Resmed VPAP Adapt SV - for Central Sleep Apnea

tomjax wrote:My question is why an APAP was not mentioned or considered.
Seems to me APAP would be the answer to the variying pressures required, particularly with REM stages.

Why is APAP not even considered?

Because they're looking at a machine designed for a specific purpose...to prevent central apneas/central hypopneas. This machine is designed primarily to treat the kind of centrals seen in Cheyne Stokes respiration in Congestive Heart Failure patients.

An APAP does not attempt to treat centrals.

The vast majority of SDB (Sleep Disordered Breathing) people have plain old OSA (obstructive sleep apnea.) CPAP, APAP, BIPAP serve them well.

But for people (especially Congestive Heart Failure patients) whose major problem is a periodic pattern of central hypopneas leading to central apneas (not getting a timely signal from the brain to "breathe", or maybe we should say "breathe right") the ResMed ASV and Respironics HeartPAP are the ticket for them. At least that's what I gather.

I could be wrong.

rested gal wrote:

tomjax wrote:My question is why an APAP was not mentioned or considered.
Seems to me APAP would be the answer to the variying pressures required, particularly with REM stages.

Why is APAP not even considered?

Because they're looking at a machine designed for a specific purpose...to prevent central apneas/central hypopneas. This machine is designed primarily to treat the kind of centrals seen in Cheyne Stokes respiration in Congestive Heart Failure patients.

An APAP does not attempt to treat centrals.

The vast majority of SDB (Sleep Disordered Breathing) people have plain old OSA (obstructive sleep apnea.) CPAP, APAP, BIPAP serve them well.

But for people (especially Congestive Heart Failure patients) whose major problem is a periodic pattern of central hypopneas leading to central apneas (not getting a timely signal from the brain to "breathe", or maybe we should say "breathe right") the ResMed ASV and Respironics HeartPAP are the ticket for them. At least that's what I gather.

I could be wrong.

ah your not wrong and you know that

But I think it's time for... yes more dumb questions... on that PSG I posted, I was not on any machine at all (diagnostic portion of the PSG) and CA's and MA's were obviously present (my sleep doc thinks they are no big deal, but I doubt he's ever ever cured anyone either).

So the question becomes... if these events are present with no machine intervention in the circuit at all and most machines try and avoid these events altogether when they are, what good will a ASV machine like this do for me in preventing them?

In other words what delivery mechanisms or factors of this machine is going to physically circumvent the centrals from taking place?

After all, it is only precisely delivering air pressure. So HOW can precise delivery of air-pressure prevent central apnea?

This is the part I don't quite fully understand yet. I could see where pressure from the machine can "manipulate the stretch receptors" and possibly impact respiratory drive (along with other factors like C02 retention etc., excluding any physical obstruction of the airway/stent). I also know that the human body is very complex and well built with many redundancy factors including those for the respiratory drive.

We also know if pressure from the machine can sometimes trigger these events (pressure induced central events) and if that pressure is avoided you can avoid the event.

I KNOW this syndrome can be present without CHF. In my last visit to my Cardiologist (a highly respected and very good one in SF bay area) that I didn't have any heart disease to be of concern, other than to watch and control my hypertension, diet and exercise regularly, the normal things we are told). We did follow up visits for 2 years and the most was controlling cholesterol with use of Niacin/Niaspan. I still take 500mg of that per day. But because I already had a one stroke at age 45 along with a family history of heart disease (dad died at age 51 from a single heart attack), I was sent through a complete cardio workup (hey I had good insurance at the time, only thing I could think of) including stress treadmill with color nuclear scan (that was awesome, could watch my heart beat in 3D), and finally a complete upper/lower angiography). After the stroke hunt everything came back negative. I even had a ultrafast CT scan (paid for out of my own pocket) and it showed my calcium/plaque buildup to be less than <1%. That PSG was the last major tests I had done and where I was finally diagnosed with OSA. I was found severe (72hr, SAO2 down to 67%), but not really all that bad, I've seen people much worse here. I used to be StageIII hypertensive, but last night after giving a pint of blood I was 96/56, had to stick my feet up in the air on the couch and take a nap

But this new ASV machine can have Magnaflow twin turbos but unless I can understand how it will physically address my central and mixed apnea, it isn't much good to me.

