[CPAP] New user, looking for tuning advice

[Gideon]

IMHO you want a minimal amount of centrals to allow your body to adjust. Just keep an eye on them.

[wkf94025]

Results from last night:

• Low AHI (3.29), with zero OA's and zero H's.  16 CA's, with over half of them in two clusters.
  
• Started with min pressure 5, didn't feel good after a couple hours, and dropped it back to 4.
  
• Kept EPR at 2 throughout
  
• Longest total night of therapy thus far
  
• Used the N20 nose-only mask
  
• Definite dry mouth/throat in the later hours.  I may try bumping the humidity setting up.
  
• Felt okay, not great, in the morning.  Starting to realize it may be weeks of getting used to the right mask, and settling on the right machine settings, before I am able to sleep 6-7 hours without waking up.
  

Overviews of key graphs:



Others screen shots from scrolling through the graphs and the left panel:  screen 2 screen 3 screen 4

Here is a detail on one of the CA's:


I welcome any feedback from the experts.

[Sleeprider]

With the default settings of 4-20 and EPR 3 your results seem okay, but are not optimized by any stretch. The problem is the minimum pressure the machine produces is 4.0 cm, and with EPR at 3, the exhale pressure does not rise until the CPAP pressure reaches 7.0 cm. Given your low overall pressures, I think you should back off on EPR to 1, and raise the minimum pressure to 5.0. I think you will find this much less disruptive as your pressure differential between inahale and exhale (IPAP/EPAP) will not be constantly changing, and any rise in pressure will also result in an increased EPAP.

[wkf94025]

@sleeprider,

I followed your recommendations last night, and unfortunately the results weren't great:  

• Settings:  pressure min=5, max=10, EPR=1, Humidity=5, ramp = 15min starting at 4cm.  Using N20 nose mask.
  
• Good news is I was able to keep mask on four 4 hours.  Bad news is that AHI=8.5, one of my highest results yet.  CAs = 29, Hs = 3, OAs = 1.  And qualitatively it wasn't a great 4 hours.  I did get 3 more hours post mask, so the day's not shot by any means.
  

What I am most curious about is why therapy pressure starts to ramp up at various points during the 4 hours.  I am tempted to try a constant pressure night, with therapy pressure set to 5cm, and exhale pressure set to 4cm (EPR=1).  I welcome your thoughts on this.  It's hard to determine cause-and-effect from this data.  I am curious which metrics of breathing (short of a full-on apnea event) most affect the machine's decision to raise (or lower) therapy pressure.

Happy to provide more details, or dropbox the data file.
First four screen shots are last night overvall, as I scroll through the graphs and the left panel data.
5th screen shot is zoomed in on first three CAs around 00:45.  Flow rate starts to become less consistent around 00:34.  Is that irregularity in flow rate what triggers machine to raise therapy pressure?
Last screen shot is my analysis of the 14 nights to date, tryiing to compare AHI and duration of therapy against the various machine settings.  I am curious what trends/correlations you see in there.  Perhaps there aren't enough sessions yet to determine any trends or correlations. The purple "quality" column is my derived stat:  duration of therapy divided by AHI, times 100.  The upper table is sorted by this quality metric, and the lower table is same data sorted by date, oldest first.  I did not record mask type, and some recent experiments with other than N20 nose mask keep leading me back to the N20 as best solution for now.

I am happy to try other machine settings in an effort to converge on best setup of my mild apnea.  

[Gideon]

Flow Limits are driving your pressure up.

I would set EPR=0 and see if that improves the centrals and see what happens to your obstructive events.  And yes, you will the therapy-emergent central apnea lottery.  Isn't that just grand?

If the above doesn't work we have another 'trick' up our sleeve.  EERS.  

  
Flow Limits are driving your pressure up.  I would set

Item 5 in treatments is EERS, be sure to also read that.
[url=http://www.apneaboard.com/wiki/index.php/Enhanced_Expiratory_Rebreathing_Space_(EERS)]http://www.apneaboard.com/wiki/index.php/Enhanced_Expiratory_Rebreathing_Space_(EERS)

[wkf94025]

Thanks Fred, very helpful.  Sorry to hear I win the treatment-emergent central lottery.  

I read this wiki page http://www.apneaboard.com/wiki/index.php...tral_Apnea
and the two research papers cited at the end of that page.  Very interesting.  I had a hunch a few weeks ago that my CA's might have me looking into EERS.

Thank you for pointing out Flow Limitations as the driver of increased therapy pressure.  Seems to be highly correlated on last night's graphs.  Can you share any additional insights as to how Flow Limitations is calculated/measured, and what to look for as I study specific events in detail?

I will try EPR = 0 tonight.

Regarding masks, any general observations between nose-only (N20), full face mask, and nose pillows with respect to addressing treatment-emergent central events?

[sheepless]

"Sorry to hear I win the treatment-emergent central lottery."

not the best award, I agree, but not all bad. unlike what I call 'native' central apnea, pressure induced treatment emergent ca will go away, so personally I'd rather have the treatment emergent kind. you might take some solace in the fact that it's very common.

[Gideon]

Thanks Fred, very helpful.  Sorry to hear I win the treatment-emergent central lottery.  

I read this wiki page http://www.apneaboard.com/wiki/index.php...tral_Apnea
and the two research papers cited at the end of that page.  Very interesting.  I had a hunch a few weeks ago that my CA's might have me looking into EERS.

Thank you for pointing out Flow Limitations as the driver of increased therapy pressure.  Seems to be highly correlated on last night's graphs.  Can you share any additional insights as to how Flow Limitations is calculated/measured, and what to look for as I study specific events in detail?

I will try EPR = 0 tonight.

Regarding masks, any general observations between nose-only (N20), full face mask, and nose pillows with respect to addressing treatment-emergent central events?

Event Definition Apnea, Hypopnea, Flow Limitation[edit]

• Apnea: 80% to 100% reduction in airflow for >= 10 seconds
  
  
• Hypopnea: 50% to 80% reduction in airflow for >= 10 seconds
  
  
• Flow Limitation: <50% reduction in airflow for >= 10 seconds
  

The ResMed Flow Limit Chart is the results of a "Flattening Index" calculation.  We do not no the calculation.  ! is the worse.  Flattening can be considered a measure of how bad the flow limitation is.  I look for something like .25 to .3 to start thinking about taking action.  That and a pressure rise that is apparently without other reasons.  Also very important to take the users perception or symptoms into considerations or you could be chasing ghosts and never come up with a better outcome.  

Also look at RERAs as they are a series of flow limitations (ending in arousal)  http://www.apneaboard.com/wiki/index.php...erapy#RERA