pressure response on Airsense 11
pressure response on Airsense 11
I've been laboring under the impression that my apap responds to events by increasing pressure incrementally. Today was the first day that I was able to examine the hourly detail via Oscar on my Airsense 11.
What surprised me was that despite no events being observed (no LL, no OA, no UA, no H) the pressure appears to be changing:
Settings APAP 5-15, Ramp 35 minutes
It looks like after the ramp period, pressure was increased - but in response to what ?
The first "event" (an H) occurred at 23:13
What am I not understanding?
What surprised me was that despite no events being observed (no LL, no OA, no UA, no H) the pressure appears to be changing:
Settings APAP 5-15, Ramp 35 minutes
It looks like after the ramp period, pressure was increased - but in response to what ?
The first "event" (an H) occurred at 23:13
What am I not understanding?
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
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- Pressure example 1.jpg (32.69 KiB) Viewed 1022 times
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Re: pressure response on Airsense 11
Most likely responding to snores and flow limitations.
Since you didn't include the other graphs...a guess but an educated guess.
Need to see the big picture....it usually offers more answers.
viewtopic/t158560/How-to-post-images-for-review.html
Since you didn't include the other graphs...a guess but an educated guess.
Need to see the big picture....it usually offers more answers.
viewtopic/t158560/How-to-post-images-for-review.html
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Re: pressure response on Airsense 11
There were no snores reported, so I did not include that graph. It does appear that the flow limits began to show some activity around the time that the pressure was increased:
So, I know from the cpap glossary that Flow limitations are an indication of collapse of the upper airway. How is that measured (or inferred) and given the levels shown here (generally 0.25 or so, how significant is that? (I guess what I'm asking is what are the units of flow limitation, for example is a 1.00 Flow limit actually a 100% collapsed upper airway?)
So, I know from the cpap glossary that Flow limitations are an indication of collapse of the upper airway. How is that measured (or inferred) and given the levels shown here (generally 0.25 or so, how significant is that? (I guess what I'm asking is what are the units of flow limitation, for example is a 1.00 Flow limit actually a 100% collapsed upper airway?)
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
"THE INFORMATION PROVIDED ON CPAPTALK.COM IS NOT INTENDED NOR RECOMMENDED AS A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE."
Re: pressure response on Airsense 11
ResMed has never really explained in much detail the whole flow limitation thing.
So I can't answer your questions. Sorry.
About all I have is this video.
https://www.youtube.com/watch?v=-gie2dhqP2c
In general snores and Flow Limitations are considered early signs of an impending airway collapse and the ResMed algorithm is designed to try to prevent the collapses so it is fairly aggressive in response to flow limitations but ResMed never really gave us the particulars in the algorithm....probably hidden in the patent somewhere but I am not going to go digging through the patents.
Also....flow limitations can also occur because of nasal congestion and more pressure won't fix those no matter how high the ResMed wants to go.
Are you having much nasal congestion at all???
So I can't answer your questions. Sorry.
About all I have is this video.
https://www.youtube.com/watch?v=-gie2dhqP2c
In general snores and Flow Limitations are considered early signs of an impending airway collapse and the ResMed algorithm is designed to try to prevent the collapses so it is fairly aggressive in response to flow limitations but ResMed never really gave us the particulars in the algorithm....probably hidden in the patent somewhere but I am not going to go digging through the patents.
Also....flow limitations can also occur because of nasal congestion and more pressure won't fix those no matter how high the ResMed wants to go.
Are you having much nasal congestion at all???
_________________
Machine: AirCurve™ 10 VAuto BiLevel Machine with HumidAir™ Heated Humidifier |
Additional Comments: Mask Bleep Eclipse https://bleepsleep.com/the-eclipse/ |
I may have to RISE but I refuse to SHINE.
If you want to try the Eclipse mask and want a special promo code to get a little off the price...send me a private message.
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Re: pressure response on Airsense 11
If you look at Resmed's software, the FL chart goes from 'rounded' at the bottom to 'flattened' at the top.
The numbers are just because that's what the graphing engine in Oscar shows.
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Re: pressure response on Airsense 11
Going to venture a reply to the OP. To put it simply, the events shown in your sleep data on the machine are the ones that the CPAP has not prevented. Events that the CPAP prevents aren't shown, since they were prevented *smile*. So the pressure can vary without an event being shown, and is likely to have been varied by the CPAP to prevent an event.
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Re: pressure response on Airsense 11
Interesting reading:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4688581/
(I have not read the whole of this article)
It appears that Inspirational Flow Limitation (which I suggest is what Resmed is referring to) is largely (mainly) defined by the shape of the inspiration flow curve.
How one goes about quantifying that on a scale of unknown units is puzzling.
What is even more interesting is the epidemology of flow limitation. My interpretation of the article is that some flow limitation is observed naturally and not necessarily a physiologic anomaly.
[quoteThese results suggest that only IFL values greater than 30% should be used to support the diagnosis of Sleep Disordered Breathing. Conversely, the IFL pattern cannot be used exclusively to determine abnormality, as roughly 5% of the normal population has IFL greater than 30% of the night.][/quote]
Interesting that Resmed should attack IFL aggressively.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4688581/
(I have not read the whole of this article)
It appears that Inspirational Flow Limitation (which I suggest is what Resmed is referring to) is largely (mainly) defined by the shape of the inspiration flow curve.
