Varying AHI Readings on BiPap Auto SV Advanced

JIMCHI wrote:Still has an AHI of 9 last night.

AHI 9 is better than AHI 14.
Thanks to SWS, it sounds like you are headed in the right direction.
I would recommend you make only one change tonight.
Increase your Pres Max to 22cmH20.
The reason for this is that Respironics recommends you keep Pres Max at least 10cmH20 above EPAP Max.
Stay on these settings for a couple of nights.
After which, If need be, you can again raise PS Min to 5.

I will try that. But my problem hasn't been that I have a consistently high AHI, it's that I have wide ranging AHIs over a period of days, ranging from 5 to 21.

One of my sleep studies indicated I did well at an EEP of 6. I did try an EPAP of 6 (min & max) on this new machine one night and I felt awful the next day, even though my AHI was 13. What do you think of my trying setting the EPAP min at 6 and the EPAP max at 12 for a night or two and see what happens? Is there any reason that the min and max settings should be near each other?

Thanks for all your advice.

JIMCHI wrote:What do you think of my trying setting the EPAP min at 6 and the EPAP max at 12 for a night or two and see what happens? Is there any reason that the min and max settings should be near each other?

As SWS explained, EPAP is not your problem. PS Min is your problem. Chasing EPAP is simply spitting into the wind.

JIMCHI wrote: One of my sleep studies indicated I did well at an EEP of 6. I did try an EPAP of 6 (min & max) on this new machine one night and I felt awful the next day, even though my AHI was 13. What do you think of my trying setting the EPAP min at 6..

CPAP and EPAP 6 and below, are non-settings.
Anybody with a CPAP or EPAP of 6 and below doesn't need CPAP therapy

With an EPAP Min of 6 and Max of 12 and increasing Max Pres to 22, my AHI last night was 18. I'll put the min EPAP back to 8. But my AHI's continue to be all over the place.

JIMCHI wrote: Is there some possibility that the machine is just incapable of fully treating my condition?

That's a definite possibility. You mentioned that you don't want a lab titration because your AHI is so variable. That's interesting. I would suggest a lab titration BECAUSE your AHI is so variable---but specifically using this machine's titration protocol to accommodate that variability.

Also, bear in mind you haven't yet explored pressure changes on some parameters that are very specific to this machine. Rather, using this machine, you have mainly explored pressure changes that would have been relevant to your previous model---per your DME's initiative. So I suggest a slight paradigm change. You now have a different model, with different pressure parameters, and even an altogether different titration protocol. Let's look more closely at your new machine's titration protocol below. Before we do, let's back up and explore what I mentioned in an earlier post about PS min. Because increasing PS min might be a good thing for you to try, or it might be a bad thing.

PRESSURE SUPPORT (or "PS") is the difference between EPAP and IPAP. In a standard BiLevel titration protocol EPAP would be set at a your CPAP equivalent pressure to address apneas. IPAP would be set higher to address hypopneas---either obstructive or central hypopneas. The higher that IPAP is set relative to EPAP, the larger your PS value becomes. So that was the premise behind my suggestion to experimentally increase PS min: to see if you could minimize all those residual hypopneas. Now the potential spoiler comes along.....

Today's relevant medical term: IATROGENIC- a problem that is unintentionally induced by medical treatment or a diagnostic procedure.
And here's an example of just that for SOME patients: Bilevel Positive Airway Pressure Worsens Central Apneas During Sleep

Recall above that I had mentioned standard BiLevel titration protocol calls for IPAP to be increased to address either obstructive or central hypopneas. Well, in the case of CPAP modality, IPAP just so happens to equal EPAP. And for those patients in the study I linked immediately above, adding or increasing IPAP on a standard BiLevel machine worsens the problem...

Now notice the BiPAP autoSV titration protocol that I linked to on this thread's previous page (below as well). That model-specific titration protocol calls for PS min to start off at 0 cm. Guess what that implies? That Respironics would have you running CPAP as your base modality throughout the night----with BiLevel proportionally kicking in on an as-needed basis only. That's an option you never had with your previous ASV model. So you and your medical team might want to consider titrating on this machine the way it was designed, rather than tweaking this machine as if you were tweaking your previous ASV model instead.

Again, you claim variability is the reason you don't want to go in the lab. I claim that getting the machine set up correctly in the lab, or at home under your doctor's advice, means setting up the machine to best accommodate your variability.

JIMCHI wrote:
One of my sleep studies indicated I did well at an EEP of 6. I did try an EPAP of 6 (min & max) on this new machine one night and I felt awful the next day, even though my AHI was 13. What do you think of my trying setting the EPAP min at 6 and the EPAP max at 12 for a night or two and see what happens? Is there any reason that the min and max settings should be near each other?

