Titrating Down: Now seeing a new Exp waveform

[SevereApnea]

Hi all

Apologies for the long post but I thought I would share this here, and  look for comments about the new waveform I am seeing on Expiration, that leads up to OSA.

This is a representative night with my new waveform.
Overview:
[attachment=25069]
Close up:
[attachment=25070]

Background:

I have been on APAP now for most of 2020 so far, and doing really well, apart from some hiccups here and there.

My Titration study showed "optimal CPAP" of 7 - 8 cm H20 but I have been using  higher pressures than that to avoid any recurrence of the events that led me to PAP therapy in the first instance (signature).

Lately I have been having headaches and chest discomfort/rawness/strain (Doc said palpitations is a valid word for this) on waking during the night or in the morning, which, looking at my data in Excel, correlate well with 95% EPAPs in the higher range.

After my Respiratory Physician confirmed no cardiac conditions (CTCA and Stress Echo all OK) he indicated it was time I self-titrated my pressures down, and wouldn't be too concerned until my AHI approached 10 or so, depending on how I felt of course. He suggested I could reduce my pressures as low at 7 - 8 cm H20 even as CPAP rather than APAP, as per titration study.

So I have been doing that slowly and progressively keeping an eye on my oximeter readings at the same time. I have noticed an interesting new blunted Expiratory waveform which often precedes my remaining OSA's. I interpret this as confirmation that the airways close at the end of expiration, usually leading to or preceding true airways obstruction.
This leads to me believe I may be close to my therapy levels.

No more headaches or palpitations and am feeling really good during the day.

Now, I don't believe the Titration study pressures are my optimal therapy.
(Usual reasons: one night in a strange environment, leads and lines and sensors everywhere, strange bed, weird hospital noises, I still had unhealed vertebral fractures and rotator cuff injuries, and had difficulty finding a comfortable sleep position. These have now largely healed and currently I am sleeping *way* better than ever and would guess a repeat sleep lab study would likely show higher pressures.)

I prefer EPR of 2.
I do use a neck collar.
I do need partial mouth taping with Scunci to control mouth leaks.
I love the combination of Resmed P30i  and N30i interchangeability (is that a word?)

I plan to continue to titrate down as low as I can and see how I go, but in the meantime would appreciate comments from the team about this expiration waveform. Is this anything to be concerned about?

[Sleeprider]

The sharp dip with no sustained flow on expiration is usually expiratory mouth breathing. It may lead to a loss of pressure during expiration and that could result in the OA event you see here. This is remarkably common, and we have seen a lot of threads showing the pattern http://www.apneaboard.com/forums/Thread-...w-somewhat It can also be an indicator of a more rare palatal prolapse, where the exhale flow is cutoff by a prolapse of the phryngeal veil. We often pull out the image below to show some basic interpretation of the flow rate chart:

[SevereApnea]

Thank you Sleeprider, I had seen some posts on palatal prolapse, but not registered their significance. I will study them more closely.

It's not there with all my Obstructions and certainly not when my pressures were higher; only appearing now that I am titrating down.

It seems that by lowering my pressure this may predispose to palatal prolapse, since I use nasal pillows/cradles and not FFM. Would a full face mask or hybrid mask reduce this likelihood?

In the meantime I will be interested to see what happens when I lower pressures even further.

If, and it seems most likely, this is palatal prolapse would this be a reason to keep pressures at a level where this does not occur?

Would it help by lowering my EPR from 2 (my most comfortable setting) to 1, or even abolishing it altogether?