Mystery solved! ever heard of "palatal prolapse" (new article)?

EDIT: I published a Palatal Prolapse summary https://sites.google.com/view/palatal-prolapse. Hoping it will help us navigate this problem!

For quite some time I had been trying to figure out mystery breathing waveforms like these

Pressure 7/14, resolving by itself


Pressure 12.1 CPAP, terminating in arousal


Pressure 13.4 CPAP, resolving by itself


Pressure 14/16.6, terminating in arousal


which looks very similar to the ones Jay Aitchsee posted here viewtopic/t112758/Mouth-Breathing-mouth ... forms.html but could not be exactly the same, since my mouth was double-taped with Micropore and as much as I try I can't breath through the tape. Indeed the machine reports no leaks.

Just found out a new (Feb 2018) article describing the mechanism how the these waveforms are created. And it would even work with a taped mouth.

"Palatal prolapse as a signature of expiratory flow limitation and inspiratory palatal collapse in patients with obstructive sleep apnea"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915321/

Essentially, in "palatal prolapse", the palate prolapses into the velopharynx during expiration...



...limiting airflow through the nose or shunting it out the mouth (if the mouth is not taped).

The article goal was to create an expiratory flow limitation index (EFLI) to detect the presence of palatal prolapse and did not focus on the treatment implications. When such pattern is detected, signaling expiratory flow limitation, EPAP must be raised. As far as I know, existing auto machines ignore expiratory flow limitation of this kind, naively assuming that if the inspiratory flow limitation is solved so would be any expiratory flow limitation. While mostly true, this does not hold for expiratory palatal prolapse. With a bi-level you can completely zero inspiratory flow limitation with high IPAP keeping the machine happy but still have loe EPAP and occur expiratory flow limitations. Such events may cause arousals (from the article)

The movement of the involved floppy tissues (soft palate and uvula) was often quite dramatic and caused arousals.

I may have to abandon the bi-level modaility and return to CPAP/APAP modality, as EPAP=14 was not enough to fix the palatal prolapse.

yrnkrn wrote: ↑

Thu Jun 28, 2018 2:56 am

I may have to abandon the bi-level modaility and return to CPAP/APAP modality, as EPAP=14 was not enough to fix the palatal prolapse.

I wonder if you are an ideal candidate for the Pillar Procedure. Not to replace CPAP, but as an adjunct which would allow lower pressures and more effective treatment.

The Pillar Procedure typically involves the insertion of 3-5 braided polyester implants (pillars) into the soft palate at the back of the mouth. Each implant is 18 mm (3/4 inch) long and is made of a polyester material that has been used in other medical implants for decades. The Pillar Procedure is usually performed in a surgeon’s office, which is one of its advantages. More-recent research has examined the benefits of the Pillar Procedure, showing that there are certain patients that seem to benefit more than others. The most-favorable patients tend to be those with small tonsils (or who had them removed already) and who are not excessively overweight.

Flow wave examples from the article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915321/ referenced above. Please see the article for more information.



I have seen similar waveforms presented by patients using a FFM. Palatal prolapse could be an explanation.

It is not clear to me that increasing EPAP will resolve palatal prolapse. Might an increase in EPAP exacerbate PP? If so, then increasing pressure support using a bilevel machine might be useful. Just a thought.

Jay Aitchsee wrote: ↑

Thu Jun 28, 2018 1:03 pm

It is not clear to me that increasing EPAP will resolve palatal prolapse. Might an increase in EPAP exacerbate PP? If so, then increasing pressure support using a bilevel machine might be useful. Just a thought.

So far the I had seen palatal prolapse at the highest PS I used, PS=7 EPAP=8 IPAP=15. There, prolapses usually happens at about 10cm:


zoomed out:


since palatal prolapses are always at middle of expiration, with Easy-breathe the pressure is much closer to EPAP than to the IPAP, so higher EPAP would affect it much more than higher PS.
Without Easy-breathe the pressure would be just EPAP. My thinking is that if at that point the pressure would have been higher, the prolapse would not have happened so EPAP is much more important.

Neverthless the upper airway is very complex dynamic system and such simplistic explaination may be totally wrong. For example it does not take into account the higher tidal volume with high pressure support.

It's much easier to breath with higher PS than higher EPAP, so I'll go easy and start experimenting with higher PS rather than higher EPAP.

