Adjusting AHI for Positional Apneas?

I must sleep on my back part of most nights due to spinal issues. During this time it has become clear that therapy ceases due to airways being severely restricted either by uncorrectible chin tucking or tissue collapse due to gravity. The resulting cluster of rapid-fire apneas is a mix of CAs, OAs, Hs, and Unidetifiables over an ≈hour with as many as two per minute. Max APAP pressure pegs during the cluster, large leaking occurs, flow limitation is extraordinarily high, and blood O2 goes down into the 70s. This continues until either I move to my side or wake up as I have this morning after 3:26 hours of sleep time exhausted as usual.

I see a common statement to set the min APAP pressure to the median pressure indicated by OSCAR, but is the median pressure wrong in this case due to it having the hour's worth of max cm in its calculation that is not delivering therapy? In other words, the hour of pegged out 15cm to 20cm (the range of max cm I've tried) is a useless attempt of the machine to treat apneas it cannot therefore this high-pressure time should not be considered when calculating a proper min. pressure. The median pressure has been skewed by the hour of nontherapeutic high pressure.

The rest of a night's sleep shows the AirSense 10 working well with up and down pressure and only a handful of apneas which recalculated without the hour's worth of up to 70 untreated apneas would be an AHI of < 1.0, not the 10.0 to 30.0, I see so often.

It would be nice if I could sleep on my side for 8 hours each night and once in a while that occurs. When it does the OSCAR report is quite acceptable and what I feel is accurate. I've tried every suggestion to resolve the positional apneas and failed. (collar, tape, chin strap, ultra-thin pillow, backstop wedge, and tennis ball)

What do you think about my giving up trying to get AHI and flow limitations down caused by positional issues? Having 15 to 20 cm of useless pressure shoved to my face for over an hour makes for poor sleep. During the continuous high pressure and event clusters, I wake often, have strange vivid dreams, and get less than 4 hours of sleep as last night. So should I and maybe others, find a way to recalculate our min. cm pressures by subtracting the positional apnea cluster data? Should we take a sampling of pressures outside the cluster(s) and average them to find our proper min. pressure?

Any advice is appreciated as I reach the end of my wit and wonder if I've wasted 18 years attempting to treat untreatable positional sleep apnea. Some may say go back to the sleep test facility (I've done that 4 times) I am weary of that, too tired to do it. I do not have advice available from an MD, DME, or sleep test technician.

Positional worsening apnea is treatable but what is needed to do that for you in your situation is to allow the pressure to go higher and not be maxed out.
Unfortunately for some people that higher pressure can cause some problems as well either with greater difficulty managing leaks or even aerophagia and belly pain.
Damned if you do and damned if you don't.

And I thoroughly understand the difficulty in staying off one's back....it's easier said than done.
I have that issue myself with needing to stay off my back (causes pain which wakes me up) and I have tried all sorts of gimmicks and doo dad gadgets to stop that unwanted behavior.

When sleeping on your neck, experiment with other items to reduce or stop neck kinking. Wedge pillows, no pillow, different height pillows, cervical collars.

Dog Slobber wrote: ↑

Thu Feb 06, 2025 11:39 am

When sleeping on your neck, experiment with other items to reduce or stop neck kinking. Wedge pillows, no pillow, different height pillows, cervical collars.

Ejbpesca wrote in the topic:

"I've tried every suggestion to resolve the positional apneas and failed. (collar, tape, chin strap, ultra-thin pillow, backstop wedge, and tennis ball."

Anything I missed in the above?

Pugsy wrote: ↑

Thu Feb 06, 2025 7:49 am

Positional worsening apnea is treatable but what is needed to do that for you in your situation is to allow the pressure to go higher and not be maxed out.

Worsening positional apnea is treatable? How? With very high pressure? I was told no CM can push through it.

When you write "allow the pressure to go higher" which pressure, the Min, or Max? I am currently lowering the Max to keep it from maxing out because positional cluster, I am not getting therapy so why allow it to be above the average pressure? The machine sets itself to an effective min. pressure with AHI of <1.0. No matter what the max cm, it pegs out during positional apnea times so it may as well also be the min right? Any doo dads I've missed that may work?

ejbpesca wrote: ↑

Sun Feb 09, 2025 9:42 am

Worsening positional apnea is treatable? How? With very high pressure? I was told no CM can push through it.

