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New User Problem with BiPAP AVAPS - Part 1
(10-10-2016, 05:24 PM)Sleeprider Wrote: Dude! That's a mess! Good job on the graphs though. I can't figure out why you're not on a ASV machine. This is nearly all central apena. Maybe you could ask your doctor that question.

Does your machine have an AE mode?
Verify you do not have COPD, asthma or obesity hypoventilation that you are aware of?

But the problem is, initially I did have mostly OA's. I am terribly obese, but have recently gotten the fear of the lord and lost 50 pounds and counting (still way high BMI) - no CHF, asthma, or COPD. But my CA's have been increasing lately which prompted the switch to the AVAPS machine. Note, the first two nights when using the modest I- & EPAPs my OA"s were still high. It looks to me like, when I gut it out and crank up the higher pressures, that's when my OA's are suppressed as they should be, but the CAs not; and instead the hypopneas are shooting up. I do not understand any of that. I have seen words that say something like "sometimes hypopneas are not really hypopneas" and my head swims. And I thought the AVAPS "guaranteed" ventilation per minute would suppress the CAs??

The PR System One BiPAP AVAPS does have 5 modes: CPAP,S (basic BiPAP), S/T (spontaneous/timed),PC (pressure control), and T (timed-all breathes machine triggered and machine timed).

I'm hoping for some input from my doc, and hopefully he can move up my appointment when he sees my interim problems. Meanwhile ....
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I hope you have a discussion with the doctor sooner than later. Meanwhile, I think the very high fixed pressure support is very bad for you and is the cause of your CA by washing out CO2. I'd like to see you at a slightly higher EPAP that resolves OA, and a low PS of 4 or less. If the PC mode was not prescribed by your doctor, you need to switch to S/T mode or AE mode if available. Your current pressure support seems to average around 6.0 and is limited by your IPAP max of 19

In my unqualified, non-professional opinion, I think you should try the S/T mode. PC mode is more of a ventilator, and I think it is really aggravating your CA. I would keep EPAP at 15 for now. If your CA does not improve significantly, you are simply on the wrong machine and need to discuss ASV with the doctor. The problem with the 1060 is it does not give a detailed respiratory flow line, so we really can't look into the details of the apnea events. S/T mode will continue to give you a backup rate, but does not focus on tidal volume. So, try S/T and see what happens with the tidal volume and the CA frequency. I don't see how it can get much worse.
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(10-10-2016, 08:42 PM)Sleeprider Wrote: I hope you have a discussion with the doctor sooner than later. Meanwhile, I think the very high fixed pressure support is very bad for you and is the cause of your CA by washing out CO2. I'd like to see you at a slightly higher EPAP that resolves OA, and a low PS of 4 or less. If the PC mode was not prescribed by your doctor, you need to switch to S/T mode or AE mode if available. Your current pressure support seems to average around 6.0 and is limited by your IPAP max of 19
Thank you Sleeprider. Interim: Finally got long review and discussion with sleep doc. We're trying some gradual changes, first of which was increase of EPAP min to 16, and increase Vt to 850. For 3 nights with these setting OA's dropped dramatically but hypopneas and CA's persisted. Here is 17 Oct data which is essentially the same for all three days.
[Image: UuB0pBLl.png]

Doc concurred CO2 wash-out may well account for CA's. Pending today's update on his recommendations other gradual changes TBA. He did admit he was not that familiar with the PR One AVAPS, and thought there was no significant difference between PC and S/T modes. I am not trying to second-guess anyone; just trying to understand.

Would increasing both EPAP min and IPAP min gradually be expected to decrease the hypopneas? How can CO2 wash-out then be prevented? Decease Vt? Decrease back up BPM?

I read the brief descriptions of the PC mode versus the S/T mode and the words seem to be almost the same. Can anyone explain the difference in simple terms for me, or give a reference for more detailed explanation? What are the criteria for selection of one mode vs the other?

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This is out of the clinicians manual for the older AVAPS BiPAP machine but maybe it will help your understanding. "The Pressure Control (PC) mode is similar to the S/T mode, except that all breaths are machine-cycled. The PC mode is a pressure-limited, machine- or patient-triggered, time-cycled mode. Therefore, the inspiratory pressure may be triggered by the patient or by the device, but IPAP will be pressure-limited with a set cycle time determined by the Inspiratory Time setting."

