Apap vs Cpap??

[DoriC]

DoriC wrote:
Pugsy, can you explain the correlation between the increased leak rate and FL,PB and Snores? In Mike's case it seems when he's on auto, as soon as his leak increases a bit so does his pressure, FL,snores and PB, and then he leaks more,etc. This happened last night when he was on auto at 11-14, after an hour or so, he started leaking, the machine showed pressure at 14 and I couldn't fix the leaking so I shut the machine, changed to Cpap mode at 12cms, and all was good for the rest of the night. Sorry for the hijack.

I posted this question on another thread and Pugsy was kind enough to offer to post my report(I'm a dummy)if I started a new thread. The leak graph really doesn't do justice to the leaks, snores and erratic breathing he was having, loud enough to scare the devil! But you can plainly see the difference when I switched to cpap mode. I've had an onoging love/hate relationship with cpap/apap forever, always wanting to be on apap for the lower starting pressure and with no input from Mike, but I can't totally convince myself that he's a straight pressure guy. I'm sure Den(wulfman) went bald after years of trying to explain it to me. I'll be interested in your thoughts.

[DoriC]

bump

[Kenneth P.]

Same here.Interesting.I start'd out on CPAP then my employer has contract'd with a sleep company.They use APAP auto.My leak rate has jump'd to 14&up.They are not concern'd.But,it does bother me

[Pugsy]

Sorry...had email closed and didn't know I had mail.
Can you send the waveform graph from last night...the little blue paper clip thingy...I didn't get it with what you sent.
Maybe you can sweet talk molette into looking at it for you...the wave form and the PB. See what he might say. I will be the first to admit that I am not the greatest at analyzing waveform graphs unless something is so obvious a blind man can see it.

Images from last night below. First short segment was the brief time in APAP mode.
I wonder if the machine was thinking all the mask leak noises were snores......just a thought.
Though on the switch to cpap mode..we still have snores but his time a truck load of OAs to go along with it...so we would assume that the snores were real and associated with the OAs.

Was he awake during all this fiddling with the mask and the change to cpap mode...when you made the change to cpap mode did he go right to sleep or stay awake for a bit of time...restless..tossing and turning stuff?

[Goofproof]

bump

You can close the pressure range down to 12 cm for the high, that way you can still have apap, and stop the leak run away. I would be more concerned about finding the cause of the leak and correcting that, 50 lpm is more than I like to see anytime 38 lpm is the most that makes me happy. Jim

[Sheriff Buford]

Dori... I sure Mike is straight...

This issue completely blows my S9 theory on leaks right out of the water!! In the autoset mode, the machine can compensate for leaks up to 24 l/min H2O. In the straight cpap mode, the machine constantly blows at whatever the pressure setting is set at. So.... does the S9 compensate for leaks at straight cpap? We have discussed this before, and if I remember right, we came to NO conclusion and my gut agrees. I'd keep him on cpap mode until you find out.

Sheriff

[DreamStalker]

Dori... I sure Mike is straight...

This issue completely blows my S9 theory on leaks right out of the water!! In the autoset mode, the machine can compensate for leaks up to 24 l/min H2O. In the straight cpap mode, the machine constantly blows at whatever the pressure setting is set at. So.... does the S9 compensate for leaks at straight cpap? We have discussed this before, and if I remember right, we came to NO conclusion and my gut agrees. I'd keep him on cpap mode until you find out.

Sheriff

Both CPA and APAP will attempt to compensate for leaks. The difference is that the APAP will also increase the pressure in response to and in addition to compensating for the leaks. That's why people who don't understand how CPAP or APAP work can get themselves all messed up trying to tweak their pressures without taking leaks into account.

In APAP, leaks may cause event flags which trigger increase in pressure which tend to cause more event flags that in turn cause more leaks and you end up with a runaway APAP algorithm.

In CPAP, the leaks may cause event flags but "constant" pressure is maintained (ie compensated for leaks) and it does not increase pressure to make leaks worse.

[Wulfman...]

Actually, an APAP (in a range of pressures) does NOT increase "pressure" when encountering leaks. It will increase the "volume" of air in an attempt to maintain the specific pressure it was delivering at the time the leakage occurred (CPAPs attempt to do the same in single pressure, it's just that they don't have the capability of increasing pressure). Some years back, I did some tests (fake naps with deliberate significant/large leaks) with one of my APAPs to find out for myself if this often-stated situation is fact of fiction.

More likely what happens for most people is that during the higher leak rate, more events (snoring and flow limitations) occur, which actually drives up the pressures. At some point, if the upper pressure is wide open, it can become a self-feeding situation ("train wreck") that typically results in the user (or the spouse) waking up to have to fix things and start over.
This is clearly evident as to what happened in Mike's APAP report.


Den

.

