Expiratory flow limitations?

[Michael2]

Hi:

Despite my AHI being zero or near zero every night, my sleep is very poor. I think this is because I am waking up many times during the night. On a typical night, I am aware of waking up anywhere from 5 - 10 times. Moreover, I suspect there are many mini-awakenings I am unaware of.

After carefully reviewing my data from my PAP machine and fitbit smartwatch, I discovered that most of my awakenings co-occur with expiratory flow limitations (EFLs) such as these:
https://sleephq.com/public/eca25573-55bf...1a90288643
https://sleephq.com/public/411b2dfe-bf4f...aa4362a753
https://sleephq.com/public/809e1b1f-6be8...e564ff4059
If you scroll down and click on Show Advanced Charts..., you can view several other charts such as Tidal Volume, Resp. Rate, and Minute Vent.

These EFLs occur anywhere from 5 - 30 times a night and are not captured by the AHI because they lead to immediate arousals without accompanying apneas or hypopneas.

What causes these EFLs? How do I stop them from occurring? When I raise my sleeping issues with my sleep doctor, she usually dismisses me by saying that my AHI is low so there is no problem. In my experience, many sleep doctors consider only AHI. Can you recommend a medical professional who is familiar with and treats tricky sleep disordered breathing conditions that may not be captured by the AHI such as PAP-induced palatal prolapse and hypocapnia? I want someone who goes well beyond AHI and looks at flow rate data if needed. I live in Pennsylvania but would be willing to travel anywhere.

I have provided more information below in case it is useful.

Thank you very much for your help. I am extremely grateful for this website.

Sincerely,
Michael


More PAP data

Full night statistics from OSCAR: See attachments
Full night of PAP data from SleepHQ: https://sleephq.com/public/c23d19ff-e6da...b7b326218e

PAP therapy

Machine: ResMed AirCurve 10 VAuto Bilevel
Mode: VAuto
Max EPAP: 25
Min EPAP: 15
PS: 7
Timax: 2.5
Timin: 0.6
Trigger: Very high
Cycle: Low
Mask: ResMed AirFit F20 Full Face
Using V-Com: Yes

If I do not set the EPAP and PS to high values, I feel I cannot get enough air like I am slowly suffocating. Without V-Com, typically I set the PS to 6 because that is the most comfortable. With V-Com, typically I find a PS of 7 to be the most comfortable.

I am using a V-Com because it seems to reduce the number of my awakenings. I can only speculate as to why that is. I suspect the rapid drop in pressure during exhalation tends to cause my EFLs by collapsing my airway (like with palatal prolapse) (I have sometimes wondered if I am suffering from palatal prolapse but my flow rate signature is different). Because V-Com smooths out a pressure change by spreading it out over a longer period of time, it may reduce the frequency of my EFLs.

Other considerations

I also use a SleepTight mouthguard for snoring and apnea:
https://sleeptightmouthpiece.com/

If I do not use the mouthguard, I feel I cannot get enough air. I can only speculate as to why that is. Despite having had a few surgeries to help open up my nasal airway, I still suffer from some nasal congestion. I think the mouthguard helps because it keeps my mouth slightly open so that some air can also go through my mouth. Most air goes through my nose, but some extra air goes through my mouth.

PSG sleep study without PAP and mouthguard

https://drive.google.com/file/d/1eGZcD0H...sp=sharing

This sleep study was done in April au-naturel -- that is without PAP therapy and my SleepTight mouthguard. I did take some trazadone to help me sleep. Note my PLM index is 20.1 but there were no associated arousals. This suggests my PLM is not causing my arousals. However, it may be that the trazadone suppressed any PLM arousals.

[Gideon]

I can see a few areas in your OSCAR charts that may be arousals but I'd need to see a zoomed shot. To be sure. But IMHO you are looking good overall. A byproduct of your high PS is that you have likely knocked most of your flow limits out and your stats reflect this. SHQ, doesn't play well on my device, besides I favor OSCAR, no surprise there

[Michael2]

Hi Gideon:

In my original post, I gave three examples from SleepHQ:
https://sleephq.com/public/eca25573-55bf-43d0-b83c-b31a90288643
https://sleephq.com/public/411b2dfe-bf4f-4bcb-88f4-d9aa4362a753
https://sleephq.com/public/809e1b1f-6be8-4ef6-9040-13e564ff4059

I have attached the corresponding screenshots from OSCAR.

I see these EFLs 5 - 20 times a night. I think they are disrupting my sleep. For more information, see my original post.

Thanks,
Michael

[Michael2]

By the way, thank you, Gideon, for OSCAR. It has been a great gift to the community. I believe SleepHQ uses it.

