Experience with Provent?

[Galactus]

Theravent offers free samples, but they enroll you in their "Loyalty Club". They will continue to send you monthly supplies of the product and charge your credit card. This is fine if the product works, but some scam companies make it almost impossible to get out of the "club". Victims wind up getting copious supplies of widgets that don't work and get charged for them, along with unreasonable S&H costs. I'm not saying that's what Theravent does, but that ploy is very common, and the fact they offer it sends up a red flag to me. Be careful! Sometimes it is very expensive to get something for free.

Thank you for pointing this out as they do not say that on the "click here for free" link only on the other details page. I will order with my special internet card that I keep no funds on. I also want to know which they are sending as the free trial as they appear to have at least three different versions. I'll check on that and see what I find. Thanks for the heads up though, most appreciated.

The way it works is to create pressure in the airway, whether during inhalation or exhalation it accomplishes the same thing, to keep the airway pressurized thereby not allowing it to collapse. Think of it this way, it doesn't matter how you pressurize the straw or from which direction, just so long as it remains pressurized. I am not saying they work I am just saying that is what they are purported to do.

Provent simply can't create positive pressure in the airway during inhale. If the pressure in the airway isn't lower than the room air, the airflow will be out, not in. The air isn't going to "swim upstream" without some sort of fan.

i.e. the pressure in your airway goes to zero or negative when you inhale with provent.

Or, equivalently, inhale doesn't start until your airway pressure becomes negative.

DocWils explained it better than I did, but it's basically as I indicated.

As to how EPAP works, it is to be noted that upper airway collapse has its origins at the end of expiration, when the pressure in the airway is at or near zero. It has been demonstrated that the upper airway cross sectional area progressively decreases in the four breaths prior to an obstructive apnea, with this area being smallest at the end of expiration, and as such creates a collapse at the next in-breath. EPAP is thought to create increased expiratory pressures which are maintained through the end of expiration and until the start of the subsequent inspiration, thus maintaining enough positive pressure to prevent collapse.

Here's a picture from their site which may also help in understanding how it is supposed to work;

[archangle]

To me, DocWils's explanation seems to be saying that if the airway doesn't collapse during the end of expiration, it's less likely to collapse during inhale. That doesn't make sense to me mechanically, but there are a lot of feedback mechanisms and strange mechanical processes in the respiratory system, so I guess it's possible. I don't have a problem with "we don't know why it does, but we have experimental evidence that that's the way it works," if it's backed up by data. Especially if there's a theory about why.

Galactus, your chart is still a picture of what happens during exhale. I understand how it works on exhale. However, it seems to imply that when using provent, there's more air left in your lungs when you start to inhale and that somehow mechanically keeps your airway open. It's possible, but it doesn't make a lot of mechanical sense to me. It seems to me that apnea happens at the back of the tongue, and that's pretty "far" from the lungs in a mechanical sense. How is more air in my lungs going to push the back of my tongue forward or the back of my throat backward?

Once again, if there's evidence it works, or an explanation, fine.

If this really works, does it indicate we should be eliminating things like flex, EPR, and bilevel if at all possible?

[archangle]

OK, apparently the idea is, if the lungs are more full, it pulls down on the trachea, which pulls down on something in your throat and may prevent airway collapse. That does make some possible mechanical sense.

[Galactus]

Archangle I agree with you that at first blush it seems counterintuitive, and not mechanically sound. I struggled with the concept as well, and didn't thoroughly understand the mechanics. I kind of took it on their imaging and on their testing to say it could work, much in the same way that I put a can of soda in the fridge and it gets cold. I have an understanding of what happens but I really couldn't give you all the scientific data. Then someone throws in that whole bury the cans in the sand and they'll be colder, and the science does make sense, and it does work but I don't want to get into understanding every detail, I just know it'll work in a pinch.

In my mind I felt that if the epap kept pressure in your airway on exhale, then on the next inhale you'd have pressure from the inhale, and as the goal was just to keep the airway open it might work as suggested. Then I fixated on the balloon, and that example worked in my mind, and that made it sound all the more possible, as it would make sense that if you took a balloon and added a valve on the end and then squeezed and unsqueezed the air should flow back and forth easier. So that made sense in my minds eye.

Their pictures, and what I looked up, added to what I understand make it seem as if it could possibly work. Though I don't think it will work for me due to severity.

If you want to know what bothered me about it, based on all everyone talks about on board it was this; They say to put them on and then breathe through your mouth until you fall asleep at which point your body will naturally switch over to breathing through your nose. I found that interesting as so many people come back from the sleep tests being told they are mouth breathers and nasal masks and pillows will not work for them, and it always seemed to me that the human body was designed to naturally breathe in through the nose not the mouth. So what they said had got me even more curious in regards to that point.

Anyway, I am going to get a pulse ox and a free trial. I just want to see what effect if any they might have, and if they would be of any value for an emergency, and all that. I kind of view them like, emergency ration food in a sealed water tight tub, you may never need it, but it's a good safety net just in case, and these are small so they can go in the wallet, next to another emergency device you may never need but is good to have.

