This VPAP Adapt is beyond me, sorry to say.

[PhyllisBalboa]

Actually you can set the machine to "Autoset" and it will function as a regular S9 Autoset, allowing minimum and maximum pressures, and an epr of 1, 2, or 3.

Hi retired_guy,

Actually, the S9 VPAP Adapt does not have the standard AutoSet mode. Only has fixed-pressure "CPAP" mode and ASV mode(s).

Well, I was looking at page 16 of the Clinician's guide and it sure looked to me like it has the autoset mode. But I haven't ever actually even seen one of these machines so I could be reading the manual incorrectly.

I looked to make sure, page 16 on my manual, gives CPAP, ASV, ASVauto. I think ASVauto is different than an auto set.

[PhyllisBalboa]

It does look like the manual I have is not the manual I wanted. So sorry for the confusion. If the option is CPAP only, then that at a pressure of 8 as originally prescribed might be a good place to start. A second place to go is to return this machine for one that will give you all the options. Such as the S9 VPAP™ Tx which is the one I got the manual for.

Too late! I left the desert for Montreal. No going back at this point. And despite all my squawking, I really do like this machine. I'll just keep fiddling, especially with all this great advice available.

I'm

[vsheline]

Yes, but I want PS to be SMALLER than 5. Why can't it be like an EPR of 1,2, or 3 on your guys' machines? I'm envious, and probably butting my head against a pretty brick wall. I have to learn to live with my machine's unfathomable rules, that's the short story.

Hi PhyllisBalboa,

PS can be as small as Min PS, which you have said is now zero on your machine. PS will start at zero and will raise itself higher only when needed to treat hypopneas and apneas.

If Max PS is too small the ASV machine will be unable to adequately treat centrals.

Remember that patients with healthy lungs may require the Max PS setting to be around 10 to allow the ASV machine to fully treat central apneas. Presumably, some patients may require even higher Max PS, since ASV machines allow Max PS up to 15 or higher.

Essentially, you are asking: why not allow the max PS to be less than 5, even though this would severely limit the effectiveness of the machine when we need the machine to intervene and prevent a central apnea?

I believe the Phillips Respironics System One BiPAP autoSV Advanced machine does allow this. For the PRS1 ASV machine, I believe PS min can be as low as zero and PS max can be as low as PS min.

But I think it is easy to understand why ResMed might think it does not make sense to allow the settings to defeat the ability of the machine to treat central apneas.

In my view, ResMed has designed a One Size Fits Most type of ASV machine. It is not as adjustable (nor as mis-adjustable) as the PRS1 ASV machine is.

It is certainly possible that you might do better with the PRS1 ASV machine. But, whichever ASV machine is used, the trade-off will be the same: a lower Max PS will cause less air swallowing but also will prevent effective treatment for our sleep apnea.

[PhyllisBalboa]

If Max PS is too small the ASV machine will be unable to treat centrals.

Remember that patients with healthy lungs may require the Max PS setting to be around 10 to allow the ASV machine to fully treat central apneas. Presumably, some patients may require even higher Max PS, since ASV machines allow Max PS up to 15.

Essentially, you are asking: why not allow the max PS to be less than 5, even though this would severely limit the effectiveness of the machine when we need the machine to intervene and prevent a central apnea?

I believe the Phillips Respironics System One BiPAP autoSV Advanced machine does allow this. For the PRS1 ASV machine, I believe PS min can be as low as zero and PS max can be as low as PS min.

But I think it is easy to understand why ResMed might think it does not make sense to allow the settings to defeat the ability of the machine to treat central apneas.

Hi Vsheline,

I rarely get centrals anymore, even with the pressure settling around 10 or so. All my events are hypopneas, with AHI's being around .2, or at least under 1, for the last 2 months. My AHI's with the higher pressures were usually over 3. So I suppose we could say that these pressures are treating the centrals, and maybe if I went too low they'd come back.

On the other hand, having a couple of short events over the whole night is well under the 5 that's given as a goal for almost being normal. So I'm already close to perfect as it is. But then I'm missing hours of usage when I have to stop using it because of the air issue. That's definitely far from perfect, and I don't sleep.