ChicagoGranny wrote: ↑

Thu Jun 28, 2018 6:26 am

I wonder if you are an ideal candidate for the Pillar Procedure. Not to replace CPAP, but as an adjunct which would allow lower pressures and more effective treatment.

I asked the Pillar company if they offer this procedure in my country. It looks simple enough. Thanks!

yrnkrn wrote: ↑

Thu Jun 28, 2018 2:12 pm

since palatal prolapses are always at middle of expiration, with Easy-breathe the pressure is much closer to EPAP than to the IPAP, so higher EPAP would affect it much more than higher PS.
Without Easy-breathe the pressure would be just EPAP. My thinking is that if at that point the pressure would have been higher, the prolapse would not have happened so EPAP is much more important.

Neverthless the upper airway is very complex dynamic system and such simplistic explaination may be totally wrong. For example it does not take into account the higher tidal volume with high pressure support.

It's much easier to breath with higher PS than higher EPAP, so I'll go easy and start experimenting with higher PS rather than higher EPAP.

For sure! Hard to know what might work.

Generally speaking, my opinion is - the lower the pressure used to obtain effective treatment the better. If you are not experiencing OAs on inspiration, I think I would lower IPAP and increase PS to lower the overall average pressure being applied.

Of course, as you point out, with such a complex system this may be exactly the wrong thing to do! Additionally, while experimenting, I think it's wise to only change one variable at a time and increasing PS alone will lower the average applied pressure.

I anxiously await your results. I think what you discover may be beneficial to others as well as to yourself.

Well, first night in. EPAP=8 IPAP=16 PS=8. I have made a settings mistake, had Trigger High with EPAP=8.
With EPAP=8 Trigger must be Very High to the have the machine trigger reliably on shallow breaths like this:



this is a phenomenon I'm already familiar with. It happened quite a lot this night which wasn't nice at all to my sleep quality.

Palatal prolapses still happened



Even mixed palatal prolapses with machine not triggering!



To fix the machine not triggering I'll set EPAP back to 9 which is more my usual.
Palatal prolapses were still happening with PS=8 I'll up the PS as well to 9.
So IPAP=9+9=18.

Next night, I had tried to use EPAP=9 IPAP=18 PS=9 but failed. My eustachian tube kept opening and closing (clicking) upon expiration. Usually when this happens I can swallow to make it go away but with PS=9 the clicks kept coming back. After some minutes i gave up and decided to sleep with higher EPAP=15 IPAP=18 PS=3 instead. This was a qualified success ; no strings of palatal prolapse such as before but one- or two- breaths PP like this



To muddy the water, by noon today my right nostril was running. Result/cause of the clicking? I'll continue experimenting and report when the picture is clearer.

More experiments, more confusing results.
First I tried 15.2/18.2 with the DreamWear Gel pillows mask and had the usual strings of PP



not very responsive to pressure increases.

Last night, I switched to a Full face mask, the BMC iVolve http://en.bmc-medical.com/product/detail/18. It's not a very nice mask but with enough tightening it was sealed.
My usual pressure 9/16 was not enough for a full face, having both flow limitations real OAs and all kinds of inspiratory weirdness, much worse than the pillows mask:



I need higher pressure with full face mask. That's common. However, what's really confusing is the expiratory waveforms,





Palatal prolapses just the same. With a fullface mask and an untaped mouth!
The air should have gone out of the mouth, yet it didn't. This could mean there's a tongue-related obstruction blocking the mouth route as well as palatal prolapse.
Or it's not palatal prolapse then? baffled.

For your consideration, a post from another thread:
viewtopic.php?f=1&t=156834&p=1246866#p1246866

Jay Aitchsee wrote: ↑

Mon Apr 30, 2018 11:04 am

Sorry, I have not got back to this thread in a while.

Here is an example of breathing that may shed some light on this subject and similar examples which are often posted by folks asking about their odd looking waveforms.

The below is an example of someone exhaling thru the mouth wearing a full face mask with lips parting on exhale and remaining nearly closed. Someone wearing tape with a leak might look similar.

The sharp dip at the beginning of exhale is the lips parting. The dips prior to inhale is a switch from oral to nasal exhale at the end of the breath. This was done while awake and rather quickly so the breaths aren't consistent, but I think they are representative.

