ResMed VPAP Auto 25 Clinician's manual

[ozij]

Gave me an excellent nights sleep, but also the pressures didn't wander very far, so I suspect that even for most people there isn't quite the dancing around we might imagine. It was a very bold initiative & I think quite clever

Of course it won't happen for most people. Most people, statistically, do very well at about 10 cm h2o == they should never see the pressure support raise their IPAP to 18! The dancing around is there for those who need it (a minority), and won't happen for those who do not.
O.

[dsm]

<snip>

But had also read that Epap must be raised very cautiously due to negative side effects (in the current Bipap prov manual).
I did then begin to change my mind to the Epap taking priority over Ipap for that reason. But I will accept that the simulator
is correct on this.

Cheers

DSM

That's very surprising. Could you perhaps tell us specifically which manual you got this warning from? As far as I know, provider manuals tell providers how to setup machines, based on doctors orders - they certainly do not assume the provider changes the pressure at will. I would be very surprised if the Respironics BipapAuto Manual had it any differently.


O.

Page 6-3 of the current Bipap Auto Prov Manual (see my post above with the links). They do say at 15 CMs to re-evaluate the patient so I accept
this caution is into the higher range. There is also the obvious issue of mask management as Epap gets raised & for many people that will be an
issue before Epap gets raised to 15 CMs.


WARNING: High EPAP pressures can cause the patient discomfort. Carefully evaluate
the patient if you set the EPAP level above 15 cm H2O.

[ozij]

Oh, I see what you mean, that's from the non-M series manual. I didn't realize you considered that "current" it is after all the older version (copyright 2005).

In any case, I read that as referring to a setting, prescribed by the doctor, and to the need to keep closer track of those patients to help with compliance; not as referring to the way the pressure changes, or which parameter is given priority.

You are right about the hardships caused by higher pressures.

I wonder if you have an explanation as to why this comment was dropped from the M-Series version (copyright 2006)?

O.

[dsm]

Oh, I see what you mean, that's from the non-M series manual. I didn't realize you considered that "current" it is after all the older version (copyright 2005).

In any case, I read that as referring to a setting, prescribed by the doctor, and to the need to keep closer track of those patients to help with compliance; not as referring to the way the pressure changes, or which parameter is given priority.

You are right about the hardships caused by higher pressures.

I wonder if you have an explanation as to why this comment was dropped from the M-Series version (copyright 2006)?

O.

Ozij

Sorry, I thought it was from the current manual ? - will go double check. Sorry if I got that back to front.

To be honest, after much thought today re Ipap dragging Epap up, I just can't see the sense of doing so. The algorithm looking at hypops & Ipap is without doubt a good one but if Epap is doing its job well, why risk disturbing that and adding additional complexity at the Epap level if the hypop being addressed at the Ipap level is only of minor relevance.

I will actually try a test tonight & use my pre-M Bipap Auto (with Biflex) where I deliberately set Epap low (8) & PS Max to 3 - these settings should produce some fluctuation & hopefully we can see an example of Ipap going high & seeing that it does indeed drag Epap up (again If I were designing this algorithm it is not intuitively what I would do). The only downside to this test is that tonight I hit my magic weight target of 80KG (175 lbs) & am at a level of fitness that is producing lots of near 0.0 AHI results on my Bipap Auto SV (even though it still goes up to 18-20 CMs in bursts in the night). http://www.internetage.ws/cpapdata/dsm- ... 8jun09.pdf

Eitherway, I am more than willing to play guinea pig to see just what might happen which may prove any suppositions I might make, quite wrong or quite right or still in doubt. I will always respect those people who experiment & publish no matter the outcome.

DSM

[ozij]

To be honest, after much thought today re Ipap dragging Epap up, I just can't see the sense of doing so. The algorithm looking at hypops & Ipap is without doubt a good one but if Epap is doing its job well, why risk disturbing that and adding additional complexity at the Epap level if the hypop being addressed at the Ipap level is only of minor relevance.

