(01-04-2015 01:55 PM)Galactus Wrote: You can capitalize and bold it all you like but you're missing the point. The way you are thinking about it is incorrect. The airway is pressurized by air pressure remaining in the airway to keep it from collapsing...
...think of it this way; Your lungs are a balloon, your airway is the part where you blow up the balloon. Blow up the balloon with a breath, release the airway, what happens? All the air exits the balloon and the airway collapses. Now take the same balloon, blow it up with a breath, and this time instead of fully letting go only allow 3/4 of the air out before blowing another breath in it. What happened? The airway remained pressurized, as all the air could not escape, and you were able to blow another breath in it. That is how they are claiming it works. I have no way to know if it is true or not, but the theory is sound.
Everyone is getting very emotional about the EPAP thing comparing it to CPAP and XPAP etc. While your doing that comparison just keep in mind that PAP simply stands for Positive Airway Pressure, as in a pressurized airway will not collapse. Don't get hung up on how it is pressurized to understand the concept here. Your thinking they are treating EPAP when in fact their description of the E portion is just to tell you they are using the exhale cycle to create PAP. Even though it may sound counterintuitive when you first look at it, it really isn't, as to whether or not it will work, that's a different story.
I could not disagree more, which pains me greatly because of how much I respect this discussion and everyone participating. And I think the point that is being missed might be that the laws of physics can't be violated.
There is always pressure in your lungs, because there is always air pressure everywhere. The way breathing works is by (I can't believe I am actually explaining this) comparative
pressure. Our diaphragm attempts to increase the cavity that your lungs are in when you inhale, making the pressure negative in comparison to the air pressure of the outside environment, and the principles of fluid dynamics attempt to equalize the pressure by drawing more air into that cavity, which fills your lungs. The opposite happens when you exhale. But inhalation and exhalation are always a result of the comparative pressure between what the pressure of the air is inside the cavity, and outside. If the pressure is greater and there is a path for equalization, air flows from the higher pressure area to the lower pressure area, regardless of inhale or exhale.
You have to get "hung up" on this enough to make that critical distinction, or it will not make sense. So yes, I am "hung up" on it to that degree, because that is the means to the end.
The problem with OSA is that there is a restriction to the fluid motion of the air during inhalation. Not exhalation. There is no need to help keep the airway open during exhalation, as exhalation is never the issue.
XPAP raises the comparative pressure (pressure is positive compared to the pressure inside your lungs combined with the positive pressure of inhalation) on inhale to force the airway open and keep it from collapsing; it actually "blows you up like blowing up a balloon" to do that, and blowing up a balloon is exactly the identical process of creating more positive pressure inside the balloon than the air pressure of the outside environment; the pressure from the environment during inflating a balloon or your lungs, is comparatively negative
to that pressure of the air inflating the balloon, or your lungs, or the laws of physics won't allow that to happen. XPAP just tilts the balance by raising that inhalation pressure.
When you exhale, it is very common to have enough pressure to accomplish that (void the C02 by exhaling) naturally, even if you have OSA, which actually causes the pressure back into the system to be comparatively higher than the XPAP pressure, making the XPAP pressure comparatively negative
I find the balloon analogy to be completely not valid due to the fact that it is based on air. Breathing is based on incoming air, and outgoing waste products (C02). Keeping air in the balloon to keep it pressurized to hold the exit path open is fine, but apply that to lungs, and what is keeping the airway open with a restrictor-based device such as Provent (not that it actually needs any help) is C02. You want to get rid of the C02, which is what exhalation is all about in the first place, not keep it inside your airway and lungs.
Something that restricts that from happening is not a good idea; its like breathing into a paper bag when you hyperventilate, which is done specifically to keep you from overbreathing oxygen (by increasing the percentage of C02). But unless you are in the middle of a panic attack, that is pretty worthless and probably not recommended.
And it is also invalid because the second you attempt to breathe in, the pressure is instantly comparatively lower inside your airway than outside your airway, and again, fluid dynamics causes the higher pressure outside your airway to press against it and collapse it. There is no baloon that stays inflated, even partly, once the outside pressure is comparatively higher than the inside pressure.
I am not emotional at all about this; I am completely calm. I am completely aware what PAP means, but maybe some don't quite understand what it means in relationship to the fluid dynamics involved. The "Positive" part refers to comparative pressure; positive compared to the unaided pressure normal attempts to breath in a SA patient during inhalation, and actually negative pressure compared to exhalation, which typically overcomes it (is pushed back by the higher pressure of exhalation).
During exhalation, a PAP device actually has comparatively negative pressure to both exhalation and the pressure relief valve in the mask. Exhalation has higher pressure than the XPAP system does during exhalation, or you would never be able to exhale. Period.
Provent has comparatively the same pressure during inhalation as unaided breathing, maybe even a little less. And it has positive comparative pressure during exhalation, at the point where no one wants or needs it.
I emboldened the comments for your benefit, not mine. Those emboldened comments? They were the actual point. I won't mention which of us missed that point, because I think very highly of all members here, and it really does not matter when someone misses a point. I would never try to use that as something to chide someone over, because we all miss points. Its just that this time I didn't, while others might have. That's all.
But quite honestly, this is Physics 101. You don't have to be a Rhodes Scholar to comprehend this, because it is simple. Although apparently, not quite simple enough.