Best Regards,

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Again, please ask your doctor to try ASV. While I understand your doctor's good intentions, and assumptions in having you on AVAPS, the only real solution to your centrals, while resolving OA is to put you on ASV with a relatively high EPAP for OA, using zero or very low pressure support for comfort, and a high maximum IPAP (25) to resolve CA. I think the Resmed Aircurve ASV is the way to go, but your doctor will have to agree. It would be great if you could just get one to trial.
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(10-18-2016, 02:08 PM)Sleeprider Wrote: Again, please ask your doctor to try ASV. While I understand your doctor's good intentions, and assumptions in having you on AVAPS, the only real solution to your centrals, while resolving OA is to put you on ASV with a relatively high EPAP for OA, using zero or very low pressure support for comfort, and a high maximum IPAP (25) to resolve CA. I think the Resmed Aircurve ASV is the way to go, but your doctor will have to agree. It would be great if you could just get one to trial.

Thanks for your time and help in following this long thread Sleeprider. Again, I am not trying to get into a p-ing contest; just trying to understand and learn. My doc wants to keep on with the AVAPS at least for several week trial before making too many more changes. He did admit to not being that familiar with the PR One model. And I may have misunderstood but I think he said that CA's could be recorded even though the machine was appropriately initiating breaths and maintaining my needed minute ventilation. (???)

Briefly, my OA's have dramatically dropped to often less than one. But my hypopneas remain in the teens at least and the "reported" CA's remain in the high single digits.

I have tried increasing my EPAP and IPAP min but I get very aggravating mask leaks as the 20 threshold is broken. (I am trying a rotation of masks and various liners and supplemental strapping, none of which has worked magic yet.) And so far it does not seem to me that pressures higher than about 16-18 EPAP and 18-22 IPAP min make a durn bit of difference in CA's or hypopneas.

Things I do not understand:

With the "guaranteed breaths" of AVAPS, my charts for tidal volume and minute ventilation remain good even though my Patient Triggered Breaths percentiles can range from 50's to 70's. Why do CA's not go away if I am receiving tidal volume initiated or delivered by the machine as needed?

Why have my previously high OA's now seem to have morphed into intractable hypopneas, and how can they be fixed?

Symptom-wise I still am having daytime nap-attacks, but wonder if part of this may be sleep-debt from those days when total AHI's were in the 40-50's.

I'll put in only one recent screenshot since there is very little change in any of the reports with my current settings.

<a href="http://imgur.com/EgBI3co"><img src="http://i.imgur.com/EgBI3col.png" title="source: imgur.com" /></a>

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[quote='jmayer180' pid='180116' dateline='1477236835']
I'll put in only one recent screenshot since there is very little change in any of the reports with my current settings.

Clicked on the wrong darn clicker. Here is edited correction.

[Image: EgBI3col.png]
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When posting images, use the IMG tags rather than HTML https://sleep.tnet.com/reference/tips/imgur

[Image: EgBI3co.png]

First, your leak rate is so high, I don't think the machine reported events are reliable. Events are 1/2 of previously posted graphs, but still very far from objectives. Wow, 890 tidal volume! If this is even real, I have never seen this.
You were previously on PC mode. Have you tried the ST mode yet?
Please confirm if your machine is model 1060P.
It would help if you would write down all of your current settings:
PAP mode
IPAP 4-25
EPAP 4-20
BPM 0-30
Ti 0.5-3
Rise time control yes/no
Rise time 1-3

None of us are overly familiar with AVAPS. I'm going to "call a friend" and have Robysue drop by if she will for another opinion. I think it is quite clear your machine as currently setup is not resolving either CA or hypopnea, inspite of the rather amazing tidal volume. What I really don't understand is, did your doctor even do a titration study?
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Thanks again Sleeprider. Ill try to post a night's stats with similar settings but a smaller leak rate.

[Image: tgeJiBUl.png]

I did switch to S/T mode even though the doc said he didn't think there would be any significant difference in my case. And so far I have not seen any significant difference although now I'm thinking about it, would it be possible my higher leak rates could be because of the different pressure delivery between the two modes?? I've always battled leaking masks when I crank up pressures to close to my recommended 25/20 even back in the BIPAP days, but not to the 70-80% rate. (Again, I acknowledge ignorance of the difference in PC vs. S/T.)

Yes, I have the 1060P. I think.
(C series, DOM 30,SN: C17333301D9EC)
Mode: S/T
IPAP max 30
IPAP min 21
Target Tidal Volume 700
Rate 15
Ti 1.5
Rise on at 2 and stopped using ramp.

Back in the day many years ago, when I had to do spirometry for part of my military physical, my FEV1 was 6.1 (141% of predicted) FVC 8.0 (138% predicted) FEV1/FVC 76 (103%) FEF 25-75 4.90- (117%) - FWIW.

My recent (and lifetime second) sleep study is described back on page 1 I think. I expected that it would not only confirm my CA's but also try titration with a new mode. But instead, it used only BiPAP and auto BIPAP. As with my first study, I had very little actual sleep time. At least it convinced the doc the CA's were real, and to go to another mode. I believe he felt we could titrate at home with the new machine, and I certainly supported this idea in lieu of another gawdawful night in the sleep lab. My DX is "Complex Central Sleep Apnea" although it is hard to believe I do not meet "Obesity Hypoventilation Syndrome" criteria.

