Help with self-titrating BiPAP for UARS - low % of spontaneously triggered breaths?

[Bibbbooker]

Over the past month I have started treating myself for UARS with BiPAP (my country's healthcare system doesn't recognise it). This morning I noticed that only 42% of my breaths of the past week had been spontaneously triggered. I took a closer look at my data from the past month and noticed that most of the periods where flow rates looked smooth, respiratory rate had been at or near the backup rate of 10. This was especially the case on my best day so far, where I had about 4 hours with significantly reduced cognitive impairment. The night before(jan19), the flow rate curve was particularly smooth. Interestingly enough, these smooth periods coincided with respiratory rates being almost-equal to the backup rate of 10 bpm. Is this a problem? How should I take this into consideration during further self-titration?

Until now, I have steadily increased EPAP/IPAP from 5/7 to 7/16 over the course of 25 days (does a higher PS make sense for a larger individual?). I intended to use u/carlvoncosel's protocol from reddit(not allowed to link because I am a new user) but have both intentionally and unintentionally deviated from it. Firstly intentionally, because I decided to speed things up when: a) the first few nights of OSCAR data showed "certain flow limitations" on nearly 100% of breaths (Mann et al., 2021) and b) I noticed that tidal volume was exceptionally low for an individual of my size (2,04m/125kg or 6'8''/275lbs). Secondly unintentionally, when I didn't turn off backup rate as the protocol only explicitly mentioned to do so for a Resmed ASV. I think the backup rate prevented any central apneas from occurring, indefinitely extending phase 2 of the BiPAP protocol if I were to strictly follow it. Instead, I stopped increasing PS when I no longer noticed improvement in terms of flow limitations when it came to the flow curves. 

The increased PS/IPAP led to some improvement symptom-wise in the form of increased energy levels and the occasional moment of reduced cognitive impairment. When I started to increase EPAP, however, I really started to notice significant improvement (can't wait for an EPAP of 8 tonight). I am optimistically continuing the protocol but am not sure what to make of the low % respiratory rate and % of spontaneously triggered breaths. Do you have any advice on how to proceed? Is my current machine sufficiently equipped for the task at hand or do I need ASV?

TL;DR: Over the past month I have been steadily increasing my EPAP/IPAP. I noticed that both my symptoms and flow rate tend to be better when the respiratory rate is equal to the backup rate of 10.  To what extent is this a problem? How do I take this into consideration during further titration? Do I need a different machine?


Mann DL, Georgeson T, Landry SA, Edwards BA, Azarbarzin A, Vena D, Hess LB, Wellman A, Redline S, Sands SA, Terrill PI. Frequency of flow limitation using airflow shape. Sleep. 2021 Dec 10;44(12)

[gainerfull]

I wasn't aware the Aircurve 10 offered a back up rate?

Are you wearing a soft cervical collar by chance? Your respiratory rate suggests you're breathing steadily, then "catching up" with more rapid breathing pretty much the entire night.

[Bibbbooker]

I wasn't aware the Aircurve 10 offered a back up rate?

Are you wearing a soft cervical collar by chance? Your respiratory rate suggests you're breathing steadily, then "catching up" with more rapid breathing pretty much the entire night.

I wasn't aware the Aircurve 10 offered a back up rate?
In the settings under "backup rate" it offers the settings "10" or "off"

Are you wearing a soft cervical collar by chance?
I am not wearing one. How would that make a difference? I am wearing a vertical chin strap and mouth taping, however. Both seem necessary to prevent leaks.

Your respiratory rate suggests you're breathing steadily, then "catching up" with more rapid breathing pretty much the entire night.
I agree, but am not sure why this is. One theory I have is that I might need a full face mask as I have trouble with nasal breathing. I figured that the pressure support would allow me to nasal breathe properly, but that might not be the case.

[Jay51]

Anything in your medical history that might help explain the frequent spikes in respiratory rate?  6'8 inches tall would help explain the gargantuon tital volumes you have achieved in some of your charts.

[Bibbbooker]

Anything in your medical history that might help explain the frequent spikes in respiratory rate?  6'8 inches tall would help explain the gargantuon tital volumes you have achieved in some of your charts.

Nothing that I'm aware of besides the trouble with nasal breathing.

My first night on BiPAP showed flow limitations nearly 100% of the night, so they also might just be recovery breaths from underbreathing before/RERA's?


I have attached 2 images: 1 showing the flow limitations during my first night on low PS, 1 showing the spike in respiratory rate during a later night on higher PS.

[zaienk]

Your are washing too much CO2 because of your high PS so you are breathing because of the backup rate of 10 that is available on recent aircurve 10 vauto, only on bipap S mode with easybreath desactivated. You can see on your chart that you are breathing around 15 time per minute with low PS and around 11 times per minute while using very high PS, which is not you should expect.
I would be you, I would switch back to vauto mode with trigger high or very high, a confortable EPAP, starting back with a PS of 4 or 5 and slowly increase if needed the PS while leaving IPAP on 20 or 25 to see how the machine manage your EPAP according the flow limitation detected.

[BoxcarPete]

Downward sloping flat tops were prevalent in my CPAP charts prior to my nasal obstruction surgery, and significantly improved without the use of any pressure support following it. Have you had your airway evaluated for obstructions?

[Bibbbooker]

Your are washing too much CO2 because of your high PS so you are breathing because of the backup rate of 10 that is available on recent aircurve 10 vauto, only on bipap S mode with easybreath desactivated. You can see on your chart that you are breathing around 15 time per minute with low PS and around 11 times per minute while using very high PS, which is not you should expect.
I would be you, I would switch back to vauto mode with trigger high or very high, a confortable EPAP, starting back with a PS of 4 or 5 and slowly increase if needed the PS while leaving IPAP on 20 or 25 to see how the machine manage your EPAP according the flow limitation detected.

Your are washing too much CO2 because of your high PS so you are breathing because of the backup rate of 10 that is available on recent aircurve 10 vauto, only on bipap S mode with easybreath desactivated.
That could be. I don't have the Vauto device though

You can see on your chart that you are breathing around 15 time per minute with low PS and around 11 times per minute while using very high PS, which is not you should expect.
I would expect resp. rate to go down if tidal volume increases in order to maintain minute volume. I would argue that I'm finally getting enough air per breath causing the resp. rate to go down.

I would be you, I would switch back to vauto mode with trigger high or very high, a confortable EPAP, starting back with a PS of 4 or 5 and slowly increase if needed the PS while leaving IPAP on 20 or 25 to see how the machine manage your EPAP according the flow limitation detected.
Unfortunately I don't have Vauto, so that won't be possible. Increasing trigger sensitivity is a good suggestion though. If CO2-washing really is the cause then I guess I'll have to roll back the PS and increase EPAP over time, right?

[Crimson Nape]

I believe the European AC10 model, blocks out the Trigger and Cycle options. These options are available on the North American model in both the "S" and VAuto modes.

- Red

[PeaceLoveAndPizza]

Could you explain why you ended up with an AirCurve 10 S? Dr recommended? Your sleep study showed central sleep apnoea’s? It was what was available?

There are typically specific reasons why a 10 S is prescribed, so trying to dig in a bit for the background.