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New to ASV, new to SleepyHead
#11
RE: New to ASV, new to SleepyHead
the normal answer to reducing hypopneas is to have more ipap pressure, hence, more pressure support, so you might try easing up your psmin, which if your min ipap is the same as your min epap, then your psmin is zero, which means it's not helping you through hyops.
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#12
RE: New to ASV, new to SleepyHead
With an ASV machine, provided your PS is high enough you will not experience many - if any - central events. Hypopneas experienced on an ASV are likely to be obstructive events, and the treatment for them is to raise the epap. It is the epap which provides sufficient pressure to splint your airway to stop it collapsing. PS responds to reductions in flow to further support your airway and overcome central events by providing ventilation. If you are seeing a lot of hypopneas try increasing the epap a little. At the same time, I think you should consider a higher minimum PS at least 2 or 3.
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#13
RE: New to ASV, new to SleepyHead
(04-04-2016, 12:19 AM)DeepBreathing Wrote: . Hypopneas experienced on an ASV are likely to be obstructive events, and the treatment for them is to raise the epap. It is the epap which provides sufficient pressure to splint your airway to stop it collapsing. PS responds to reductions in flow to further support your airway and overcome central events by providing ventilation. If you are seeing a lot of hypopneas try increasing the epap a little. At the same time, I think you should consider a higher minimum PS at least 2 or 3.

respectfully, I believe you are wrong about raising epap. everything I've read and heard says that EPAP is set to control apneas, and ipap is set to control flow limitations, snoring, and hypopneas. that's how the resmed titration guide says to determine needed pressures, it's also explained in that way in this youtube video

I believe the correct response here is to increase PS, as you mentioned, but not epap, unless he's having obstructive apneas.
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#14
RE: New to ASV, new to SleepyHead
There may be a difference between ASV machines and others in this regard, but as tmoody is running an ASV then we should address the protocols for those machines. Unfortunately the Philips titration protocol reference guide https://www.sleepapnea.com/downloads/100...fGuide.pdf refers only to "obstructive events" and "central events" without drilling down further into whether the event is apnea, hypopnea or whatever. The Resmed guide http://www.resmed.com/us/dam/documents/p...lo_eng.pdf does quite specifically state that for VPAP Adapt ASV machines, epap is used for obstructive apneas, hypopneas and RERAs. The instruction is to increase EPAP by 1 cm H2O every 20 minutes until obstructive events are eliminated. I've attached some extracts from this guide.

From my own experience, I have reduced the occurrence of hypopneas by increasing min EPAP, so I know that this works in practice.

[attachment=2327]
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#15
RE: New to ASV, new to SleepyHead
I haven't made any changes yet. First, I'll post last night's data, minus the flow graph, because I forgot to put the card back in...

[Image: fBh2VUjl.png]

This is typical of my last few nights. Almost no centrals. Some PB (Note that due to the SH bug, the value reported on the machine is about double what you see on the report); in fact, last night's PB is higher than what I've been seeing lately, though much much lower than what it was on the DreamStation. Although the AHI is below 5, almost all events are hypos.

Side note: I'm not sure how to interpret the "patient triggered breathing" values. Shouldn't that just be a single percentage, as opposed to min, max, and med?

I also don't really understand PSmin. It's not in the wiki. Reading through the discussion here, there's disagreement about what to change to try to reduce the hypos. Also, are my IPAP and EPAP minimum values already on the high side, compared to the "average" user?

So...I suppose there's no harm in trying different things. I haven't yet looked into the provider settings. Maybe I'll try bumping up EPAP min first and see what happens? If nothing, I'll put it back down and try bumping IPAP min.

I notice in the ResMed extract that there is some mention of "obesity hypoventilation." Could that be the issue? MyBMI is currently 32.3, so I'm obese. At 244, I'm 20 or so pounds less than I was last summer, but still fat. I carry a lot of muscle, so I don't "look fat" to a lot of people, but there's still a good bit of abdominal fat especially. I know weight loss doesn't cure apnea, but perhaps I can expect a reduction of hypos if I can drop another 20. Just thinking through all the possibilities.
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#16
RE: New to ASV, new to SleepyHead
Quote:I also don't really understand PSmin. It's not in the wiki. Reading through the discussion here, there's disagreement about what to change to try to reduce the hypos. Also, are my IPAP and EPAP minimum values already on the high side, compared to the "average" user?

OK, a quick refresher on the terminology

EPAP - Expiratory Positive Airway Pressure - is the pressure your machine applies while you're breathing out. It's this pressure which maintains a patent upper airway.
PS - Pressure Support - is the additional pressure your machine applies as you breathe in.
IPAP - Inspiratory Positive Airway Pressure - is the actual pressure applied as you breathe in

EPAP + PS = IPAP

PSmin and PSmax (also written as min PS and max PS) are simply the minimum and maximum amount of pressure support.

On an auto ASV, the machine will vary EPAP in response to obstructive events and precursors such as snoring. It will increase pressure by an amount equal to PS every time you inhale. It will increase PS in response to anything which causes the flow rate to fall. There's a chart in the attachment to my previous post which demonstrates that. In your case you have PSmin set to zero, which means that the machine isn't giving you any additional assistance to inhale until some sort of event occurs. You could also turn it around and say the machine isn't giving you any pressure relief when you exhale.

It's normal to set PSmin to a least 2 or 3 (or higher) so that you're always getting that little extra assistance, and it also allows the machine to respond just a little bit faster when an event occurs. So to that extent your IPAP is lower than normal. For what it's worth I'm running an EPAP of 9 point something.

Quote:This is typical of my last few nights. Almost no centrals.