Why in the world assume hypopneas are (I am quoting you surprising statement) "of minor relevance" ?
Hypopneas are defined by a significant drop in breath flow, they often cause arousals, and desaturations. They could be "residual events" appearing after the tendency to full collapse of the airway has been solved. While EPAP pressure is enough to avoid total collapse of the airway, it is purposely just that, and not high enough to avoid all other events. Therefore, EPAP level would not be enough to avoid partial collpase of the airway on inspiraton. I strongly disagree with your assumption that in general "the hypop being addressed is of minor relevance". I don't remember anyone assuming that about the type of events recorded as hypopneas by Respironics machines - I'm truly amazed that that is your position.

I hope you sleep well tonight! Thank your for testing out whether the BIPAP auto does indeed work as has been described by Respironics.

O.

[-SWS]

To be honest, after much thought today re Ipap dragging Epap up, I just can't see the sense of doing so.

In other words, when this situation happens both IPAP and EPAP move in tandem to all supported types of obstructive sleep events.

So how does that situation differ from what the Resmed auto BiLevel model does when it also moves IPAP and EPAP in tandem to obstructive sleep events? As a follow-up question do you see either sense or nonsense in Resmed dragging that same pair of pressures together constantly?

Unlike the Resmed case, Respironics will move EPAP and IPAP bound "in constant tandem" as an exception---not the rule (whether that's good or bad for any given patient). So with the Respironics machine if you need IPAP to move independently (e.g. to achieve more "ventilation" or WOB reduction) then you set Max PS at or near the maximum value of 8 cm. If you want little or no variation between those two, then you set Max PS at or near the minimum value of 3 cm---or just run the machine as an ordinary BiLevel. All three BiLevel scenarios should serve a variety of underlying etiologies. If marginal albeit variable obesity-related hypoventilation is involved, for instance, then setting Max PS at 6 cm or 8 cm can theoretically help offload any variable effects of marginal obesity-related hypoventilation---via hypopnea response.

...why Ipap would override the Epap setting allowing for the potential for that to cause
'possibly' more serious side effects than the Ipap by being raised, is trying to resolve.

It does seem to me to be just a bit counter intuitive.

As I mentioned above, this situation really amounts to what Resmed constantly does: move IPAP and EPAP in tandem for all obstructive sleep event types supported by the algorithm.

However, regarding what's "counterintuitive" with respect to creating "more" problems or "less" problems: intuition and empiricism don't always intersect. Right? Isn't that sole caveat really the central purpose of epidemiological studies----including those performed by manufacturers?

Recall that these two auto BiLevel machine models are targeted for obstructive patients---not complex or central dysregulation patients. The majority cases would thus imply that those pressure increases are usually addressing obstruction and not inducing complex central dysregulation. Regardless, the Respironics model employs NRAH logic while the Resmed model avoids responding to apneas above 10 cm EPAP in an attempt to cope with unintentional pressure-induced central dysregulation. In-house epidemiological validation from both manufacturers and FDA approval (among other agencies) allow for both designs as viable treatment protocols.

[rested gal]

I am more than willing to play guinea pig to see just what might happen which may prove any suppositions I might make, quite wrong or quite right or still in doubt. I will always respect those people who experiment & publish no matter the outcome.

DSM

ROTFL!!!

Cue some rousing, inspiring music to grow louder in the background as dsm heroically trades the astronaut suit for a guinea pig costume!!

Another milestone "experiment" coming up soon!



Seriously, congratulations on your weight loss. That, I respect your doing.

[dsm]

I am more than willing to play guinea pig to see just what might happen which may prove any suppositions I might make, quite wrong or quite right or still in doubt. I will always respect those people who experiment & publish no matter the outcome.

DSM

ROTFL!!!

Cue some rousing, inspiring music to grow louder in the background as dsm heroically trades the astronaut suit for a guinea pig costume!!

Another milestone "experiment" coming up soon!



