Resmed VPAP Adapt SV - for Central Sleep Apnea

StillAnotherGuest wrote:It'll be interesting to see that algorithm. I would offer that you might not be able to report out AHI (AI, anyway) because central apneas may not be accurately assessed using ASV. Let's say ResMed uses a 75% reduction in flow to define an apnea. As soon as AdaptSV sees an impending apnea, it rapidly increases pressure to achieve 90% of Target Ventilation relative to recent baseline. So if it works even close to the way it's supposed to and it's set up correctly, you shouldn't really see too many apneas. This does not automatically infer that the CSR or CSDB cycle has been broken, which is what you really want to know, but this can be inferred from other parameters, like Minute Ventilation (which might even be a little more sensitive in tracking cyclical phenomena).

Or maybe it's a marketing thing. If you do have apneas, then maybe "It's not all that amazing."

Or maybe they're gonna use SAG's idea of Incomplete Event Attack (IEA).

Speaking of which, those AdaptSV Minute Ventilation waveforms are real examples of the stated phenomena.
SAG

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SAG,

Yes, it does seem that the AutosetCS2 machine can't really report the same type of AHI data a regular Auto/Cpap will largely because it has corrected the bulk of the problems before they became problems.

Just to clarify for other readers, the AutosetCS2 machine has a target of maintaining a min 90% ventilation from the current baseline. Put another way, if you are breathing 8 litres / min and you start to drop away from this by breathing less, the AutosetCS2 after you have dropped to 90% of the 8 lpm will kick in and start to 'ventilate' you (force air in to maintain the 90% level from the previous 8 lpm). Thus it has the unique ability to switch from passive ventilation (you are driving it) to active ventilation (it starts trying to drive you).

In effect it is attempting to prevent a looming flow limitation (or hypopnea which is a flow limitation with certain pre-determined characteristics (50% drop in airflow within 10 secs + an SpO2 desat occurring at the same time - allowing that in general a SpO2 desat is a 4% drop in SpO2 in a 10 sec frame)).

But as with all ambitious technologies, it has its challenges. One being the leak issue & 2 being the new problems it creates while solving others.


DSM

frequenseeker wrote:
He also answered my question about why it is uncomfortable during the Learn Patient phase. It is designed to deliberately push over and under the ventilation baseline to determine the algorithm, because it cannot otherwise passively learn the patient's ventilation. After this short phase it should be comfortable and effective, so it is just something to be endured.

Uncomfortable during the Learning Circuit? Its not uncomfortable, its a machine- it can either pass the learning circuit with a particular mask or not, and the Swift cannot pass, nor does any mask with smaller diameter lead hose or severe restrictions of air flow. If the Swift works so well, why didn't ResMed include it as a mask option? I still don't buy that its effective, it may 'work', in the sense that the machine is on and able to respond somewhat, but is able to be as effective as possible? Its like having a sports car, but always using it in 2rd gear- sure it runs, but is it running optimally? I know you've spoken with a rep from ResMed- is he a sales rep or is actually a sleep professional? Sales reps will tell you whatever you want to hear unfortunately. I'm lucky that our regional rep use to be the lead sleep tech at the sleep lab I go to and had worked with my sleep doctor for years, so I trust his recommendations much more then most reps. Also, why did you have your brother go with the Swift? Does SmartStop/AutoOff work with the Swift or not?

I still can't comprehend being so attached to one particular mask that you would potentially allow it to compromise your therapy, especially when you've went to such great lengths to travel to BI to be diagnosed with CSDB and all. I would love to be able to go back to using my ComfortCurve, which was my mask of choice for 2 years, prior to that, I used a Swift. I understand marks on the face from masks, but most of the time they don't continue once you have your mask adjusted properly, after the first week or so; and even then, most mask marks disappear fairly quickly in the morning. I'm dealing with a more complex situation, with my Dermatographism and Pressure Urticaria flaring up. It doesn't matter how loosely I wear my mask or how careful I am about were it touches my face, if my body produces too many mast cells, I can end up with raised red welts that easily result in the top layer of my skin peeling off if repeated pressure is applied to the same area- somewhat like a blister, but not exactly. Bandaids don't help, because its the pressure itself- besides, 99.9% of bandaids use a corn based adhesive, which leaves me with a worse problem from contact allergy. Heck, I developed Pressure Urticaria on my elbow from leaning on the arm of my chair too much (sure does make me a little paranoid about sitting for too long in one place).

