Auto EPAP algorithm reaction time for Aircurve ASV

[Michaely6]

I was just wondering if the auto EPAP algorithm for the resmed Aircurve ASV is the same as the auto EPAP algorithm for the airsense 10 and VAuto or does the EPAP on the ASV react much faster and on a breath by breath bais just like the pressure support on the ASV?

[jaswilliams]

The epap rises slowly over time I don’t huge rises when I tried it I never went much higher than 8 the PS has much more impact on OA’s and Snores

[Michaely6]

Thanks. I figured that I rises slowly just like the vauto and airsense. I watched Lanky lefty's video about ASV which prompted me to make this post because I definitely do no agree with his take regarding the epap on the ASV. He stated that their is no reason to have the EPAP set to anything above 4 due to the sophistication of the machine but I believe it is still best to set the EPAP to a setting where it will eliminate all or most of obstructive apneas. Any thoughts?

[SarcasticDave94]

My EPAP Min is 9, set just below my median.

[Michaely6]

My EPAP Min is 9, set just below my median.

How did you determine your EPAP when you titrated on the ASV? Because I notice that my EPAP doesn't change much no matter what I set it to (and yes it is in auto mode). If I set my minute to 4, the med will only be like maybe 5  and if I set it to 9, the medium will be maybe 9.5. I just wanted to know why the EPAP seems like it only stays close to what I set it to no matter what number it is.

[sheepless]

the machine will work from whatever your settings are. the goal is to use the lowest settings that resolve your events.

I started with fixed epap only, 5 or 6 cmw to begin, no ps. raised epap incrementally until most ua and h resolved. then set min epap at roughly 1 cmw lower than my med value best resolving oa and max spap at 12 or 15. then experimented with ps til best ahi and comfort.

I think the fairly vague titration guide for asv tells us to set asvauto to default settings including ps while raising min epap against events.

[Michaely6]

the machine will work from whatever your settings are.  the goal is to use the lowest settings that resolve your events.

I started with fixed epap only, 5 or 6 cmw to begin, no ps.  raised epap incrementally until most ua and h resolved.  then set min epap at roughly 1 cmw lower than my med value best resolving oa and max spap at 12 or 15.  then experimented with ps til best ahi and comfort.

I think the fairly vague titration guide for asv tells us to set asvauto to default settings including ps while raising min epap against events.

I guess im a little confused by your approach. When you say that you set a fixed epap, are you in CPAP mode on the ASV? Also how can you have a medium if the EPAP is set to fixed as you said it was? Wouldn't the medium be the same number as your fixed EPAP value?

[sheepless]

the question was how to determine epap.

probably fine in asv mode but I was thinking asvauto mode.

yeah, good point that median will equal fixed set pressure, sorry. intent was to adjust one thing at a time starting with epap. maybe what I meant was once you find the epap value that best resolves events, one option is to set min epap 1 cmw lower and set max higher at 12 or 15 depending on your need. after some time with a range, readjust to 1 less than what your median ends up being. probably not much better or worse than starting with default epap range and working min epap up in similar fashion.

that's how I found my min epap setting and as I recall pretty much what the asv guide says.

edit: thinking a little more, I guess if I was to opt for fixed epap, I'd use asv mode and if I opted to adjust min epap within a range, I'd use asvauto mode. it's been a while...

[Sleeprider]

I have coached a lot of users in using ASV, and there are significant differences between Resmed and Philips, but both benefit from optimizing the minimum EPAP pressure. Starting with EPAP at 4 does work for many people, but EPAP tends to rise when apnea do not respond to pressure support, and the event usually flagged UA. I see no reason not to optimize EPAP min to a level that mostly resolves OA events, then letting the machine do its job with CA and H. We even find people suffering persistent hypopnea with ASV are better treated with higher EPAP and sometimes higher minimum PS. There is one rule of thumb for ASV titration; in spite of the "general rules", people respond as individuals, and optimization may require trial and error.

Over-simplification of the EPAP min setting will put many people at a disadvantage, and in my opinion a better objective is to set EPAP min in a way that it never varies more than 3-cm. We have seen some members require higher EPAP min to get effective therapy, so I would disagree with LeftyLankey on that generalization. On the other hand, individuals with more conventional central and complex apnea, and even CSR, seem more likely to tolerate default recommended AutoASV settings. Things get more convoluted when we try to compromise for aerophagia, positional apnea and some users with high AHI and leak rates that don't seem to respond optimally to ASV therapy with any machine. In fact a low leak rate is often a predictor of success.

[sheepless]

unlike Sleeprider, my 'knowledge' is limited to my own asv use. I'm not sure if Sleeprider confirmed or contradicted anything I said but he has a lot more experience with more machines and many more users than me so generally I'd follow his suggestions before mine.