Mouth/nose breathing is determined by the location of the soft palate, so all of these waveforms are indeed very similar.

While asleep, the muscles relax and the soft palate is "flying in the wind" back and forth, sometimes getting stuck into the velopharynx or on something and so makes the mouth/nose switch.
That's what they call "palatal prolapse" in the article. You can see in my previous posts how the flow sometime recovers nicely as the out flow decreases and imagine the soft palate falls back (down?). It's the same result waveform as the awake-time breathing route switch you showed but the reason for the switch while asleep is likely different.

Two more nights, first EPAP=9 IPAP=17 PS=8

another example


second night EPAP=15.2 IPAP=18.2 PS=3


Mouth is 100% sealed and machine reported leak rate is zero.
These patterns, whatever they are, are not very responsive to EPAP and maybe somewhat responsive to PS.

Is the above with nasal or FFM?

Regardless, the breaths beginning at 2:53:00 appear to begin wih a sharp exhale, then a reduction in exhale rate which remains level until a dip just prior to the next inhale, which mimics my example of mouth exhale through slightly parted lips, as posted above, with the dip prior to inhale being the switch to nasal breathing. If not for your assertion that there couldn't be any oral exhalation due to tape, these waveforms would look to be typical of mouth exhalation. A machine would usually register a leak when mouth exhalation is present while wearing a nasal mask, but would not while wearing a FFM.

Have you tried lowering the pressure? You increased PS, but held EPAP generally the same which increased IPAP which seemed to produce discomfort. You haven't mentioned OA during this discussion. Do you need IPAP at the current levels to suppress OA? If not, how about lowering IPAP to a pressure which seems to prevent OA and then then lowering EPAP from there with increasing PS? My thinking here is to make the therapy as comfortable as possible while maintaining effectiveness.

Aside from the abnormality in appearance, are these waveforms otherwise troublesome? Are they worth trying to correct? You mention they sometimes end in arousals, but might not these arousals be normal and experienced with or without these waveforms present?

These are with DreamWear Gel pillows and mouth 100% taped. I slept just one night with the FFM. To completely avoid OAs, I need EPAP>=9 with medium trigger or EPAP=8 with very high trigger. Anything lower and the machine sometimes misses a shallow breath and does not start the IPAP cycle. So far I had seen these patterns at pressures (EPAP/IPAP, rounding to nearest cm):

6/9
7/14
8/13
8/14
8/15
8/16
9/12
9/13
9/14
9/15
9/16
9/17
10/13
10/14
10/15
11/11
11/14
11/16
12/12
12/16
14/14
15/18

I can't set EPAP any lower without inccuring tons of OAs. With 7 I did have OAs and should not go there.
With low PS I have terrible inspiratory flow limitations so most of the examples are high PS. Nevertheless, note the 11/11 and 12/12 (PS=0).
9/14-15 is most comfortable to breath with.

Arousals - a string of 'distressed' breaths followed by big recovery breaths is usually a RERA. Few examples at various pressures:

#1


#2


#3


#4


It's hard to imagine not waking up on the last one...

How bad are these? maybe one or two times per hour. Not anything near AHI>15 but not neglible either.

Recognizing the location and mechanism of airway narrowing and airflow routing may be interesting, but it is, to the best of my knowledge, not significant for titration of airway-pressure-based treatments for OSA.

The study adds to knowledge of mechanism and location, but it is not clinically significant beyond that, as far as I can see. EFL or no EFL, the gold standard remains well-titrated and well-executed PAP therapy.

Obstruction may occur first in a particular way in a particular location, but experience has shown that if you simply try to surgically, or otherwise, address the dynamics of one location, obstruction for the OSA-prone patient then just begins to occur at the next location in the airway most prone to obstruction. This is one of the primary reasons that surgical and jaw-position approaches to OSA are much less successful than PAP.

The beauty of PAP therapy is that it simultaneously addresses ALL possible locations of airway collapse or narrowing throughout, instead of focusing on only one location inside the upper airway at a time.

At some point in the future, further studies based on that one may be helpful for determining which approach someone who cannot or will not PAP might consider. But even that will require much deeper investigation than that study provides. The charts, diagrams, and graphics are only about recognizing something that is happening, but none of it is useful, yet, for determining treatment choices or approaches.