Am I recycling exhaled air with P10 pillow?

[SleepyWes]

Newbie here using the P10 pillow. Fits nicely and comfortable so far. I have the same concern as others have expressed about breathing stale exhaled air back into the tube. Yes the mesh on the P10 ventilates, but it doesn't seem like enough relative to the volume and rate of exhalation. If the exhalation pressure coming out of your lungs is greater than the machine supplying fresh air, and the vent doesn't allow enough for to escape thru the mesh between breaths, how is there not a buildup of CO2 in the tube? From feeling the exhaust flow through the P10 vent during exhalation, it is less than when at rest between breaths

Has anyone actually monitored personal O2 levels to see whether these stale air complaints are "in our heads" or whether it's a real issue? My machine is the Resmed Airsense11 Auto and I have been playing with the heated coil and humidity settings. My pressure settings are 4.0-16.0 as it auto detects and ramps up and down as needed.

I have forced hot air in the house and it gets bone dry in the winter. First two nights I think I set the humidity too high and the tube plugged up with water from condensation collecting in the lowest point of the drapes tube. I drained it in the middle of the night.
3rd night I tried the humidity auto setting but kept the tube temperature high around 84F. Temp in the house at night is around 60F. No water plugging but I had to quit after 3.5 hours because I woke up feeling like I was breathing stale air out of a paper bag (like how others described).

How do I know if that sensation is from breathing warm moist air from the heated tube? Or if it's from my own exhalation? Why wouldn't there be a CO2 sensor placed in the machine just as a safety measure considering that it's (a) possible to block a vent and (b) the vent may not provide not adequate exhaust rate?

I'd love to get some feedback on this. Thanks!!

[Pugsy]

How do I know if that sensation is from breathing warm moist air from the heated tube? Or if it's from my own exhalation?

I can tell you that the warm moist air is from the heated hose...it is but you won't believe me.

Why wouldn't there be a CO2 sensor placed in the machine just as a safety measure considering that it's (a) possible to block a vent and (b) the vent may not provide not adequate exhaust rate?

Because it isn't needed and CO2 sensing isn't easy and it sure isn't cheap.

Try the F & P Solo nasal pillow or the F & P Nova Micro or the ResMed Swift FX.....they have venting systems you would probably find acceptable.

BTW....I have used the P10 for years and years and those diffused vent holes work just fine.

But if you don't believe me....try something else.

[Dog Slobber]

ResMed all the mask manufacturers have been designing masks and measuring CO2 retention and venting for years. It's more than adequate.

My pressure settings are 4.0-16.0 as it auto detects and ramps up and down as needed.

If you want to work on something your APAP settings of 4-16 is what you need to adjust.

Almost always a minimum setting of 4 is inadequate and provides a poor therapy.

[SleepyWes]

Thanks.

Pugsy, I believe you about the heated tube. Just wondering of others find relief by turning the temp down, and what the right balance is to prevent condensation? I'm going to first try turning down the heated tube temp and see if slightly cooler air gives me a better sensation.

Dog: After that I'll try turning up the minimum pressure.

[Conrad]

Thanks.

Pugsy, I believe you about the heated tube. Just wondering of others find relief by turning the temp down, and what the right balance is to prevent condensation? I'm going to first try turning down the heated tube temp and see if slightly cooler air gives me a better sensation.

Dog: After that I'll try turning up the minimum pressure.

Same mask here and a similar machine.

I have both the tube temp and reservoir temp set on auto and have zero issues with condensation. The ambient temp in my bedroom is approx. 60f at night.

Before using the P10 I used the Swift FX, now there is a noisy exhaust port!

I don't feel as if there's an issue with rebreathing any of the exhaled air at all.

[McSleepy]

All masks are designed to make CPAP users rebreathe a significant portion of the air coming from the machine. I'm not aware of any manufacturers publishing that information, but it can vary wildly even with how it's worn. There just isn't a simple design that will allow that not to happen (a check valve would be very uncomfortable), but they do it because it's perfectly safe. You don't need to have "fresh" air to breathe normally. Look at this Information Sheet from the USDA. It says that while "fresh air" contains about 500ppm of CO2, the air you breathe may contain up to 15,000ppm (or 30 times more) before you star feeling any effects. My personal experience? I use highly modified masks and I do worry about that. And I do have a SpO2 monitor that I've use to track my O2 desaturation on a few occasions - no problems, at all. I do have a very mild arrythmia (multiple Holter and Zio studies show a small amount of events), probably caused by lifelong OSA, only treated halfway in my life, and I still only had one problem in 22 years of being on CPAP, and it was my doing: after one "maintenance" of my mask, I had almost completely blocked the exhaust and woke up with a sustained AFib (atrial fibrillation). Luckily, I knew what it was so I went straight to the hospital (after first dropping off the kids at school), and they had to cardiovert me (my choice over spending days in the hospital on meds), and I was back to normal immediately.

I wouldn't worry about rebreathing air under normal circumstances.

McSleepy

[robysue1]

As someone who has used both the P10 and the Swift FX at low pressures, I'd like to add my two cents: The leak rates for me that show up in Oscar were basically the same when I was using a PR DreamStation BiPAP AUTO, a machine that reports total leak and no some adjusted number for the excess leakage.

In other words, using a PAP machine that didn't massage the leak rate numbers, I got total leaks with the P10 that were comparable with the Swift FX, a mask with exhaust venting that can be described as feeling like a jet airplane even at low pressure. So I don't have any serious doubts that the intentional leak rate built into the P10 is sufficient to prevent significant rebreathing one's own exhaled CO2.

As for heated hoses, cold bedrooms, and rainout issues: I don't like inhaling particularly warm moist air, and I can't imagine setting the hose temperature as high as 84F. We keep our bedroom cold. As in this winter we're keeping it right around 50F due to some construction issues. I'm currently still using my unheated hose with my Resmed AirCurve 10 VAuto's heated humidifier set to its max setting of 8. (Anything less than that, my nose gets far too dried out.) Yes, I get some rainout at times. I lift the hose, it runs back to the machine, and I settle back down and go back to sleep pretty quickly. I do run the hose under my bedcovers and sleep with my head under the covers as well.