As you know, I have purchased every autopap on the market attempting to address what you seen on that PSG. I've even purchased units of the same flavor only to get a different firmware level. I can easily get my AHI numbers down, in fact that has never really been a problem.

What I suspect is those CA's and MA's are still present (4 PSG's say they are) and with conventional home therapy they go completely unseen by autopap reporting.

But the main problem I've had after 5yrs of therapy is I'm more tired when I get up from sleeping 10 hours than when I went to bed. I've sometimes felt better not sleeping for 2-3 days. I've even been to a Hematologist and had several studies done looking for other factors like blood disorders. I did have malignant melanoma found a few years back and had a 3.5" diameter chunk of skin removed from my chest with followup, as far as I know they got it all.

Then I thought not enough exercise, so I spent $3600 on a Precor 5.33 EFX elliptical machine sitting in my family room and I do use regularly, I push my heart to 90% for 45 minutes several times a week monitoring with a Polar heart monitor strapped to my chest since its tied to and part of the machine. So its not like I don't get any exercise. But I tell you what, its getting awfully hard to get up on that machine because I'm so tired. I even got your depressed suggestion, took Wellabutrin and Zoloft for over a year. I've even played with the allergy routines for a while, everything keeps pointing back to those CA's. You can only have so many PSG's and know they still are there.

I know I have what was described as CSDB, but over the years I found I could limit its impact by controlling pressure. I know if I limit my pressure to 9cm, there are fewer events. But my Remstar Auto was flat-lining at 9cm, the ideal pressure found on 4 different PSG's, so I bumped up the Max limit by 2cm. This morning when I woke up it was flat-lined again, this time at 11cm, still have to pull the report to see exactly what happened. I appear to have my leaks well under control using a UMFF, reports say avg. leak is 38.11L/m. UMFF leak chart at 9cm is 35L/m. So my leak is only .03L/m, I think that is the best one can expect from a UMFF.

Snoredog, my take is that you had a decent distribution of central apneas (CA) and mixed apneas (MA), and even more obstructive apneas (OA), all before CPAP was applied. Unfortunately once CPAP was applied it looks like you really didn't get much sleep.

My friend, you also have a highly unusual case of increased acoustical vibrations with heightened pressure. Those acoustical vibrations are right in the frequency range of snore. Your autoPAP detects those as snore, whether they are snore or not. The fact that you have so many mixed and central apneas really gets me to wondering if you are really experiencing vocal chord closures. The fact that pressure exacerbates your acoustical vibrations also gets me to wondering if your pressure-induced noises that are being APAP-detected as snore might actually be vocal-chord related. Either way you're highly atypical, regarding that increase of either genuine snore or vocal chord acoustics with increased pressure.

Note the clinical patient requirements for the Beth Israel Adapt-SV study that Frequenseeker cited a few posts above. Those doctors conducting that Adapt-SV trial at Beth Israel, by the way, are the very same doctors who authored the Harvard CSDB medical study we have been discussing and analyzing. They are arguably the world's leading sleep researchers on the topics of CSDB and vocal-chord-based SDB. If you check the patient criteria that Frequenseeker casually mentioned a few posts above, you can see those Beth Israel researchers are very likely looking very hard for the margins and gradients of CSDB. My guess is that they are also looking at Adapt-SV in relation to afferent and vagal based etiological possibilities when you see aerophagia explicitly mentioned (and thus a vagal-LES relationship implicitly associated). They are also looking for patients who are either intolerant of CPAP (which seems to be characteristic of CSDB) and patients who do not respond as they should to CPAP despite adequate compliance (which may presumably be characteristic of marginal-to-moderate CSDB).