Was I correct about what you posted last fall- that your average pressure increased as you raised your EEP? You didn't mention anything about that part of my post, and I was wondering what else it could be.

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dsm wrote:
Just to clarify for other readers, the AutosetCS2 machine has a target of maintaining a min 90% ventilation from the current baseline. Put another way, if you are breathing 8 litres / min and you start to drop away from this by breathing less, the AutosetCS2 after you have dropped to 90% of the 8 lpm will kick in and start to 'ventilate' you (force air in to maintain the 90% level from the previous 8 lpm). Thus it has the unique ability to switch from passive ventilation (you are driving it) to active ventilation (it starts trying to drive you).

It works both ways- it determines a target minute ventilation, based on previous so many seconds/minutes, and if your breathing doesn't result in a matching MV, it makes adjustments either way to help guide you in the right direction. If you think of a standard BiPAP ST, it has a fixed target based on one aspect of your breathing, breaths per minute (BPM). Even if you breath 12 times per minute, does each breath cycle equal 5 seconds? Or could you have a few that are 6 seconds and a few that are 4 seconds? You can see where a fixed timed backup rate can get in your way- we are humans, not machines...if left to our own devices, do we march in formation or to the bear of our own drummer? Too high of a back rate, and you'll find yourself tripping over it- or being that soldier who turns right when everyone else turns left; you end trying to exhale when it wants you to inhale and never feeling like you get to finish your own sentences, which can further throw off your breathing. With regular BiPAP ST, you could take 12- 5 second breaths, but what if you only exchanged 1/4 the amount of air you normally do? Those 12 breaths may look great from the machine end, but suddenly your O2/CO2 levels are off because you are not moving enough air. Mix together the wrong lengths and too little air exchange, and you've got a mess.

The Adapt has a constantly moving target based on Minute Vent, which equals Tidal Volume x BPM, taking into account both volume of air exchange and number of times per minute. SAG can correct me if I'm wrong, but I don't think the Adapts backup rate of 15 is the same as a normal BiPAP STs backup rate of 15. The Adapt has a listed backup rate, in part, due to insurance & Medicare. If it didn't, it would be billed under a regular BiPAP, not BiPAP ST, which are considerably different in price. I have never felt forced to breath more often then I need to while on the Adapt. Its hard to explain, but I think I'm the only person here with considerable experience with both BiPAP ST and the Adapt. The Adapt is very good at convincing me to breath, much more so then BiPAP ST, but its not an in your face, do it now type of convincing that a regular ST tries to give. Its more of a gentle nudging and guiding that leaves you wonder how someone got you to agree to something- you don't really remember them asking and you don't remember saying yes, you just know you're doing it. You can have fun trying to adapt your breathing to the the target MV, but as soon as you do, its going change, because its based on your input...in other words, it soon becomes as silly as a dog chasing its own tail.

The first thing I do with any BiPAP ST is check how long it takes for the backup rate to kick in, by holding my breath to simulate a central apnea. This lets me know the Timed rate is working and will kick in when I need it...not that I'll necessarily take the hint to breath, mind you, but at least I know its doing its it part. Its as easy as pie with regular BiPAP STs, I could go several breath cycles. Not so with the Adapt, before I realize it, I'm taking a breath...I told you it was sneaky. Its like trying to have a staring contest with sculpture- you know you can't win. I even tried breathing through my mouth, with a nasal mask on, and it still won out...leaving me scratching my head. I use to be able to feel myself slip into some major period breathing as I drifted off to sleep, that was my norm for the past few years, but not any longer. My breathing is completely regular as I fall asleep, which makes falling asleep and staying asleep much easier. I had started taking it for granted, until the other night, when my breathing was once again irregular due to exposure to popcorn popping, as my allergy to corn has increased. Great, now I can finally stay awake through movies, thanks to my Adapt, but I can't go to the movie theater