Seriously, congratulations on your weight loss. That, I respect your doing.

RG you got away with one bitchy remark. Don't you think that was enough

DSM

[dsm]

Here is the chart from last night night showing the very small PS band and indeed illustrating the Ipap taking priority.
The night was fine until about 3am - got cramps in right ankle. Back to Bipap Auto SV tonight.

Cheers

DSM


The file is quite large - wasn't able to strip off the pages of empty summary data. Tried all sorts of date ranges but it kept producing 23 pages.
http://www.internetage.ws/cpapdata/dsm- ... 9jun09.pdf

[dsm]

I extracted the main data from the report - it illustrates the Epap-Ipap relationship very well. The MaxPS was set to 3
as a way of ensuring that Ipap when raised, would take Epap with it and, MinEpap was set deliberately low (8 CMs) in
the expectation this would ensure some events were found. (my titration CMs is 13). As can be seen the 3 CMs gap is
maintained while the algorithm uses its event sensing to control pressure.

What is interesting from the charts is, do we see Epap pushing Ipap up or Ipap pulling Epap up. ?

My educated guess is that Ipap pulled Epap up based on that there are no AI events recorded at all so the probability is
that Ipap was rising in response to both the FL, VS & HI events & being set 3 CMs above Epap, Epap got pulled up in step.

#3 BUT, on further analysis, the gap between Epap & Ipap sort of appears to be only 2 CMs (see chart 3) ! (it is actually
difficult to read these charts because the granularity isn't that obvious).

If that gap is only 2, then Epap was pushing Ipap up because if it was Ipap driving (which is what one would imagine from
the pattern of events) then the gap would be 3 CMs (MaxPS).

Anyone else have any theories ?

#4 After more careful analysis of chart 3. The gap starts of at 2 CMs but ends up being 3 CMs so here is another assessment
In approx the 1st hour or so, Epap & Ipap remained 2 CMs apart, the Ipap began rising above Epap untill it was MaxPS above it
(3 CMs), then a gap of 3 CMs was maintained. So it started off as 2 (to be expected) but went to 3 (as 1st guessed at).

DSM

[-SWS]

What is interesting from the charts is, do we see Epap pushing Ipap up or Ipap pulling Epap up. ?

When EPAP pushes IPAP up, PS will always be exactly 2 cm (that's the machine's hard-coded min PS). When IPAP pulls EPAP up, PS will always be exactly max PS (in this case exactly 3 cm, as selected by the user).

My educated guess is that Ipap pulled Epap up based on that there are no AI events recorded at all so the probability is
that Ipap was rising in response to both the VS & HI events & being set 3 CMs above Epap, Epap got pulled up in step.

VS raises EPAP by design. VS will never raise IPAP according to Respironics (unless IPAP is getting "pushed" by EPAP raises). So if VS occurs, then EPAP is what gets raised by design. Here's a summary of which obstructive events raise which pressures:

VS: raises EPAP
FL: raises IPAP and/or EPAP according to designated time/sequence criteria
Hypopnea: raises IPAP (unless within close-proximity of an apnea for 2X criteria to raise EPAP)
Apnea: raises EPAP

EPAP can push IPAP up when current PS = min PS (hard-coded at 2 cm)
IPAP can pull EPAP up when current PS = max PS (user selectable between 3 cm and 8 cm)

[dsm]

What is interesting from the charts is, do we see Epap pushing Ipap up or Ipap pulling Epap up. ?

When EPAP pushes IPAP up, PS will always be exactly 2 cm (that's the machine's hard-coded min PS). When IPAP pulls EPAP up, PS will always be exactly max PS (in this case exactly 3 cm, as selected by the user).

My educated guess is that Ipap pulled Epap up based on that there are no AI events recorded at all so the probability is
that Ipap was rising in response to both the VS & HI events & being set 3 CMs above Epap, Epap got pulled up in step.

