No Answers Yet For Problems With ASV

[NotMuffy]

I am thinking I will read that entire post many more times, and then I may have a faint glimmer of understanding.

Deborah, I don't understand all that either. Deborah

OK, simply put:



Loop Gain is defined as the Ventilatory Response (R)(the hyperpnea following a respiratory event) divided by the Ventilatory Disturbance (D)(the respiratory event). If the response exceeds the initial disturbance (LG = > 1.0), then the system becomes perpetual (apnea begets apnea).

[NotMuffy]

The post to which Avi is referring can be found here-- http://www.binarysleep.com/phpbb2/viewt ... &&start=30.

Hoo-boy, that thread was painful to watch.

[NotMuffy]

What Needs Fixing Before Trying To "Fix" It.

Yes, finding out what needs to be fixed before attempting to fix it does make sense.

OK, so what is it that you're trying to fix?

[toodiaNop]

Desidero parlare con voi su questo tema.

[ameriken]

Yesterday afternoon, I took a nap and ended up turning the machine off after about 20 minutes. I kept feeling a bump in my breathing. Inhale- bump- exhale. And I felt like the machine was forcing itself on me, like my airway was being raped by the pressure. I turned it off, cussed at it for awhile, rolled over, and rested for awhile. When I went to bed, I didn't have Happy Joyful thoughts about the machine. Again, that bump when I was breathing. So, I reset everything back to the original ASV settings and fell asleep with no troubles. I will post the graph later.

Just jumped into this rather late and read your above post, Paper Nanny. While I do love the machine and have had some results with it, I've also had the same issues and posted about it a couple of weeks back. I'm a new user to the same ASV and I know exactly what you're talking about with the 'bump' and with the machine 'forcing itself' on you. It's like the machine reverses itself on you, like driving a car forward in drive at about 5 MPH and then suddenly putting it in reverse. I also spoke with my DME because I thought there was a problem with the machine itself, and she is looking at my graphs and trying to find out if there is a problem with the machine or what.

Here is the thread I posted about the same issue, I thought I'd post the link and the original post here since it seems to be a similar issue. I'll let you know if I find out anything pertinent from the DME, which I doubt.

viewtopic.php?f=1&t=65377&p=610543#p610543

I started using this machine about 2 weeks ago for OSA, CSA, and other SBD's. When I am falling asleep, I like how it responds to and assists my breathing. When I inhale, it increases pressure and when I exhale, it decreases pressure. However, I've recently noticed something that I don't know if is normal, or a possible problem with the machine.

It occurs after I've slept for a few hours. I'd wake up, look at the time (maybe 330 or 4 am) and then try to fall back asleep. That's when I notice the machine seems to be 'fighting' me a bit. Instead of responding to my breathing like it normally does, it seems to force an inspiration when I am not ready to inhale, and then it forces an expiration when I am not ready to exhale. When I am still exhaling it is pushing pressure for me to inhale, and then vice versa. It seems as if it has a pattern it is forcing me to follow, rather respond to and working with my own breathing pattern. In fact it almost felt like it was pulling air out of me when I was trying to inhale. It is just not responding to my breathing the same way it did when I first went to bed. It seems to want me to follow it's pattern rather than vice versa. This morning, after fighting with it a little while and trying to adjust to it, I finally fell back asleep and later when I woke up it was again performing normally and felt great.

I called the DME and they weren't sure what was going on and said to unplug it, plug it back in and see what it does the next nite. I did that yesterday and it did the same thing this morning.

Are there any users of this machine that may know what I'm talking about? Is this something normal, or does it sound like there could be a problem with the machine?

[Paper_Nanny]

Here is the thread I posted about the same issue, I thought I'd post the link and the original post here since it seems to be a similar issue. I'll let you know if I find out anything pertinent from the DME, which I doubt.

viewtopic.php?f=1&t=65377&p=610543#p610543

I replied in your original thread.

[rested gal]

The post to which Avi is referring can be found here-- http://www.binarysleep.com/phpbb2/viewt ... &&start=30.

Hoo-boy, that thread was painful to watch.

heheh, it sure was, wasn't it? Caused you worse pain (RT'ish pain) than it did me, of course; but even I had some "roll eyes" moments reading it ....whew.