I think this is indicative that your PS and IPAP are set appropriately. As per my earlier comments, I think you could reduce the hypopneas but raising the EPAPmin a little bit.

Quote:obesity hypoventilation

I don't really know about that. Though judging by the size of the spare tyre I'm carrying it's time I found out!

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#17
RE: New to ASV, new to SleepyHead
(04-04-2016, 09:10 AM)DeepBreathing Wrote: OK, a quick refresher on the terminology

EPAP - Expiratory Positive Airway Pressure - is the pressure your machine applies while you're breathing out. It's this pressure which maintains a patent upper airway.
PS - Pressure Support - is the additional pressure your machine applies as you breathe in.
IPAP - Inspiratory Positive Airway Pressure - is the actual pressure applied as you breathe in

EPAP + PS = IPAP

PSmin and PSmax (also written as min PS and max PS) are simply the minimum and maximum amount of pressure support.

Thank you for that explanation! Things are starting to get a little clearer.

Quote:On an auto ASV, the machine will vary EPAP in response to obstructive events and precursors such as snoring. It will increase pressure by an amount equal to PS every time you inhale. It will increase PS in response to anything which causes the flow rate to fall. There's a chart in the attachment to my previous post which demonstrates that. In your case you have PSmin set to zero, which means that the machine isn't giving you any additional assistance to inhale until some sort of event occurs. You could also turn it around and say the machine isn't giving you any pressure relief when you exhale.

That makes sense, although it feels to me as if the machine is always blowing to some extent during exhalation. If I hold my breath in the middle of an exhalation (on purpose), there's air blowing out the...blowhole? Vent! But maybe it detects my stopping and kicks in instantly.

Quote:It's normal to set PSmin to a least 2 or 3 (or higher) so that you're always getting that little extra assistance, and it also allows the machine to respond just a little bit faster when an event occurs. So to that extent your IPAP is lower than normal. For what it's worth I'm running an EPAP of 9 point something.

Thank you, this is very helpful.

Quote:
Quote:This is typical of my last few nights. Almost no centrals.

I think this is indicative that your PS and IPAP are set appropriately. As per my earlier comments, I think you could reduce the hypopneas but raising the EPAPmin a little bit.

Okay, I'll bump the EPAPmin from 8 to 9 tonight and see what happens for a few days.

Quote:
Quote:obesity hypoventilation

I don't really know about that. Though judging by the size of the spare tyre I'm carrying it's time I found out!

I very much doubt that obesity is the whole story about anything concerning apnea, but I do think it's an aggravating factor. And I suspect that inner abdominal fat, as opposed to the more visible spare tire kind of external fat, is likely to be worse, because it crowds the organs and makes the diaphragm have to work harder to contract. That's just my own view, but I think it's known that substantial weight loss improves (but does not cure) sleep apnea.

I've been redoubling my effort to lose weight--hence the ketogenic diet. At 62, it ain't easy, but the pounds are slowly coming off. If I'm able to reduce my hypos now and lose ten more pounds over the next month or so, maybe I'll see about tweaking my settings again.
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#18
RE: New to ASV, new to SleepyHead
I got into the setup menu with no problem, first taking the memory card out, and found the EPAPmin setting goes in increments of .5, so I just bumped out up to 8.5. We'll see if that makes any difference.
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#19
RE: New to ASV, new to SleepyHead
Quote:That makes sense, although it feels to me as if the machine is always blowing to some extent during exhalation. If I hold my breath in the middle of an exhalation (on purpose), there's air blowing out the...blowhole? Vent! But maybe it detects my stopping and kicks in instantly.

Yes the machine is constantly blowing air - that's the EPAP. It needs to maintain this pressure to keep your airway open, and won't go below the minimum EPAP you have set. This is why a lot of newbies find it hard to exhale against the pressure. If you increase the PS a bit, you'll probably find things a bit easier. But as you're changing your EPAP tonight, leave the PS change till later. Only change one thing at a time and wait a week or so to see how the results are trending. Patience is a virtue.

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#20
RE: New to ASV, new to SleepyHead
(04-04-2016, 11:54 PM)DeepBreathing Wrote: If you increase the PS a bit, you'll probably find things a bit easier. But as you're changing your EPAP tonight, leave the PS change till later. Only change one thing at a time and wait a week or so to see how the results are trending. Patience is a virtue.

I thought I changed just the EPAPmin, but this morning the SH report says both EPAPmin and IPAPmin were bumped to 8.5. Is that to be expected?

As you can see, my AHI went up last night, from 3.8 to 4.2. It's not a huge increase, and the trend for the past three nights has been upward anyway (1.6, 3.3, 3.8, 4.2). Centrals went from zero to 1, not a significant change. PB dropped to .4%, so really the only significant change is another increase in hypos, which is consistent with the recent upward AHI trend. There appears to have been one major OA...151 seconds? if I'm reading it right.

Other changes include patient triggered breaths. Last night, the "min" value was 9. I don't know what this means, but this is the lowest value I've seen. I understand what patient triggered breaths are, but I don't understand the number. Is it breaths per minute?

I also had more vibratory snores last night than I've seen before. And Timed Breath, whatever that is, was the highest I've seen.

Obviously, I'm still just learning how to interpret SH data. I have no idea how many of these details, if any, might be explained by the small adjustment to EPAPmin (and apparently also IPAPmin). On the whole, it didn't feel like a bad night's sleep, but of course I'd like to see things moving in the other direction.

I don't know if it's relevant, but I went to the gym and had a good workout before dinner. Sometimes I feel like I'm less relaxed at night on workout days.
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