P10 Vent Rate

[AshSF]

Hi: I recently changed to a Resmed Airfit P10 and I have adjusted very well to a nasal pillow mask from my F10 FFM earlier. My unintentional leaks are less than 2Lpm all night. My AHI is below 0.5 every day and my RERAs have dropped to 0.00 on most days.

My question is this:
My start pressure is 7.5cm H20. At this pressure my P10 mask should vent at a rate of nearly 28Lpm. My sleepyhead graph shows that it only vents at 19L-20L per minute. P10 manual says that its designed vent rate at 4cm h2o is 20Lpm. And some rebreathing may occur at low pressures. So should I be concerned that my mask is venting even less than 20Lpm?

Should I try and increase the vent rate by any creative tricks. I have tried brushing the vents vigorously but it didn't move the vent rate on SH.

The reason I am concerned about this is that even though I may wake up with an AHI of 0.0, I feel like I am not feeling refreshed in the morning.

Thanks.

[Sleeprider]

There is no need to do anything to modify the mask. You have a slightly lower vent rate, but if you were rebreathing excess CO2, you would automatically start hyperventilating.

Download the Sleepyhead software http://sleepfiles.com/SH/index.html?
Take a look at your detailed daily sleep data for clues on why you're not refreshed. You can have zero AHI and a high RERA or flow limitations which are very disruptive to good sleep. If you need help interpreting this, you can post the data here and you'll get help. The DS560 does record these events even though they do not show up on your machine's screen.

[Sleeprider]

Regarding vent rates, lets assume a tidal volume of 600 mL per breath and 20 breaths per minute. That would be 12 Liters of air per minute. With a design vent rate of twice that volume, you are not rebreathing any appreciable volume of expired air. I guarantee you do not have anywhere near that tidal volume or respiratory rate during sleep, but you'll have to check your Sleepyhead numbers to know.

[AshSF]

I do check my RERAs using my PRS1 560 machine on SH 0.9.8.1. I am posting my last night's report and the summary report since I started using P10.

My RERAs are 0.0 on every night except one night.
My pressure doesn't spike too much. Looks like PRS1 just keep doing the hunt and peck all night.
My Flow Limitations have mostly disappeared since going to P10.
My VS and VS2 have greatly reduced.
Most nights, I have 1 or 2 events total.
I am also sleeping more than 7 hrs each night continuously.
So I think I have optimized most of the variables here. So why the feeling not refreshed. Earlier on my F10, I used to have total leaks in 40+Lpm range and my AHI was < 1.5, RERAs were < 1.5 but I was much more fresh in the mornings.

Any insights into what else may be going on. All I can think of is the total leak rate being close to minimum designed for the mask. Should I be looking at anything else (TV, MV, RR?).

Heres my summary report since I started P10
[attachment=1259]

Here is last night graphs
[attachment=1260]

Just saw Sleeprider's comment. My stats for P10 days for
TV: W-Avg: 515ml
MV: W-Avg: 6.9Lpm

[Sleeprider]

Data looks excellent...much better than mine. You could chase out the snores with another 0.5 cm pressure but I don't think that your answer lies in machine tweaks or even AHI. You seem to have done as much as possible to clean up sleep apnea and related arousals.

Have you recently had a full wellness exam and done comprehensive blood work including male hormone levels, vitamin D? I got kind of a surprise last summer in that regard, and it explained a lot. Lots of other physical and mental stress can impose on our sense of well-being and energy levels.

[AshSF]

I got my blood work done pre-cpap. Everything was in great shape including Vit D, B12, All hormones and all panels.

Looking at the data prior to P10, When I was on F10 FFM, my RDI was averaging 1.1 and I was feeling great all day.
On the P10, my RDI is averaging 0.24 but I am not feeling so great.

After looking at all data points, the leak rate is the only one that is very different. Total Leak rate on F10 used to average 37Lpm. On the P10, its 20.3Lpm.

[justMongo]

Regarding vent rates, lets assume a tidal volume of 600 mL per breath and 20 breaths per minute. That would be 12 Liters of air per minute. With a design vent rate of twice that volume, you are not rebreathing any appreciable volume of expired air. I guarantee you do not have anywhere near that tidal volume or respiratory rate during sleep, but you'll have to check your Sleepyhead numbers to know.

That's called minute volume. I run 15 BPM and a TV of 500ml.
My minute volume is 7.5 LPM.