[NotMuffy]

The post to which Avi is referring can be found here-- http://www.binarysleep.com/phpbb2/viewt ... &&start=30.

Hoo-boy, that thread was painful to watch.

heheh, it sure was, wasn't it? Caused you worse pain (RT'ish pain) than it did me, of course; but even I had some "roll eyes" moments reading it ....whew.

Yeah, ol' Claude there thinks he's the Cat's Meow. This time he really screws everything up with

Pressure support (PS) is the difference between IPAP and EPAP when using BiLevelPAP (BPAP). It is based solely on pressue not volume or air being moved. It typically provides for reduced work of breathing, since the expiratory pressure is lower than inspiratory, and the patient has to use less effort to breath out. PS provides the ability to take larger breaths, since the inspiratory pressure is higher than the expiratory pressure. BPAP is called NPPV, or Non-invasive Positive Pressure Ventilation (incorrect term) in the respiratory world, typically when used in the wake patient to stabilize arterial blood gas values, many times during weaning from ventilators.

Among other things, that's a reversal of old semantics-based debate that there's no such thing as a respirator (it would need to perform cellular metabolism).

Then trying to use FDA to prove his point:

And this is proven by the FDA authorizing these machines as NON-LIFE SUSTAINING devices. They cannot ventilate.

Well Claude, the FDA refers to these as 868.5905 Noncontinuous ventilator (IPPB).

Not that anyone should necessarily use the FDA as the defining authority in a medical discussion in the first place.

Fortunately, Ted says

I don't know who taught you respiratory, but you are way off.

and Claude must have read what he wrote and slinks away.

[NotMuffy]

It is based solely on pressue not volume or air being moved.

Pressure is used to increase volume (this is a Pressure-Limited, Volume-Variable Mode).

BPAP is called NPPV, or Non-invasive Positive Pressure Ventilation ...many times during weaning from ventilators.

If you're using NIPPV in weaning, you probably have a weaning failure, so that's a misleading generalization. The Weaning Task Force says:

Several studies have recently proposed the use of noninvasive ventilation (NIV) for extubated patients in different clinical situations, including prophylactic intervention in COPD patients who failed SBT [26], patients with repeated SBT failure [27] and post-surgical patients. However, the effectiveness of NIV remains to be determined. The increased use of NIV raises the question of how to define weaning success or failure. The current authors propose the following definitions. Weaning success is defined as extubation and the absence of ventilatory support 48 h following the extubation. Weaning failure is defined as one of the following: 1) failed SBT; 2) reintubation and/or resumption of ventilatory support following successful extubation; or 3) death within 48 h following extubation.

In conclusion, NIV cannot generally be recommended for any of the specific topics mentioned previously.

http://www.srlf.org/Data/ModuleGestionD ... on/556.pdf

Can any PAP machine, even the "great and wonderful" Vision from Respironics actually inflate the alveoli to the point that they exchange the gases...? The answer is no.

The answer is yes.

We have shown many a PSG that the machine toggles, from timed settings, between inspiration and expiration, but yet the patient desaturates. Now exactly how is that?

You screwed up the titration.

It is because the PAP used up to 30cm/H20 is NOT enough to exapnd the lungs to the point of causing ventilation.

Don't be silly. Of course it is.

Our usage of PAP is MANDATED on the patient's respiratory system to cooperate and take the breath when presented with the toggled Inspiration. BUt if the patient does not take a sufficient sized breath of pressureized inspiratory flow, they will not 'ventilate." Ergo, NPPV using a machine that can only go up to 30cm/H20 is not ventilation in its own right.

Nope, wrong before, still wrong now.

but the machines do not ventilate.

Sigh.

Without the patient's unconscious cooperation with the toggled inspiratory breath, the PAP machine WILL not expand the alveoli to the point that gas exchange can cross them, this in return means that RESPIRATION cannot not occur as the Co2 in the lungs cannot leave the lungs WITHOUT the cooperative breath of the patient.

That's really wrong. Exhalation is passive and needs no cooperation.

So no matter the scenario, the underlying piece of information that we always leave off of the algorithm is the human breathing system. These machines were never designed, nor do they offer the ability to act anything more than splints, or stimulating devices to assist the patient in taking the actual breath. They are assistive devices. Yes, they can be pressed into service to assist those with very unstable or fragile breathing systems (eg. weaning from true ventilators, ALS or other neuro-degenerative disorders, etc) where the splint and the stimulation, and with it the reduction in work of breathing assists these patients into being able to respire on their own, but with the machine to assist them.

