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THE ROAD TO SUCCESS...almost there, help fine tuning please!
#11
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
You seem to be doing very well on the Vauto. It's interesting that tidal volume is the same or slightly higher, while inspiration time is much lower, and closer to 1:2 to expiration time at the same respiration rate. I don't know that this has any significance, but it is an observation. The sense of having your longer slow breaths cutoff when you first mask up does not show up on the charts. Might be interesting to look at the Insp Time chart. I recently increased my TiMax to 3.0 with no effect on therapy, but I can take those long slow breaths without the machine cycling to EPAP.
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#12
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
Hi Sleeprider, thanks for looking at this, appreciate your time and comments.

Yes the charts look fine, I just need to feel better on waking up. Goal now is to eliminate side effects as listed earlier.

Hypothesis: my side effects are pressure related, I must be sensitive to pressure.

So, last night I lowered MinEPAP to 5.4, lowered MaxIPAP to 11.2, lowered PS to 2.8 to try and contain things.
Ti Max at 2.4.

The night felt better, both during the night and on waking up.

Actually felt better this morning, only woke once, breathing easier, chest feels more open than usual, so that's an improvement.

I have attached 2 OSCAR charts from last night, one zoomed just for interest, showing Insp time.

I also include a ResScan chart because it allows me to clearly display the Set Pressure and other limits. I figure if I am in between the lower and upper ranges my body can adapt (homeostasis) as it needs to. If not, it is limited by the machine, and that may be part of the problem. (I notice the advice often given here to start with wider pressure range, and PS = 4, I might come back to that in the near future and see how that goes.)

I do notice Inspiration time maxing out at the beginning of each session and just before the FLs at around 04:50. (see annotated chart). So, yes I will take your advice and increase that to 3.0 seconds and see what happens.

Plan for Tonight:

Min EPAP still at 5.4 (I may go lower later on: theory: trying to lower the duration of Time at higher pressures)
Max IPAP back to 12 or a bit higher so as to not limit machine response to FL and events.
Up the PS back to 3.0 to try and knock the FLs. I am a bit hesitant to push this up too high so early on.
Up the Ti Max to 3.0 seconds.
Keep Trigger Sens at High and Cycle at Medium (and await advice about these for later).

Thanks for your comments, 
Chris.

Last night 23 Jan 2021:

               


PS: it would be cool if we could place the Min and Max prescribed pressures in Oscar just like ResScan. It gives me a feel of where I am in the prescribed range, both for pressures and other values. Future OSCAR release feature?

PPS: yes, the Insp Times and Exp Times seem to be different between the Autoset For Her and Vauto, I will have to dig deeper into the charts manually to see if this lines up, but for now I am really trying to fine tune for comfort.
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#13
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
Interesting how the flow rate flattens like a flow limit where you hit TiMax.
Sleeprider
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#14
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
Right...!? I think,.... meaning?  Thinking-about

Are you implying that limiting the Ti Max contributes to Flow Limitation?

Or vice versa, that when we experience Flow Limitations it means it would take longer to reach ideal Vt and there is not time for this to happen, which is reflected in a compromised Flow Chart?

Last night I moved the Ti Max back to 3.0 and like you said it "felt" better. I may look at moving this up a bit at a later date.

The article by McArdle page 1777 references how the Resmed calculates FLs, looking at shape, tidal volume, and duty cycle (ratio of inspiratory time to total breath time). So I am a bit worried that we may inadvertently change the way it calculates the FL by messing with the Ti Max, and other settings like Trigger and Cycle sensitivity.

All getting a bit deep for my pea-brain, but it does lead one to think, and wish I knew more about this.

Looking at my First Night on Vauto 12 Jan 2021, I can see what you are saying though: 
Ti Max was set at default 2.0 seconds. When the Insp time is bumping up against the 2.0 seconds the Flow Chart is raggedy. When Insp Time settles down to a middle of the range, the Flow chart expands, flow rate is higher and the Flow Chart approaches what I assume we should be aiming for for most of the night? So there is a correlation there, but I don't know what.

   

So many questions: 
How high can we safely set the Ti Max?
How will changing the Cycle Sensitivity effect all this?
Does changing the Trigger Sensitivity effect this?
Are there any downsides to this?

Earlier you said:

"I recently increased my TiMax to 3.0 with no effect on therapy, but I can take those long slow breaths without the machine cycling to EPAP"

If I might ask, why did you up your own Ti Max and what were you expecting?
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#15
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
When your inspiraiton lasts longer than TiMax, the machine cycles back to EPAP before you complete inspiration. This causes a flattening in the inspiration wave because the breath is no longer supported by pressure support. So yes, it is a direct causal relationship.

The description in that article of how flow limitation is calculated looks like someone describing something they don't, or more likely the calculation is not accurately described.

Quote:Flow limitation was assessed by the site using the sponsor’s (ResMed Ltd.) flow limitation tool to perform automatic analyses of high-fidelity flow signals (25 Hz). The flow limitation tool utilizes the shape, tidal volume, and duty cycle (ratio of inspiratory time to total breath time) of each breath and automatically identifies whether each breath is flow limited or not.