[DocWils]

I think the problem is that you think about the human body as being fast-reactive, like a machine, but soft tissue isn't quite so fast to react, so the collapse at pressure zero isn't quite so much like a valve closing as a veil of tissue falling into itself. It is just slow enough that the extra pressure forced back into the throat by the exhalation during EPAP is enough to prevent collapse. That, and the fact that it takes a cycle of 4 breaths to reach a full collapse, and if that cycle remains interrupted then the process of collapse is lessened or halted to some extent.

G - I understand your questioning about mouth breathing, and yes, I have observed the same thing. Not everybody naturally breaths through their nose, although we are programmed to - it is in fact far better for us, our body is programmed to process oxygen differently when breathing through the nose than through the mouth, but there are cases where the programming breaks down due to habit or due to medical problems. They don't switch over automatically when asleep. And this is not good. The nasal passages do a better job of filtering the air as it enters the lungs. In addition, the smaller diameter of the nasal passages creates pressure in the lungs during exhalation, allowing the lungs to have more time to extract oxygen from them. When there is proper oxygen-carbon dioxide exchange, the blood will maintain a balanced pH. If carbon dioxide is lost too quickly, as in mouth breathing, oxygen absorption decreases. So, as you can see, our bodies are designed to breath through the nose, and negative factors create habitual or instinctive mouth breathing.

[Jim Bronson]

FYI: Theravent is sold on Amazon as a snoring remedy, along with other miracle cures. No club membership required. The reviews are interesting.

[archangle]

I think the problem is that you think about the human body as being fast-reactive, like a machine, but soft tissue isn't quite so fast to react, so the collapse at pressure zero isn't quite so much like a valve closing as a veil of tissue falling into itself. It is just slow enough that the extra pressure forced back into the throat by the exhalation during EPAP is enough to prevent collapse. That, and the fact that it takes a cycle of 4 breaths to reach a full collapse, and if that cycle remains interrupted then the process of collapse is lessened or halted to some extent.

Are you suggesting that something like it stretches or compresses the tissue during exhale and then the tissue doesn't spring back into its original shape immediately? Sort of like squeezing a sponge or memory foam and it doesn't spring back immediately. If you think about the way raw meat moves around when you're preparing to cook it, this makes some sense. Or the way you can press dimples into the legs of someone with edema?

For instance, I find that CPAP pressure often clears up a stuffy nose for me. I'm assuming that the pressure squeezes fluid out of the tissues in my nose and reduces swelling.

All of those explanations do make some sort of sense. That doesn't mean it actually works that way, but the concept is possible.

[DocWils]

Sort of, in a Lies to Children sort of way, yes. It is far more complex, obviously.

[Mrussell]

I see some partial BS in their marketing materials. The reason I say partial BS, is because it's B's for most people, but not for some. Sort of like Rogaim for hair loss. The website said something like like 1 out of 20 people had "countable hair regrowth." That means, you can take a before and after pictures, and count the difference in new hair strands proving it works. Then they go o. To sayso.ething like 16 out of 20 people FEEL there is hair regrowth. I could goive 20 people a jar a mayonnaise and get 16 out of 20 bald men desperate to feel young again to "feel" there was hair regrowth. They then go on to say, trying to downplay it, that it's only been proven to work on one particular type of baldness on one spot, the "bald eagle" spot in the back, not the receeding hairline in the front. But they try to imply that it MIGHT work on those other spots two, but they just didn't test that. And THATS the "partial BS" They onow full well that it's only effective in a small number of patients and even then only if they have that particular form of the condition.

  And that's what I think is the deal with provent. Most people's OSA is such that the airway collapses on inhalation. That's what you'd expect, you draw a vacuum on a floppy tube of skin and it might just collapse. But a smaller number of peopke (myself included) have expiratory OSA. The airway collapses on exhallation. When it happens, it feels like the back of my throat just kinda flopped over there passages to my nostrals. I wake up and open my mouth,exhale and draw in a deep breath to get some air. If I don't open my mouth, try as I hard as I can, I simply cannot exhale through my nose, it's sealed off. The full face CPAP mask made it worse. It would happen LITTERALL every time I dozed off. The nasal pillow style works great though. In fact, I had to turn off the expiratory pressure relief on my S9. I don't need less pressure exhaling, I need MORE. 

So I suspect nasal EPAP is only going to have any sort of effect on people with expiratory OSA. Statistics where you lump everyone together will show a smallish, but noticable effect because the sample of patients with the right condition is diluted. And based on the way they market it, they know perfectly well that most patients won't benefit from it. They deliberately misrepresented all sleep apnea in their marketing material as the expiratory kind. After all, they want to cash in on the huge market for sleep apnea treatments, not a subset of a small fraction of OSA sufferers who have a uncommon variant of the condition. Just like the makers of rogain want to sell to all bald men, not just those with the fryer tuck spot.