Christine, I've always enjoyed reading your clear, articulate descriptions of your experiences with central sleep apnea and ST machines. You outdid yourself on this one! Great info about what the ASV does and how you're doing on it.

-SWS wrote:

Resmed Technology Fact Sheet wrote: However, as the apnea/hypopnea persists, the device increasingly uses the backup respiratory rate.

The above mentioned recent-average calculation and subsequent comparison of post-expiratory pause is where the ASV algorithm presumably responds in one of four approximated ways (toward delivering that variable or "sliding" time-based back up rate): 1) cycles spontaneously (because detected patient inspiratory flow is on time relative to recent average), 2) cycles at or close to a recent time-based average (but before human inspiration is detected, because that spontaneous human-based inspiratory trigger is thought to be somewhat latent relative to recent averages), 3) cycles less-close to that recent time-based average (again, for lack of a timely spontaneous human-based trigger, and as the machine gradually migrates toward that 15 BPM back up rate or limit), or 4) eventually cycles at that 15 BPM rate or limit (once again for lack of a timely spontaneous human-based trigger, and because the ASV progressive back up limit of 15 BPM has finally been reached).

Okay, more on my post-subway-station conjecture of just how ASV employs its "sliding" or perhaps even "alternating" back-up rate of 15 BPM. In my own mind, it's clear that steps one (spontaneous), two (primary back up), and four (15 BPM back up) happen, based on Resmed's description. Again, step two is an ASV back up rate calculated from "recent average". And step four is that capped or limited ASV back up rate of 15 BPM.

But the question is, whether ASV smoothly transitions from step two (recent average) to step four (15 BPM), by smoothly implementing intermediate steps (step three happening perhaps multiple times). Or does ASV simply alternate between a patient's "recent average" back up rate and 15 BPM? Looking more closely at Resmed's text that I have highlighted in this post, it sure sounds as if those progressive intermediate steps might be skipped altogether.

If that's true, then "recent average" is everyone's primary ASV back up rate, while 15 BPM is their secondary back up rate. And that secondary back up rate of 15 BPM would be increasingly used for persistent apneas/hypopneas, on an as-needed basis. I'm thinking this second possibility of alternating back up rates (alternating "recent average" and 15 BPM) is actually a much better match than that first "progressive sliding" scheme for back up rates (starting at "recent average, then progressively sliding to 15 BPM).

I'm going to eventually take a peek at the ASV patent description once again. However, patent descriptions are not at all required to exhaustively disclose low-level design. SAG may even have access to a training module that explains in detail how ASV transitions from a "recent average" back up rate to that 15 BPM back up rate. Others may be able to find out back up rate transition details from their Resmed field reps.

But I definitely agree with Christine about ASV back up rates. Based on Resmed's text description, the ASV does not employ a fixed 15 BPM back up rate as traditional bilevel machines might.

[on edit: I lost my original post during the edit/quote process. The above text was supposed to be a separate follow-up post to my missing post. Bummer! Also edited description of postulated steps.]

-SWS wrote: I think frequen's doctor is probably describing the ASV process of baselining human respiration itself ("learn patient") versus ASV impedance-based pressure calibration ("learn circuit"). When the ASV is first powered on there are no "recent averages" by the way of human respiration for the machine to work with, to calculate and compare against. And that would certainly imply a necessary patient baselining procedure by the algorithm at startup. So "learn circuit" would happen prior to a sleep session. But the first part of the sleep session would also entail a respiratory-parameter baselining procedure, by the ASV algorithm itself toward "learning the patient".

