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[Equipment] Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
#51
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
I agree with Fred (Bonjour) no need to block the side vents and the valve should still work as a safety device without its normal venting.

I don’t have this type of mask of swivel but that looks like it should stop any venting from the mask
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#52
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-27-2019, 01:42 AM)jaswilliams Wrote: I agree with Fred (Bonjour) no need to block the side vents and the valve should still work as a safety device without its normal venting.

I don’t have this type of mask of swivel but that looks like it should stop any venting from the mask
You were right.  I now have an EERS that functions, but that also means I only have one night of valid data.  All data from previous nights using the EERS prototypes should probably be discounted.  

Settings
Pressure 8 - 13
EPR - 3
EERS Tube length - 12 inches

   

Outputs/Observations
  1. Leak rate was zero except for two leak events, probably relating to pushing the mask against my pillow or to waking up.
  2. Pressure increases still correlate to Flow Limit activity.
  3. 25 total Clear Airway events through the night but the bulk of them occurred before going to sleep and early this morning when I know I was wide awake.  I know that because I had picked up my phone to read mail, news articles, and Facebook entries.  I think that the CA event number is way overstated, but admit it surprises me the machine declares CA's when I'm awake and fully aware that I am breathing.
  4. 0 Obstructive events
  5. I awoke about 1:30 (after only a little over 4 hours of sleep) and did not go back to sleep.  No idea why.  I was in no way uncomfortable with the equipment, air pressure, air flow, ....
  6. I do have to yet solve a condensation problem.  The water that formed inside the tube and mask did not annoy me, but it was significant.  I'm going to try wrapping a small towel around the EERS tube and securing the towel with Velcro ties tonight. The humidity setting on my CPAP is at 4.  I suspect I could try lowering that as well.
  7. I see no change in the hair brush appearance of the flow rate graph.  
Any other observations/advise out there!

Sorry to have been so slow to develop my understanding of my machine and the EERS construction.  I feel a bit embarrassed at my slow discovery process, but want to thank everyone that has contributed to that process and kept pushing me along the way.  And I suspect I'm not completely at the end of that process yet.
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#53
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
This is what I was expecting to happen with your CAs. Looks to me they're likely gone while you're asleep.

I wonder what others make of the TV numbers?

Maybe 12 inches is too much?
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#54
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-27-2019, 10:57 AM)sherwoga Wrote: I see no change in the hair brush appearance of the flow rate graph.  

I think once you get the EERS titration settled (6 vs 12 and such), and confirm you're then fine at EPR of 3, you'd want to experiment with more pressure.

But I defer to others on this thread who have more experience.
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#55
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-27-2019, 11:32 AM)slowriter Wrote: This is what I was expecting to happen with your CAs. Looks to me they're likely gone while you're asleep.

I wonder what others make of the TV numbers?

Maybe 12 inches is too much?

Are you suggesting the TV number went up with EERS volume.  If so we should see a trend in TV using 1, 2, and 3 6-inch lengths of the EERS tubing.  I have sufficient tubing segments to do that over multiple nights.  Any potential problem with such an experiment?
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#56
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-27-2019, 12:21 PM)sherwoga Wrote:
(11-27-2019, 11:32 AM)slowriter Wrote: This is what I was expecting to happen with your CAs. Looks to me they're likely gone while you're asleep.

I wonder what others make of the TV numbers?

Maybe 12 inches is too much?

Are you suggesting the TV number went up with EERS volume.  If so we should see a trend in TV using 1, 2, and 3 6-inch lengths of the EERS tubing.  I have sufficient tubing segments to do that over multiple nights.  Any potential problem with such an experiment?

I can't comment on your last question, but on the rest, yes: I'm hypothesizing just that.

In general, in the few recent people here that have experimented with EERS have seen CAs go down and TV go up.

Often, both are those things are valuable, but I do understand from recent discussion here (WillSleep has raised this) there's dangers in TV that is too high. 

For comparison, I'm a 6 foot male, and my normal median TV is around 500.

When I tried 6 inches of EERS, it went up to about 600.

I think, for me, 600 is potentially a bit high, and my normal numbers (sans EERS) are good.

It just struck me your numbers are pretty high.

But I don't fully understand all this, so hope others will weigh in.
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#57
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
I guess, if it were me, I'd start with the shortest length, and post the results, and probably only go longer if the CAs were on ongoing problem.

Edit: the only reason I suggested the longer length above is because we still weren't sure if the EERS was working correctly; that was assuming it was.
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#58
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
Looking at data in support of EERS.

To pair with data set, can you repeat, all the same, but without EERS? This should include the same mask model, but not modified.

Long term to complete a table, EERS = 6, 12, 18 inches vs EPR = 0, 1, 2, 3 with all else the same. with several days of data for each to minimize daily fluctuations.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter

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#59
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-27-2019, 02:21 PM)bonjour Wrote: Looking at data in support of EERS.

To pair with data set, can you repeat, all the same, but without EERS?  This should include the same mask model, but not modified.

Long term to complete a table, EERS = 6, 12, 18 inches vs EPR = 0, 1, 2, 3  with all else the same.  with several days of data for each to minimize daily fluctuations.
In short, yes, I will repeat as requested and then develop a data set. 