Whatever equations are used to describe the shape of the curve is the most critical part, and this does not describe how that is used with tidal volume, and inspiration time ratio to calculate flow limitation. Anyway, we can simply observe the shape of the flow rate to know whether it is flow limited, and not have to rely on the FL index. I'm not at all worried about how the TiMax setting affects this ratio. The setting is completely independent of the equation, and a longer inspiratory time, when it occurs, is still part of the calculated FL. The longer Ti will result in increased tidal volume as a complete normal flow is enabled, so calculated flow limitation will be lower.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#16
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
Sleeprider, thanks again.

So, to summarise what you are saying, if I understand you correctly.

1. It's better/as good to eyeball the Flow Rate than look at the FL numbers.
2. I can safely increase the Ti Max to a higher value without effecting the machine's calculation of FL. 
In other words increasing the Ti Max will not affect the Resmed ability to respond to FLs and OSAs.

For most of the night my Ti is around 1.5 to 1.7 but in problem areas I am thinking I may need to this to go longer. Would this help improve flow limitation and tidal volume?

Looking at the average of the Median Insp Times on the Autoset For Her vs VAuto in the last month, they are quite different.

Autoset For Her, (EPR between 2 and 3) average Insp Time = 2.5 
Vauto with PS mainly at 3, average Insp Time = 1.56

Not sure why the difference, though or what it means.
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#17
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
Still needing to perfect this.

Two steps forward and one back. 

My numbers on the Vauto are good.
My health is not where I need it to be.

I still get palpitations when I mask up, and wake up with distended leg veins during the night and in the morning. These are incompetent venous perforators, I am sure this is due to PAP therapy, they are quite painful during the day, only ever had them since PAP therapy. I will have to get them treated, but not before I can control the cause, which is highly likely a Side Effect of PAP therapy.

Last night I had to get up and "recover" for more than an hour, with faster breathing, what I call Air Hunger, and painful distended leg veins. Getting a bit frustrated, sorry to say.

Eventually decided to go right back to basics and set CPAP 7 no EPR. See sessions 3 and 4 in the charts below.

Background: my sleep Tech said the Vauto 'breathes for you'. When I mask off I am relieved to get rid of that pressure, and take some time to recover.

Certainly there is a sustained PEEP effect during the night, and many articles discussing reduced cardiac output due to this, even at low pressures. I am worried this is what is happening here.

Theory: if I can somehow initiate inspiration more naturally, thereby increasing my own negative intrathoracic pressure this will help venous return from the legs to the heart. PAP and PS seem reduce this physiological effect for me at any rate.

So, I decided to go right back to basics, and I switched to CPAP 7, EPR off. Felt a bit different to start off with, but I slept fine. Yes, harder to breathe in, but that is doing exactly what I need, increase venous return to the heart.

The good: leg veins were not sore this morning, nor distended. Arm veins less distended. Hands more pink so there is a definite improvement in circulation. Ventilation, RR, Vt and MV all seem similar. Oxygen levels good in both sessions.

The Bad: the Flow limitations, which up to now are what I assume are disruptive to my sleep.

The Ugly: Me. I have no idea how to proceed with this. When I mention this to my Sleep Tech and Resp Doc I get a blank stare.


So I am hoping to seek some guidance about finding a middle way, a compromise somewhere in the middle.
Am I completely misunderstanding what is going on?

I might try APAP 6 - 10 (EPR = 1)?
Should I go back to Vauto Min EPAP 4 Max IPAP 14 or so with PS 4, as is so often suggested as a starting point for self titration?
If so, can I improve my own inspiration induced negative intrathoracic pressure by fine tuning the Trigger and cycle sensitivity? If so, how?

If I have Trigger Sens to low or very low, will this delay the onset of PS, thus enable more time for peripheral venous return?

Can I delay Cycling back to EPAP by setting that on Low or Very Low to lengthen my Ti, so allowing for a longer inspiratory time and better venous return?

I am thinking of going back to my Autoset For Her, but even with the For Her mode and the Soft Mode I still suffered from the sore and distended leg veins.

At a bit of a loss here, so am hoping for some inspiration at this point.

Almost there, but after a year I am still frustrated at my own lack of understanding. 

Apologies for the frustration! Dont-know

Full night:
   

Vauto part of the night:
   

CPAP part of the night:
   
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#18
RE: THE ROAD TO SUCCESS...almost there, help fine tuning please!
I thought I knew a thing or two about this therapy, but when it comes it how it affects venous return, I haven't got a clue. I think you can disregard that your sleep tech said the Vauto breathes for you. I'm sure you are wondering if the portion of the work done by your PAP equipment reduces venous return, and so you're experimenting with removing that factor by using CPAP and various configurations of VPAP. Per my disclaimer above, I don't buy it and think any effect is negligible. I think your PAP therapy is totally unrelated to your perceived poor venous return, and you need to look elsewhere with your regular physician and quit making your sleep tech come up with wrong answers. We are not equipped to advise or discuss circulatory problems here, and this needs to go to your physician, not a forum. I honestly think you are barking up the wrong tree to associate this issue with your otherwise excellent PAP therapy.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
Download OSCAR Software
Soft Cervical Collar
Optimizing Therapy
Organize your OSCAR Charts
Attaching Files
Mask Primer
How To Deal With Equipment Supplier


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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