F30i valves block external vents when exhaling

I just received a Resmed AirSense 10 Card to Cloud with the F30i head assembly and the heated feed tube. When I put on the mask and breath unnaturally slowly I pass the face leak test, but when I start breathing the way I normally do exhaling causes the flaps that I'm assuming are supposed to block the feed tubes so the CO2 can go out the front vents seal the front vents instead and I can't breath out. Looking at the mask it seems to be a fault of the design, and yet I'm not seeing anything on the net and I'm having a hard time believing I'm the only person to ever see this. Is this the way all the masks are designed? I'm getting a replacement from a different vendor (I didn't write the name down) but if this valve design is universal I could end up in the same boat.

Is this something that others have run into, and if so does anyone have a solution to work around this problem?

You might be talking about the anti-asphyxia valves.

This mask, as do many others, has two kinds of vents.

1. Normal vents (without valves) to prevent rebreathing air. These must be open at all times.

2. Anti-asphyxia valves to allow easy breathing should the machine stop pumping air. These valves must close when the CPAP is in use. If they are damaged and open, the mask will vent too much air and the therapeutic pressure would not be maintained.

Everything ChicagoGranny said.

Plus:
If you're very new to CPAP (which I assume you are) the feeling of exhaling against the prescribed incoming CPAP pressure is strange, annoying, and for some of us may even be frightening when we start out -- but you get used to it after a while. You have to get used to it, because it's that higher, incoming pressure that keeps your airway from collapsing. As long as you're breathing unnaturally, the anti asphyxia valves remain open and you don't get the necessary pressure. I actually give a forceful exhale when I start therapy, to make them pop shut.

Be patient. Learn to breathe out against the pressure. It's not a design flaw.

Blocks wrote: ↑

Thu Jun 08, 2023 7:39 am

does anyone have a solution to work around this problem?

There isn't a problem. You don't yet know the roles of the valves/vents on the mask.

Blocks wrote: ↑

Thu Jun 08, 2023 7:39 am

When I put on the mask and breath unnaturally slowly I pass the face leak test, but when I start breathing the way I normally do exhaling causes the flaps that I'm assuming are supposed to block the feed tubes so the CO2 can go out the front vents seal the front vents instead and I can't breath out.

No.

The "flaps" that connect to the base of the supply tube connectors are anti-asphyxia valves. They are designed to open and allow air to come through the mask connectors, should the device lose power. This is so you can breathe relatively easy, if your machine or power fails.

Disconnect your mask from the hose, put it on in front of a mirror, the valves will be open and allow unrestricted through the holes at the base of the supply tube connectors.

As much as they appear to be designed to open and close the supply tubes, they don't.

Repeat the same process as above, with the mask connected to the hose, machine turned on and breathe. You should see the valves close, and prevent venting from leaving the mask at the tube connectors.

With really low pressure and fairly deep inhales, you may be able to draw sufficient breath as to open the valves. This is a sign of the machine not supplying enough pressure.

There may also be some confusion as to what is meant by open and closed. Your description seems to suggest that the valve is "closed" (up against the base of the supply tube), thus preventing gas from travelling back up the supply tubes. That doesn't happen.

The closed position is when the valve shuts against hard plastic of the cushion connector.

There is sufficient CO2 venting through the 25 holes drilled into the middle of the mask without the need of the valves to force gas out.

https://ap.resmed.com/knowledge/aav-anti-asphyxia-valve

>There is sufficient CO2 venting through the 25 holes drilled into the middle of the mask without the need of the valves to force gas out.

I have 25 dimples with pinholes so small I can't see clearly through them even with reading glasses for lying down with a tablet inches from my face. I initially assumed they were nothing but dimples for decoration. When I did the initial face mask seal tests what people were calling the anti-asphyxia valves were still partially open to the front of the mask to the outside world and I felt like I was still pressing hard against the air from the machine when exhaling and the machine said the seal was good so I assumed they're supposed to be open to get the volume I'm exhaling out. When those anti-asphyxia valves slam shut it feels like my head is being blown up like a balloon.

To see if I could exhale through just those 25 pinholes I popped off the tube from the machine and covered the hole above my head with my hand then exhaled hard enough to close the anti-asphyxia valves and pushing as hard as I could without additional force from the machine I couldn't exhale at 1/4 the rate I need to for breathing without the mask. Assuming the machine must apply more pressure than I do to insure I'm not pushing CO2 back up the hose to breath it in again those holes would have to move the sum of my air and the machine's air through those 25 pinholes at more than four times the rate that they can pass just my breath when exhaling for me to breath at the rate I need.

To see how I did against the machine itself I tried breathing back into the feed tube directly at it's highest setting and while inhaling blows up my insides uncomfortably the resistance to me exhaling was far less than the mask, so while very uncomfortable even if I can't sleep like that yet I think I could breath often enough that way. I didn't exhale too much as I didn't want to push air all the way to the motor and I cleaned the tube after, but it feels like those 25 pinholes are nowhere near enough.

The reseller indicated there was a medium mask with large headgear and a "wide" mask with medium headgear and a large mask. Since I have a big head I went with the medium mask which feels fine. Would the "wide" mask have bigger CO2 vent holes?

Tens of thousands of people use that mask and exhale comfortably with it. And the anti-asphyxia valves are closed when the system is in use. You are probably experiencing a mental reaction to wearing a pressurized mask. This feeling that you can't breathe out is not uncommon in newbies. If you can relax and forget about your breathing, you can fall asleep and your autonomic nervous system will "breathe gently" all night.

Blocks wrote: ↑

Fri Jun 09, 2023 3:30 am

When those anti-asphyxia valves slam shut it feels like my head is being blown up like a balloon.

This is not an uncommon feeling when first commencing CPAP usage. You have to train your mind to focus on other things. You have to relax and let your body breathe. Your body has done this for years without conscious instructions from your brain.

Blocks wrote: ↑

Fri Jun 09, 2023 3:30 am

but it feels like those 25 pinholes are nowhere near enough.

They are exactly the right size. You are not exhaling through those holes. You exhale into the mask and the system pressure exhausts air through those vents. Retrain your brain to think you are not exhaling through those holes.

Blocks wrote: ↑

Fri Jun 09, 2023 3:30 am

Would the "wide" mask have bigger CO2 vent holes?

No. The holes are properly designed to clear exhaled air from the system.

Which pressure settings are you using?

Those holes are tiny because they only need to let air leak through.
Some of us cannot even see the holes without magnification.
But they are there, and occasional cleaning keeps them clear.

My new Pulmonologist wanted me to set my pressure to 6-18 vs 12-18 I have used for 6 years. The anti-asphyxia valves on the elbow on the F20 mask flutter with pressure at 6 and EPR at 3. The mask vibrates because the exhalation pressure is too low which allows the value to partially open the anti-asphyxia valves. Pressure must be above 8 (EPR = 5) on this mask to keep the anti-asphyxia valves from partially opening on exhalation then closing on inhalation. The anti-asphyxia valves should, at all times, block the elbow vents if the unit is on and providing pressure. The elbow on the F30i appears to be the same or similar to the f20 elbow.

Blocks wrote: ↑

Thu Jun 08, 2023 7:39 am

When I put on the mask and breath unnaturally slowly I pass the face leak test, but when I start breathing the way I normally do exhaling causes the flaps that I'm assuming are supposed to block the feed tubes so the CO2 can go out the front vents seal the front vents instead and I can't breath out.

Could the problem be minimized by setting EPR = 3?