x-y axis mismatch

[ovmeadows]

Why is the minus side of the Y-axis so much higher than the plus side?

   

[Jay51]

I think you are talking about the flow rate chart.  Correct me if I am wrong.  

You have a 2.8 second exhale that is roughly twice the length of your inhale (roughly half or so of 2.8 seconds).  Not a big deal.  Exhale is when the line slopes downward at any time.  Any time the line starts to ascend, that is inhaling.  There is a zero line for reference.  

From all of my research, a long exhale is simply used to expel more CO2.  With my ventilator, my charts could possibly look like yours also, as I have been diagnosed with hypoventilation; and exhaling the maximum amount of CO2 with each exhale is desired.

[coutherino]

I'd guess it's of a combination of being on BiLevel, and still having some pretty clear obstruction. Naturally with BiLevel your EPAP is going to be lower than your IPAP, so you'll experience much less resistance when exhaling compared to if you were just on CPAP, allowing the waveform to drop lower.

But more than that, you're definitely still having some flow limitation. The tops of those waves are... definitely not round, and most of them appear to be quite jagged. I'd almost guarantee you were snoring during that screenshot.

As long as you're not experiencing any complete obstructive apneas at this pressure, I'd recommend just raising your IPAP by 1 or 2 cmH2O first, and seeing if that resolves it. That being said, it would definitely be easier to make a recommendation if you sent a screenshot of this full night, along with a few 4–5 minute sections like this one at points leading up to arousals or events your machine tagged, to see if it's actually affecting your sleep.

[ovmeadows]

Thanks. 
2 screens attached.

   

   

[coutherino]

Hm, yea. I feel very confident in saying that the arousal in the screenshot you sent is being caused by the flow limitation preceding it, likely due to an increase in respiratory effort. Not only that, your breathing remains wonky for around 3 minutes as you stir, until you eventually have a central near the end due to all the CO2 you expelled during that bit of deep, ragged breathing. This seems to be occurring all throughout the night, likely in most of the places you're seeing those sharp spikes in the flow graph. Some of them also have centrals being tagged afterwards. It's almost certainly disturbing your sleep, and raising your IPAP should, in theory, resolve this. But it might take some extra tweaking. Solving the flow limitation with the increased IPAP could very well cause the troughs of the waveform in your flow rate graph to flatten out a bit, too. With a full view of the night like this, it makes it easier to see how erratic it is.

Your leak isn't very high, but it's quite variable, which is something you're probably gonna want to address eventually. It's difficult to know how much it is actually waking you up, and how much of it is just caused by you shifting due to all the RERA's you're experiencing throughout the night, but still. I suppose that's a problem for another day. For now, just consider trying the changes I recommended and reporting back afterwards. I hope this helps.

[ovmeadows]

The following sittings could be of interest:
Timax: 4.0s
Timin: 1.1s
Trigger: low
cycle: very low

[coutherino]

I'm not sure that having a low trigger and cycle will help your current issue. What are you using for all those right now, or are those your current settings? I'm just gonna assume those are your current ones. Is there any specific reason why you changed it to those in particular? If anything, I'd expect to see some improvement with setting them higher, especially trigger. Glancing back at your flow rate graph, that could explain the almost notch-like looking flow limitation right at the start of each breath, where it should be a smooth increase. If your trigger is low, you have to exert more effort to breathe before the IPAP actually kicks in.

I'd highly recommend changing your trigger from low to high. Normally I think it's best to control for one variable at a time, otherwise you mind end up fixing something one night and having no idea what really made the difference. But I'm pretty confident that will help.

As for cycle, it might be fine where it is. I'd recommend changing it to low or medium, though.

Just based on the flow rate graph, it seems you have a set rise time instead of Easy-Breathe turned on, correct? If so, what is it set at?

If you're interested in my specific recommendations, here they are:

EPAP: 13
IPAP: 19
Trigger: High
Cycle: Medium

You can leave everything else as is. If these don't have any effect, we'll probably have to keep increasing your IPAP. Hopefully this response wasn't too overwhelming.

[ovmeadows]

Thanks.  Will try your recommendations tonight maybe several.  I'm weary of the higher pressure, fear mask leaks, dry eyes and dry mouth.

[coutherino]

I understand. Have you considered using a nasal mask? It would likely be much easier to manage leak in combination with tape.

If you are not able to due to an issue like a deviated septum, or chronic congestion, I completely understand. But if not, I would definitely recommend giving one a try if you haven't already.

[ovmeadows]

Easy breathe is either "on" or "off" mine is "on".

Forgot to replace my SD card last night, a rare event.  Device did show it was on fot 6 hrs and 15 min AHI of 0.50.  Feel like I had yet another restless night.

Do you have a recommendation for a nasal mask.  I have tried one a few years ago but got the sore nose (began CPAP 2017).