But when you use an approved mask, or at least a mask that can pass the Learning Circuit on its own, there is no period of uncomfortableness when you start up. The only way I could replicate it was to use my Swift mask, having run LC with my Vista. And you want to talk about uncomfortable...Swift + Adapt is more then uncomfortable, its miserable. When I put my Vista or Activa on, even if I forget to run the LC when I switch or if I've just run the LC, its smooth sailing from the start, relaxing, soothing, I can put my head down and fall asleep blissfully...and when have you ever heard me say that in all these years until now? Yes, I love my Adapt and what its done for me. Back to my old dancing analogies, its like having a ballroom dance partner who can read your mind and predict what you're going do to next.

With the $*%& Swift, I felt like I fighting the machine, it was triggering backup rate when it didn't need to be, and worse yet, I started feeling light headed and not comfortable at all- much more like a 'break dancer' then a ballroom dancer, and not even a good break dancer. This went on for some time, never really settling in to that blissful comfort I'm use to with my Adapt. It was a little less when I put the Swift back on the next time, without rerunning the LC, but still not great and I certainly would not want to sleep overnight with a combination of Swift & Adapt. I put my Vista back on, without running the LC again, it was back to being just as smooth and graceful as normal, even after having had the Swift on and running so erratically. Auto shutoff also does not work with the Swift, just as I expected, and it even made auto off not work as well with my Vista, until I reran the LC.

With the Swift, it was as if the Adapt couldn't read me and in a lot ways, felt like the VPAP II STA's I had tried over the years, which isn't good. You remember the struggle I had with VPAP II STA's and the lengths I went to early on, before I was switched to Synchrony BiPAP ST. I'm so glad I had my own, personal Respironics BiPAP STD to test against then and had successful first month with a Quantum PSV, otherwise I would have never know the benefit BiPAP ST could give me, even though it couldn't stop all my centrals. Basically the Adapt acted like a BiPAP ST more then an ASV, with a few extra quirks thrown in with the pressure changing. So I guess if someone is so attached to using one particular mask over type of machine, they might as well get a BiPAP ST and set it with a back up rate of 15.

I did manage to fall asleep for a short period of time this afternoon with the Swift on, but it was not anything like what I'm use to now. My sleep wasn't as deep and I definitely didn't feel restored at all, like when I normally take an occasional afternoon nap with my Adapt. The strange thing is I wasn't that tired before my nap, and now I actually feel worse...a little too much like I did before I started on my Adapt for my liking. I think I have a Swift hangover or something

It was weird to have a mask affect treatment that drastically and I cannot understand how Beth Israel can say it 'works fine' with the Adapt, unless they are going by what people say who have never used anything else with the Adapt for long enough to compare. There is a reason ResMed didn't include it as an approved mask, and I cannot understand how a well respected doctor could recommend otherwise. This is not a case of prescribing a medication off label for a generally accepted use, this is akin to prescribing a medication when its contraindicated by a black box warning. ResMed said not to use their Swift mask with their Adapt, and I if they could have included it, they would have. Of course I also don't understand how the docs at BI didn't know the backup rate is set at 15, by default either. It has to be part of the prescription to have the Adapt covered as a BiPAP ST, instead of a regular BiPAP. Makes you wonder sometimes.

-SWS wrote: Okay, more on my post-subway-station conjecture of just how ASV employs its "sliding" or perhaps even "alternating" back-up rate of 15 BPM.

No fair changing out your post when I had already quoted you


Another couple points I forgot to mention about my Swift/Adapt trial-

• I was able to hold my breath and simulate a central much more easily with the Swift mask then normal. The Adapt just wasn't as convincing at getting me to breath, which we know isn't a good thing. The Adapt is the first machine that's been good at convincing me to breath.
  
  The BPM screen stayed at or near 15 a lot more then it does with other mask, also pointing to the Adapt not being able to properly read me like it normally can.
  
  Did I mention I never want to see my Swift anywhere near my Adapt?