There is absolutely no doubt in my mind that if your neuro calls them or writes a referral letter, Snoredog, you are a patient they would just love to trial on Adapt-SV at the present moment in their research. You are a cryptic man with cryptic pressure-related responses and daytime symptoms that nicely fit their research criteria of the moment. And you can probably get a letter of medical necessity for that study as well, since your years of xPAP therapy still manage to leave you fatigued by day. I would recommend seeing those researchers at Beth Israel a million-fold over simply getting an Adapt-SV and trying it at home. Those are three very brilliant researchers who are perhaps more likely than any one else in the world to get your highly unusual SDB/CPAP problem straightened out. That's my honest opinion, Snoredog. Cease a priceless moment while you can, friend.

P.S. My understanding is the "defensive" airway closures that occur during the nadir of CSDB central apneas are vocal chord based. Thus if you suspect a mild or marginal CSDB-related etiology, then you might also suspect a vocal-chord based etiology for at least some of your obstructions and mixed apneas (quite possibly your pressure-related acoustical vibrations as well).

SnoreDog,

Re your comment about what can prevent centrals. I think you are right that these machines can't prevent them. But I am not sure it was ever expected they would or could.

Wouldn't prevention of Centrals be a medical condition requiring medical (non mechanical) intervention ? - medication or surgery (if there were any).

I may be missing the point but it seems that mechanical intervention is merely a way of alleviating the problem rather than preventing it.

The central has to commence, be detected accurately, the response calculated and executed, and, the effect monitored as the treatment is active. That is all I understand the asv style machines can achieve.

As for your obvious frustration with your own circumstances , I feel much the same with mine at this moment. Having at last got a reasonable (for me) Bilevel that records nightly data, I have begun looking at the output and am somewhat gob-smacked to see the machine reporting AHI's each night, in the 40s to 50s !!!. My sleep study AHI that got me onto cpap therapy was lower than these.

FrequenSeeker just now sent me copies of his(her?) readings off her VPAP & they look pretty damned good to me compared to the mash of red lines & blue lines showing on my own charts. I sent him(her) my *.rpf files but he(she) is not able to read them so will shortly send him(her) screen grabs of them. Am just about to download last nights data & I am not sure I really want to look at it.

I have been using a Bilevel with T control (the PB330 KnightStar A/C) unfortunately it does not record nightly data so I have only been going on how I feel & that has been on the foggy headed side the past few weeks.
I was very keen to get data from a good Bilevel S/T which was why I bought the Bipap S/T machine but as mentioned elsewhere I have issues with it which were then compounded by the realization that it too doesn't record nightly data on AI HI etc:, just an average for the whole night. Its nightly data recording focusses on BPM & Volumes & that doesn't help me in terms I can make use of.

It would be interesting to try a asv machine.

This therapy sure has its ups & downs

DSM

#2

After some varying of adjustments suggested by FrequenSeeker, it came home to me that these past 6 weeks I have been experiencing severe nasal congestion & blockage - that may partially (if not fully) explain the sudden blow-out in HI AI figures.

I will lower ipap to 13 (maybe 14 later) & epap to 10 - max Insp to 2 & min Isp to 0.5 & try that for a night or so.

D

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

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

I have placed these screen grabs on my website.
As most will realise, the machine is a standard Bilevel
(no T control on this particular one - I expect to have
a VPAPIII S/T model in about 2-3 weeks).

http://www.internetage.com/cpapdata/dsm-vpap3-1/

With AHIs in the 40-60 range - not very impressive

DSM

#2 Some explanation of the charts. The date/time is incorrect
for the 1st 4 nights of the 5 shown as the machine came from
the US and was still set for US date/time. I changed that prior
to the last chart (last night's data).

Also the leak rate in the 1st 3 nights is unusually high because
I found the uper vent in the UMFF was leaking until I pushed
it back into place. On 4th & 5th nights the leak rate drops back
to a more acceptable figure.

The 1st 3 nights were just over 2 weeks ago. Used it for 3
nights just to try it out. Wife complained about the whine/hum
so I reverted to my PB330 A/C.

I resumed using the VPAPIII 2 nights ago after putting the
machine under the bed & with a pillow on it, wife still complains
about the motor whine/hum - I am not at all bothered by it.