Mike

[Gideon]

Last one first.
3. You are inhaling and holding your breath, likely changing position, less than 10 seconds so no event. This is followed by a brief period of recovery breathing.

2. Same as 3 but I suspect your movement was a bit rougher.

1. A sleep state change I suspect, no big deal.

I do see some minor flow limitations that I wouldn't be concerned with.

[Michael2]

Hi Gideon:

Thanks a lot for your feedback. It is invaluable as I try to better understand my unrefreshing sleep.

While I hesitate to ask because I risk testing your patience, could you please chime in on the five additional snapshots below? If none of these five snapshots are examples of an EFL causing an arousal, then I will need to change my hypothesis from "it is EFLs causing my arousals" to "my arousals are causing changes in my flow rate chart that look like EFLs."

With respect to the events shown in the snapshots, I see such events about 5 - 20 times a night depending on the night. Are 5 - 20 arousals per night normal? Usually, I am consciously aware of about 5 - 10 such arousals per night, but my flow rate chart and fitbit sleep stage data suggest there are more arousals than I am aware of. 

Since I started PAP therapy about six years ago, I have had to steadily increase my EPAP pressure from 7 to 15 and my pressure support from 2 to 6. I sometimes wonder if my high pressures are causing hypocapnia. With my Trigger setting set to Very High, I see zero or near zero central apneas (CAs). When I change my Trigger setting to Medium, I sometimes see quite a few CAs. Could hypocapnia cause frequent arousals even in the absence of CAs? I am thinking of experimenting with EERS:
https://www.apneaboard.com/wiki/index.ph...ace_(EERS)

Best,
Mike

Snapshots:
1. https://drive.google.com/file/d/11G9yDeD...sp=sharing
2. https://drive.google.com/file/d/1vzV0BaW...sp=sharing
3. https://drive.google.com/file/d/13rMLA4u...sp=sharing
4. https://drive.google.com/file/d/1ehqS8b-...sp=sharing
5. https://drive.google.com/file/d/1ZYYZr0E...sp=sharing

[Gideon]

Do me a favor, set the zero line in the Flow rate chart. Why? Because everything above it is inhale and everything below is exhale.. then I'll mark up one or two for you. That helps with interpretation.
Also post what you think is your most normal flow.

Glance shows the same kinds of things. Arousals are causing your disruptions. Unless I see a notable difference in amplitude flow limits are not your problem. You will never be totally without flow limitations.

[Sleeprider]

I was going to come back and say exactly what Gideon just did. Your arousals do not come from respiratory anomalies, they cause them.

[Michael2]

Here are the same five snapshots with the zero line added:
1. https://drive.google.com/file/d/1kHWDlAi...sp=sharing
2. https://drive.google.com/file/d/1lV_m537...sp=sharing
3. https://drive.google.com/file/d/1ESkk5xo...sp=sharing
4. https://drive.google.com/file/d/19dt9I9H...sp=sharing
5. https://drive.google.com/file/d/1v3Eu73K...sp=sharing

---

I was going to come back and say exactly what Gideon just did. Your arousals do not come from respiratory anomalies, they cause them.

Any insight into my two questions above (highlighted in bold below)?

With respect to the events shown in the snapshots, I see such events about 5 - 20 times a night depending on the night. Are 5 - 20 arousals per night normal? Usually, I am consciously aware of about 5 - 10 such arousals per night, but my flow rate chart and fitbit sleep stage data suggest there are more arousals than I am aware of. 

Since I started PAP therapy about six years ago, I have had to steadily increase my EPAP pressure from 7 to 15 and my pressure support from 2 to 6. I sometimes wonder if my high pressures are causing hypocapnia. With my Trigger setting set to Very High, I see zero or near zero central apneas (CAs). When I change my Trigger setting to Medium, I sometimes see quite a few CAs. Could hypocapnia cause frequent arousals even in the absence of CAs? I am thinking of experimenting with EERS:
https://www.apneaboard.com/wiki/index.ph...ace_(EERS)

[Sleeprider]

Your AHI is consistently zero, as are flow limits and any apparent respiratory based issues. Arousal is a common feature of normal sleep and it is a kind of hard-wired mechanism that may have contributed to our survival in our early evolution. https://www.verywellhealth.com/arousal-d...ep-3014849 https://en.wikipedia.org/wiki/Arousal If you research sleep arousal you will quickly learn that some level of arousal is very normal, and it varies between individuals. It is generally not related to respiratory distress or effort, but often is when sleep apnea is inadequately treated. You are not inadequately treated.

You don't have hypopnea or other respiratory issues. I admire your persistence, but when you have solved the CPAP puzzle to this excellent outcome, it's time to start looking elsewhere for the cause of your arousals, or accept them as normal and not get stressed about it, or treat them with natural or pharmaceutical options.