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UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
#1
UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
Hello,

Due to recommendations from some members here, and on the UARS subreddit, I got a V Auto to try and improve my sleep.  I was previously using a PRS One 560 Auto for a long time, with limited success.  I was at 10 - 12.5 cm H2O with A-Flex x3.  A few days before getting the V Auto, I tried to use a constant pressure of 12.5 cm H2O, still with A-Flex x3 and noticed a large improvement.  I don't know if this means I sleep better with fixed pressures.

Anyways, on both machines, I found that I get periods where my exhale waveform is very jagged.  For example: 

[Image: vElEYud.png]

and

[Image: 1Mrc3ld.png]

Does anyone know what might cause this?  Is it from expiratory flow limitation?  Should EPAP be lower?

I do get periods of normal flow rate, but it's for the minority of the night (1/5th of the night at best.  Usually less):

[Image: vG68tTN.png]

Another thing I've noticed is that when looking at my whole night, there are frequent spikes in my flow rate.  Would these be from arousals?  I do wake up frequently at night, change positions, and then go back to sleep.  Does that mean my therapy is still not as effective as it should be?  Here's an example (some spikes highlighted in red):

[Image: TuQHkAD.png]

Can anyone share some insight please?
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#2
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
Looks like expiratory snoring, the leak chart for the full night supports this.

The spikes could easily be arrousals, would need a 2-minute view to confirm
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
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#3
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
I disagree with expiratory snoring, because of the consistent timing. I think we see your pulse here. Snoring looks more like a short-wave zig-zag line, but when you lay on your back and left side the heart can cause a pulse effect in the flow rate that is more pronounced in the expiratory wave. The last image shows occasional high flow-rate spikes that we can't really identify from the 5 mile elevation, but they are not uncommon.
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#4
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
(06-29-2020, 06:24 PM)bonjour Wrote: Looks like expiratory snoring, the leak chart for the full night supports this.

The spikes could easily be arrousals, would need a 2-minute view to confirm

Thanks for your reply.  Can I have expiratory snoring without the machine flagging any snoring?  I seldom get any snore flags.

Here are a couple 2 minute views of spikes.  They happen very frequently (can be 8 mins apart, 12 mins apart, 20 mins apart, etc) throughout the night, every night.  Is that normal?:

[Image: NvjLeSf.png]

[Image: JqMRpy8.png]

(06-29-2020, 07:06 PM)Sleeprider Wrote: I disagree with expiratory snoring, because of the consistent timing.  I think we see your pulse here.  Snoring looks more like a short-wave zig-zag line, but when you lay on your back and left side the heart can cause a pulse effect in the flow rate that is more pronounced in the expiratory wave.  The last image shows occasional high flow-rate spikes that we can't really identify from the 5 mile elevation, but they are not uncommon.

Thanks for your reply.  That's interesting about the pulse thing - I'll try to see if I can verify if it only happens when I'm sleeping on my left side or back.  

When you say 5-mile elevation, are you talking about how far the graph is zoomed out?  I have posted some closeups above in my reply to bonjour.
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#5
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
Those look like episodes of arousal breathing to me. I'll be interested to hear what the experts say.

In these charts it's clearer that you're having cardiogenic oscillations between breaths. That's the little squiggle above/below the zero line. (This is also called a cardioballistic effect or artifact.) I didn't know it could also manifest during exhalation, so I learned something today!

From the American Thoracic Society:

"Cardioballistic artifact is a normal physiologic occurrence that may be seen in the airflow signal, nasal pressure and esophageal pressure-monitoring channels, chest or abdominal belts, and EEG channels. It is most often observed during exhalation and during central apneic events. The mechanisms of transmission of cardiogenic oscillations in the airflow channel or other respiratory channels have been debated. The observation that voluntary upper airway obstruction uniformly results in loss of cardiac oscillations led to the theory that they may be an indicator of upper airway patency, with the idea that changes in intrathoracic pressure produced with each heartbeat result in movement of air through the patent upper airway. However, during sleep, such oscillations over-imposed on airway signals have been observed in the presence of directly visualized upper airway occlusion and in an animal model with complete anatomical separation of the upper airway, lending to the belief that these oscillations occur irrespective of the airway patency. In such cases, intra- and extra-thoracic mechanisms have been hypothesized. For the former, it is believed that the heartbeat displaces air from the intrathoracic cavity causing a pressure wave that bounces against the occlusion. For the latter, pulses in the vessels above the site of obstruction, especially those located relatively superficially within the tissues of the upper airway may cause a similar pulse wave. One further speculation is that transmission of cardiogenic oscillations to the airflow signal may be influenced by the degree of respiratory muscle tone. When there is high muscle tone during respiratory effort, the transmission of the pulse wave is diminished."
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#6
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
Thanks Dormeo. Here is the new wiki page. http://www.apneaboard.com/wiki/index.php...cillations
Sleeprider
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#7
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
(06-29-2020, 11:29 PM)Dormeo Wrote: Those look like episodes of arousal breathing to me.  I'll be interested to hear what the experts say.  