What if I lowered the min ps to 0 (actually at 1 right now), max ps to 5? That would bring the max pressure closer to 9 if I set my epap to 4. If I felt like I was suffocating I could raise the epap a bit. With the longer ramp, that might make it better.

And I really, really appreciate all the advice you've given me.

[vsheline]

I rarely get centrals anymore, even with the pressure settling around 10 or so. All my events are hypopneas.... So I suppose we could say that these pressures are treating the centrals, and maybe if I went too low they'd come back.

It seems possible that the Max PS of 6 which you have been using has been only high enough to change your central apneas into hypopneas. But, for all we know, you may also be having obstructive hypopneas, which would have been obstructive apneas except they were treated (or partially treated) by your machine raising PS as high as 6.

What if I lowered the min ps to 0 (actually at 1 right now), max ps to 5? That would bring the max pressure closer to 9 if I set my epap to 4. If I felt like I was suffocating I could raise the epap a bit. With the longer ramp, that might make it better.

My concern regarding lowering EPAP is it may worsen obstructive events, if you are having any.

But yes, you can try lowering EPAP to 4, Min PS to 0, Max PS to 5.

However, if Min PS is zero and if EPAP is 4, I think you would probably feel uncomfortable, like it requires too much work when breathing in, and you may be unable to fall asleep.

Instead, you could try lowering EPAP to 4, but raising Min PS by an equal amount. For example, if EPAP has been 6 and Min PS has been 1, you could try lowering EPAP to 4 (a change of 2) while raising Min PS to 3 (also a change of 2); and Max PS would need to be 5 higher than Min PS. Although this would NOT lower the max pressure (the highest allowed IPAP would remain unchanged), it WOULD lower EPAP, and it WOULD raise PS which helps us breathe, and therefore would allow central hypopneas to be treated more effectively.

Even when the EPAP is very low like 4, unless our airway is collapsing from EPAP being too low, we will not feel uncomfortable as long as PS is high enough.

Once you have gotten used to an EPAP of 4, then you could try lowering Min PS and Max PS a little.

Here is something important: to find out whether the hypopneas are central or obstructive, zoom in during each of the hypopneas until just a minute or just a few minutes fills the horizontal axis, and look closely at the Flow plot, to see whether they are central (Flow curve will be smooth during exhalation which is during negative Flow) or whether they are obstructive (Flow curve will be ratty, stop-and-go, like we are gurgling during exhalation).

If the hypopneas are obstructive, lowering EPAP would probably make them worse.

[jcarerra]

You mentioned earlier that, when you had high settings, the machine often drove itself up to high pressures. It would really be interesting to figure out WHY it was doing that as you are now having fairly good numbers with lower pressures!

That could be an almost impossible task though, but it could be instructive.

[PhyllisBalboa]

My concern regarding lowering EPAP is it may worsen obstructive events, if you are having any.

But yes, you can try lowering EPAP to 4, Min PS to 0, Max PS to 5.

However, if Min PS is zero and if EPAP is 4, I think you would probably feel uncomfortable, like it requires too much work when breathing in, and you may be unable to fall asleep.

Instead, you could try lowering EPAP to 4, but raising Min PS by an equal amount. For example, if EPAP has been 6 and Min PS has been 1, you could try lowering EPAP to 4 (a change of 2) while raising Min PS to 3 (also a change of 2); and Max PS would need to be 5 higher than Min PS. Although this would NOT lower the max pressure (the highest allowed IPAP would remain unchanged), it WOULD lower EPAP, and it WOULD raise PS which helps us breathe, and therefore would allow central hypopneas to be treated more effectively.

Even when the EPAP is very low like 4, unless our airway is collapsing from EPAP being too low, we will not feel uncomfortable as long as PS is high enough.

Once you have gotten used to an EPAP of 4, then you could try lowering Min PS and Max PS a little.

OK! This is a great plan. Will try tonight. In the meantime, I slept with the machine last night for 4 hours, I had 1 hypopnea (12 seconds) and no other events, with a ramp of 40 minutes. Woke up after the 4 hours with air issues, went off for the rest of the night and had light dosing and bad dreams. Here are my stats from that night (AHI=.23, 4 hours sleep)

Channel Min Med 95% Max
EPAP 4.20 4.18 4.20 4.2
IPAP 4.20 5.38 9.58 10.0
MinuteV 0.0 5.50 7.25 12.38
Resp. 0.0 14.6 19.6 30.0
Flow L 0.0 0.0 0.09 1.0
Leak R 0.0 0.0 3.60 9.60
Snore 0.0 0.0 0.02 0.20
Insp.T 0.0 1.52 1.88 9.94
Exp.T 0.44 2.52 3.12 10.0
TargetV 3.88 4.88 5.75 6.12
Tidal V 0 360 500 960
(sorry about the alignment. I guess I'll have to go from Sleepyhead to Excel to this forum)

Here is something important: to find out whether the hypopneas are central or obstructive, zoom in during each of the hypopneas until just a minute or just a few minutes fills the horizontal axis, and look closely at the Flow plot, to see whether they are central (Flow curve will be smooth during exhalation which is during negative Flow) or whether they are obstructive (Flow curve will be ratty, stop-and-go, like we are gurgling during exhalation).

If the hypopneas are obstructive, lowering EPAP would probably make them worse.

OK, I see 2 graphs about flow. Which one? Flow Rate or Flow Limit. Sorry, I don't know much about flow yet. Still so much to learn.

---

You mentioned earlier that, when you had high settings, the machine often drove itself up to high pressures. It would really be interesting to figure out WHY it was doing that as you are now having fairly good numbers with lower pressures!

That could be an almost impossible task though, but it could be instructive.

I agree. It's still happening, though, pressure going up suddenly with no apparent indication that it should. I'm going to get brave pretty soon and post some graphs!

[vsheline]

Here is something important: to find out whether the hypopneas are central or obstructive, zoom in during each of the hypopneas until just a minute or just a few minutes fills the horizontal axis, and look closely at the Flow plot, to see whether they are central (Flow curve will be smooth during exhalation which is during negative Flow) or whether they are obstructive (Flow curve will be ratty, stop-and-go, like we are gurgling during exhalation).

If the hypopneas are obstructive, lowering EPAP would probably make them worse.

OK, I see 2 graphs about flow. Which one? Flow Rate or Flow Limit. Sorry, I don't know much about flow yet. Still so much to learn.

---

I meant the Flow plot, not Flow Limitation plot.

"Flow" is the name for the estimated Rate of airflow into (positive Flow) or out of (negative Flow) our airway (nose or mouth or both). "Flow" is equal to the rate of airflow in the hose minus all leaks (both intentional leak out the vent holes and unintentional leak anywhere else).

Flow Limitation (FL) is completely different. FL is a measure of obstruction or restriction or resistance to airflow in our airway during inhalation. When Flow Limitation is high, this means our airway is becoming partially collapsed during inhalation, which limits how much airflow we are able to get past the restriction and into our lungs. Flow Limitation may cause hypopnea or RERA (Respiratory Effort Related Arousal). RERA is an arousal which was caused by respiratory effort, but which was not accompanied by a 40% or 50% reduction in airflow, so it is not counted as an hypopnea. So although RERAs are arousals which disturb sleep, RERAs are not counted in the AHI.

[jcarerra]

You can think of Flow as "the amount af air we breathe in and out" as it happens--not the total.

As an analogy, imagine a hose filling a bucket. Flow would be the total in the bucket. during the intake phase, the amount is getting higher (inhale), and when you stop filling and slowly pour it our (exhale), the amount in the bucket decreases.

Here is an example of what Flow looks like with my hypos and apneas

[Whitewabit]

Phyllis .. found this explanation of Pressure Support and how it works thought you would like to see it .. the web site is .. http://www.ccmtutorials.com/rs/mv/psv.htm ..