More verbosely, this is an ideal situation for a "designed factorial experiment".  This kind of experimentation is what I was doing fairly routinely at the end of my career as a scientist working for a chemical company.  It has the advantage of developing some understanding in fewer nights sleep. Without attempting to get into a full explanation (of the statistics especially), I would propose setting up the designed experiment with just the two input factors of EPR at 0 or 3 and EERS at 0 or 18 for a total of four combinations.  This would result in my collecting ONE data set over four nights of sleep.  That data set would be for EPR, EERS setting pairs of 0,0; 0,18; 3,0; and 3,18 on nights 1, 2, 3, and 4, respectively. But to have any real meaning, the experiment would have to be replicated and I would start out replicating at least twice to generate THREE data sets over a total of 12 nights.  That should be enough to understand (at least at a first approximation) how EERS and EPR impact my sleep performance.  Then I would go back and "test" that understanding by using some or all of the intermediate setting combinations possible from what you proposed.

But before doing all this work I still have questions, the answers for which, will fix other experimental conditions.  So, I would appreciate your thoughts about my last three nights. 

November 26 was my first night of using a properly designed 12-inch EERS and EPR at 3.  Condensation was very significant.  Humidity setting on my CPAP was 4.  I awoke after only 4 hours of CPAP use for a bathroom break and I did NOT go back to sleep.  While the numbers were all good, my assessment of the sleep that night and how I felt the next day was "terrible".

November 27 was my 2nd night, but I shortened the EERS to only 6 inches, keeping the humidity setting at 4 and the EPR setting at 3.  I also tried to insulate the EERS tube in multiple layers of terry cloth created by folding two wash cloths (about 10 x 11 inches) over once and then wrapping them one at a time around the tube.  I secured the wrapped cloths with Velcro strips and the cloths did stay put.  Condensation inside the tube was minimal to zero, but I still had water on the inside surface of both my mask and the Whisper Swivel II vent, as at the very ends of the EERS tube.  I awoke after only 3 hours of CPAP use for a bathroom break and I did NOT go back to sleep.  My assessment of the sleep that night and how I felt the next day was even more "terrible".

Last night, November 28, I went back to no EERS with EPR still at 3 and humidity setting still at 4.  I observed no condensation.  My numbers are pretty good, but some central and obstructive events are both back.  I awoke at after about 5.5 hours of CPAP use for my bathroom trip.  I again did not go back to sleep, but I feel much better.  I'm sharing last nights data (attached screen shot).  The data for last night does correspond to one of the required 12 nights of data for the designed experiment detailed above, as long as I don't change anything (for example, the humidity setting). 

   

The CPAP Pressure Range for all three nights was from 8 to 13 cm water.  The value for the maximum of 13 is a full 5 cm water less that what I had been using prior to your very first recommendation (here) to me to reset my EPR to 1 and begin lowering my maximum pressure.  It was progressively lowered from 18 to 13 over the time period corresponding to my stumbling around trying to construct a properly functioning EERS.  During that period my observation is that lowering the EPR had had a very significant impact on lowering CA events.  The max pressure changes might have had some impact, but multiple times (including last night) I have seen the pump pressure go all the way to the maximum. I am left wondering if it would be better to put the maximum pressure back up to 18 before starting the designed experiment.  Doing so might result in theory in a greater range in the results data making it possible to detect real differences above the statistical noise.  If the range in the data ends up being too small, that statistical noise could be all we see. On-the-other-hand, not doing so could improve my sleep somewhat during the course of the designed experiment. 

So there are at least 2 pump settings that I need to be confident about.  I don't want to have to change either maximum pressure or the humidity setting during the data collection.  If they do have to be changed, it would be almost mandatory to restart the experiment.  What do you recommend for each of those two settings? I'm asking for your input since it is you that is asking for the collection of the data.  That is to say I need your input and help in this "Design" phase of the experiment.  

Two more items that need to be assessed are 1) going back to sleep after a bathroom trip and 2) the list of the significant outputs we need to evaluate at the end of the data collection. 

Dont-know I don't see how I can control going back to sleep.  But if this persists as a problem we could get into the data collection and have to select our best guess for the settings and try to get my sleep improved at that setting. This would be tantamount to abandoning your request of data support for the EERS.  Just want you to be aware of this. 

Thinking-about Part of designing an experiment well is knowing up front what it is you want to get out of the experiment.  The OSCAR software makes a fabulous record that could be reviewed after the data is all collected and harvested for additional information, but it would be far better to start the experimental record of the outputs right at the beginning of the experiment.  Output variables obvious for consideration to be included in that record are:
  1. CA event index
  2. Total CA Events
  3. OA event index
  4. Total OA events
  5. Tidal Volume (one or more of Median, 95%, and Maximum)
Do you think you would want all of these and/or others?  For example, some attempt to characterize Flow Limits, RERA events, Hypopnea Events, Undeclared Events.....

Looking forward to hearing from you.  This could be useful to you and to other CPAP users suffering from complex apnea and/or treatment emergent cental sleep apnea.  It will be fun experimentation for me.  Probably greatest benefit of all would be my improved confidence in my apnea treatment.
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#60
RE: Fabrication of an Enhanced Expiratory Rebreathing Space (EERS)
(11-29-2019, 09:59 AM)sherwoga Wrote: Output variables obvious for consideration to be included in that record are:
  1. CA event index
  2. Total CA Events
  3. OA event index
  4. Total OA events
  5. Tidal Volume (one or more of Median, 95%, and Maximum)
Do you think you would want all of these and/or others?  For example, some attempt to characterize Flow Limits, RERA events, Hypopnea Events, Undeclared Events.....

I'm just going to comment on this part.

If we're just trying to assess impact of EERS (before moving on to other aspects that impact your sleep quality), I think (and hope bonjour will correct or confirm) you want to track median TV, MV, RR. So I'd add the latter two.

Generally, it seems the relation among those three numbers with EERS is TV and MV go up, but RR stays more-or-less stable. I guess with MV and RR, you could technically omit TV.
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