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Fast pressure rises/and at max
#11
RE: Fast pressure rises/and at max
(10-14-2015, 09:13 AM)regbeach Wrote: Here is a zoomed flow pattern from the Oct 6 data I posted.

[Image: 85qgB5i.png?1]


1. Is she awake during part of this? I think I see repeated sleep flow pattern like at 35 and 34:30.

It looks to me like she is asleep during the zoomed in portion and having obstructive apneas, and is occasionally being aroused enough to breathe a few breaths before obstructive apnea sets in again.

The "Flow" is the instantaneous rate of airflow (in liter per minute) into our lungs (when waveform is above the horizontal axis) and out of our lungs (when below the axis).

During an obstructive apnea the PS is always cycling on and off at the backup respiration rate (8 breaths per minute, one breath cycle per 7.5 seconds).

When there is virtually no Flow even though PS is near 12, her airway is closed so hard that pressure increases of 12 and pressure decreases of 12 are unable to cause airflow into or out of her lungs. She needs higher EPAP to keep the airway open, but EPAP cannot be raised unless IPAP can be raised, and IPAP is already maxed out.

If the Max IPAP were 24 (24 = Max EPAP + Max PS), the EPAP would be free to raise itself up to its Max of 12 whenever it wants. Likewise, if Max IPAP were 24 and if EPAP were already maxed out at 12, PS would be free to raise itself up to its max of 12 (bringing IPAP up to 24) if needed.

Of course, higher pressure would likely cause more leaking, but perhaps a mask liner would adequately solve a leak problem.

I need to use very high pressures, and currently the F10 mask is my favorite, but I cannot use the F10 without using a mask liner to eliminate mask burping/trumpeting and to soften leaks so they are not bothersome. I use RemZzzs.

Quote:4. What are the 3 IPAP lines in the pressure graph? Min IPAP, IPAP and Max. IPAP. They don't seem to correlate with the EPAP up and down movements so the min./max don't seem to be EPAP + PS min/max.

Not sure, but the 3 lines for IPAP seem to act like some sort of short term max, average and min lines, perhaps averaged over a period of a minute or so.

To clearly see what is actually happening with the pressure it would be good to plot a "High Rate Pressure" waveform, if SleepyHead can do that. (Not sure; I use ResScan, which works only with ResMed machines.)

The High Rate Pressure waveform would show the EPAP pressure during EPAP and would show the IPAP pressure during IPAP, and the difference will always be the PS.

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#12
RE: Fast pressure rises/and at max
(10-15-2015, 01:16 AM)vsheline Wrote: If the Max IPAP were 24 (24 = Max EPAP + Max PS), the EPAP would be free to raise itself up to its Max of 12 whenever it wants. Likewise, if Max IPAP were 24 and if EPAP were already maxed out at 12, PS would be free to raise itself up to its max of 12 (bringing IPAP up to 24) if needed.

Of course, higher pressure would likely cause more leaking, but perhaps a mask liner would adequately solve a leak problem.....I use RemZzzs.

To clearly see what is actually happening with the pressure it would be good to plot a "High Rate Pressure" waveform, if SleepyHead can do that. (Not sure; I use ResScan, which works only with ResMed machines.)

Mask liner- Many noises were resolved by washing mask daily. F10 does sometimes gap though (then flutter or trumpet -perfect word I needed months ago).
Maybe the liner would help with the gap?

Please advise- I saw instructions on line that showed to put line on mask seal, then tilt head down and place mask on face, then headgear and then pull liner down, grasping it near chin.
I put my mom's mask on after she is laying down on a wedge pillow. Is that possible to do with a liner? Or will it get misaligned? The directions would be challenging.

I understand the Max IPAP math and, theoretically, agree with it. However, I have seen the IPAP exceed the max of 18 during the night. Sometimes it happens for a split second, screen blinks a number in the low 20s, then shows a 16 (for example). Other times, my mom is awake and the pressure is clearly 21 or 23.

I sent a detailed message to sleep dr yesterday. I did bring up the math and max pressure though so expect it will be changed. I am tempted to change it myself tonight. She is out til Fri. Ugh.

There is not an option in Sleepyhead for max. pressure graph. Graphs don't appear customizable.

Thank you.

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#13
RE: Fast pressure rises/and at max
Update to last post- I spoke to a Clinician at Philips today and asked:
1. about max. pressure setting on machine vs. EPAP max + PS max,

Contrary to what I have read on this forum- he first corrected me that EPAP min + PS max = Max pressure. I triple confirmed with him that it is EPAP min (not max). This is the max. pressure that the machine will try to deliver if not constrained.
Then, I noticed in the Set-up Manual, it describes PS max = Max Pressure - EPAP min.

This explains why my mom's machine is set at max pressure of 18 (ie. EPAP min of 6 + PS max of 12). And, not set at max + max = 24.
Though I agree that max + max = max setting is logical; it is not inline with Philips set-up manual or "clinician-speak" when we talk to drs or clinicians- just FYI.


2. about the fact that I actually see IPAP values on the screen exceeding the max. pressure,
He didn't have an explanation for this.

3. if the max. pressure being reached was constraining the machine in increasing EPAP to clear obstruction.
He said that obstructions get the priority. Anytime there is an 80% reduction in flow for 10 sec or more, EPAP will increase by a pre-determined about. He said EPAP overrides PS.
My thought- maybe this is somehow why max pressure is exceeded sometimes.

Still waiting on dr.
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#14
RE: Fast pressure rises/and at max
I finally spoke to dr. about sleep lab titration. (I still don't have report to post yet). Her recommendation is completely different than what we have been discussing based on her daily reports. I am in disbelief but trying to have faith.

She did not look at the daily screenshots I sent her. I asked about increasing EPAP min and explained that I can see that OAs are occurring at the the min of 6 and even 7. She said based on the titration that more events happened at higher pressures. Even though my mom didn't have REM sleep in the lab, she said the best pressure to try is:
IPAP of 10, EPAP of 6 and leave them constant.
Back up rate will be changed from 8 to 16.

She said my mom had more events at higher pressures.
She said in this study her OSA was moderate whereas it was characterized as severe in the first one. She also said there were mixed OA/CAs but no straight CAs this time.
She said if it doesn't work then we can discuss a TRACHEOSTOMY that would be capped during the day. I said since we haven't made any pressure revisions in the last year last maybe we could try some things if this change didn't work first.

Oh my...please tell me to trust the dr.

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