I want to use this VPAPIII machine as it is the 1st useable
Bilevel in the collection that actually records detailed nightly
data. I have a Bipap Pro 2 & am willing to give that 1 or 2
nights by using a nasal pillows mask but really want to be
able to use UMFF so I can get apples to apples comparison
of results. But with UMFF mask I can't get a good pattern
going on that machine.

Am interested as to if the VPAP III S/T when it turns up,
will have some impact on the HI readings showing in these
charts.

I must admit I at first just didn't believe them as I thought
I was getting a reasonable night's sleep. I am concerned at
what I feel is a foggy headedness increasing over the past
couple of months. I went through a similar initial wow factor
then decline when I started on cpap/auto. The improvement
was distinct and noticeable when I started with the PB330 A/C
set with timed mode on.

I have been wondering if it is possible that some of us on
cpap therapy, may build up a kind of reaction to the therapy
over a few months & thus begin to negate it. I have been
feeling this was happening to me. When I look at the linked
charts, I can't believe the AI & HI numbers allowing that my
ipap is set at 15 !. The worrying thing for me is the consistency
of the patter night to night & when I compare my charts to the
ones FrequenSeeker sent me - I am somewhat deflated.
FrequenSeekers charts look so clean !.

DSM

SWS wrote:

P.S. My understanding is the "defensive" airway closures that occur during the nadir of CSDB central apneas are vocal chord based. Thus if you suspect a mild or marginal CSDB-related etiology, then you might also suspect a vocal-chord based etiology for at least some of your obstructions and mixed apneas (quite possibly your pressure-related acoustical vibrations as well).

Thanks for the info prior to above, if you squeeze those CA, MA and Hypopnea events into a single line, I'm one big arousal without a machine.

I don't have any problems getting a LMN, but Boston right now might as well be in the antarctica for me as I lost insurance coverage back in April due to outsourcing. But I think you are right, I need to explore the vocal-cord etiology aspect a bit more, could also explain my poor shower singing ability

This is why I couldn't ever use the Resmed machines... they triggered so heavily on snores, then when they increased pressure for addressing the snore, that same pressure triggered even more central hypopnea, these of course would either not show up at all or if they did they show up they were mistakenly seen as obstructive which triggered another pressure response.

For most of the past 5 years I've just used a RemstarPro w/Cflex set to 9.0cm as my regular machine, but the fatigue has persisted. I only used the autopap to pull occasional reports.

DSM wrote:

SnoreDog,

Re your comment about what can prevent centrals. I think you are right that these machines can't prevent them. But I am not sure it was ever expected they would or could.

Wouldn't prevention of Centrals be a medical condition requiring medical (non mechanical) intervention ? - medication or surgery (if there were any).

I may be missing the point but it seems that mechanical intervention is merely a way of alleviating the problem rather than preventing it.

The central has to commence, be detected accurately, the response calculated and executed, and, the effect monitored as the treatment is active. That is all I understand the asv style machines can achieve...

That is my thinking also DSM, I could see if the pressure delivery mechanism was the cause of these central events that with careful manipulation of pressure you could possibly control or prevent them to a certain extent.

But when they occur without any pressure delivery how can it address that. I've always felt that when these centrals events occur, I find it is like I just forget to breathe, then the very next aspect is a very low level hypnic-like shock felt in the center of the chest/heart, which startles me back to breathing again. In fact, I can duplicate this on any given night simply by turning to my right side and falling asleep there. But since I know it happens there, I try and avoid sleeping on my right side for that reason.

When I try to describe this phenomena to my doctors you ought to seen the looks on their faces. I know I also have obstructive events in addition to the central ones and reason I try and treat those with cpap. I think cpap keeps those well under control and keeps my O2 levels up but I believe my residual fatigue has to be caused by those unaddressed centrals. I just don't see how a machine can address them.

Oh well, I'll keep chuggin along.

DSM:

Just looked at your charts, man it's like you are getting no therapy at all.

Have you tried setting the machine to like straight 6cm and letting it just record? I can't see how that could be any worse, your treated numbers are high.