Did you know that none of these machines will increase the pressure (or even try) DURING the actual apnea event?
Doesn't matter what the pressure is or where it wants to go DURING the apnea event.

The whole idea with cpap is to PREVENT the airway collapse in the first place and that can mean an increase in maximum needs to be allowed and sometimes even an increase in the minimum so the machine can increase to wear it needs to be to PREVENT the airway collapse in a timely manner.

There isn't a cpap/apap machine anywhere that can actually "blow the airway open and move saggy tissues" when it is actually happening.

Treatment choices are available for those with back sleeping apnea issues and for whatever reason they can't just stay off their backs....not always to our liking or without problems but they are available.

Pugsy wrote: ↑

Sun Feb 09, 2025 9:52 am

ejbpesca wrote: ↑

Sun Feb 09, 2025 9:42 am

Worsening positional apnea is treatable? How? With very high pressure? I was told no CM can push through it.

1. Did you know that none of these machines will increase the pressure (or even try) DURING the actual apnea event?
Doesn't matter what the pressure is or where it wants to go DURING the apnea event.

2. The whole idea with cpap is to PREVENT the airway collapse in the first place and that can mean an increase in maximum needs to be allowed and sometimes even an increase in the minimum so the machine can increase to wear it needs to be to PREVENT the airway collapse in a timely manner.

There isn't a cpap/apap machine anywhere that can actually "blow the airway open and move saggy tissues" when it is actually happening.

3. Treatment choices are available for those with back sleeping apnea issues and for whatever reason they can't just stay off their backs....not always to our liking or without problems but they are available.

1. & 2. My machine finds a therapeutic min. pressure regardless of the min. I have been choosing. Right away it goes to it and succeeds with <1.0 therapy for hours out of positional apneas. That min. adjusts up and down except during positional apnea time. During that time the pressure stays maxed out. The machine was set to 8-20 when given to me. Outside of positional apneas, APAP fluctuates between 10 and 12 no matter if the min. is set to 8 or 9 or 10. So what is the purpose of the max over 12? And what is the purpose of AHI if it is skewed by an untreatable positional apnea?

3. What are those treatment choices or where can I find them, please?

[/quote]

ejbpesca wrote: ↑

Sun Feb 09, 2025 10:12 am

So what is the purpose of the max over 12? And what is the purpose of AHI if it is skewed by an untreatable positional apnea?

AHI is an index of the times you stopped breathing. If you'r breathing is disrupted when you're on your back, your AHI will be higher, and that means your therapy is not that good. Important info, though AHI without flow data is not informative enough.
If sleeping on your back makes you stop breathing you see it in the AHI.
When you sleep on your back, you need more pressure to keep your tissues from sagging. This "more" is what you get in the maximum pressure, which - according to what you write - you don't need when you're not on your back.
Pressure is there to prevent your breathing from being interrupted by sagging tissues. For some people, the sagging is much worse when they're on their back.
An automatic machine knows it has to raise pressure when it identifies obstructive events happening, and will do so, after the first indications, up to the maximum you give it. If you limit the machine's maximum pressure, it will not give you sufficient pressure when you're on your back, and your AHI will be worse - as wiil the impact of breathing disruptions on you health.
The purpose of maximum pressure is to let the machine raise pressure high enough to keep your sagging tissues from obstructing your breathing, under the worst conditions.
The purpose of minimum pressure to let you have the lowest pressure possible.
For people with positional sleep apnea, the machine will supply lower pressure in one position, but will go as high as necessary or only as high as you let it, in the other position.

ozij wrote: ↑

Sun Feb 09, 2025 6:37 pm

ejbpesca wrote: ↑

Sun Feb 09, 2025 10:12 am

So what is the purpose of the max over 12? And what is the purpose of AHI if it is skewed by an untreatable positional apnea?

