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Airsense 10 not flagging apneas??
#11
RE: Airsense 10 not flagging apneas??
Thanks for chiming in on this Sleeprider!  Let me try to give you some additional history that might be helpful:
I have taken a look at this problem for about 6 weeks now which is as long as I’ve had my auto machine.  Before that, I had an S9 brick.  I’m sure the jagged flow is very much related to flow limits as you’ve mentioned.  It also seems to be related to pressure but I think that is really because the AirSense 10 increases pressure in response to flow limits as it should to circumvent apneas.  So, pressure, flow limits and jagged waveforms all seem to increase and decrease together.  This is what I’ve seen in the data.  Do others also present jagged waveforms when flow limitation is present or is that an individual matter?  I could see where it could be an individual matter just as some people respond to flow limits with a snore and others like me do not.  Probably an anatomical thing. 
Ramp:  Yes, the data I started the thread with shows a series of apneas that started with the ramp.  I think this is due not to some funny stuff with the ramp but really just due to the fact that before the ramp completes, a therapeutic pressure has not been reached.  For the first few weeks, the ramp was off and the min pressure was 5.  I got a lot of apneas until a pressure of about 10 was reached.  That happened almost every night.  I have a problem starting with 10 or 12 because it’s difficult to fall asleep due to the pressure and noise.  I find it much easier to start lower and this is why I enabled the auto ramp.  The idea in using the auto ramp is to speed up the time from the onset of sleep to the onset of a therapeutic pressure (6-mins from sleep to 10cmH2O as it is set now) so as to minimize the time that apneas are likely while still providing a comfortable condition to dose off.   I think this has worked pretty well...  Why? With the auto ramp enabled, the burst of apneas you saw is about as bad as it ever gets.  That only happens at the beginning and typically I pass through the ramp with no events.  Probably one of 5 nights I’ll see an apnea burst but not as bad as what you saw.  Also, my AHI score is very good most often being less than 1.  So, what I’m suggesting here is that using the ramp as I am may be a good trade by providing very few added events in return for pre-sleep comfort.  On those few nights where I get a burst as you saw, it would take my score from about 0.4 to about 1.5 which is still just fine.  Of course, as we’ve seen the AirSence will only report the 0.4; I’ve calculated the 1.5.  If I’m not missing anything here about the ramp, I think it can be left as is.  Do you agree or is there more going on with the ramp that I’m overlooking??
Central Apneas:  I was having a handful of these mostly at higher pressures but in the last 10 days or so I haven’t seen any.  I’ve heard these can subside as you acclimate to the therapy pressures.  Does this make sense?
EPR:  This was set to 3 when I first started with the AirSense 10.  I didn’t like the pulsating effect so I changed it to 2 and this solved the problem.  I didn’t notice any changes in events or waveform as a result of this change.  I think I could go back to 3 though since it wasn’t that bad.
I’ll try a min pressure of 12 and EPR back to 3.  I’ll keep the ramp as it is pending your comments on what I wrote above.  We’ll see what happens and I’ll report back.  
I’m very curious about the erratic flow rate and would like to know if it’s a problem or not.  It certainly isn’t a problem that is reflected in the AHI score but I’m not convinced.  I suspect that its due to vibratory effects derived from a partially obstructed airway, kind of like a balloon sputtering around the room. 
“What is going on here at 00:00 or 02:00 that looks like shallower breaths mixed with larger ones?”  I’m sorry but I don’t know what you are referring to here.  I hope I don’t have some funky breathing disorder! 
“Why is the net leak rate stable at 15 L/min, when it should be near zero?"  I agree there must’ve been some problem here.  The other night I found the hose was spraying a small air-stream and was on a little crooked.  Last night the leak was way down between 0-3 so I think its fixed now.
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#12
RE: Airsense 10 not flagging apneas??
OK, I’m back with the last two nights of data.  I changed the min pressure from 10 to 12 and kept the max at 20 and changed EPR from 2 to 3.  Auto ramp is still on as I mentioned in post #11 above.  I looked things over and there are no apneas during the ramp which is more usual than undetected apneas which happens less often as I mentioned earlier.  No central apneas either.  These have really subsided over time.  
Dwd1249 asked about my nose.  It seems to be reasonably clear to me and an allergy doc said it was though he also suggested I take Nasacort for sneezing attacks I sometimes get.  For normal breathing I don’t experience resistance thru the nose though I often mouth breath at night which is why I never cared for nasal pillows and early migrated to a FFM.  
I did read the dwd1249 thread.  Thanks for that DeepBreathing and dwd1249.  Lots of parallels here, I know!
For the second night’s data only, I changed over to my F20 FFM where I had been the F10 FFM.  The F20 makes more noise but I think it seals a little better under high pressures.  Leakage doesn’t seem to have been much of a problem but check anyway.  
The data is organized first zoomed out followed by zeroing in on several locations so you can see breathing waveforms.  Here’s where you find the first night’s data:
https://imgur.com/a/j72rZ  
This probably looks better than the earlier posts but this has always been a moving target.  When pressures stay lower, flow limit is lower, tidal Volume is higher, the waveform and the resp rate are both more reasonable.
The second night’s data trended a little worse than the first night.  It is found here:
https://imgur.com/a/52Upo
To my eye, neither of these nights seems different than past histories but my eye may not pick everything up so I’d like to hear from those who know better.  I still see lots of ugly breathing here particularly in the second night.  
As I mentioned earlier it looks to me like a flow limited path is the cause of the ugly waveform.  It raises the question if this is normal in other people to have such distorted breathing while flow limits are high and pressures raise up.  Does anyone know?  
When I use the DreamStation the waveforms look different and a little better but still not good.  That machine does not go to the high pressures I see with the AirSense 10 and I get more events logged.  I can post some DreamStation data if it will help.  
I look forwards to any suggestions or explanation as to what might be going on here.  Thanks for the help!
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