BiPAP ST User Needs Help with Centrals/Hypopneas

Mary Z wrote: I don't know of any OSA/ Complex sleep apnea, central sleep apnea treatment that would disable your spontaneous respiratory drive. ASV inserts a breath or breaths when you're supposed to take a breath and don't, but no therapy inhibits your own drive to breathe.

First, let's talk about your correct use of the word "therapy". Because that word is important in the context of this thread's discussion IMO. When you said "therapy", I assume you meant that:
1) a suitable treatment platform is being utilized, and
2) that treatment platform is already optimized (rather than introducing iatrogenic effect(s) at unacceptable rates)

Let's take a peek at the seventh row in Brian's data below:


That seventh row means that Brian's machine (and not his spontaneous drive) initiated his breaths: 29.1%, 32%, 39%, 29.4%, 18.7%, 36%, and 20% of the time on each respective night.

Now let's see how often Brian's machine (versus his own spontaneous drive) initiated his breaths that first night he moved his machine's Pressure Support (PS) to a fixed value of 7cm (recall that PS=IPAP-EPAP):


Also bear in mind Brian is using a BiPAP S/T machine above, rather than an ASV platform. But Brian's home experiment that night resulted in his machine initiating his breaths 65.4% of the time---rather than his intact spontaneous drive being allowed to initiate those breaths. Compare that number with the red numbers I have above. So that home experiment set a new record. With that home experiment, Brian went from initiating most of his breaths during sleep to having the machine initiate roughly two-thirds of his breaths. Note the machine's backup rate was not changed. Rather, Brian's respiratory drive changed in response to those new machine settings.

I don't think using a machine that way on a short-term basis is harmful. But I still question whether there are long-term risks---known or unknown---associated with unnecessarily preempting most of Brian's spontaneous breaths each night---year after year. That's the basis of the question about risk that I suggested Brian ask his doctor. And it's also the basis of why I would want to explore the other treatment modalities such as ASV: toward allowing spontaneous drive to initiate most of Brian's breaths rather than machine trigger.

Bear in mind there are patients, unlike Brian, who do not have an intact spontaneous drive. Those patients must rely on machine timing for initiation of all or most of their breaths. When a patient with an intact spontaneous drive must have two-thirds of their breaths initiated by machine timing, then the therapy platform or settings are likely not suitable IMO...

And I suspect that's why Brian's doctor is now arranging an ASV trial.

Mary Z wrote:... but no therapy inhibits your own drive to breathe.

I think that statement is wrong. Machine-induced central apneas are examples. And above we can see that PAP therapy is capable of introducing an iatrogenic effect that can inhibit respiratory drive at a given rate. We can infer, with those 20/13 settings, that the BiPAP S/T: 1) inhibited the rate at which Brian initiated his breaths, then 2) mechanically interceded with initiation of those now-delayed and now-missing breaths, and additionally 3) performed significant Work of Breathing reduction and mechanical ventilation via that large and constant PS change.

Listen to -SWS, he's got the science behind his reasoning. (I had a snide remark to the effect that "I give up, have it your way" that wasn't in the spirit of helpfullness on this forum). Sorry.

Mary Z wrote:I give up- have it your way.

I think the idea with these message board discussions is to TRY and have it the factual way, rather than having it your way or my way.

But sleep clinics and xPAP manufacturers have ALWAYS worked with/around the iatrogenic effect of PAP therapy inhibiting respiratory drive---more so with CompSAS patients. Patients on the message boards will occasionally exacerbate that iatrogenic effect as they experiment with machine settings. That's what happened when Brian's patient-triggered breath rate literally plummeted when he experimentally changed nothing other than IPAP...

It's been a rough few nights, so I'm not as rich in data as I might have hoped to be, but here's last night with a backup BPM of 14 and the inspiration time bumped up to 1.8.

(Sidenote on my change to inspiration time: when looking at the copy of the titration report I got in the mail on Saturday, I noticed that a Ti of 1.8 was what the clinician had used. Somehow, I guess that setting wasn't communicated along the chain from sleep study center --> doctor --> DME -- which probably explains why I was having such a hard time breathing on the 1.0 setting on my BiPAP when I got it and why I had to bump it up to 1.4 just to feel like I wasn't going to hyperventilate!)

It's interesting how I bottomed out in terms of not breathing after about the third hour, stayed lousy for about an hour, and then went right back to cruising along OK on my own.

BrianinTN wrote:It's been a rough few nights, so I'm not as rich in data as I might have hoped to be, but here's last night with a backup BPM of 14 and the inspiration time bumped up to 1.8.

Brian, that data looks encouraging!

BrianinTN wrote: (Sidenote on my change to inspiration time: when looking at the copy of the titration report I got in the mail on Saturday, I noticed that a Ti of 1.8 was what the clinician had used. Somehow, I guess that setting wasn't communicated along the chain from sleep study center --> doctor --> DME -- which probably explains why I was having such a hard time breathing on the 1.0 setting on my BiPAP when I got it and why I had to bump it up to 1.4 just to feel like I wasn't going to hyperventilate!)

Huge sidenote IMO. Telling and sad.

BrianinTN wrote: It's interesting how I bottomed out in terms of not breathing after about the third hour, stayed lousy for about an hour, and then went right back to cruising along OK on my own.

I agree. I'm glad S/T mode was there to back you up. You only had two residual events that whole time.