AHI is an index of the times you stopped breathing. If you'r breathing is disrupted when you're on your back, your AHI will be higher, and that means your therapy is not that good. Important info, though AHI without flow data is not informative enough.
If sleeping on your back makes you stop breathing you see it in the AHI.
When you sleep on your back, you need more pressure to keep your tissues from sagging. This "more" is what you get in the maximum pressure, which - according to what you write - you don't need when you're not on your back.
Pressure is there to prevent your breathing from being interrupted by sagging tissues. For some people, the sagging is much worse when they're on their back.
An automatic machine knows it has to raise pressure when it identifies obstructive events happening, and will do so, after the first indications, up to the maximum you give it. If you limit the machine's maximum pressure, it will not give you sufficient pressure when you're on your back, and your AHI will be worse - as wiil the impact of breathing disruptions on you health.
The purpose of maximum pressure is to let the machine raise pressure high enough to keep your sagging tissues from obstructing your breathing, under the worst conditions.
The purpose of minimum pressure to let you have the lowest pressure possible.
For people with positional sleep apnea, the machine will supply lower pressure in one position, but will go as high as necessary or only as high as you let it, in the other position.
[/quote]

In my case, 20cm does not give therapy to repeated apneas (20-30 AHI) while sleeping on my back. The max pressure period (up to 2 hours) raises the median pressure figure which is so often suggested to be the best min. pressure setting. I think median pressure indicated is not correct in my case. Factoring out the max. pressure time will get an accurate median pressure figure. Also, if it is only during untreatable apneas due to back sleep that the APAP goes to the max cm setting then that is the wrong max setting. Would not the max cm reached by the APAP during treatable sleep be the correct max setting? And should not the median figure for min. pressure be found only until the pegged-out high pressure and its duration during untreatable back sleep have been factored out of the average pressure for the sleep session?

In other words, having 20cm blowing on your face during untreatable back sleep due to tissue sagging/collapsing is not only useless, but it can produce aerophagia, make sleep worse than apneas alone, skews the AHI of sleep that is being treated, and skews the median pressure of the sleep session.

The median pressure you read off the machine means the machine supplies that pressure or more for 50% of the night. It isn't "skewed" by the maximum pressure. It's a median, not an average. Averages are affected by extreme numbers. Medians are not. If - random example - your median is 10, you can be spending 40% of the time at 10.5, and 10% at 20 -- or 5% of your time at 10.5 and 45% of the time at 20 -- the median won't change.

Some people need - and use - machines that go to pressures higher than 20. Those higher pressures keep their tissues from sagging, preventing obstructive events.

ejbpesca wrote: ↑

Mon Feb 10, 2025 4:28 pm

Would not the max cm reached by the APAP during treatable sleep be the correct max setting?

How do you define "correct"?

ejbpesca wrote: ↑

Mon Feb 10, 2025 4:28 pm

In other words, having 20cm blowing on your face during untreatable back sleep due to tissue sagging/collapsing is not only useless, but it can produce aerophagia, make sleep worse than apneas alone, skews the AHI of sleep that is being treated, and skews the median pressure of the sleep session.

Here's how I understand those statements, assuming all your recorded apneas are obstructive:

• When you sleep on your back, a pressure of 20 is not enough to keep your tissues from sagging
• therefore you choke.
• A pressure of 20 gives you aerophagia - you want to keep your machine from going that high.
• You prefer having apneas to suffering from aerophagia
• And that's why you keep the machine from going up the to a high maximum

No machine knows when you're on your back or not, no machine knows (reliably) whether you're asleep or not, hence the AHI the machine reports, taking into account all you mask time, is uninformative for you.

As a rule, people who need pressures higher than 20 to keep them from choking when they sleep are given Bi-Level machines. Those can go higher. Higher pressures are more likely to cause aerophagia.
However
Bi-Level machines have also been known to help some people get the necessary pressure without aerophagia.
Aerophagia and acid reflux are related. And you suffer from the a bad case of the latter as well.

ejbpesca wrote: ↑

Fri Sep 30, 2022 9:17 am

I have been hospitalized with acid reflux three times over the years so I guess it is a serious case. I've controlled it over the decades with the Zantac that was taken off the market. All other meds are not working. I may be able to get the old Zantac by prescription by a willing doctor though. It originally was by prescription only. It was a miracle drug I used for 35 years.

See what can be done nowadays to have it treated.

ejbpesca wrote: ↑

Sun Feb 09, 2025 10:12 am

1. & 2. My machine finds a therapeutic min. pressure regardless of the min. I have been choosing. Right away it goes to it and succeeds with <1.0 therapy for hours out of positional apneas. That min. adjusts up and down except during positional apnea time. During that time the pressure stays maxed out. The machine was set to 8-20 when given to me. Outside of positional apneas, APAP fluctuates between 10 and 12 no matter if the min. is set to 8 or 9 or 10. So what is the purpose of the max over 12? And what is the purpose of AHI if it is skewed by an untreatable positional apnea?

3. What are those treatment choices or where can I find them, please?

Are your detailed charts posted in one of your threads?

ChicagoGranny wrote: ↑

Tue Feb 11, 2025 12:30 pm

ejbpesca wrote: ↑

Sun Feb 09, 2025 10:12 am

1. & 2. My machine finds a therapeutic min. pressure regardless of the min. I have been choosing. Right away it goes to it and succeeds with <1.0 therapy for hours out of positional apneas. That min. adjusts up and down except during positional apnea time. During that time the pressure stays maxed out. The machine was set to 8-20 when given to me. Outside of positional apneas, APAP fluctuates between 10 and 12 no matter if the min. is set to 8 or 9 or 10. So what is the purpose of the max over 12? And what is the purpose of AHI if it is skewed by an untreatable positional apnea?

3. What are those treatment choices or where can I find them, please?

Are your detailed charts posted in one of your threads?

My OSCAR charts may or may not be in a thread here due to my deletions or purging of server data. I can post one here to show what I'm referring to in the statement above. I feel what I experience with APAP therapy is not unique and my theories about AHIs and median pressure as per OSCAR reports are important for those who also experience untreatable positional apneas. No cm pressure can provide therapy for this type of air blockage that shows up as 20 to 30 apneas per hour from AirSense 10 data. I never see this issue addressed. Why tell a forum member to set their min. pressure to the median pressure when that number has had max pressure in its calculations that are not providing effective therapy. Does not the median pressure include the machine's time on max pressure in calculating median pressure? Any pressure that is not producing effective therapy is useless. Higher APAP pressure settings can be detrimental to sleep and if they are not treating apneas why include them in a median pressure calculation?

Since I adjusted my max pressure downward, my median pressure is down. Once I extract the untreatable apnea events caused by sleeping on my back my AHIs are <5 not the 10 to 30 shown. I understand bi-levels go higher than 20 cm. I have been told that 25 cm or even higher will not prevent the air flow restriction caused by positional apnea. The only way to eliminate those apneas is to take actions I have tried but they failed.

Thank you for your time and consideration.
ejbpesca

ejbpesca wrote: ↑

Tue Feb 11, 2025 1:42 pm

Why tell a forum member to set their min. pressure to the median pressure

I've never seen an experienced forum member give this as general advice.

I don't like giving specific advice on pressure settings without seeing the line charts.

My sleep clinic/doctor prescribed bilevel 24/18. I didn't like the idea.

Thanks to this forum, I started using a foam cervical collar. I self-titrated to APAP min 10.0/max 20.0/EPR 3. Thanks to the collar, my average pressure has been 11.0, average EPAP 8.0, 99% pressure 13.2 over the last 12 months. That's primarily sleeping on my back.

If I force side-sleeping, a pressure of 7.0 takes good care of me. Clearly, I have positional sleep apnea.

Looking forward to seeing your detailed charts.

ChicagoGranny wrote: ↑

Tue Feb 11, 2025 3:14 pm

Looking forward to seeing your detailed charts.

This chart shows a cluster of apneas I suspect as being positional. During the cluster, there is a large leak session. Outside the cluster shows therapy is effective. I propose I should ignore the high AHI of this chart because I cannot correct the positional apnea with a collar/tape/backstop pillow/tennis ball etc. What I need to monitor is how well therapy is going when I am receiving it which is not during the episode of positional apneas. The max cm I set does not matter because even tapped out at 20 cm the apneas come. I have reduced my max to prevent large leaks that are as disturbing to sleep as apneas. The leaked air blowing across my face/eyes wakes me repeatedly.

I appreciate the advice here about wearing a collar but for some collars make no difference and some find them intolerable.

Screenshot 2025-02-12 at 12.08.29 PM.jpg

Here is an example of reduced maximum pressure to 12.4 cm to prevent large leaks. Since a higher max pressure setting, not even 20cm, will not treat the cluster of apneas I may as well get rid of the sleep-disturbing large leaks caused by higher pressure and lower it to prevent large leaks as shown on this chart.