Positional Apnea and going for CPAP

[Sleeprider]

Flow limits are persistent and lead to respiratory effort related arousals. It's nice to have a perfect AHI, but I couldn't live with these settings. I take back my previous settings and raise you to 7.0 minimum, 10.0 maximum EPR 3. This will start you at 7/4 pressure and allow up to 10/7 pressure. All of these flow limits and arousals are due to pressure being too low to maintain the airway and support good respiration. Zoom into your flow rate at about a 3-minute resolution and you will see a bunch of flattened inspiratory waves where you are essentially sucking for air like drinking a milkshake through a narrow straw. If you will accept my suggested settings, it will be more like the milkshake being pumped through the straw to assist your effort. As far as feeling better, that comes in time, and you haven't resolved the arousals. Look at the inspiratory flow spikes.

[EddyDee]

Thanks so much for your explanation.

Attached is a zoom in on a point where the machine detected flow limitation and raised the pressure. To my untrained eye it doesn't look like anything major is going on at that moment. The second waveform from the very left hand side at 01:13:00 looks much worse, but the machine did nothing. Could you educate me on what to look for?

Also, when I look at the zoomed out view I sent yesterday, I don't see that the flow limitations go away after the machine raises the pressure. Isn't that what we would expect to see?

[EddyDee]

OK I think I get why the FLs are being flagged in the screenshot in my previous post - because the flow curve is flat-topped, right?

However I still don't understand why FLs don't reduce after the machine raises the pressure?

[EddyDee]

BTW on the OSCAR chart I resized the FL y axis, so it goes up only to 0.3

[Sleeprider]

Excellent graph. Here we see a respiration flow rate that has a downward sloping peak, sometimes with a jagged or double peak. This is a classic form of flow limitation, and the Autoset is responding to it by increasing pressure by about 1-cm through the period.  We can see the exhale pressure remains at 4.0 cm through the entire period while inhale pressure increases.  Once pressure reaches 7.0 cm, the full EPR 3 will be realized, and then the EPAP pressure will finally rise.  My recommendation is pretty standard. Start the minimum pressure at 7.0 and leave maximum pressure at 12.0 so that your inhale and exhale pressure move together and can properly address both the flow limitation and relieve obstruction. Based on what we see here, the minimum pressure of 7.0 with EPR 3 will avoid the flow limits we see at the lower pressures, and I don't think you will see much variation in pressure above that.   The flow limits do respond once IPAP pressure his at 7.0 and EPR is finally maximized.  

[EddyDee]

I've followed Sleeprider's recommendations and I've been running with Min Pressure = 7.0, EPR = 3 for more than a year now.
Statistically everything is great!
My AHI averages well below 0.5 each month, and I often have nights with 0.0.
95% FL is 0.02 each month.
Pressure never hits 10.0.
Leaks aren't an issue, 95% Leak Rate is between 5 and 15 each month, and time above LL threshold is around 0.2%.
Graphs look pretty good too.

Problem is, I haven't been able to shake off severe daytime sleepiness, especially in the mornings. I have reasonably good sleep hygiene and no obvious reason I can think of to explain this ongoing sleepiness.

There is a bit of spikiness in the flow rate, I closed in on some examples.

I've had blood tests which are all fine. I'm set to meet my PCP soon, and not sure what to ask her for next. Are those spikes worth looking into more closely? I can't see what else to optimize in my treatment of OSA/SDB.

[Sleeprider]

You have some spontaneous arousals, but they do not appear to arise out of the CPAP therapy or respiration. I suppose it might be possible to determine where these arousals come from, but it's not a very easy task. I think your presentation above is informative as to your therapy and how these events arise out of apparently nowhere, and you may want to share that with your doctor. I'm certain there are no knobs to turn to resolve this and your therapy is optimized.

There is a possibility that bilevel therapy with a bit more pressure support would resolve the residual flow limits we rarely see in your charts, and it would likely eliminate the few CA events by using a higher trigger sensitivity. Neither of these options is available with CPAP. If your doctor is supportive of using bilevel therapy with EPAP min 7.0, IPAP max 10.0, PS 4.0 and trigger sensitivity high, then you might be able to get coverage on an upgraded device. Many members have simply self-financed a bilevel upgrade. This thread by Deborah K is instructive in that process. https://www.apneaboard.com/forums/Thread...to-Bilevel

[Fantasieimpromptu]

Do you need to use the tennis ball technique forever? Or at some point you get used to sleeping on your side?