Varying AHI Readings on BiPap Auto SV Advanced

[-SWS]

Hey, it's good to see YOU weighing in, deltadave...

...the Respironics BiPAP autoSV uses a sliding four-minute window to average and then target peak flow

...do you have a Peak Expiratory Flow Meter?

JIMCHI, if you happen to have an issue with low peak flow, then the BiPAP autoSV can under-target as I think deltatdave wisely implies... And that, in turn, might explain why the IPAP has been riding low relative to either hypopneas or possibly hypoventilation...

How did last night's manufacturer-recommended EPAP range and PS range work out? Did you have to bail out early on?

[JIMCHI]

Here's my report from last night. I used Photobucket, as suggested, to upload the copy. I don't know how else to do it. I had no problems last night with the settings, but the AHI didn't drop at all. The Patient Triggerd Breaths dropped down to almost 50% about 3 hours into sleep and my Avg Minute Vent number went down about 1 point from where it usually was. The VS number took a huge jump to 10 when it usually has been 0 or 1. So, now what? Dr. said to try increasing Press Max to 30 if last night wasn't successful. Overall, this report looks as bad or worse than any of my others.

Yes I have a peak flow meter. My scores are usually around 450. I just checked this morning and I am at 500. As I am asthmatic, my doctor says that's an OK number.

[JIMCHI]

Maybe this will help. Here is a direct link to Photobucket with the 3 reports which I posted.

http://s1235.photobucket.com/albums/ff436/jimchi/

[Pugsy]

The images are being shown at 80% of full size, that is what is making them smaller with less detail.
You can change the image size to 100% and they will show up better. You can use the scroll thing to move the top portion of the report off the screen so that the bottom is included then take the screen shot.

[-SWS]

So, now what? Dr. said to try increasing Press Max to 30 if last night wasn't successful. Overall, this report looks as bad or worse than any of my others.

I strongly doubt the algorithm is capable of yielding a well-targeted PS for YOU by opening the PS range with that PS min=0 setting... That was the premise behind our experimental PS min increments...

If it were me I would eventually see what happens by changing PS min back to 5cm while leaving all the other parameters intact for at least a night. That test would likely yield better ventilatory assistance with the higher PS min. But it would also test to see if there were ANY benefits for you by allowing the algorithm to automatically address your variable obstructive component (via the full EPAP min through EPAP max range). But I'd bounce that proposed change off my doctor...

In the mean time, I think we should still wonder if the Respironics targeting of peak flow might be under-ventilating you compared to the Resmed algorithmic approach of targeting minute volume. So why not compare apples with apples? You can do that by converting overnight Respironics data to minute volume as follows: Use your Respironics-measured average tidal volume and breaths per minute to calculate your minute volume. First, divide your average tidal volume's ml number by 1,000. That gets you liters (l) instead of milliliters (ml). Multiply that converted number by your measured respiratory rate to get your average minute volume in liters/min.

THEN compare Resmed overnight minute volumes with Respironics overnight minute-volumes----to see if either flow-targeting approach just so happens to fall short compared to the other...

[JIMCHI]

I'll change the PS Min to 5 for a couple of nights and see. My doctor is in a very busy office and is usually not immediately reachable by phone, so I'll just make the change on my own. I may try his suggestion of upping the the Pres Max to 28.

I have no means of comparing the Resmed and Respironics machines. I have no software for getting data off the old Resmed machine.

I definitely feel worse today than I have on the other settings I had been experimenting with. If I continue to do so, I will just go back to the settings I was using a few days ago and wait until he's able to get some direction from the Respironics Clinical Lab.

I'm also beginning to feel my condition just isn't treatable.

[-SWS]

I'm also beginning to feel my condition just isn't treatable.

Well, that sentiment is premature, JIMCHI. There are quite a few treatment avenues to explore depending on what information surfaces during your current query. Some of those might entail setting this machine up differently to compensate for breathing nuances/etiology. One example to compensate would be peak flows that sink a little too low for this four-minute sliding target algorithm...

Three experiments worth comparing toward assessing this algorithm's suitability for your breathing nuances/etiology:

1) automatic obstructive and automatic central treatment- via the full EPAP range and full PS range (last night's)
2) automatic obstructive treatment with PS manually set for higher ventilation- via the full EPAP range but PS min experimentally set 5cm and higher
3) automatic central treatment with EPAP fixed at your best obstructive-treating value- via the full PS range but EPAP manually fixed to best stent obstruction

Okay, comparing those three scenarios helps us figure out which part(s) of the treatment algorithm falls short for you. And speaking of treatment options for CompSAS, one suitable option for you might be EERS in addition to PAP:
search.php?keywords=EERS

Is what you're believing what you're really seeing?

Deltadave seems to wisely question whether you are a TRUE case of CompSAS...

[Banned]

And speaking of treatment options for CompSAS, one suitable option for you might be EERS in addition to PAP:

I like that!
Can we plug his mask vents and add 2 liters of 02 before trying PS Min 6?

[NotMuffy]

When I say big, I mean BIG!!!!!:



There's old people who can't see here!

[deltadave]

Boy, that looks gnarly!

In re:

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.

although there's only a little data to work with, up until last night's D/L, the obstructive component was essentially zero (the algorithm would done a little more to address it).

So at at least now you know where the obstructive/central interface is.

I would also add

4) Sleep disturbance masquerading as SDB.

[deltadave]

And speaking of treatment options for CompSAS, one suitable option for you might be EERS in addition to PAP:

I like that!
Can we plug his mask vents and add 2 liters of 02 before trying PS Min 6?

No.

[Banned]

Boy, that looks gnarly!

No wonder he feels like crap, today.
EPAP Min is struggling to reach 7cmH20.
Avg. Presuure Support is 3, when it should be 6.

Hey deltadave,
You are using the avatar that SAG suggested for dsm.

Anyway, welcome brother!

[JIMCHI]

I've had an awful time today. I'm absolutely exhausted, feeling woozy, and have made mistake after mistake on computer work I was doing today that demanded accuracy. I can't have another day like this tomorrow . Will upping the Min PS to 5 hopefully get rid of these extreme symptoms? Or should I immediately just go back to the settings of a few days ago and wait for my doctor to get more guidance. I really appreciate all the help and suggestions everyone is giving me.

[Banned]

Your settings for tonight are:

Pres Max 30
EPAP Min 4
EPAP Max 15
PS Min 5
PS Max 15
BPM Auto
Flex 2

You won't feel great tomorrow, but you will feel better than you did today.

[Kiralynx]

Oops, sorry, gyrl,

I didn't think anyone with EPAP 6 was listening.
At least you are maintaining 4 points of separation between EPAP and IPAP.
Don't you find that 1 residual Apnea/Hypopnea annoying?
Is it an Apnea or a Hypopnea?
Lets go gunni'n for it.
Get your AHI down to 0.

Most of the time they're hypopneas... and at least 3 times a week I will have an AHI of 0. And, to be honest, I'm sleeping so soundly I don't notice it... unlike pre-ASV when I was constantly awakened by pain resulting from sub-par oxygenation.