In these charts it's clearer that you're having cardiogenic oscillations between breaths.  That's the little squiggle above/below the zero line.  (This is also called a cardioballistic effect or artifact.)  I didn't know it could also manifest during exhalation, so I learned something today!

From the American Thoracic Society:

"Cardioballistic artifact is a normal physiologic occurrence that may be seen in the airflow signal, nasal pressure and esophageal pressure-monitoring channels, chest or abdominal belts, and EEG channels. It is most often observed during exhalation and during central apneic events. The mechanisms of transmission of cardiogenic oscillations in the airflow channel or other respiratory channels have been debated. The observation that voluntary upper airway obstruction uniformly results in loss of cardiac oscillations led to the theory that they may be an indicator of upper airway patency, with the idea that changes in intrathoracic pressure produced with each heartbeat result in movement of air through the patent upper airway. However, during sleep, such oscillations over-imposed on airway signals have been observed in the presence of directly visualized upper airway occlusion and in an animal model with complete anatomical separation of the upper airway, lending to the belief that these oscillations occur irrespective of the airway patency. In such cases, intra- and extra-thoracic mechanisms have been hypothesized. For the former, it is believed that the heartbeat displaces air from the intrathoracic cavity causing a pressure wave that bounces against the occlusion. For the latter, pulses in the vessels above the site of obstruction, especially those located relatively superficially within the tissues of the upper airway may cause a similar pulse wave. One further speculation is that transmission of cardiogenic oscillations to the airflow signal may be influenced by the degree of respiratory muscle tone. When there is high muscle tone during respiratory effort, the transmission of the pulse wave is diminished."

That is fascinating, thank you very much for sharing.  I'll try to replicate the test that you did that is listed in the wiki, and see if I get the same results (http://www.apneaboard.com/wiki/index.php...cillations).

Do my screenshots with the arousal episodes give any clue as to what is causing them?  Frequent arousal during my sleep is a big issue that I have.  I've tried higher pressures to see if it will improve sleep quality, but it usually has the opposite effect since I don't seem to tolerate higher pressures very well (aerophagia and/or feeling overwhelmed by the higher pressures).
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#8
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
Thank you so much for the replies, everyone.  I'm super grateful for all of you.

Can anyone shed some light as to what is happening in the following waveforms?  It happens quite frequently as well, and am not sure what to make of it.  It seems like on exhale, i'm having trouble with my airway briefly, and then proceeding to exhale normally.  Could this be palatal prolapse?  I do think I have an issue with the soft palate - I feel as if the airway is "flappy" (for lack of a better word) in that region, and can be flapped shut.  (Sometimes as I'm drifting off to sleep, I awaken suddenly feeling stress and if that area had closed off while I was falling asleep).  Does any of this make sense?):

[Image: tWNzIYw.png]

and some more:

[Image: Hkkd7U1.png]
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#9
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
(06-30-2020, 07:57 AM)Sleeprider Wrote: Thanks Dormeo.  Here is the new wiki page. http://www.apneaboard.com/wiki/index.php...cillations

Terrific!  Thanks, Sleeprider.
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#10
RE: UARS - Jagged Flow Rate on Exhale + Frequent Flow Rate Spikes
jdip, the examples you posted above appear to be closer to a breath-hold at the end of inspiration. We seen a normal inspiration wave with flow rates near 20 mL/second and which drops to just below zero then holds at zero for a brief moment before commencing with expiration. I can't explain why a pause in expiration is happening, but it does not have the appearance of PP which is an abrupt termination of expiratory flow. If you feel expiration is inhibited for any reason, you could increase the cycle sensitivity setting to high to reduce pressure a bit sooner as inspiration slows. I really have not dealt with this before and it does not seem to be hurting your therapy.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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