No reason unless spreading those two apart causes an iatrogenic problem. If you would like to home titrate, with your doctor in the loop, you can set your machine up according to the Respironics titration protocol---but with 6cm instead of 4cm as EPAP min. The "EPAP-min modified" Respironics settings would then become:

EPAP min= 6
EPAP max=15
PS min=0 (there's your CPAP base modality that your previous ASV model did not offer)
PS max=15
Max pressure=30 (I'd consider initially capping this safely lower for a home titration, and then gradually increasing)
Rate =auto
BiFlex= 2 or 3 (or turn off if BiFlex seems to bother you)

But I would definitely recommend getting your medical team in the loop for a home experiment like that.
Once again, here's the BiPAP autoSV suggested titration protocol: http://bipapautosvadvanced.respironics. ... otocol.pdf

Thank you very much. I am seeing my doctor on Monday and I'm taking all my daily print outs from Encore Reader.

I will ask about the home titration you suggest. I wasn't aware that the Respironics machine is so much more advanced versus the Resmed Adapt SV.

Due to my lack of knowledge, I am a bit confused by the data I'm getting. All of my daily reports show CA= 1 or 0 (I presume these are central apneas). My OA's (obstructive apneas) are 1 or 0 also. The AHI number is driving almost exclusively from the H (hypopnea) readings. I guess I don't really understand what a "hypopnea" is -- does it mean the machine can't distinguish between a central and obstructive apnea so calls it a "hypopnea" ? What is typically done when this occurs.

I really appreciate everyone's understanding of my lack of knowledge and efforts to help me.

JIMCHI wrote: I wasn't aware that the Respironics machine is so much more advanced versus the Resmed Adapt SV.

I think of your current ASV model as having a couple more handy features rather than being significantly more advanced over previous generation ASV models. And despite your model being enhanced, there's also a chance that your Resmed ASV model treated you better---if Resmed just so happened to have accommodated your breathing nuances a little better. We have had posters who found the Resmed ASV more suitable after trying both brands, and we have had posters who found the Respironics ASV more suitable. The newer Resmed and Respironcs ASV machines are not as well-compared on this message board as the prior-generation ASV models were.

JIMCHI wrote: All of my daily reports show CA= 1 or 0 (I presume these are central apneas). My OA's (obstructive apneas) are 1 or 0 also. The AHI number is driving almost exclusively from the H (hypopnea) readings. I guess I don't really understand what a "hypopnea" is -- does it mean the machine can't distinguish between a central and obstructive apnea so calls it a "hypopnea" ? What is typically done when this occurs.

Apneas and hypopneas are both breathing or flow reductions---with an apnea being more flow-reduced than a hypopnea. Either can be central or obstructive, and either in abundance can be problematic---regarding both sleep and daytime symptoms. Your machine tries to differentiate central apneas from obstructive apneas; but it cannot differentiate central hypopneas from obstructive hypopneas. So when you see a hypopnea scored on your overnight reports, you can't know if it was central versus obstructive.

banned wrote:CPAP and EPAP 6 and below, are non-settings. Anybody with a CPAP or EPAP of 6 and below doesn't need CPAP therapy

In some CompSAS cases, a constant CPAP pressure of 6cm is enough to induce or worsen a central problem. That's when setting EPAP min below 6cm makes sense: to stent with the EPAP pressures on an as-needed basis using the EPAP-min through EPAP-max range. Whether that can efficiently solve the iatrogenic CompSAS problem is unknown on a case-by-case basis I would think. Hence the purpose of an in-lab titration with PSG diagnostics IMO.

Thanks again. I'll discuss all of this with my doctor on Monday. So far as the difference between the Respironics and Resmed machines, I don't feel any different. I feel pretty good and, as I mentioned, probably 75% better than I did before I was treated at all. I also had been on just a regular CPAP machine for awhile after I was first diagnosed and that helped very minimally. Frankly, the only reason I have all these concerns now is that the Respironics machine and the Encore Reader allow me to view my actual data and it's showing that my AHI's are high. If it hadn't been for that, I would have just gone on my merry way. And, aside from the night when I set the EPAP min and max at 6, I have felt pretty much the same every day regardless of whether the AHI was 5 or 23. Maybe I have no clue as to how I would feel if my AHI were 4 or less every day for a period of time. And while I seem to feel OK despite the varying AHI's, maybe the high readings mean my heart or other organs are under undo stress.

I'll let you know what my doctor says Monday.

-SWS wrote: So you and your medical team might want to consider titrating on this machine the way it was designed, rather than tweaking this machine as if you were tweaking your previous ASV model instead.

Great stuff, SWS!

But since originally proposing dial-wing'n by gradually increasing PS Min, which did drop his AHI buy 5 points, wouldn't it be prudent for this guy to continue on the 'tweaking path', if not just for tonite? The following would be the new settings, if he decides to continue down the "tweaking Path".