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Sleeprider asked me to stop by an offer some opinions.

First, I'm not an AVAPS user nor am I a doctor. I am a knowledgeable patient who uses a BiPAP for treating OSA, but who has read pretty extensively about a number of sleep disordered related conditions. That said, here is what I have to offer in this thread:

1) Leaks
Leaks were under control on the first screen shots, such as the ones for Oct. 4 and Oct. 5. Leaks are no longer under control on the screen shots for Oct. 8 and Oct. 20. Until the leaks are back under control, the data during the Large Leak flags must be regarded as potentially inaccurate. Given the size of the Large Leaks, I'd actually regard all data recorded during the Large Leak flags as EXTREMELY INACCURATE.

Goal number 1 should be to get the leaks back under control. Personally I would suggest going back to the original settings when the leaks were under control even though the therapy is clearly NOT working. More on that in a bit.

2) The doctor's role in this mess
I am glad that jmayer180 is working with his doc. A doctor's professional training and advice is going to be needed to get the therapy optimized. On the other hand, it's a shame that the doc is not totally familiar with the PR System One AVAPS machine that he has prescribed to jmayer180 and it is a bit concerning that the doc does not seem to be aware that there are some important differences between an AVAPS running in PC (pressure control) mode and an AVAPS running in S/T (spontaneous/timed) mode. It's also a bit concerning that the doc does not seem to understand that a more appropriate machine for treating complex sleep apnea is the PR System One AutoSV Advanced machine.

I'm not sure the links are allowed, but I'm going to put them in any way. The PR web pages have specific information about both the AVAPS and the AutoSV machines on-line.

Information about the PR System One AVAPS is at http://www.usa.philips.com/healthcare/pr...ventilator

Information about the PR System One AutoSV Advanced is at http://www.usa.philips.com/healthcare/pr...v-advanced

I would strongly encourage jamyer to print out all the documentation on both machines from these web pages and give copies to his doctor in advance of the next appointment. It is reasonable to ask the doctor to contact PR for information about which conditions the AVAPS is designed to treat and which conditions the AutoSV is designed to treat. Perhaps if the doc hears PR say "Use the AutoSV for treating complex sleep apnea" the doc will be more willing to consider switching jmayer to an AutoSV. Or perhaps the doc will be more willing to explain to jmayer why the doc believes the AVAPS is a better choice based on something in jmayer's medical history that we are unaware of.

Goal number 2 is to provide the doctor with as much information as possible about AutoSV machines.

Goal number 3 is to convince your doctor that you really should be sent to the lab for a full night titration study on a PR AutoSV machine to determine initial settings on that machine.

3)Lack of Flow Rate Data
It is frustrating for us that the AVAPS does not record the breath-by-breath flow rate data in a way that SH can display it. But there's nothing we can do about that fact. It does, however, mean that we're working in the semi-dark. Interestingly, the PR web pages do state that DirectView management software (for clinicians) does offer "reporting software for breath-by-breath analysis." If that's the case, one would hope that jmayer's doctor has the software (or is at least willing to get the software) and is willing to look at the breath-by-breath flow rate data.

Goal number 4 is to convince the doctor that PR makes software that should allow the doc (or one of his techs) to look at your current AVAPS data on a breath-by-breath basis OR to explain to you why this either can't be done or is unimportant when it comes to figuring out what to change in the AVAPS settings.

4)PC mode on an AVAPS
I just don't know enough about PC mode to understand how it works. My very limited understanding is that PC mode uses a fixed IPAP pressure in a way to insure that the required (set) Tidal Volume is delivered in the (set) time for the inspiration. This is indeed a real (non-invasive) ventilation mode where the machine is supposed to be able to "breathe" for the patient as near as I can tell, and in that case it's not clear at all what parameters are used to score the CAs. That also means that we're all working in the semi-dark here. I could speculate on what I think the machine might be doing, but it would be nothing more than idle speculation with no real grounding in factual knowledge. And I don't want to do that.

It's also completely opaque to me about what criteria the AVAPS running in PC mode uses to increase the IPAP pressure.

It may be useful to post the Tidal Volume chart instead of the Respiratory Rate chart since PC mode apparently uses a target TV to determine the IPAP pressure.

4)Obvious lack of efficacy of the AVAPS PC therapy
My overall impression of what the data is indicating about the obvious lack of efficacy in the data is this:

Way too many CAs. And it's not clear at all why they're happening. I suspect the problem is that the PC mode is just not set up to quickly respond to breathing becoming unstable by drastically increasing the IPAP over as few as 4-5 breaths.

