CPAPtalk.com

Note the circled portion in the graph at about 1:30 to 1:40 in the animated explanation at the following link:

http://www.proventtherapy.com/view-vide ... -animation

The narrator says of the breathing of that patient: "There is positive intranasal pressure of approximately 12 cm of water maintained until the start of the next inspiration."

I do not believe they have faked the graph, though you may feel free to argue with it. That's what forums are for, after all.

I find the mention of mild hypercapnia later in that animation to be interesting, as well.

But because of the adhesive used I will never try it. The breath right strips I tried one weekend just about remove all the skin of my nose. The idea of glue on my skin every night for the rest of my life turns me off

That's no skin off my nose, either.

I agree. I think that's a valid concern that many of us have, BlackSpinner.

jnk wrote:
I do not believe they have faked the graph, though you may feel free to argue with it.

The graph shows inspiration occuring while intranasal pressure ranges from 15 cm to approximately -2 cm.

I am sure the gals and guys at Ventus gave the charts much more thought than I have. But there is something missing here.

Someone will have to explain to me how air can flow from an area of lower pressure (the bedroom) to an area of higher pressure (the human airway in the graph).* In my experience with bicycle pumps, weather systems, and burst bubbles it has always worked in the opposite direction.



*Without using a CPAP.

BlackSpinner wrote: The idea of glue on my skin every night for the rest of my life turns me off

But don't forget the idea of wearing a pressurized mask for just one night turns millions of poor souls off.

I hear ya, NachtWürger. I've never been any good at interpreting squigglies, myself. It is too easy to confuse pressure with flow, and everything always looks upside down to me. I mostly leave the squigglies to -SWS and Dave.

The bottom line, to this patient, is that Provent works for some people, and that it apparently does so mostly because of the results of positive airway pressure during expiration.

Thus, from my point of view anyway, a discussion of inspiration is bascially beside the point in this context. Remember that my begging to differ with you was only about your statements concerning Provent and expiration, not inspiration. It seemed to me that you were telling Mary that pressure would drop before the body's diaphragm made it so and that it would happen because of something about the vent in the Provent, and I wanted to correct that statement, since I am of the opinion that such an impression would be a misconception.

And I was only trying to be helpful, as I'm sure you know. I hope you aren't offended by that, like the way Roster used to get.

jnk wrote:
The bottom line, to this patient, is that Provent works for some people, and that it apparently does so mostly because of the results of positive airway pressure during expiration.

I swore I would not take the time to read the studies but with my curiosity piqued I am taking a few brief peeks and found this statement -

The exact mechanism through which nasal EPAP treats OSA is
still unclear, but several mechanisms appear most likely:

1) Positive end-expiratory pressure (PEEP) leading to increased
end-expiratory lung volumes (or FRC) that increases
longitudinal traction on the pharynx, rendering it less
collapsible (“tracheal tug”).11 Indeed, the role of increased
lung volumes in decreasing the compliance of the upper
airway has been well described in the literature.12

2) Dilatation of the upper airway by EPAP which carries over
until the start of the next inspiration.13

3) Mild hypercapnia due to hypoventilation which would lead to
increased respiratory drive to the upper airway.13

http://www.proventtherapy.com/hcp/asset ... essure.pdf

Note that this statement claims positive end-expiratory pressure but makes no claim of positive inspiratory pressure. (As well it should not IMO.)

Note also that this statement was written by the MD researchers and the statements in the brochures and on the website and even the charts you referred to were most likely produced by marketing types.

Should we assume that the marketing types misinterpreted and/or misrepresented some of what the scientists were telling them? Besides it would be difficult for the marketing guys to get all three of the above mentioned mechanisms into one chart.

NachtWürger wrote:

"2) Dilatation of the upper airway by EPAP which carries over
until the start of the next inspiration."

That I agree with.

NachtWürger wrote:This vent allows the pressure to drop to normal at the end of expiration.

That I don't.

But hey, that's just me.

And what do I know.

If it works, it might be something to have on hand in case of a power outage or disaster.
Camping, though--I'm packing heavy hardware.

They look interesting for short trips away.

Has anyone tried one with an oximeter?