It's too bad you couldn't try out a Remstar Auto BiPap. I think it records details and also records snore data which seems to be missing from your data.

This is really for Johnny: I wish a vendor like cpap.com would come up with a rental program for a Remstar Auto Bipap for a week at a time. Wouldn't bother me if it was a refurbished unit. I know I would be willing to pay shipping to and fro and daily rate to see if a machine could address my sdb. I just have a hard time spending $1200 on another machine right now and finding it wasn't any better, but I may have to do that. You guys could call it cpaprental.com

Snoredog, whether the Adapt-SV can prevent central apneas... That's apparently a grey marketing area, in my opinion. Resmed's premise of the Adapt-SV machine, according to their own marketing literature, is to completely eliminate all central apneas. You cannot eliminate all central apneas by allowing some to occur. So the logic and premise of Resmed's marketing claim clearly implies that central apneas can be eliminated.

Now Resmed and their Adapt-SV marketing are one thing. Reality is another thing entirely. I believe that for the correct central apnea etiology, that the Adapt-SV can eliminate all central apneas, which necessarily includes prevention. Resmed's marketing literature very strongly differentiates Adapt-SV from ordinary BiLevel S/T as specifically being able to match that instantaneous slope, phase, and proportional peak value that ordinary BiLevel cannot achieve with such precision. Resmed attributes that as being: 1) ventilatory support, and 2) so synchronized with respiration that central apneas that would have otherwise occurred with BiLevel PAP are clearly avoided or prevented.

The second-hand anecdote that I received from a world-leading CSDB research clinic essentially commented that too much "residual disease" remained on many of their CSDB patients while trialing Adapt-SV. Although I read that correspondence with my own eyes, there were no details regarding which SDB components were outstanding, which patients, under which conditions, etc. Now SAG points out that when patients have an obstructive SDB component that requires a good amount of "manual control" (namely elevated baseline EEP) that some CSDB patients may find that elevated EEP (think traditional EPAP as a near-equivalent) to trigger central apneas. I agree with that likelihood as well. And, in fact, that may be the basis for the excessive "residual" CSDB that I had personally read.

However, there may be other reasons as well. Namely the Adapt-SV algorithm itself inadvertently desynchronizing with respect to human respiration. That can occur because of leaks or it can occur because of shortcomings in the algorithm itself. Fuzzy logic or no fuzzy logic, once an algorithm inadvertently destabilizes central respiration, it can take quite a few respiratory and CPU cycles to get that respiration back in synchronization. And if an algorithm is inclined to inadvertently destabilize respiration once, it is inclined to inadvertently destabilize respiration repeatedly throughout the night under the same patient-machine discoordinate circumstances.

Bottom line is I do think Adapt-SV can completely eliminate central apneas in some patients. I do think Adapt-SV has more development in store, based on that credible preliminary clinical-research anecdote I read. I don't know if the Adapt-SV can completely eliminate Snoredog's events, however.

Snoredog wrote:In fact, I can duplicate this on any given night simply by turning to my right side and falling asleep there. But since I know it happens there, I try and avoid sleeping on my right side for that reason.

Gilmartin, Daly, Thomas in the currently cited CSDB Medical Study wrote: Variably 'mixed' rather than pure obstructive or central ('control') patterns are common and easily recognized. Examples include mixed apneas, variable degrees of flow limitation intermixed with periodic breathing, position-dependent variability (central while not supine, obstructive when supine)

(note: bold and underlined emphasis above are both mine).

Snoredog... There's yet another compelling CSDB correlation for you in the two paragraphs above... They're calling for you....

DSM, I see what you mean. Indeed, a residual AHI of thirty-to-fifty is not good. That IPAP/EPAP spread seems wider than usual. Have you tried moving EPAP closer to IPAP?

Also, which xPAP platform yielded the best AHI score? And which xPAP platform seemed to yield the best daytime clinical response regardless of AHI? I can definitely see why you are watching the Adapt-SV issue so closely. If I were in your shoes I would want to try it as well. What kind of results did CPAP yield during your PSG?