BrianinTN wrote: (Sidenote on my change to inspiration time: when looking at the copy of the titration report I got in the mail on Saturday, I noticed that a Ti of 1.8 was what the clinician had used. Somehow, I guess that setting wasn't communicated along the chain from sleep study center --> doctor --> DME -- which probably explains why I was having such a hard time breathing on the 1.0 setting on my BiPAP when I got it and why I had to bump it up to 1.4 just to feel like I wasn't going to hyperventilate!)

So thanks to your DME's mistake you never had a chance to trial your original BiPAP S/T prescription at home. Do you think it's a good idea to go back now and evaluate your full prescription at home?

Welllllllllllll, I hate to lay the blame without full information. So here's the full backstory: a few weeks ago, after my first night on the BiPAP, when I felt like I was hyperventilating trying to keep up with it, I did call my DME to ask her whether all the "other settings" (i.e., the stuff other than IPAP and EPAP), such as BPM, were part of my prescription, and she said yes. So, I called my doc's office subsequently to verify the settings. And while his nurse did confirm the setting of 16 BPM, she said she didn't see anything on the orders about inspiration time. So this may or may not be a DME thing. I mention this whole story only so someone stumbling upon this thread weeks, months, or even years later who feels like, "Hey, this doesn't feel right!" won't feel feel afraid to call their DME and their doctor to be sure ALL the settings were properly imported.

Anyway, back to the thrust of what you were saying: you make a good point. My sleep study is tonight, so we'll see what happens then, but it's worth another shot tomorrow night to see how the 20/16 does with the proper inspiration time. To be perfectly honest, though, if all things are equal, the lower pressures are definitely more comfortable! I sure do wish my data had looked good at 13/10; that was so much nicer than even now at 20/13.

That ASV was infinitely more comfortable last night. Night and day difference. FIngers crossed that insurance doesn't pitch a fit and decide not to cover it. (There was no testing to show BiPAP "failing" during the PSG -- they just jumped directly into the ASV titration. Maybe my home reports from my BiPAP are enough? I sure hope so.)

BrianinTN wrote:That ASV was infinitely more comfortable last night. Night and day difference.

It sounds like ASV is the best modality for you.

BrianinTN wrote: FIngers crossed that insurance doesn't pitch a fit and decide not to cover it. (There was no testing to show BiPAP "failing" during the PSG -- they just jumped directly into the ASV titration. Maybe my home reports from my BiPAP are enough? I sure hope so.)

Your residual fatigue that magnified when you used the BiPAP S/T is proof enough for failure. The comfort/discomfort comparison between sleeping with BiPAP S/T versus ASV is additional proof of BiPAP S/T failure.

I hope you get your new, comfortable machine soon!

That makes two of us. The technician (who's been in the field for 25 years) said the ASV "worked like a charm." They did ask me to fill out another Epworth Sleepiness Scale. I notched an 11 this time, compared to I think a 5 or a 6 when I went in for my first diagnostic study last year.

I wouldn't be quite so concerned if my insurance were leasing or renting my machines, but they bought the CPAP outright (billed at $2000K; they paid $1300) and then bought the BiPAP S/T outright (billed at $8000; claim still shows "pending" so I can't see what they actually are paying). When I talked to a person at Blue Cross last week and told her the situation, she did indicate they would tend to take a hard look at medical necessity for an ASV, but I couldn't ascertain whether that was a standard line or related to what they've already paid out.

Several posts ago, you posted three PDFs (two from ResMed, one from Respironics) about ASV reimbursement guidelines for DMEs -- mostly relevant to Medicare, but with applications to standard insurance too. Since my last PSG ended with a titration that appeared good (AHI<5 for 3 hours on BiPAP S/T 20/16), and we started last night with the ASV titration with no PSG data in between to show failure on the BiPAP, I'm hoping they won't deny the claim and insist the BiPAP S/T should good enough. Hopefully the doctor's letter plus last night's data will be enough.

No sense in worrying, I suppose, even though I'm exceptionally talented at doing so!

Thanks for your posts, SWS. I continue to learn from you.

I got a copy of my sleep study report and wanted to post it, in its entirety, for you folks to see. In any event, I'd welcome input. No word yet on when I might get my hands on the ASV, but I figure it's better to start asking you all questions now! This seems...too simple, especially from what I've read of other patients needing quite a bit of ASV tinkering.

BrianinTN wrote:I got a copy of my sleep study report and wanted to post it, in its entirety, for you folks to see. In any event, I'd welcome input. No word yet on when I might get my hands on the ASV, but I figure it's better to start asking you all questions now! This seems...too simple, especially from what I've read of other patients needing quite a bit of ASV tinkering.

Those PSG results are nothing short of stellar.

Those settings are the out-of-the-box Respironics default settings---and they sure seemed to work beautifully for you! Essentially your Advanced model ASV stays at 4cm CPAP as your "treatment base"--which is good if you don't tolerate unnecessary machine pressure. When you present obstructions like snore, FL, or even apneas the Advanced algorithm will automatically raise EPAP. When you present central apneas, the backup rate will automatically kick in with the EPAP-to-IPAP transition. When you present hypopneas, PB undershoot, or central hypoventilation, then IPAP will increase to the right amount, per-breath, toward getting that breath back on flow-target.

You are lucky to have received those excellent results. By golly, that machine seemed to work as designed, right out of the box!

Sleep Efficiency almost 87% !! That is sooooo good!

You and ASV were made for each other, Brian.
So happy for you!

If you can get your other sleep disorder (PLMD - Periodic Limb Movement Disorder) under control, you've got it made.

Thanks folks. I'll keep my fingers crossed that when I get the ASV at home, things are as good as they were in the lab. I appreciate all the input and will, of course, keep you posted!