Somewhere along the line of attempting to quote my own text for today's previous post, I accidentally the post from last night. There should be one more previous -SWS post than appears. Today's first accidentally replaced or eclipsed last night's long -SWS post. Very frustrating!

christinequilts wrote:But when you use an approved mask, or at least a mask that can pass the Learning Circuit on its own, there is no period of uncomfortableness when you start up.

I'm certain that statement fits you well, Christine. However, across the patient population there are supposedly varying degrees of "biologic discomfort" related to CPAP intolerance. During that initial ASV patient baselining procedure (not the "learn circuit" routine) the over-ventilation/underventilation targeting process should theoretically account for varying degrees of discomfort across the patient population, commensuarte with each patient's CPAP intolerance.

The Swift just may factor in here. However, a very plausible alternate explanation might be that frequen's CPAP intolerance is actually greater than Christine's. If so, frequen's heightened perception of discomfort during ASV patient-baselining might be well explained by heightened CPAP intolerance. After reading plenty of posts and emails, I really suspect that frequen is CPAP pressure intolerant to some heightened degree. If so, frequen should theoretically find the ASV baselining process less comfortable than other ASV patients might perceive.

christinequilts wrote:

-SWS wrote: Okay, more on my post-subway-station conjecture of just how ASV employs its "sliding" or perhaps even "alternating" back-up rate of 15 BPM.

No fair changing out your post when I had already quoted you

See my comment above about accidentally losing last night's post. If you or anyone else happens to have that lost text to insert/quote, I woud be eternally grateful. I didn't save that text since I foolishly composed it on line.

christinequilts wrote:Another couple points I forgot to mention about my Swift/Adapt trial-

• I was able to hold my breath and simulate a central much more easily with the Swift mask then normal. The Adapt just wasn't as convincing at getting me to breath, which we know isn't a good thing. The Adapt is the first machine that's been good at convincing me to breath.
  
  The BPM screen stayed at or near 15 a lot more then it does with other mask, also pointing to the Adapt not being able to properly read me like it normally can.
  
  Did I mention I never want to see my Swift anywhere near my Adapt?

Your Swift/Adapt trial is an exceptionally good anecdote in my opinion, Christine. Hope frequen seriously revisits that angle/possibility based on your excellent descriptions.

I don't buy that CPAP intolerance is playing more of a major role then use of a non-approved mask, especially when you take into account my history with various machines, complexity of my CSA and lack of adequate control of my centrals & periodic breathing with other machines. It honestly did not feel like I was using my Adapt and if I didn't know any better, I would have said someone hooked me up to a different machine, by the way it acted was so dramatically different. If it did that with a regular mask, my DME would have gotten a call in the middle of the night to replace it immediately. It was not functioning within normal parameters.

LC is integral to the function of the Adapt. They don't have us do it just because, it is so the machine can function properly. I pulled on my clinical manual and here is what is says (sorry for any typos):

From the Clinical Manual:
Learn Circuit
The Air Circuit Learn function (LEARN CIRCUIT) provides a way of factoring the impedance of the air tubing assembly into the the delivered pressure. The Air Circuit Learn function must be run every time impedance in the air circuit is altered (eg, addition or removal of an antibacterial filter or addition or removal or a humidifier), or the flow generator is moved to a significantly different altitude. Set up the whole system (flow generator, air tubing, mask and other component) before running LEARN CIRCUIT. Do not cover the mask. If the LEARN CIRCUIT fails, the VPAP Adapt SV reverts to the last successful impedance value.


