SpO2 data to the reports.

DSM

[-SWS]

Doug, central apneas can be (supine) positional as well:
http://jap.physiology.org/cgi/content/full/99/6/2433

Further evidence of the association between upper airway narrowing and central events is derived from an observed increase in central apneas in the supine position (55) and a reduction in central events with the use of continuous positive airway pressure (CPAP) treatment

Periodic breathing can be positional as well.

But let's consider that vanilla OSA diagnosis of yours in light of the results you typically get on the BiPAP autoSV: http://www.internetage.com/cpapdata/dsm ... 5jun08.pdf
There we have something very different than OSA-targeted platforms deliver. Even OSA-targeted BiLevel does not rely on timed backup rates. Rather OSA-targeted BiLevel is purely spontaneous. You, my friend, rely on a timed backup:

Average Breaths Per Minute=14.1
Average Patient Triggered Breaths: 99.2%
Therefore Average Breaths Per Hour=846
Therefore Average Machine-Triggered Breaths Per Hour=68

Now bear in mind that if those were apneas being responded to that would be a residual AI of 68 (residual only after IPAP/EPAP or even CPAP finishes addressing vanilla OSA via ordinary airway inflation). But with that vanilla OSA diagnosis your doctor gave you and that vanilla OSA static pressure he prescribed to inflate your airway, you should really be good with the above vanilla EPAP=11 and IPAP-min=14 to address those vanilla obstructions, right? So what residual AHI did your doctor achieve with his static vanilla pressure? And what was his prescribed vanilla pressure for a guy who needs a timed backup at the not-so-OSA-vanilla rate of 68 breaths per hour?

Shouldn't your 14/11 cm H2O inflate your airway adequately to meet your doctor's vanilla-prescribed OSA pressure? And despite that airway inflation your BiPAP autoSV makes you feel better by triggering breaths at the rate of 68 per hour. I see where VPAP S/T gave you plenty of timed back up breaths, but at the expense of inducing excessive BPM.

Vanilla OSA? Really? Since when does vanilla OSA need all that timed backup?

[dsm]

SWS,

Yes that patient triggered breaths info did catch my eye but I did not know what to make of it. 99% of anything suggests a very high success rate so I assumed that statistic was not saying a lot other than I did the bulk of my own breathing triggering. But the way you have presented that data makes interesting reading.

Perhaps to bolster your point, I only ever felt happy for the 1st time on cpap therapy with my PB330 Knightstar Ventilator which I set with a timed back up rate of 6 BPM. I set it that low to allow the long slow nasal breathing I was used to. I never feel comfortable using a machine without a timed rate, but that was an intuitive reaction rather than anything I could quantify in respiratory terms.

The Bipap SV seems sooo tolerant of my nasal/mouth/nasal breathing.

DSM