Now you seem to be drifting into CPAP, but if you're calling it a RAD, and back into NIPPV, then you screwed it up again.

These things do not inflate the lungs, the increase the pressure to make it easier to inflate the lungs, but they do not, on their own inflate the lungs.

Simply amazing!

Sort of like they cannot blow up a balloon, but they can cause the balloon to be in that static partially inflated state PRIOR to actually drawing the huge breath to get the balloon over the inertia (hysteresis) of being uninflated. Anyone who has blown up a balloon knows that point. Puff up the balloon, then doe the extra effort to inflate it.

You think saying "hysteresis" makes you look smart?

[Mr Bill]

I've been away for a few days so I know this is behind the discussion curve but I wanted to respond to this point.

As Ozij has implied, slow breathing is fine if the SpO2 level isn't causing desats. From my experience it was the slow breathing that would upset my wife. She would push me when she couldn't hear me breathing. I used to wonder why she did it as to me all was fine, except there was the falling asleep at work problem.

Moving to a bilevel then an ASV has got rid of the daytime sleepiness. CPAP never worked for me. Dealing with the daytime sleepiness was critical to the type of work being done & a very strong desire to remain employed.

My understanding of ASV (certainly the Vpap Adapt SV) is that it starts off the night seeing the user breathing at a slightly elevated BPM rate & tracks this (in a 3 min window). Then as the user relaxes & goes into deeper sleep the machine tracks the change. Normally breathing rate does tend to slow (but can increase during REM sleep). If the rate combined with the minute ventilation drops too far the machine will increase the Ipap pressure (that is widen the PS) and start tracking to the builtin fallback rate of 15 BPM. I believe the Bipap AutoSV will do the same. However, there was a report that if the Bipap AutoSV is set to auto BPM, the rise time can become too slow. (see http://scholarworks.boisestate.edu/cgi/ ... s%20asv%22 - last paragraph). That may be sorted out in the latest models but it did reflect my own experience when using the original Bipap AutoSV, which by and large was a wonderful machine (still have it).

As hinted at to Mr Bill, adjusting risetimes is a very tricky matter & best done with *expert* clinical guidance. Just as an aside IIRC risetime can only be adjusted on the Bipap AutoSV when in BiLevel mode. I think it is a function of the algorithm when in ASV mode.

For you Deborah, I see the issue is do you suffer from 'erratic breathing' patterns that the ASV is not best at addressing. I have no real idea at this point if that is the case - NotMuffy has pointed out what info he needs to help determine that.

DSM

My RT and I never messed with the rise time but your post confirms my suspicion that the fall back rate of 15 BPM existed. Falling asleep at first was difficult because as my breathing slowed, it would pound me with pressure. It took a couple tries over about a week to get it right. If memory serves correctly, my RT first lowered fall back rate to 12 BPM which was still too intrusive and then finally we dropped it to 8 and then it was like Nirvana. My average sleep times quickly rose from 4.5 hours a night to 6.5 hours. Just fixing that backup rate lets me get to sleep each night and looking at the Encore BPM graph, the BPM marchs right up to ~18 BPM after I have fallen asleep.

As a geochemist who once took a digital signal processing class, I suspect if its more difficult for the algorithm to accurately decide if breaths are on time if the breath rate is low. Add to that, some erratic breath timing, and its going to score a whole lot of events.

Acting as a BIPAP it seems to be scoring lots of events both CA and hyponea. But acting as an ASV it would intervene on the CA but still score the hyponea.

"snip"

The ASV machine really is best at adjusting respiration on people who have predictable patterns of periodic breathing. Those with unpredictable patterns may not benefit at all & this is what I believe NotMuffy is pointing out & raising the flag on. e.g. In Cheyennes-Stokes respiration, the periodic breathing pattern has a predictable cycle of waxing & waning & the machine's algorithm is tuned to looking for that pattern and preempting it. Erratic breathing can counter the ASV algorithm. Some forms of SDB 'illness' will cause erratic breathing & bi-level is often the better choice.DSM

"snip"
Yes I am beginning to understand this point. ASV is not the sovereign remedy. Thank you DSM and NotMuffy for having the patience to explain this.