How one goes about quantifying that on a scale of unknown units is puzzling.
What is even more interesting is the epidemology of flow limitation. My interpretation of the article is that some flow limitation is observed naturally and not necessarily a physiologic anomaly.
[quoteThese results suggest that only IFL values greater than 30% should be used to support the diagnosis of Sleep Disordered Breathing. Conversely, the IFL pattern cannot be used exclusively to determine abnormality, as roughly 5% of the normal population has IFL greater than 30% of the night.][/quote]
Interesting that Resmed should attack IFL aggressively.
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
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Re: pressure response on Airsense 11
While that's effectively true, it doesn't provide any information.RogerSC wrote: ↑Wed Oct 20, 2021 2:17 amGoing to venture a reply to the OP. To put it simply, the events shown in your sleep data on the machine are the ones that the CPAP has not prevented. Events that the CPAP prevents aren't shown, since they were prevented *smile*. So the pressure can vary without an event being shown, and is likely to have been varied by the CPAP to prevent an event.
APAPs raise pressure in response to four things:
- Snores
- Flow Limitations
- Hypopneas
- Obstructive Apnea
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Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Re: pressure response on Airsense 11
Why? Try breathing through a straw for a few minutes, see how you feel.
That's flow limited breathing.
Get OSCAR
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
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Re: pressure response on Airsense 11
Just so you know: not all flow-limited inspiration is flagged in Oscar, I think because the ResMed data don't provide a basis. You can zoom in on your flow rate in Oscar (try 1 minute intervals) to see what your flow traces look like.
Some people aren't bothered by FLs at all; others are bothered a fair amount. For people who are bothered by them, the best way to treat FLs is to introduce pressure support. (EPR is pressure support. EPR is measured via subtraction from IPAP; on some other kinds of machines, PS is measured via addition to EPAP.) Basically the boost in pressure when you inhale can support smoother, less effortful inhalation.
But as Pugsy cautions, FLs that are caused by problems in the nose can't be fixed this way -- only problems due to sagging tissues in the pharynx.
Some people aren't bothered by FLs at all; others are bothered a fair amount. For people who are bothered by them, the best way to treat FLs is to introduce pressure support. (EPR is pressure support. EPR is measured via subtraction from IPAP; on some other kinds of machines, PS is measured via addition to EPAP.) Basically the boost in pressure when you inhale can support smoother, less effortful inhalation.
But as Pugsy cautions, FLs that are caused by problems in the nose can't be fixed this way -- only problems due to sagging tissues in the pharynx.
_________________
Machine: AirCurve™ 10 VAuto BiLevel Machine with HumidAir™ Heated Humidifier |
Mask: Bleep DreamPort CPAP Mask Solution |
Oscar software is available at https://www.sleepfiles.com/OSCAR/
Re: pressure response on Airsense 11
No, I did not know that. I assumed that Resmed's firmware flags events, and OSCAR simply reports what Resmed writes to the datacard.Just so you know: not all flow-limited inspiration is flagged in Oscar,
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
"THE INFORMATION PROVIDED ON CPAPTALK.COM IS NOT INTENDED NOR RECOMMENDED AS A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE."
Re: pressure response on Airsense 11
Not questioning your analogy, but wouldn't shallow breathing also be flow limited?
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
"THE INFORMATION PROVIDED ON CPAPTALK.COM IS NOT INTENDED NOR RECOMMENDED AS A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE."
Re: pressure response on Airsense 11
No, there's no correlation at all.
it's right there in the name. FLOW limitation, and in this context, "flow" means "flow rate" not "quantity".
You can still take a full breath (tidal volume) while being flow limited, it just takes more work, and time to get the same volume of air as you can with an open airway.
Did you try the exercise?
"shallow breathing" doesn't really have any defined meaning, as Miss Em says, your TV is normal, hypopneas are a reduction in TV over what the normal breathing TV for that person is. (and are not the same as flow limitations)
Last edited by palerider on Wed Oct 20, 2021 4:08 pm, edited 2 times in total.
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Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Re: pressure response on Airsense 11
Resmed flags events, Oscar reports them. Flow limitations aren't events, which is why there's a running average chart of the severity of flow limitation on breaths.
Get OSCAR
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Accounts to put on the foe list: dataq1, clownbell, gearchange, lynninnj, mper!?, DreamDiver, Geer1, almostadoctor, sleepgeek, ajack, stom, mogy, D.H., They often post misleading, timewasting stuff.
Re: pressure response on Airsense 11
I am honestly trying to understand this. As a starting point can you answer a question I raised earlier, specifically, what are the units (Yaxis) of the the graph of Flow Limitation as reported by Resmed? (OSCAR's explanation of the Y axis of the Flow Limitations graph is "severity graded 0-1.0" )
Does Resmed provide this grading (and OSCAR reports) or are suggesting that OSCAR calculates running grades based on other parameters?
Since it appears that flow limitations is an important factor, is there an similar factor with Respironics (dreamstation) machines?
_________________
Machine: AirSense 11 Autoset |
Mask: FlexiFit HC431 Full Face CPAP Mask with Headgear |
Humidifier: DreamStation Heated Humidifier |
"THE INFORMATION PROVIDED ON CPAPTALK.COM IS NOT INTENDED NOR RECOMMENDED AS A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE."