Remstar Auto - Non-responsive events?

cpaper · Post by **cpaper** » Mon Feb 21, 2005 9:19 am

Anyone know what exactly non-responsive events are as reported in the software?

Gregg

wading thru the muck! · Post by **wading thru the muck!** » Mon Feb 21, 2005 10:33 am

These are events that the machine did not resolve... Left-overs! If you have an unresolved AHI of 5 or less that is supposed to be good. I shoot for 1 +/-, but 5 should be just fine. The key is whether or not you feel better.

cpaper · Post by **cpaper** » Mon Feb 21, 2005 12:34 pm

...So when the report gives the AHI these are the ones that the machine resolved? In that case is this equivalent to your AHI without CPAP?

wading thru the muck! · Post by **wading thru the muck!** » Mon Feb 21, 2005 12:51 pm

The numbers show in the data are the unresolved events. The ones it didn't catch. It would be nice if it could also count up the one ones it did get, but this is really not possible since the actually did not happen. It can't count what didn't happen. The only thing you can do is use the AHI you had during your sleep study and compare it to the AHI while using the machine. You could also attempt to set your apap to a fixed low pressure and let it count up the events, but you do this at the risk of feeling pretty crappy in the morning.

rested gal · Post by **rested gal** » Mon Feb 21, 2005 1:54 pm

Cpaper, wader put it well - since the autopap is supposed to prevent sleep disordered breathing events from even happening, the machine is never going to tally up "what didn't happen". That's the beauty of the preventive way autopaps work.

Of course, a few events can sneak by any guard gate. That's when you'll see some hypopneas, apneas, limited flows and snores appearing on the Encore Pro software chart and graph. Those are events that happened despite the machine trying to keep them away. As long as the AHI (apnea/hypopnea index) stays below 5, the machine is doing its job.

I may be wrong about this explanation of "NR" (non-responsive events), but...(deep breath)... here goes: When the REMstar auto senses from your breathing that the throat is starting to close and needs more pressure to keep it open, the machine will first try three small increments in pressure to begin restoring the good airflow it wants to see. But, if those three small hikes in pressure don't start to change the situation, the REMstar auto immediately thinks something like this: (If it could talk. LOL!)

"Hmmm, I've tried raising the pressure a little three times now, but that's not making the airflow any better. The throat may not have been closing after all. The throat may actually be open. The brain may just not be sending the signal to breathe. This may be a central apnea instead of an obstructive apnea. I better not keep on trying to raise the pressure right now, since higher pressures can cause more centrals to happen. I'll sit back a bit and wait to see if the brain will do the work on this one."

Increased pressure is known to be a factor in sometimes causing central apneas - "pressure induced centrals." Central Apnea as a sleep disorder is one thing - with the brain forgetting many, many times to send the signal, "breathe now."

However, it's normal for anyone to occasionally have a random "central" or two. That's true whether you have Obstructive Sleep Apnea and are on cpap treatment, or have no sleep apnea at all - a "normal" person. Even "normal" people occasionally have a random central from time to time during sleep. Nothing to worry about if they don't happen often and are scattered.

Autopaps are designed (each manufacturer in their own way) to take that into account...that an occasional central can happen. The REMstar is designed to NOT go into overdrive, so to speak...to NOT keep increasing pressure more and more and more for a restricted airflow which doesn't show any response at all pretty quickly. To paraphrase the old adage, "Let sleeping dogs lie.", the REMstar will nudge it a bit, but will leave it alone if a small nudge (three nudges, actually) don't get any response.

Oversimplifying considerably (which is the only way I know to do it...I'm not a machine expert) it's somewhat like this:

The REMstar is designed to think, "Well, if these little increases in pressure are making no improvement whatsover, the throat must already be open. The brain has simply forgotten to breathe for a few moments. There's no reason for me to keep nudging and pushing. Gotta just wait for the brain to do its part now." Which the brain does when the buildup of carbon dioxide in the person's system makes the brain/body absolutely INSIST on drawing a breath. The machine marks its unproductive 3-time attempts as a NR - nonresponsive - no response to the three little pressure increases. It may or may not have been a "central apnea", but probably was. No big deal.