Let's put our heads together off line on that. Also, SAG may have some very keen professional insight for you as well.

SWS,
Based on feedback from FrequenSeeker, I have dropped ipap to 14 & epap upped to 10 (I had tried this before but came back to 15/8 as I had no feedback from the machine (PB330) by way of detailed data to tell me if it was good or bad.

Also I have set bpm to 12 - Imax to 2.0 (may vary it up to 2.5) and set Imin to 0.5 & am leaving rise time at 250ms for now.

I also just tried the Bipap S/T & did similar settings but on it I set rise time to 2 and Imax to 2.0 also.

What became clear was in both cases as set above, I could hardly get a full breath in thru my nose before both flipped - no problems with mouth.

So I then hit my nose with a spray Otravin (is very congested at the moment).

With nose very clear, I tried both machines at these settings & this time both seemed ok.

The VPAP III and the Bipap S/T both seemed to match my breathing pattern, but only once I decongested my nose to the max with the spray.

As I long suspected, the flow through my nose is very restricted.

When I use a nasal pillows mask I get a lot of mucus build up in node/throat & feel awful (in the throat) for an hour or so after getting up.

At last having a machine that is providing decent feedback and with help from folks here, I may get a really good insight into how to get the absolute best from xpap therapy.

But, those HI numbers are a worry.

DSM

#2 - another clue just now from FrequenSeeker re the past few weeks nasal congestion - do I have GERD - yes I am being treated for and yes the reflux seems to be playing up a bit these past weeks . Funnily I just asked the same question of another poster here at cpaptalk (did they have GERD) as it seems a likely cause of their symptoms.

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, Nasal Pillows

Yes, DSM. As you can probably tell from my knee-jerk reaction with that blitz of questions, I was a little worried. I do that with friends. I agree that a major GERD flare up could be to account for your episodic jump in AHI. Apnea-correlative GERD is an absolute spoiler for so many of us.

Snoredog wrote:or most of the past 5 years I've just used a RemstarPro w/Cflex set to 9.0cm as my regular machine, but the fatigue has persisted. I only used the autopap to pull occasional reports.

Snoredog, there's yet another CSDB correlation: easier tolerance of CPAP than APAP. At least take a hard-copy of the Gilmartin, Daly, Thomas CSDB Medical Study to your neuro with all your own CSDB correlations neatly highlighted in yellow or pink marker. That way they don't have to continue scratching their heads when you tell them you have central apneas sleeping on your side. CSDB patients are rare. So are your extremely unique symptoms. I can understand why your neuro is scratching his head. You're probably his or her only patient with those symptoms, Snoredog.

it is like I just forget to breathe, then the very next aspect is a very low level hypnic-like shock felt in the center of the chest/heart, which startles me back to breathing again. In fact, I can duplicate this on any given night simply by turning to my right side and falling asleep there.

Snoredog, sounds alot like vagal dysfunction.

do I have GERD - yes I am being treated for and yes the reflux seems to be playing up a bit these past weeks

DSM - GERD often involves vagal dysfunction.

The worrying thing for me is the consistency
of the patter night to night & when I compare my charts to the
ones FrequenSeeker sent me - I am somewhat deflated.
FrequenSeekers charts look so clean !.

DSM - my graphs look so clean because I have few events now, but without the deadair space I am a zombie despite the "clean charts" without enough CO2. And now I am investigating the possibility that along with the vent being so far from my nose and the high pressure that I need to obliterate the REM events and which also prevents the lower pressure requiring non REM events are all giving me another problem: wrong messages to my kidneys for salt and fluid retention.

If it isn't one thing its another.....

-SWS wrote:
<snip>
Also, which xPAP platform yielded the best AHI score? And which xPAP platform seemed to yield the best daytime clinical response regardless of AHI?
<snip>

SWS,

This issue has been the bane of my Bilevel experience...

PB330 Knightstar:
does no data recording. It really is a clinical machine designed for monitored use - has lots of alarms built in - it does have a comms link - but no recording. It has the most adjustments on any Bilevel I have seen outside of hospital models. Is a very nice unit & very quiet.

