Stupid Question: Can you block the outgoing air from mask?

Couldn't find any question in the FAQ about this. I don't think I am leaking at all, sleepyhead doesn't report any leaks, but my mask always has some kind of air exiting around the connection of the tube to the mask, is this normal? I just assumed it was to help remove exhaled CO2.

Whether it is or isn't normal: Is it okay to like sleep face down into the pillow and block this air outflow? I normally sleep face nearly down at like a 45 degree into my bed and with my mask on it blocks that air outflow. I don't want to mess up my airflow though so I have been careful not to do it, but it sure makes sleeping a lot harder!

No you shouldn't block the exhaust holes. You need to be able to get rid off the cabon dioxide.

The mask is designed with a vent to help remove exhaled CO2. On the mask you have listed in your signature, the vent is the oval shaped piece of plastic that is on the bridge of your nose with all the little holes in it.

I believe some air loss at the swivel connection between the mask and hose is normal due to the design of the swivel conection.

I would not recommend blocking the venting of the mask.

Hope this helps,
Chris

sventory wrote:Couldn't find any question in the FAQ about this. I don't think I am leaking at all, sleepyhead doesn't report any leaks, but my mask always has some kind of air exiting around the connection of the tube to the mask, is this normal? I just assumed it was to help remove exhaled CO2.

Whether it is or isn't normal: Is it okay to like sleep face down into the pillow and block this air outflow? I normally sleep face nearly down at like a 45 degree into my bed and with my mask on it blocks that air outflow. I don't want to mess up my airflow though so I have been careful not to do it, but it sure makes sleeping a lot harder!

You are correct the mask venting is to prevent CO2 build up.You would not want to completely block this. Most people when they sleep on their stomachs turn their head to one side and sleeping on the edge of the pillow helps also. When I slept on my stomach, I slept with one arm under the pillow that raised my head which was turned to the side. The other arm was on the pillow which kept it down away from my mask.

There are others who sleep face down (self included) and various fixes have been found - do a forum 'search' on tummy sleeping for some ideas, or PM me for mine (which is a bit radical, but has worked for years).

The short answer is yes, and you don't want to do that. But there is a big can-o-worms behind that question.

I have a mask that is easy to bury and block, at least it makes noise when partially blocked which wakes me up sometimes.

Our human noses are formed so you can still breath when your nose is pressed up against a mother's breast.

I took a cue from that and glued a small (3/8") long post to my mask, some masks have the port protected, much better design IMHO.

If you want even more details, I have had a lot of experiences from CPAP that lead me to believe the CO2 as well as O2 levels greatly affect the quality of sleep, and I have studies to back them up (to a point, CO2 is more limited data, O2 restriction is generally accepted already).

Things like a chin strap too tight that restricts blood flow gives me a massive headache. So I switched to the ResMed chin strap, which does not go under the ears and restrict blood flow to the brain as easily as the other types do when too tight.

Years ago when first starting out I set my machine on autoset (when set from 4-16 it never went above 4), I woke up a few hours later to dreams of drowning and asphyxiation, again massive headache (I have migraines that are easily triggered), this I assume is reduced O2 and increased CO2 together. I then raised it to 9 with EPR 3, better but still woozy. EPR of 3 meant that the exhale the pressure drops to 6, not enough to exhaust much more air than 4. So I raised it again to 10 and no EPR, much better. I found air volume exhaust curves published for those masks (it actually is on the little insert you get with the mask), the exhaust rate is linear with the pressure, too low and you get too much CO2 and too little O2 from rebreathing stale air. So I then tried drilling a little hole in the mask to increase exhaust, not good, nasal cavities dried out (this was with the S9's weak humidifier, the S10 is much more powerful so maybe I should retry this sometime). But the point is I found a sweet spot that made my sleep better. My prescription is 9, but I found 10 gave me better sleep.

After that I still thought the main focus is oxygen, CO2 (other than avoiding asphyxiation from bad mask exhaust) hadn't really made it into my thinking very much.

That all changed when recently I bought a CO2 meter, mainly after I read a recent study that showed CO2 levels of 900 caused people to score 1/3 lower on a cognitive test, drop the level to 550 and they scored normally (400 is outside air). 950 is much lower than current workplace CO2 guidelines are set for. This is the only science I have, it is reasonable (but not yet proven) to assume that if your brain won't function well awake at 950 CO2, it may not be able to rest as well either.

I measured my workplace and my home for CO2 levels. The workplace was great, but my home was not. So I started cracking a door when I worked from home, nice, I could focus better, sweet. Over a few weeks I noticed that my unusually 'great' night sleeps correlated with when it was windy outside which dropped indoor CO2 level when I was sleeping to around 500, in particular I felt better rested in less time. This was my big epiphane for CO2 and sleep quality. I was seeing 700-900 as my indoor CO2 average with all the windows shut. So I started sleeping with a window cracked, and vary the crack size to shoot for < 600 CO2 (this adds some small expense in the winter). The improvement was immediate and consistent. Wow, and I have never heard anyone mention this before, so I post this here every once in a while to raise awareness.

This and many other stories is why I think you need to be a rocket scientist to get the most out of CPAP, or hang out around here long enough.

sventory wrote:Couldn't find any question in the FAQ about this. I don't think I am leaking at all, sleepyhead doesn't report any leaks, but my mask always has some kind of air exiting around the connection of the tube to the mask, is this normal? I just assumed it was to help remove exhaled CO2.

look in the back of your mask manual, there's a chart of vent rate (or 'intentional leak') that shows just how much air is supposed to vent out of the mask per minute (it's a lot, usually between 20 and 50 liters per minute, depending on pressure.)

sventory wrote:Whether it is or isn't normal: Is it okay to like sleep face down into the pillow and block this air outflow? I normally sleep face nearly down at like a 45 degree into my bed and with my mask on it blocks that air outflow. I don't want to mess up my airflow though so I have been careful not to do it, but it sure makes sleeping a lot harder!

as long as your pillow isn't covered with an airtight pillowcase, there shouldn't be any problem with sleeping however you want to.

people say "don't block the vents" and that's absolutely correct, but a pillow and pillowcase aren't airtight, and will more diffuse the vent than block it. some of the newer masks have built in diffusers so the air doesn't jet out in a narrow stream, but more wafts out in all directions, gently. the latter is what would happen if you've got your face somewhat down on the pillow.

Interesting comments about air quality - thanks! It looks like the meters are kinda pricey - which one do you use? I checked amazon and these are their best sellers in that category: http://www.amazon.com/gp/bestsellers/in ... 5006564011