Where does the air go?

[Melman]

The splint is maintained by pressure and, yes, the pressurized air flows down the windpipe. Keep in mind that it is much less than the pressure required to inflate a balloon. It's not enough to cause any damage or even force the air into your lungs. Your lungs and airway are subjected to much more pressure when you inflate a baloon.

[sheepless]

I'm not sure if cpap and apap are considered noninvasive ventilators but I believe the asv is. is it fair to say that while they assist our breathing effort by opening the upper airway, and in the case of asv nudge us to breathe when slow to initiate a breath, they're insufficient to actually breathe for us? that the (air) pressure opening the airway and flowing into our lungs isn't enough flow by itself (without our own respiratory effort) to satisfy our need?

[jomama]

the pressurized air flows down the windpipe.

So...where does the air go once it flows down the windpipe?

[DaveL]

So many people here know more than I do...
I've been trying to figure it out for over 30 years.

Conclusion first. I'm a lot better off using CPAP than I was before. Before was over 30 years ago....that's how long I've used it.
cpap blows constantly.
I breath in; I breath out.

So where does the air go?
when I inhale the air is going into my lungs.
when I exhale my air with CO2 goes out from my lungs to the mask and out the holes on the mask. it mixes with the in-coming air.
Breathing is a good thing.

I check two things.
When I remember I check my machine in the morning. That tells me how long I used the machine and what my index was.
When I don't feel well, I take my SD card out and put it into my computer. I boot OSCAR. It tells me lots. It tells others here a lot more. I have lots of learning to do.

Meantime, I wish that I had an autopap machine. I like the idea that it sits there ready until I need it. I think exhalation would be easier. I live in Ontario Canada. I've regularly said I'd like an autopap. Not yet.

[DaveL]

the pressurized air flows down the windpipe.

So...where does the air go once it flows down the windpipe?

Read this again after writing my last post.

When we breath in, the air goes down our windpipe.
When we breath out, the air we exhaust goes out the windpipe. 
So my take is that when we breath out it feels harder, because the machine is blowing in...

My numbers are good using my cpap this way. (If it ain't broke don't fix it!)
My machine has a feature that reduces the pressure when I exhale.  I haven't needed this feature, and I don't use it. (tell myself this often: the kiss principle. keep it simple ... )

[WhyMe]

the pressurized air flows down the windpipe.

So...where does the air go once it flows down the windpipe?

The pressure isn’t high enough to force it into your lungs, so the pressurized air hits a traffic jam when it runs into the rest of the air that is pressurizing your airway - it can’t go any further, so it goes out the vents.

[Sleeprider]

All air is under pressure. At sea level, atmospheric pressure is 1033 cmH20. Your CPAP is only adding 7 to 15 cmH20 to atmospheric pressure. Where does the air go? I is inhaled and exhaled just like atmospheric air, but at a slightly higher pressure. The pressure extends to your lungs, and there are medical applications for this "aveolar pressure" in recruiting air volume and improving oxygenation, compared to not having that extra pressure. The pressure does slightly inflate your airway from the sinuses and soft palate, all the way to the air sack (aveoli) in your lungs. However, the pressure is not so strong that you cannot exhale against it. Your inhale effort is easier thanks to the pressure, and the pressure keeps your airway inflated as you exhale, but you can easily exhale against the pressure.

[jomama]

All air is under pressure.  At sea level, atmospheric pressure is 1033 cmH20.  Your CPAP is only adding 7 to 15 cmH20 to atmospheric pressure.  Where does the air go? I is inhaled and exhaled just like atmospheric air, but at a slightly higher pressure. The pressure extends to your lungs, and there are medical applications for this "aveolar pressure" in recruiting air volume and improving oxygenation, compared to not having that extra pressure.  The pressure does slightly inflate your airway from the sinuses and soft palate, all the way to the air sack (aveoli) in your lungs.  However, the pressure is not so strong that you cannot exhale against it.  Your inhale effort is easier thanks to the pressure, and the pressure keeps your airway inflated as you exhale, but you can easily exhale against the pressure.

Ahh, I think I get it now. Thank you. And thank you to everyone else who chimed in, too!

[Sleepster]

Okay, so this is interesting. Before, I thought that the "splint" was maintained by a constant flow of air moving down through your throat/windpipe, but what you're saying is that that is not happening?...

What I'm saying is you're thinking about incorrectly. You are thinking in terms of air flow, but instead you need to be thinking about air pressure.

that it's just pressure that is what's keeping the airway open. But wouldn't that mean that that pressurized air (sorry, not sure how to say it), doesn't stop at the bottom of the throat, but goes all the way down the windpipe into the lungs?...

Yes, the pressurized air goes all the way down into the lungs. This doesn't mean the air from the CPAP machine goes all the way down into the lungs! Think of tiny little pressure sensors spread throughout, from the airway down into the lungs. The pressure at the bottom of the lungs can go up simply because the air molecules are closer together, not because they were blown into the lungs.

It takes very little pressure to keep your airway open compared to the pressure you need to inhale.

Look at this video:

https://youtu.be/6Up8Ciyyfzg?t=69

"CPAP delivers a flow of air to the upper airway" it says. And it shows air flowing down into the throat/airway.[...]

It depicts the physics somewhat correctly if you interpret the cloudy regions as regions of higher pressure, not necessarily regions where CPAP air has entered.

[jomama]

Yes, the pressurized air goes all the way down into the lungs. This doesn't mean the air from the CPAP machine goes all the way down into the lungs! 

Any idea how far down it does go? Just out of curiosity...