And from the User Manual:
The Air Circuit Learn function takes approximately 20 seconds to run. It allows the unit to 'learn' what pressure it needs to build into its calculations, based on the components in the system. Select LEARN CIRCUIT every time you add or remove a component (eg, mask, humidifier) or move to a significantly different altitude.
To run this function:
1. Set up the entire VPAP Adapt SV system (flow generator, mask, humidifier, etc) as you wish to use it.
2. Make sure that the mask is unobstructed so air can flow from the mask to the flow generator.
3. Turn on the VPAP Adapt at the power switch.
4. Move through the menus until you reach LEARN CIRCUIT and select 'yes' by pressing the Left key.
5. A message will remind you to check that the airflow from the mask is clear. select 'start' with the Left key.
6. A progress screen is displayed while the Air Circuit Learn function is running.
7. When the function is complete, a screen will appear saying that the circuit has been learned successfully. The next menu item item is then displayed. Commence treatment...
If there is a problem with the circuit a screen saying 'Invalid Circuit' will be displayed instead of the progress screen. Check that all the connections between pieces of equipment are secure. You may need to return to the previous chapter of this manual to check that you have set the system up correctly.

So I don't think there can be any question about the LC and how important it is to use masks & components that pass the LC. By putting the Swift on, after running LC with a Vista, the impedance is clearly changed by the smaller diameter mask tube and the restriction of the nasal pillows themselves. I won't list all the various mask I have tried with the Adapt, but anything that has a smaller diameter mask tube will not pass, like the Dream Seal, Simplicity, or ComfortLight with the over the nose attachment, even though the mask part itself is relatively open. Mask like the Comfort Select and Comfort Gel with direct hook up to the hose and no major restriction on airflow pass the LC fine, using a similar listed ResMed mask selection, though each person still has to decide on their own if using a non-approved mask is appropriate through trial and error.

Looking up 'impedance' in the dictionary and you get a lot of stuff related to electricity & such, I'll leave that to the engineers. My basic take on it is that say I plan a quilt top with standard 1/4 inch seam allowance (impedance), with 40 seams across and 80 seams down that is suppose to be 50"x70", simple enough. But when I sit down to sew, I accidentally used a 1/3" seam allowance, because I changed the presser foot (Vista=1/4", Swift=1/3") after I ran all the calculations & planned everything (ran Learn Circuit). Suddenly my 50"x70" quilt only measures 43.6"x57.2"...and someone is going to have cold toes. If something as small as the difference between 1/4" & 1/3" can make that much of a difference when compounded by multiple seam allowances, think about all the calculations the Adapt is performing every second...and if the calculated impedance is off, all its calculations are going to be wrong, from Tidal Volume to BPM to Minute Vent to Target Vent to Leaks, Mask Fit, Median Pressure, etc. Would you want to use your APAP if someone reprogrammed it with different numbers?

christinequilts wrote: <snip>

It works both ways- it determines a target minute ventilation, etc: etc:

<snip>

Christine,

Many thanks - very clear commentry & an excellent description.

Thanks

DSM

Christinequilts wrote:So I don't think there can be any question about the LC and how important it is to use masks & components that pass the LC.

My initial take also, Christine. I was surprised to hear that Frequen's doctor, as well as her brother's doctor, and both Resmed reps allowed the Swift for ASV use despite LC failure.

Christine, if you ever get the chance to pass the Swift/ASV impedance issue past your own Resmed factory rep... Would love to eventually hear what SAG's and Lubman's factory reps say about Swift/ASV use as well. So far two Resmed factory reps (frequen's and her brother's) are in agreement that the Swift can be used. They just disagree about how to impedance-calibrate the circuit.

Very counter-intuitive stuff, indeed. Then, of course, the world's leading CSDB researcher plausibly telling frequen that ASV patient baselining entails ventilatory overshoot/undershoot as it fixes or calculates a target. Then, of course, ventilatory overshoot itself is thought to be the root of that physical discomfort in CSDB and perhaps other CPAP-intolerant patients. Rhetorically: since when can the severity of any given pathophysiological component be neatly mapped or universalized across any patient population? Certainly not with the pain component of fibro, Christine. And probably not with the physical discomfort or CPAP-intolerance levels involved in CSDB and SDB patients who are pressure-disinclined.