[Mr Bill]

So back to being existential, the graphs look scary but its not necessarily as bad as it looks. Reminds me of being moved to Namibia, Africa when I was 10 years old. I should have been entering 5th grade. They tested me and then set me back a full grade for not being up to level in the language Afrikaans. Metaphorically, the ASV is scoring you very heavily for erratic breathing. But, despite the poor test scores, you are getting some sleep with this assistance. If you have a while to wait before getting the tests NotMuffy suggested; which mode (BIPAP or ASV) is giving the better oximetry? I would try that for the time being and not worry too much about the EncoreViewer graphs. In other words try not to be too anxious about the graphs from either mode. Both seem to be giving you some sleep and that is far better than none.

@DSM and NotMuffy: I had no idea that spinal fluid played a role in CO2 respiration regulation. This is fantastically interesting.

[Paper_Nanny]

Yesterday, I called Mister Sleep Doctor's office to get information on the pulmonary function testings I will be having done later this month. Told the receptionist that's why I was calling and was transferred to the nurse.

My two main questions were: Which tests are included in the PFT? and What is the direct number to the department at the hospital where the testing will be done?

First question was being asked so I could get a list of the individual tests. The order has the box checked next to "Complete Pulmonary Function". Figured I would get the list of tests, post them here, and see if there were any others I should make sure I got, even if they weren't usually included in the PFT.

This is the summary of that part of the conversation.

You don't need to worry about any of that. The hospital knows which tests to do.
Well, yes, but I need the list anyway.
They will be checking for lung capacity and defects.

(Odd way to phrase that. Are they really checking for lung capacity or are they checking what the capacity is?)
Which tests will they be using to check those? I just need a list of the test names. I don't need a description of anything.
You know, no one has ever asked me this before.
That's okay. I'm asking now.
Well, there is: inhaling with force, bronchospasm, carbon monoxide diffusing capacity, plethysmography body, FVC and DLCO.

Does anyone else think she was reading off a list and either wasn't paying attention to what she was saying or she didn't understand what she was saying? Does not carbon monoxide diffusing capacity= DLCO? And is not the usual word order body plethysmography? Unless it is on a list as "plethysmography, body", mayhaps to differentiate from "plethysmography, psychological" or "plethysmography, spiritual"?

What about the Negative Inspiratory Force Test? Will they be doing that?
I don't know which tests the hospital does when they do a complete PFT. Why do you want to know about that test?
I wanted to be sure it is included. If not, I will need MSD to order it separately. Also, I had a question about the Negative Inspiratory Force Meter.

And before I go further, I need to make a momentary digression. When Husband and I went to get our marriage certificate, the woman filling out the forms asked Husband where his mother was born. Husband replied, "In Nebraska." Form woman looked annoyed and said, "Well where was it?" Husband said, "I'm not sure exactly where, but it was in Nebraska." Form woman looked quite irritated and shrieked, "In a basket? She was born in a basket? Well, where was the basket?"

Husband and I refer to that often in situations where there is that sort of slip between what I am saying and what the other person hears. That slip between my reality and someone else's where communication gets a little weird. If Husband had been in on the conversation yesterday, he may have suggested I ask The Nurse where her mother was born.

Also, I had a question about the Negative Inspiratory Force Meter.
Sounding completely befuddled, Nurse replied, I don't know what you mean by The Meter."]
I thought maybe she didn't hear me correctly. Yes, the meter.
I don't know what Meter you are talking about.
I don't know if there are different types of Negative Inspiratory Force Meter, but I would think all of them have something on them with numbers, maybe a circle with numbers, like on a blood pressure cuff? Numbers to say what the pressure was. I have a question about that.
No, no, there's nothing like that. It's all done in a box.
In a basket?
No, in a box!! If you want, I can give you the phone number for the department where the testing will be done. Maybe they can explain it to you.

So, I never even had to ask my second question! But, I am chickened out for now on calling the RT department at the hospital. I can't handle too many of those reality slippages at once. I need to recover from that one before calling the hospital. Also, before I call the hospital, I wanted to tell ya'll about that conversation with nurse because maybe I was the one who was slipping. Question for you's: Was I asking the question wrong? What do I need to ask in order to find out the range on the NIF meter?

