Nate, I'm over the non-topic related posts. I think I answered your question as to when I'll get my results. 'Nuff said.
Back to the order at hand, I was a research neuroscientist for about 10 yrs (about 12 years ago), and PubMed was one of my core sources for current research information, especially since it includes the briefs which precede an article's publication. Having been in the medical research field, I KNOW some of the best treatment options aren't even on the market yet - which is frustrating. But they do all need to be tested and PubMed has the most recent research results.
My "newer is better" leaning may be why I am prone to try the newest new-fangled gadget, like Provent. I set that aside and did some research for Nate tonight and learned a bit myself. The research was based on your rather pertinent question here:
NateS wrote:
Clearly, cpap did not treat my Central Sleep Apnea, but made it worse. Is there any evidence suggesting that Provent treats Central Sleep Apnea? If not, what are the consequences of leaving it untreated? Is it possible that, like cpap, Provent may make Central Sleep Apnea worse? These are the questions I asked myself, which led to me reluctantly abandoning my resistance to the mask and machine and my initial plan to try Provent. (And although I was surprised to find that my adjustment to an ASV machine (S9 VPAP Adjust) was much easier than I had expected, that is not my point here.)
I searched pubmed for the terms epap (the type of treatment Provent is) and central sleep apnea and didn't find much direct research. There was a published study in Dec 2011 which sought to "compare the performance of the advanced servo-ventilator (BiPAP autoSV Advanced) with conventional servo-ventilator (BiPAP autoSV) in treating central sleep apnea (CSA)." Interesting thing is, the "advanced" part of the new SVA machine is that it has an EPAP component:
The features of autoSV Advanced include an automatic expiratory pressure (EPAP) adjustment, an advanced algorithm for distinguishing open versus obstructed airway apnea, a modified auto backup rate which is proportional to subject's baseline breathing rate, and a variable inspiratory support
The conclusion was that it was more effective than the conventional machine, but they didn't attribute that to a single "advanced" feature like EPAP. Here's the abstract link:
http://www.ncbi.nlm.nih.gov/pubmed/22131607
Another article coupled EPAP with BPAP (whatever that is) to study it's effect on CSA on patients with heart failure. Again, not a direct study of EPAP on patients with CSA and it's combined with another form of treatment, BPAP (I'm still not sure what that is). Still, it was more effective then BPAP alone:
Flow-targeted dynamic BPAP support (mean EPAP, 6.5+/-1.7 cm H2O; maximal IPAP, 21.9+/-2.1 cm H2O) further reduced the AHI to 4+/-1/h of sleep compared to the untreated (p<0.001) and CPAP or BPAP night (p=0.002). After the first night of flow-targeted dynamic BPAP support, patients rated on an analog scale (range, 0 to 10) the treatment as comfortable (6.9+/-0.6), and the sleep quality as improved compared to previous nights (7.4+/-0.6).
Of course they conclude the "Flow-targeted dynamic BPAP" was effective. Here's the link to the summary:
http://www.ncbi.nlm.nih.gov/pubmed/17951617
NOTE: If you're unfamiliar with "p" value, it's a measure of significance against the null hypothesis. In practice, any number below .005 is considered statistically significant - meaning the treatment being studied has shown to be more effective against the control treatments. So "p=.002" is pretty significant and p<0.001 is uber-effective.
Nate, maybe an EPAP device alone isn't the answer; perhaps, as these studies show, it may be beneficial as part of a hybrid treatment strategy. The EPAP seems to be effective with obstructed airway apnea, which seems to be the bulk of the advancements for the "BiPAP autoSV Advanced" and the "dynamic BPAP" treatments in these articles. Both are interesting articles though I'd like to see what EPAP device they used (they don't mention Provent by name). I hope it helps you a bit to see what's out there. You may want to search for central sleep apnea to see what other things are on the rise for CSA treatment.
Nate, why didn't you ever try Provent? To me, it's something I have to try before moving to a machine. I realize not everyone has that choice. Provent seems to have the Apnea researchers confused, cuz they don't know who or why it works for who it works for. As Rapaport mentioned it kind of rattles the cages a bit since there's some underlying reason they haven't discovered why it works - or doesn't.