NachtWürger wrote:

jnk wrote:
I do not believe they have faked the graph, though you may feel free to argue with it.

The graph shows inspiration occuring while intranasal pressure ranges from 15 cm to approximately -2 cm.

I am sure the gals and guys at Ventus gave the charts much more thought than I have. But there is something missing here.

Someone will have to explain to me how air can flow from an area of lower pressure (the bedroom) to an area of higher pressure (the human airway in the graph).* In my experience with bicycle pumps, weather systems, and burst bubbles it has always worked in the opposite direction.



*Without using a CPAP.

NachtWürger wrote:This vent allows the pressure to drop to normal at the end of expiration.

Your statement may mislead because it is very much a simplified version of what happens. In the video, https://www.youtube.com/watch?v=bDgfl2XxyOk, Ventus states there is no end-expiratory pause with the device in place. Without a pause in expiration the diaphragm contracts, the lungs expand, and the airway pressure drops rapidly. When the airway pressure becomes negative inspiration will begin.

I think the blue line in the graphic is incorrect. It shows inspiratory nasal flow while there is still a positive pressure in the airway. You are correct that this is not possible. Even with CPAP the pressure in the airway must be less than the pressure CPAP is pumping in order for there to be nasal flow in the direction of inspiration.

However this does not reduce the facts that airway pressure is maintained throughout expiration and the expiratory pause is eliminated. This gives inspiration "a window to jump in" and get a breath before the airway collapses.

I never thought about this before but it would seem in the untreated patient the long expiratory pause gives the airway great opportunity to collapse.

The mouthbreathing issue still bothers me very much and even more so after I read this page - http://www.proventtherapy.com/assets/Pr ... uccess.pdf

This is close to encouraging you to mouthbreathe at the start of your night. The tip to keep a glass of water at the bedside is quite discouraging to me.

Nevertheless Provent is a very interesting concept and I wonder if it could be applied in a different way that would make it more effective?

Gerald? wrote:They look interesting for short trips away.

Has anyone tried one with an oximeter?

I don't think any long term members have tried it. We usually get posts from someone that drops in and asks about it or posts, but lacks credibility.
I found this while looking for trial offers. http://www.sleepguide.com/forum/topics/provent-therapy
The best I have found so far is $20 for a 10 day trial... not sure what the shipping will be.

I have an appt with a new dentist who I know has apnea and thought I would ask him for a script to try it. I have fairly mild OSA(AHI 11) but lots of arousals and pretty serious desats without xpap, and I suspect this would cause more. I do have a Zeo and an oximeter to monitor the results to some degree though.
Has anyone seen better deals on trials?

NightMonkey wrote: . . . When the airway pressure becomes negative inspiration will begin. . . .

I think a pneumo doc or RT probably considers the beginning of inspiration to be the contraction of inspiratory muscles which in turn cause an increase in lung volume which in turn affects pressure in the upper airway. So the medical scientists at Provent are explaining to fellow medical professionals in the Provent literature what Provent is designed to do, and that is to maintain positive pressure in the airway until the body itself causes negative pressure there. That is probably one of many reasons it can be said perfectly accurately and logically from research doc to clinical doc that the positive pressure remains until, and through, the start of inspiration, I believe. The flow of breathing may be measured at the nose, but inspiration as a biological process discussed by medical professionals starts much deeper in the body. Or something like that.

jnk wrote: The flow of breathing may be measured at the nose, but inspiration as a biological process discussed by medical professionals starts much deeper in the body.

That makes sense.

Being a visual person I am still puzzled by their graphic showing inspiratory nasal flow while the airway pressure is positive. But I will get over it starting now.

Maybe I will get a prescription for a trial amount of the devices at my next doc visit.

NightMonkey wrote: . . . Maybe I will get a prescription for a trial amount of the devices at my next doc visit.

If your condition is mild enough to try it without a PSG, go for it and post a review. But to me, monitoring sustained O2 is not enough. The damage to the body and mind from bad sleep can be insidious. So I would not take the chance without proof of personal effectiveness in preventing fragmented sleep for me.

As for the graphic, I am simply not educated enough to understand that relationship between volume, pressure, and flow in how it relates to human breathing with two funny-looking bandaids on the nose.