Pres Max 22
EPAP Min 8
EPAP Max 12
PS Min 5
PS Max 10 (Note: raising PS Max from 7 to 10)
BPM Auto
Flex (Off)

If the above parameters do not yield an AHI of less than 9, than most likely he does have a variability problem.
In which case he should do everything you mentioned, after you suggested he tweak Min PS.

By the way, my Enhanced Adapt SV crapped out on me.
I'm back on the original Adapt SV that is doing just as good a job, except for the chest pain.

SWS, your posts in this thread very enlightening.
I may buy a BiPAP Auto SV Advanced just to experience the difference are between the original BiPAP Auto SV.
As long as the BiPAP Auto SV Advanced can still keep my feet warm on the long-hauls to Saigon, I should be good.

What say yee?

JIMCHI wrote: I'll discuss all of this with my doctor on Monday.

That really sounds excellent.

In summary, your problem seems to be too many residual hypopneas---assuming the machine is scoring those hypopneas correctly. Furthermore, we have several possible hyopnea scenarios on our hands. And each of those hypopnea scenarios allows for different treatment strategies as follows:

1) Residual Obstructive Hypopneas: Despite standard BiLevel titration protocol calling for an IPAP increase to address those, they can alternately be addressed with higher EPAP because they are obstructive. Think of EPAP as stenting or inflating the airway to address your obstructive component. Think of IPAP as either venting the airway to better ventilate your central events, or further stenting the airway during inhale to address obstructive hypopneas. If hypopneas are undifferentiated, then an IPAP increase works for central or obstructive hypopneas.

2) Residual Central Hypopneas: These should be addressed by better ventilating via the EPAP-to-IPAP transition rather than stenting with higher EPAP. That means increasing IPAP, which also increases your PS value (PS=IPAP-EPAP).

3) Iatrogenic Central Hypopneas: These might require the opposite treatment strategy of the non-iatrogenic type. If your residual hypopneas are actually machine-induced, then getting PS min down to 0 cm can sometimes help; and getting EPAP min reduced can sometimes help as well.

In short, your machine endeavors to address your obstructive variability using EPAP min through EPAP max. But your machine endeavors to address your central variability using PS min through PS max.

Banned wrote: SWS, your posts in this thread very enlightening.
I may buy a BiPAP Auto SV Advanced just to experience the difference are between the original BiPAP Auto SV.
As long as the BiPAP Auto SV Advanced can still keep my feet warm on the long-hauls to Saigon, I should be good.

What say yee?

Budget permitting... why not?

Banned wrote:
But since originally proposing dial-wing'n by gradually increasing PS Min, which did drop his AHI buy 5 points, wouldn't it be prudent for this guy to continue on the 'tweaking path', if not just for tonite?

Why not -- I still have 2 nights before I see my doctor. Will try your suggested settings.

SWS - are you a doctor or a respiratory therapist?? You sure seem to know a lot. I really appreciate your involvement.

Do either of think think there is any possibility that my machine is defective?? When I first got it in mid-December it was showing my leak rate was like 3 or 4 LPM. This didn't make any sense as the minimum expected leak rate for the mask and pressure I was using was at least 26. It showed low numbers like this for 2 weeks and showed on the report that the DME printed out. Then the night after she downloaded the data, suddenly my leak rate went to a range of 26-30. I told her that the original data made no sense and that there was a sudden change. As I was very concerned that I had a defective machine, she called both the Respironics sales rep as well as Respironics Tech Support and they both told her there is nothing wrong. I just find it strange that I am also getting rather strange (widely varying) results on my AHI's.

JIMCHI wrote: SWS - are you a doctor or a respiratory therapist?? You sure seem to know a lot. I really appreciate your involvement.

I'm glad you asked, JIMCHI. I forgot to mention that I have NO medical training.

JIMCHI wrote: I just find it strange that I am also getting rather strange (widely varying) results on my AHI's.

I don't think AHI variability is rare in CompSAS cases. I'm not sure what to make of the unreported leaks. But Encore reporting software has a history of being flawed IMO. However, that's the reporting software and not the treatment algorithm.

-SWS wrote: I forgot to mention that I have NO medical training.

I have no medical training either, but unlike SWS, sometimes it shows.

No, your machine is not flawed. My Enhanced Adapt SV is completely inoperable. That would be flawed.

I made the adjustments Banned suggested for last night:
Pres Max 22
EPAP Min 8
EPAP Max 12
PS Min 5
PS Max 10 (Note: raising PS Max from 7 to 10)
BPM Auto
Flex (Off)

The AHI this morning registered a 7. One of the better numbers I have had. The chart of the Patient Triggered Breaths was also the smoothest of the 5 weeks I have been charting it. The average was 98.2% with little variation, while most of the previous nights had periods when it dropped to 70-75%.

Any additional tweek you want me to try tonight?