I would say both can be significant factors. For example I have noticed I get more aerophagia when trying higher EPAP with my autoset, my PS stays the same so increasing EPAP/IPAP is obviously the contributing factor to my aerophagia. I have noticed that many users have aerophagia issues when changing to ASV from cpap/bilevel even though they and they often used higher EPAP without issues before doing so, the higher PS (and therefore IPAP) and the addition of backup rate are clearly factors that also influence aerophagia.
Your doctor is only correct that higher EPAP will help if your issue is obstructive apnea and your airways aren't stinted open. If it is central apnea then increasing EPAP is going to decrease your max PS available and decrease the machines ability to treat your central apnea.
I tried finding some recent OSCAR data but don't see any. I saw the following thread had some from over a year ago. I would be interested to see results before and after the recent EPAP change. For now I am going to theorize based on the old data.
http://www.apneaboard.com/forums/Thread-...y-AM-hours
This attachment made me wonder if doctor was onto something about this being obstructive and potentially positional based. I see comments were made about positional apnea in that thread and it sounds like you unsuccessfully have tried to treat positional apnea. I say unsuccessfully but is that because it didn't treat your positional apnea or because you don't have positional obstructive apnea?
http://www.apneaboard.com/forums/attachm...?aid=21883
This zoomed in attachment made me question the idea that these are obstructive. Although these don't appear to be obvious central apnea as we often see with treatment emergent cases the one thing that really stood out to me is how every single pressure wave gets transferred through to your flow rate chart similar to how the forced oscillation technique transposes onto flow rate in central apneas when using a autoset or vauto. Imo the reason your spikes in flow rate are that visible for each pressure spike is because your airways are open which means there is a significantly larger volume of airway/lung space to compress which requires more air flow. If this was obstructive then the only air to be compressed would be that in the hose and your upper airway and I don't believe you would see such large flow rates.
http://www.apneaboard.com/forums/attachm...?aid=21885
I read through a little bit of your old posts and see that your main issue has always been central apneas, potentially due to an injury. Imo this original diagnosis was probably correct and you primarily suffer from central apnea. Imo this machine is trying to force you to breath but the backup rate and pressure support aren't able to kick start your spontaneous breathing effort like they are trying to do.
If this theory is correct then your machine (ASV) may not be ideal for your situation. ASV relies on spontaneous breathing effort and is not indicated for use in chronic hypoventilation which you clearly have hence the required oxygen use. ASV + oxygen may be enough to maintain your oxygen levels but you would need a recording oximeter to confirm (if you don't have one you should imo). If central apnea is the problem then decreasing your EPAP to get more max PS could actually help as long as the lower EPAP doesn't allow airway to collapse causing obstructions. The current idea to try higher EPAP will make treatment worse if the issue is central in nature.
The machine that is probably more indicated for your use would be ST-A with IVAPS. This machine acts similar to ASV but targets a minimum level of ventilation (ASV targets a fraction of your previous spontaneous ventilation) and has a different more square shape waveform that can supply more air/ventilation even if you aren't spontaneously breathing. Unfortunately I think it could also make your aerophagia worse due to the square shape/more forceful air supply.
Have you ever had a titration study done? Would like to know the results if so.