VS raises EPAP by design. VS will never raise IPAP according to Respironics (unless IPAP is getting "pushed" by EPAP raises). So if VS occurs, then EPAP is what gets raised by design. Here's a summary of which obstructive events raise which pressures:

VS: raises EPAP
FL: raises IPAP and/or EPAP according to designated time/sequence criteria
Hypopnea: raises IPAP (unless within close-proximity of an apnea for 2X criteria to raise EPAP)
Apnea: raises EPAP

EPAP can push IPAP up when current PS = min PS (hard-coded at 2 cm)
IPAP can pull EPAP up when current PS = max PS (user selectable between 3 cm and 8 cm)

SWS

Many thanks - that does clarify the pattern nicely.

DSM

[-SWS]

Doug, how did you sleep with that AHI of 0.3? And how did you feel the next day?

Does SV still feel significantly better for you compared to this auto BiLevel model that Respironics targets for obstructive SDB?

[dsm]

Doug, how did you sleep with that AHI of 0.3? And how did you feel the next day?

Does SV still feel significantly better for you compared to this auto BiLevel model that Respironics targets for obstructive SDB?

Steve,

I was fine for most of the night - woke a few times (battling a chest cold) & was actually thinking that maybe I could stay with this
machine awhile (as mentioned earlier weight hit 80KG yesterday & am now heading to 78 as the final target). ###2 I was also aware
on the occasions I woke, that I was nose breathing & doing ok (took both Nasonex & Otrivin sprays before bed to make sure). Just
to restate, for most of the night thought it was progressing well & working well despite me setting epapMin to 8. ###

But, then I hit the last 3 hours & started to detect things that I take as negative experiences.
- started to feel 'heavy headed'
- got cramps (strong ones)
- woke up with a familiar 'dizzy' feeling (not alert & raring to go like I normally am)
- am at work & not feeling the same zest as after using the Bipap Auto SV - no great difference but very noticeable.

I then though nup, don't want to risk the great extended results I have been getting from the Bipap Auto SV (& the Vpap Adapt SV).
Right at the moment the Bipap Auto SV is delivering outstanding nights with mostly 0 AI & next to no HI (as shown in an earlier link).

I do attribute the success I have been having to that extra PS the Bipap Auto SV delivers. I am sure that many of us here have
been through that cycle where therapy is good & we are able to better control our exercise & eating vs battling a sluggishness
that seems to overtake us when it isn't working.

In comparing the Vpap SV to the Bipap SV, both seem to deliver consistently good results but I do get cramps when using the
Vpap SV but almost never when using the Bipap SV. I believe my sleep is deeper using the Bipap SV than the Vpap SV but the
days are good with both, at times the Vpap SV days seemed a bit better but no so much that I would be worried.

The cramps are also there when I use cpap my Vantage travel machine & as with last night, the Bipap Auto (biflex).

In balance & despite the big weight reduction (97KG to 80 KG in the past 6 months or so), I believe I need to stay
on cpap therapy & am very sure that the SV therapy is what makes the difference. If I really believed I could have
stayed with the Bipap Auto (biflex) for a few nights I would. It is a verrry quiet machine (wife commented about
how quiet it was compared to the Bipap SV).

I am still intrigued at the relationship to dizziness on waking, getting leg cramps, why this seems to vary between
machines (am still thinking it is CO2 related).

DSM

#2

Here is a link to the prior 4 nights using the Bipap Auto SV, the last 3 of the 4 nights are even better than the data
from the Bipap Auto (biflex) but, you can see that the SV algorithm was working quite actively all night. Something
in these SV machines makes a big difference. I would like to be able to articulate what it might be but don't have
that level of expertise. If I could take a stab at what it might be, it would be that the Servo Ventilation becomes highly
effective in the 3 or so hours before waking. By this I mean that although the SV is working similarly through the whole
night, it seems to me, the greatest benefits occur in the period mentioned (again am just taking a stab at what the
'magic' might be).

http://www.internetage.ws/cpapdata/dsm- ... 8jun09.pdf - Some near 0.0 nights.
(ignore the 1.0 AI / HI scores as for this machine the software gets it wrong. 1 solitary apnea will show as 1.0 instead
of 0.8 - basically just count the shown AIs & HIs & divide by 8 - allow it to be 2 apneas in the score bar is thick).

