SH chart - what is happening here?

[katestyles]

SCUNCI! SCUNCI! SCUNCI!

ftw

LOL
OK call me skeptical, but how will a porous scunci stop me exhaling through my mouth?

Don’t ask Zonker you’ll get a selfie

He sent me this!!!

Hannibal lecter.png (376.75 KiB) Viewed 638 times

[palerider]

SCUNCI! SCUNCI! SCUNCI!
ftw

LOL
OK call me skeptical, but how will a porous scunci stop me exhaling through my mouth?

It won't. But, it *discourages* it.

Chin straps hold your jaw closed, but do nothing at all to prevent mouth leaks. you can clench your jaw tight and still breathe perfectly fine through your mouth, because teeth aren't air tight.

The scunci presses gently on your lips, which keeps them together a bit, and makes it a *little* harder for air to go out.

[palerider]

Like this?


rather than this, which I think is an arousal, not a central

Please go back and fix the vertical scaling on the flow rate, like you did before. I can't see squat with it squished so badly.

[zonker]

Don’t ask Zonker you’ll get a selfie

no, katie is being nice to me, so i won't inflict it upon her.

(or WILL i?)

[zonker]

SCUNCI! SCUNCI! SCUNCI!

ftw

LOL
OK call me skeptical, but how will a porous scunci stop me exhaling through my mouth?

as others have said. but i have some mighty stubborn lips, so i add a wee small hairband around my bottom lip. plus a glasses cleaning cloth next to my lips as the whole rig tends to cause saliva to pool at my lips.

works for me.

[katestyles]

I was asking about the difference between a true central and a "central after arousal.

I believe this

screenshot-20190317-152846.png (109.91 KiB) Viewed 600 times

was after arousal
and this was (possibly) a true central.

[palerider]

So here's my experiment from last night for your consideration, PR. It wasn't as controlled as I'd like and while it doesn't show that leak equals MV as I suggested, it does show the two are related. Perhaps not being able to hold the exhale at the zero level skews the results?
Three periods of mouth exhalation with nominally decreasing leak values from left to right corresponding to nominally decreasing MV values. Leak values of 7.8, 7.2, and 6.0 compared to MV values of 6.0, 5.3, and 5.2 respectively, the difference between Leak and MV being close to a constant 1.8.
Edit: Or, the 1.8 difference could be due to vent rate. See discussion below. I'm using the N30i for this.
leakvsMV.JPG

Here's mine:

mouthexhale.png

Ok, I was wrong about it not showing up on leak... Thank you for helping me learn something.. (it's always interesting when I'm wrong about something, because I learn something, and I love learning things... currently studying to get a ham license).

That's what I get for doubting your analysis, I learn something

I don't know if it's a vpap auto thing that caused the flow rate to 'average out' instead of all staying above the zero line. I was very carefully inhaling through my nose and exhaling through my mouth.. Then at the end, I was mouth breathing without letting the air rush out from my nose.

[palerider]

. I have no clue what the vent rate is for the bleep, perhaps it can be found in the documentation that came with the mask.

ResMed mask vent rates are around 37 L/min at 10-12 cmH2O pressure.

Bleep docs say 31lpm @ 10cm (in the manual on their website).

[palerider]

. In real life when I did my experiment using 25 IPAP I got less than 25 L/min vent

Wow, that's really low. check your vent rates at your normal pressures to make sure you're getting enough clearance of exhaled breath.

[palerider]

and this was (possibly) a true central.

Typically, "true" centrals just taper off to nothing, without any bigger breaths beforehand.

If you see larger breaths or irregularities before a central, it's probably not a true sleep central.

It's much easier to see with the smaller range on the y axis, isn't it

[raisedfist]

I have excessive mouth breathing via exhaling through the mouth, and it does not show up on the leak graph or statistics. It does hamper my therapy greatly though, as I feel like a semi-truck hit me when I wake up. Then I don the full face mask, and that feeling goes away.

[Jay Aitchsee]

I was asking about the difference between a true central and a "central after arousal.

I believe this
screenshot-20190317-152846.png
was after arousal
and this was (possibly) a true central.

Could be. The first looks like a disturbance CA (Leading with a deep breath), but it could be just a normal arousal. The second looks like it occurs during an awake or disturbance from leak. Your CA index doesn't appear to be high, only 0.67 on your last post. I wouldn't say that requires fixing. Better to work on your OA. At 2.58, I would consider that too high.

In other words, neither looks like what you would call a "true central".

[Jay Aitchsee]

Thanks for posting your experiment, PR. I would be interested to see how the value of your leak compares to your MV.

I don't know if it's a vpap auto thing that caused the flow rate to 'average out' instead of all staying above the zero line. I was very carefully inhaling through my nose and exhaling through my mouth.. Then at the end, I was mouth breathing without letting the air rush out from my nose.

I think it might have to do with the way it calculates negative flow, as we know, there is really no negative flow so the machine must set an arbitrary 0 line at some positive level and calculate from there taking into account mask vent rate, leaks, etc. Since inspiration must equal expiration, maybe it just sets a 0 reference at a point that will yield that result. Mine was was the same using a lowly autoset. As you said, "it's complicated".

I have excessive mouth breathing via exhaling through the mouth, and it does not show up on the leak graph or statistics. It does hamper my therapy greatly though, as I feel like a semi-truck hit me when I wake up. Then I don the full face mask, and that feeling goes away.

If you're using a nasal mask, chances are the vent rate of your mask is less that being expected and the leak is being hidden by that. See the discussion a little further up this thread. Why not just wear a FFM full time?

[raisedfist]

If you're using a nasal mask, chances are the vent rate of your mask is less that being expected and the leak is being hidden by that. See the discussion a little further up this thread. Why not just wear a FFM full time?

I do wear a FFM almost all the time. Occasionally I wear the nasal mask when I develop a mark/sore on my face from the FFM. Usually happens when I don't shave/take care of the cushion for a while. Oops.

[Jay Aitchsee]

If you're using a nasal mask, chances are the vent rate of your mask is less that being expected and the leak is being hidden by that. See the discussion a little further up this thread. Why not just wear a FFM full time?

I do wear a FFM almost all the time. Occasionally I wear the nasal mask when I develop a mark/sore on my face from the FFM. Usually happens when I don't shave/take care of the cushion for a while. Oops.

A leak wouldn't be expected with mouth exhalation while wearing a FFM.