But yeah, I think the Swift is highly suspect (for the reasons I mentioned several pages earlier). At the very least, the Swift might be causing more pronounced overshoot/undershoot during the ASV baselining process as it calculates a fix. And that might be what frequen's noticing.

christinequilts wrote:...and if the calculated impedance is off, all its calculations are going to be wrong, from Tidal Volume to BPM to Minute Vent to Target Vent to Leaks, Mask Fit, Median Pressure, etc.

Christine, there are separate pressure and flow sensors inside the ASV. The LC routine is for impedance-based pressure calculations, rather than flow calculations. I don't think it's a given that pressure-based LC miscalibration will absolutely skew flow measurements, or even closed-loop system feedback for that matter. Those flow measurements are used toward calculating flow targets. Again, LC was pressure and impedance-based, presumably toward intitial impeller-based rotational multipliers. I would personally want plenty more low-level design details to absolutely agree or disagree with you on that statement, Christine.

But I can definitely see LC miscalibration causing patient baselining to be more harsh initially, since numeric multipliers relative to impeller roation would be initially off. But then closed-loop adaptive servo should eventually measure then correct rotation numbers via closed-loop servo feedback. Impeller-sourced pressure rotations simpy get mismatched up front, then rotationally adjusted via closed-loop feedback from there on.

But flow gets accurately measured and accurately targeted all along from what I can tell, despite the LC false start relative to impeller rotations.

My rep, who use to be the lead tech at a major lab- the one I go to, said some people were using the Swift and that they were reporting it was 'working', but he didn't buy it for a minute. He would prefer ResMed mask only, with the FFM being first choice, but definitely no to any mask that couldn't pass the LC. I got to hear a lot more because it was the first one set up at my DME's location, so it was my setup and their hands on training all in one, as it had been several weeks since their intro class on it as a company.


I still say that if the machine can't calculate the impedance correctly, its going to through everything off. Remember the external sensor tube ends the end of the regular tube, so signal is getting lost in the smaller diameter Swift tube too.


The BI doctor also didn't know the backup rate was 15, or that its more of a backup backup rate...we need SAG to come up with abbreviation for it. And FQ also posted that she had communicated with them about her average pressure going up as she increased her EEP/base pressure, and they couldn't figure that out either. And you can tell from those numbers that FQ is not getting much extra pressure, so with a Swift, she was basically on a BiPAP T set at 15- note I took the S out. Like I noticed, I narrowed down to around 15 BPM more with the Swift, but I think it was more misreading by the Adapt and having a mind of its own- it didn't recognize when I was breathing very well at all, it really was like being on a straight TIMED set up the more I think about it, then even a true ST.

christinequilts wrote:The BI doctor also didn't know the backup rate was 15, or that its more of a backup backup rate...we need SAG to come up with abbreviation for it.

Heheh! I love SAG's abbreviations, too. If he doesn't cough one up for us, let's go with your own implied BBR.

christinequilts wrote:I still say that if the machine can't calculate the impedance correctly, its going to through everything off.

I think the volume and pressure measurements should be OK, I don't believe Learn Circuit has any bearing on that. But if this thing works chiefly by a component of PAV, if you make it think that there's more resistance in the circuit than there actually is, then what you got now is a REAL expensive BiPAP that has a mind of its own. And it's not gonna think what you want it to think.

And you can tell from those numbers that FQ is not getting much extra pressure, so with a Swift, she was basically on a BiPAP T set at 15- note I took the S out. Like I noticed, I narrowed down to around 15 BPM more with the Swift, but I think it was more misreading by the Adapt and having a mind of its own- it didn't recognize when I was breathing very well at all, it really was like being on a straight TIMED set up the more I think about it, then even a true ST.

Let's see. If FQ is now being overventilated, then that could result in hypocapnia. So the addition of dead space isn't correcting the problem, it's correcting the solution.

-SWS wrote:After reading plenty of posts and emails, I really suspect that frequen is CPAP pressure intolerant to some heightened degree.

Intolerant, yes. CSDB, no.
SAG