D

[dsm]

To be honest, after much thought today re Ipap dragging Epap up, I just can't see the sense of doing so.

In other words, when this situation happens both IPAP and EPAP move in tandem to all supported types of obstructive sleep events.

So how does that situation differ from what the Resmed auto BiLevel model does when it also moves IPAP and EPAP in tandem to obstructive sleep events? As a follow-up question do you see either sense or nonsense in Resmed dragging that same pair of pressures together constantly?

Unlike the Resmed case, Respironics will move EPAP and IPAP bound "in constant tandem" as an exception---not the rule (whether that's good or bad for any given patient). So with the Respironics machine if you need IPAP to move independently (e.g. to achieve more "ventilation" or WOB reduction) then you set Max PS at or near the maximum value of 8 cm. If you want little or no variation between those two, then you set Max PS at or near the minimum value of 3 cm---or just run the machine as an ordinary BiLevel. All three BiLevel scenarios should serve a variety of underlying etiologies. If marginal albeit variable obesity-related hypoventilation is involved, for instance, then setting Max PS at 6 cm or 8 cm can theoretically help offload any variable effects of marginal obesity-related hypoventilation---via hypopnea response.

...why Ipap would override the Epap setting allowing for the potential for that to cause
'possibly' more serious side effects than the Ipap by being raised, is trying to resolve.

It does seem to me to be just a bit counter intuitive.

As I mentioned above, this situation really amounts to what Resmed constantly does: move IPAP and EPAP in tandem for all obstructive sleep event types supported by the algorithm.

However, regarding what's "counterintuitive" with respect to creating "more" problems or "less" problems: intuition and empiricism don't always intersect. Right? Isn't that sole caveat really the central purpose of epidemiological studies----including those performed by manufacturers?

Recall that these two auto BiLevel machine models are targeted for obstructive patients---not complex or central dysregulation patients. The majority cases would thus imply that those pressure increases are usually addressing obstruction and not inducing complex central dysregulation. Regardless, the Respironics model employs NRAH logic while the Resmed model avoids responding to apneas above 10 cm EPAP in an attempt to cope with unintentional pressure-induced central dysregulation. In-house epidemiological validation from both manufacturers and FDA approval (among other agencies) allow for both designs as viable treatment protocols.

SWS,
Very clearly explained & I understand the points. I guess by saying raising Epap when the data doesn't show a need seems a bit 'counter-intuitive' I am saying so from the mindset of someone who has become convinced that the Servo Ventilation approach of adjusting only Ipap & leaving Epap alone, seems to have made a world of difference to my therapy.

I know the Auto algorithm goes looking for hypops & flow lims etc: vs the SV looking for irregular breathing, but, consistently the best therapy I get is from SV. I am wondering if the Auto bilevel approach is for some people is a wasted effort that in time will be pushed aside by some variation of volume monitoring, perhaps combined with some algorithms for adjusting Epap (kind of along the lines of what Weinmann are doing at the moment). Am back to thinking we may still be in the dark ages when it comes to devising the needed therapy vs what is delivered in many of the high end machines of today.

I am sure it will take many years & many comparative studies before a clearer picture emerges, but, for me the SV has been an incredible discovery that leaves me feeling sorry for all the folk I see writing how they started on cpap therapy & are watching the effects fade away. Having been there & done that then finding a solution that is consistent to the point I now no longer fear a relapse of that awful fading daily alertness, I keep asking myself just what is different about the SV vs the Auto/Cpap. I have almost 18 months nightly data from both SVs & can see an improving pattern that is pretty linear.

In summary. The SV leaves Epap alone & only adjusts Ipap - agreed, it is not using the same approach, but the results for me speak for themselves.

DSM