New User - CO2 Vent Question

[JohnHornbuckle]

Hello, 

I am new to CPAP (ResMed Airsense 11 with Dreamwear FFM) and just about to start my third month. I have tried 3 different masks and ultimately ended up sticking with the Dreamwear FFM, which I find to be very comfortable. I do have one concern and I suppose this would apply to any mask that I wear. I sleep in odd positions and move around a lot at night, so I am always waking up with my arm or hand asleep from being under my pillow, etc. I am also waking up a couple times per night with the CO2 vent on my head blocked by a pillow, while the one in front is blocked by my comforter at the same time. When I wake up to this, I am usually quite out of it, so I am not sure if this is 100% accurate - it feels like I am not getting enough air and that the machine has stopped pumping air. I immediately move the blockages and a loud gush of air comes out of both vents and then it feels like the machine starts running again. I don't know if the machine really stops running during this time or if it just feels that way. Is this dangerous at all? Is the machine recording my sleep during this time or does it think I have my mask on so it stops recording? My MyAir score is usually very close to 100 every night with my only deduction being in number of mask removals. I usually only take my mask off once or twice to go to the restroom but it usually shows 3-4 removals. I am concerned that I am not getting enough oxygen during these times as I have no idea how long the blockage is going on before it wakes me up and I am also concerned if I am having apneas during this time that are not being recorded because the machine thinks my mask is off.

[staceyburke]

The app you are using really tells you nothing except for the insurance to see if you are compliant. 4 hours use a night and if your AHI is less than 5. 

I would suggest you do two things. First download OSCAR from the top of the site (completely free) use an SD card while you sleep and get the charts Oscar provides. You can post those here and we can help you with your therapy. 

2nd. IF you are concerned with O2, you can purchase a device for 100 to 150 dollars to record your oxygen levels all night.

[kappa]

If you're managing to block both sets of vents (many masks only have a single set of vents) you are going to be rebreathing more CO2 and you will likely increase your ventilation rate and make you feel starved of air (your O2 sats may or may not be impacted and you can't really sense O2 levels anyway). OSCAR will give more information as to what is actually happening.

[Gideon]

CO2 is what provides our main drive to breathe! Specifically the need to flush CO2 out of the system. (How can get pretty complicated with what the Chemosensors are actually sensing. So elevated CO2 levels make some sense as to your not getting enough air.

The vent in front is the critical one as that is the one that vents the CO2. You need to stop blocking these ports!

The 'vent' on top I think is an anti-affixation valve and is closed until the machine loses power, then it opens.

[kappa]

The dreamware FFM has 17 vent holes in front of the mouth in addition to 2 large anti-asphixia valves adjacent to the magnetic clips. There are an additonal 16 vent holes in the elbow that connects from the frame to the hose on the top of the head. This is similar to F30i, N30i, etc. Blocking the main vents (nearest the nose/mouth) with increase dead space and rebreathing (similar to EERS) while blocking both sets will lead to excessive rebreathing as the whole hose/machine becomes dead space.

[JohnHornbuckle]

Hello, 

I am new to CPAP (ResMed Airsense 11 with Dreamwear FFM) and just about to start my third month. I have tried 3 different masks and ultimately ended up sticking with the Dreamwear FFM, which I find to be very comfortable. I do have one concern and I suppose this would apply to any mask that I wear. I sleep in odd positions and move around a lot at night, so I am always waking up with my arm or hand asleep from being under my pillow, etc. I am also waking up a couple times per night with the CO2 vent on my head blocked by a pillow, while the one in front is blocked by my comforter at the same time. When I wake up to this, I am usually quite out of it, so I am not sure if this is 100% accurate - it feels like I am not getting enough air and that the machine has stopped pumping air. I immediately move the blockages and a loud gush of air comes out of both vents and then it feels like the machine starts running again. I don't know if the machine really stops running during this time or if it just feels that way. Is this dangerous at all? Is the machine recording my sleep during this time or does it think I have my mask on so it stops recording? My MyAir score is usually very close to 100 every night with my only deduction being in number of mask removals. I usually only take my mask off once or twice to go to the restroom but it usually shows 3-4 removals. I am concerned that I am not getting enough oxygen during these times as I have no idea how long the blockage is going on before it wakes me up and I am also concerned if I am having apneas during this time that are not being recorded because the machine thinks my mask is off.

The app you are using really tells you nothing except for the insurance to see if you are compliant. 4 hours use a night and if your AHI is less than 5. 

I would suggest you do two things. First download OSCAR from the top of the site (completely free) use an SD card while you sleep and get the charts Oscar provides. You can post those here and we can help you with your therapy. 

2nd. IF you are concerned with O2, you can purchase a device for 100 to 150 dollars to record your oxygen levels all night.

If you're managing to block both sets of vents (many masks only have a single set of vents) you are going to be rebreathing more CO2 and you will likely increase your ventilation rate and make you feel starved of air (your O2 sats may or may not be impacted and you can't really sense O2 levels anyway). OSCAR will give more information as to what is actually happening.

CO2 is what provides our main drive to breathe!  Specifically the need to flush CO2 out of the system. (How can get pretty complicated with what the Chemosensors are actually sensing.  So elevated CO2 levels make some sense as to your not getting enough air.

The vent in front is the critical one as that is the one that vents the CO2.  You need to stop blocking these ports!

The 'vent' on top I think is an anti-affixation valve and is closed until the machine loses power, then it opens.

The dreamware FFM has 17 vent holes in front of the mouth in addition to 2 large anti-asphixia valves adjacent to the magnetic clips. There are an additonal 16 vent holes in the elbow that connects from the frame to the hose on the top of the head. This is similar to F30i, N30i, etc. Blocking the main vents (nearest the nose/mouth) with increase dead space and rebreathing while blocking both sets will lead to excessive rebreathing as the whole hose/machine becomes dead space.

Thanks all. I figured out how to lower the risk of this happening. I normally sleep with 4 pillows and I lowered it down to 2, and I haven't noticed the vents being blocked for the last couple nights. I also downloaded OSCAR and posted my first screen shot in a new thread.