Healthdyne Bilevel:
No data recording.

Bipap S/T (gray model):
Records only BPM and tidal volumes not detailed AI HI numbers. It does
provide a single AHI for a night's session.

Bipap Synchrony:
I assume it is the same as the Bipap S/T

Bipap Pro 2:
Does provide nightly data.

Bipap AUTO:
As for Bipap Pro 2.

VPAP III & VPAP III S/T:
Both provide detailed nightly data.

VPAP II & VPAP II S/T:
I don't know if these do, I suspect yes.

PB425:
I believe this does record nightly data.

So the only 2 machines I have that could supply nightly data are the VPAP III & Bipap Pro 2. Of these 2, the VPAP III has more adjustments and although it isn't a T machine, it does seem to act line one in terms of maintaining a breathing pattern. I only got my hands on this VPAP III recently & it took me a while to get round to setting it up & using it (I knew the motor noise was going to be an issue with wife)

Yesterday, armed with the settings suggested by FrequenSeeker, I tried VPAP III out for a while & noticed that if I deliberately stopped breathing it very quickly went from epap to ipap. If I try this with the Bpap Pro 2, it will stay at epap (it has no Max Insp time setting while the VPAP III does). It
seems that the VPAP III is closer to an S/T than a Bipap Pro 2 is.

I had been very happy with the PB330 until the past couple of months - in retrospect I believe this following sequence may possibly explain my increased nasal congestion & the deteriorating results as shown in the charts.

1) Winter comes, exercise (morning walks) decline
2) Weight goes up approx 5 kilos (11 lbs) - total weight 213 lbs - 6ft tall
3) Daily pariet tablet for GERD seemed fine but now aware of reflux sensation again
4) Started to get severe nasal congestion
- thinking it can't be hayfever, wrong season
- seems to clear itself once I am in bed & asleep but not always
- noticed the congestion is usually at its worst in mid afternoon & evening
- FrequenSeeker mentions that GERD can be the cause of nasal congestion the penny dropped - GERD effects showing up after main meal times !

So I am now of the opinion that the cause is a mix of increased weight (seasonal) and reflux action causing nasal congestion

Seems that dealing with SA is a constant balancing act

DSM

DSM, if that acid reflux disease is causing your nasal congestion, then it actually transcends being GERD and becomes LPR instead.

http://www.entnet.org/healthinfo/topics/GERD.cfm

Also, do you remember when your AHI numbers were good, but you still didn't necessarily feel energized by day? Might not be a bad idea to at least consider GERD/LPR as quite possibly causing excessive sleep arousals at night, despite pariet treatment.

Then there is the issue of LES closure. Some people take medicines to neutralize and/or minimize stomach acid production. However, if the LES closure is still poor, fluids may still manage to work past the LES, especially while lying supine (good old gravity doesn't keep it down as when we are standing or walking). My point is that even with medicine we still produce enough digestive acids to break down our foods. And if the LES closure itself is extremely poor, then sometimes acid reflux medicine alone does not completely solve our problem.

On a somewhat related note there are some CPAP patients who experience aerophagia at even extremely low CPAP pressures. Again, terrible LES closure comes to mind. Interesting that the Beth Israel researchers are willing to study aerophagic CPAP patients, since the LES can be vagus nerve dysregulated as Frequenseeker said. So can the vocal chord be vagus nerve dysregulated as well, which is yet another SDB area of specialty for those same Beth Israel researchers who wrote the CSDB medical study that has been cited in the Apnea -v- Hypopnea thread.

DSM, Frequenseeker is of the female gender. Too bad that we're both very happily married. She's both unattached and very attractive. Heheh! Sorry, Frequen... I'm sure you just knew I was gonna slip something like that in since DSM didn't know for sure whether Frequenseeker was a he or she. .

Interesting:

I found this article searching for "vagal dysfunction" (Paradoxical vocal cord movement (PVCM)):

http://www1.wfubmc.edu/voice/topics/differential.htm

Sorta goes back to what SWS suggested, scroll down to paragraph entitled "Brainstem Abnormalities".