Gee, I hope SWS gets back from vacation soon!! LOL

WillSucceed · Post by **WillSucceed** » Mon Feb 21, 2005 2:03 pm

Great Explanation, Rested Gal.
Can you tell us how the PB 420E deals with the issue of centrals? Does it make three small pressure increases, or does it have some other method of dealing with what it thinks is a central?
Thanks!

wading thru the muck! · Post by **wading thru the muck!** » Mon Feb 21, 2005 2:04 pm

rested gal,

I don't recall, does the Encore Pro software tally the Central Apneas. I guess that would be the same as the apneas without cardiac ocillation the Silverlining software reports.

rested gal · Post by **rested gal** » Mon Feb 21, 2005 2:41 pm

Wader, yes...the NR's in the REMstar's Encore Pro charts are roughly the equivalent of the Ca's in the 420E's Silverlining charts. The machines go about trying to identify possible "centrals" differently, but essentially, yes.. "NR = Ca" Sensing Cardiac oscillations - heartbeat sounds - through an open throat. Apnea WITH cardiac oscillations.

WillSucceed, I'll try to think up an "if the machine could talk" scenario for the PB 420E's brain. I'm tellin' ya, I wish SWS were back!!! This is getting tougher than I can handle. I'm not a doctor nor an engineer. And you saw in another topic how math throws me for a loop!

As far as I know, the PB420E does not make the three little pressure increases to "test the water". The 420E relies on whether it senses heartbeats in the airflow. If it does sense heartbeats, the throat is open and the apnea is more likely to be a "central". If the machine does not hear heartbeats, the throat is starting to close - an obstructive event - to be dealt with by pressure increase. (I think - could very well be wrong.)

cpaper · Post by **cpaper** » Mon Feb 21, 2005 3:33 pm

Cheers Rested and Muck!

"Ping!" that's the penny dropping! I feel like I can anylise my statistics in confidence now. Was only half sure before.
(I really don't wear my user name well - yet! )

Thanx for the excellent lesson!

Gregg

Liam1965 · Post by **Liam1965** » Mon Feb 21, 2005 3:45 pm

rested gal wrote:The 420E relies on whether it senses heartbeats in the airflow. If it does sense heartbeats, the throat is open and the apnea is more likely to be a "central". If the machine does not hear heartbeats, the throat is starting to close - an obstructive event - to be dealt with by pressure increase. (I think - could very well be wrong.)

If this is correct, I'm in awe. I've always thought it was pretty amazing the amount of data Auto's could apparently gather just from the very minute pressure differentials in the air, but for it to be able to detect heartbeats (either via sound over the other sounds coming through, or by even more miniscule pressure differentials) is amazing technology.

Not that I think it's impossible, but the idea just... makes my jaw drop.

Liam, who'd better close his dropped jaw, he's got CPAP air leaking out of his mouth.

rested gal · Post by **rested gal** » Mon Feb 21, 2005 4:28 pm

Liam, honey, why do you think we've all been badgering you to get a you-know-what?

It doesn't even matter which "what" you get... so don't agonize over which "what". Just bounce right back to that doctor whom you like so well and say, "I'd like a you-know-what, please."

If you get a you-know-what WITH you-know-what, like I have, you just might be able to sleep....finally. Worth a try.

If you don't-know-what (but I think you do) look HERE.

wading thru the muck! · Post by **wading thru the muck!** » Mon Feb 21, 2005 4:36 pm

How is "you know who" suppose to ask for "you know what" if "He" doesn't even know who "He" is.

And if you don't know what I'm talking about look Here

Liam1965 · Post by **Liam1965** » Mon Feb 21, 2005 4:48 pm

Oh, man, you two.... I haven't laughed that hard in DAYS....

That was wonderful.

Thank you!

Liam, not gonna crack a joke here, he couldn't compete.

Guest · Post by **Guest** » Thu Feb 24, 2005 12:59 am

wading thru the muck! wrote:These are events that the machine did not resolve... Left-overs! If you have an unresolved AHI of 5 or less that is supposed to be good. I shoot for 1 +/-, but 5 should be just fine. The key is whether or not you feel better.

This is exactly why many sleep doctors don't recommend auto paps.

rested gal · Post by **rested gal** » Thu Feb 24, 2005 1:25 am

This is exactly why many sleep doctors don't recommend auto paps.

I could very well be wrong, but my understanding is that it's "normal" for non-OSA people to have occasional apneas/hypopneas and perhaps even a few centrals during sleep. That's why an AHI under 5 from a sleep study is considered "normal" and not needing cpap treatment, isn't it?

Also, OSA patients who are not on autopap at all, but are on cpap and bi-level devices can have a few events. In all instances, from the "normal" population to the "apneic" population on various types of machines, there will be occasional random events during sleep. I guess I'm missing your point, Guest, as to "exactly" why doctors single out autopaps to bash?

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Remstar Auto - Non-responsive events?

Remstar Auto - Non-responsive events?

Central event