It's also very interesting and telling that in the Oct. 4 data, the thickest cluster of CAs is scored when the machine has chosen to leave the IPAP down at 10cm (min IPAP) for a thirty minute period between 4:00 and 4:30. An AutoSV Advanced machine would be increasing the IPAP pressure rather drastically at the beginning of that cluster and there'd be a wide gap between IPAP and EPAP until the breathing stabilized.

Way too many Hs. I suspect that most, maybe all, of the H's are actually central hypopneas rather than residual obstructive ones. In other words, it is my belief that if the therapy were correctly treating jmayer's complex sleep apnea the number of Hs would decrease at the same time the number of CAs decrease.

Way too many OAs in the early data
The early data have way too many OAs, most likely because the EPAP is not high enough. Once jmayer increased the EPAP a bit, it looks like the number of OAs has started to come down, but its not clear if they have come down enough. (Those pesky Large Leaks are part of the problem.)

Goal number 5 is to print off as much data as you can, preferably using Encore since the doc will understand the validity of Encore data. Deliver it to the doc's office with a note that you want the doc to contact you after he has had a chance to study the data.

5) A note about how AutoSV works
As sleeprider has pointed out, a more appropriate machine to use for complex sleep apnea would be an AutoSV. The way an AutoSV works is essentially this:

The EPAP is used to control the obstructive events. If the ASV is running in an advanced mode, the EPAP is allowed to vary. So the machine can respond to obstructive events (OAs, snoring, and flow limitations) by increasing the EPAP.

The IPAP and PS is used to control the central events. If centrals (or clusters of Hs with particular characteristics) start to happen, the machine rapidly increases the IPAP by as much as 5-10cm over the course of maybe 5-10 breaths in an attempt to trigger inhalations and to prevent the CO2 undershoot from happening. This stabilizes the breathing and once the patient is breathing on his/her own again, the machine rapidly decreases the IPAP pressure to insure that a CO2 overshoot does not develop.

The AVAPS's ST mode would be similar to the AutoSV in that in ST mode the machine would be tracking spontaneous patient inhalations and only step in with additional IPAP when the breathing becomes unstable. The PC mode seems to be providing "assistance" regardless of whether the patient is initiating any inhalations on their own. The amount of assistance (the PS = IPAP - EPAP) does seem to be variable based on mjayer's data, but it not clear how the machine decides how much assistance to give the patient.

6) Where to go from here AND some questions for jmayer
First the questions:

Jmayer, have you ever had a titration study done using an AVAPS machine? If so, do you have a copy of that study's results, both the summary data and the recommendations? If you haven't had an AVAPS titration done, then do you know how the doc decided on the initial settings for your machine? Because my own feeling is that if you have NOT had a proper titration on the AVAPS with the machine set to PC mode, the doc is just guessing about the settings and the data says he's got those settings wrong.

Obviously continuing to work with the doc is required. But how can jmayer get his doc to actually start paying attention to what's going on?

First, I'd make sure that the doc sees the data. I'd print off the Encore report and deliver it, along with the specs of the AVAPS and AutoSV machines, to the doc's office with the written request that the doc get back in touch once he's had a chance to look at the data and the specs on the two machines. I'd also prepare for the next appointment with some important questions about the efficacy of the therapy. Here's my suggested list of questions:
  • What is your (i.e. the doc's) definition of ``effective'' therapy for my complex apnea?
  • Given that the AVAPS machine reported AHI numbers are way, way too high, what suggestions do you have for changing my settings?
  • Given that PR suggests the AutoSV is the appropriate machine to use for treating complex apnea, would you authorize an AutoSV titration study?
  • If the doc doesn't want to switch you to an AutoSV AND you have not had an AVAPS titration, then you need to ask the doc: Can you authorize an AVAPS titration so that we're not guessing about what the settings on the machine should be?

Finally, I would hesitate to do too much experimenting with the AVAPS PC mode's settings. Non-invasive ventilation is not as complicated as invasive ventilation, but even so, getting something seriously wrong could make a bad situation worse.

The only settings I would be willing to play with might be the min EPAP (which you've done) and the max IPAP (as required to play with the EPAP) and the min PS setting. It appears that min PS is currently set to 0. It might be worth increasing the min PS to something like 1 or 2 to see if nothing bad happens in the sense that things become WORSE. If things are no worse with a min PS = 1 or 2, then you might try using a min PS = 3 or 4 to see if things start to move in a better direction.

Jmayer, I wish you the best of luck, and I hope this has helped you understand a bit more about your very complex situation. I also do think you need to bring up the idea of an AutoSV Advanced titration with your doc. The current therapy is just not working and it's time to try to get the doc to think beyond "AVAPS is the way to go"

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