[jdm2857]

More likely what happens for most people is that during the higher leak rate, more events (snoring and flow limitations) occur, which actually drives up the pressures.

But why would the leaks cause events unless they resulted in decreased pressure?

[Goofproof]

More likely what happens for most people is that during the higher leak rate, more events (snoring and flow limitations) occur, which actually drives up the pressures.

But why would the leaks cause events unless they resulted in decreased pressure?

Wulfman is correct, that's why you need to have a tight rangeon your apap pressures, if your top pressure is higher than you need, it can cause a chasing your tail result.

Leaks do cause lower pressure, that causes more events, that causes the pressures to be treated at a higner pressure to try to lower the events, but it really causes more leaks, that causes more of the same results. IE, the apap dog chasing it tail. When it catches up with it's tail your treatment is poor, leak rate is high, and many give up frustrated.

Don't allow your apap to go more than 1 cm over your 95% treatment pressure, unless you need to adjust do to poor ahi control.

The best thing, don't use a mask you can't get the leak rate under 38 lpm. I know some machines say they can handle a much higher leak, however their interest is selling you a product, NOT in your successful treatment. Jim

[DreamStalker]

Actually, an APAP (in a range of pressures) does NOT increase "pressure" when encountering leaks. It will increase the "volume" of air in an attempt to maintain the specific pressure it was delivering at the time the leakage occurred (CPAPs attempt to do the same in single pressure, it's just that they don't have the capability of increasing pressure). Some years back, I did some tests (fake naps with deliberate significant/large leaks) with one of my APAPs to find out for myself if this often-stated situation is fact of fiction.

More likely what happens for most people is that during the higher leak rate, more events (snoring and flow limitations) occur, which actually drives up the pressures. At some point, if the upper pressure is wide open, it can become a self-feeding situation ("train wreck") that typically results in the user (or the spouse) waking up to have to fix things and start over.
This is clearly evident as to what happened in Mike's APAP report.


Den

.

That's sort of what I said but actually Jim said what I said ...

More likely what happens for most people is that during the higher leak rate, more events (snoring and flow limitations) occur, which actually drives up the pressures.

But why would the leaks cause events unless they resulted in decreased pressure?

Wulfman is correct, that's why you need to have a tight rangeon your apap pressures, if your top pressure is higher than you need, it can cause a chasing your tail result.

Leaks do cause lower pressure, that causes more events, that causes the pressures to be treated at a higner pressure to try to lower the events, but it really causes more leaks, that causes more of the same results. IE, the apap dog chasing it tail. When it catches up with it's tail your treatment is poor, leak rate is high, and many give up frustrated.

Don't allow your apap to go more than 1 cm over your 95% treatment pressure, unless you need to adjust do to poor ahi control.

The best thing, don't use a mask you can't get the leak rate under 38 lpm. I know some machines say they can handle a much higher leak, however their interest is selling you a product, NOT in your successful treatment. Jim

The moral of what we all said however is that leaks do matter and getting them under control should be job one before messing with optimizing the pressure settings of your therapy.

[DoriC]

thanks for all the good advice. I know that controlling leaks is #1 and I have a pretty good handle on that most of the time alternating between Quattro FF and UMFF. For now I'll use straight cpap at 12 and if he still has events with leaks under control than I'll try 12.5 and 13 if necessary. He seems to have trouble with higher than that. I guess I may be in a position where it will be a tradeoff between leaks and events. The other question I have is whether he does better with S9 or PRS1 which I'm experimenting with now this past week. What's confusing is that his numbers seem to be better on S9 but he seems to feel better during the day with the PR even though his data is worse! I think I gave myself a headache!!

[Stormynights]

What's confusing is that his numbers seem to be better on S9 but he seems to feel better during the day with the PR even though his data is worse! I think I gave myself a headache!!

I thought the same thing DoriC.

[DoriC]

Stormy, can you go into some detail about your observations as I can't get any reliable input from Mike. Thanks.

[Wulfman...]

thanks for all the good advice. I know that controlling leaks is #1 and I have a pretty good handle on that most of the time alternating between Quattro FF and UMFF. For now I'll use straight cpap at 12 and if he still has events with leaks under control than I'll try 12.5 and 13 if necessary. He seems to have trouble with higher than that. I guess I may be in a position where it will be a tradeoff between leaks and events. The other question I have is whether he does better with S9 or PRS1 which I'm experimenting with now this past week. What's confusing is that his numbers seem to be better on S9 but he seems to feel better during the day with the PR even though his data is worse! I think I gave myself a headache!!

If the machines are set up (for all intents and purposes) identically, there should be virtually no difference in therapy. By that I mean straight pressure, no exhale relief, etc. I suspect there might be some discrepancies in the data reporting, but much of that can change from night to night anyway, so it's really hard to nail down the differences. It might be an interesting experiment to conduct. However, I would do at least one week (or month) at a time with each.


Den

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