Also, I have to ask... Any volunteers to make the call for me?? Anyone want to call the RT department at the hospital here and ask them which tests are included in the complete PFT and does it include a Negative Inspiratory Test and if so, what is the range on the NIF meter? (I am not sure if I am serious about that request or not. )

Deborah

[Paper_Nanny]

@DSM and NotMuffy: I had no idea that spinal fluid played a role in CO2 respiration regulation. This is fantastically interesting.

Yes, fantastically interesting indeed. Please, do tell us more!

[Paper_Nanny]

What Needs Fixing Before Trying To "Fix" It.

Yes, finding out what needs to be fixed before attempting to fix it does make sense.

OK, so what is it that you're trying to fix?

World hunger. A big problem, indeed, but not one likely to be fixed in this forum.

Maybe not so much what problem am I trying to fix as what questions am I trying to answer.

Question #1: Is there even a problem with my breathing while I am asleep? A few weeks ago, I wouldn't have asked that, but your post about my initial PSG makes me wonder.

Question #2: If there is a problem, what is it?

Question #3: What is the best way to treat the problem?

At the end of May, when I started this thread-- viewtopic.php?f=1&t=64550&st=0&sk=t&sd=a-- I would have answered this way.

#1: Yes, there is a problem. #2: I have OSA and CSA. #3: I am being treated with BiPAP ASV. I question the effectiveness because there is a downward trend in my percent patient triggered breaths and an upward trend in my AHI, especially the H

Now I would say #1: I don't know. #2: OSA? CSA? SDB of another sort? No problem? #3: I don't know. Doesn't the answer depend on the answers to #1 and #2?

What do I want? I want my sleep to be the way it was on the best nights after I got my ASV. I slept well. Deeply. Dreaming. I woke up feeling refreshed, chipper, perky, energetic. And I loved that feeling!! On those nights, my patient triggered breath percentage was high, my AHI was low. I seem to recall that being the way it was for the first 8- 10 weeks.

I had my follow up appointment with MSD at the beginning of May. I told him how wonderful things were going. There was an occassional night that was different. Once in awhile, every now and then, I would have a night where I woke up feeling just as tired as I had been when I went to sleep. On those nights, PTB was usually not so high, AHI was not so low.

And that is sort of where I think am. I actually feel reluctant to post that because maybe that's not really where I am! Maybe I have really been somewhere else these past weeks and have forgotten that.

Meeesh!! I hate days like this, where my mind feels clogged up with myelin lint. My thought processes seem to be slopping and slogging through a barely there, misconnected network of mish mashed neurons, transmogrifying everything in my past. Yeah, that's what I want to fix. <big sigh> It always does seem to come back to that.

Great word, transmogrify, is. Thanks for reminding me of its existence, Mr. Bill! And thanks to everyone who has been following my journey and helping me out along the way.

Deborah

edite to add a comma and fix a set of parentheses

[Paper_Nanny]

Also, I have to ask... Any volunteers to make the call for me?? Anyone want to call the RT department at the hospital here and ask them which tests are included in the complete PFT and does it include a Negative Inspiratory Test and if so, what is the range on the NIF meter?

As I was writing that, i was thinking that if I were asked do that, I could call someone else's hospital and get that information with no problem. So, I just pretended I wasn't me and I was calling for someone who was also not me. For a moment, I thought about changing my sign in to "NotPaper_Nanny" or "NotDeborah", "The_Post_Rapture_Remains_ of_Deborah". "Absence_of_Deborah". But no, for now, I will remain Paper_Nanny. It fits better.

I called the hospital. The RT I spoke with said the Complete Pulmonary Function Test includes: Spirometry, DLCO, Plethysmography, and, if indicated, a breathing treatment with albuterol and a repeat of the Spirometry.

And how about a NIF?? Only if it is ordered separately. And, even then... Well, it's hard to explain, she said. They don't actually have a NIF Testing Machine. They sort of improvised one. Well, not all of them, pretty much just Ki did. It is accurate, but it's something Ki made out of a pneumometer. They have only used it on patients who are on life support.

I am pretty sure I could get an order for the test. But, how do I get an order saying they have to get a real NIF meter first? Or do I need that kind of order? Is Ki's NIF meter sufficient? Ki was not in today. He will be in tomorrow. I can call him then if I want. Or someone else can volunteer to call for me.

Deborah