"the max pressure for the Apenea Command' 420E

waikikisnowman · Post by **waikikisnowman** » Wed Sep 14, 2005 2:25 pm

I recently purchased a 420E.

But I am confused by the "the max pressure for the Apnea Command'

I understand that this is there to prevent Central Apneas

But does this mean if you set the pressure range say 8 - 16 it will not go above 10 to respond to Apneas ?

My API is greater then 50 with this setting

My triturated pressure was 14

So I think I need to tighten my pressure range closer to 14 - so can I softly set the

"the max pressure for the Apnea Command' to a higher level say 14 ?

WillSucceed · Post by **WillSucceed** » Wed Sep 14, 2005 2:35 pm

If you require more than 10 to treat a non-central apnea, the 420E will go up as high as your max. pressure of 16, if needed. If it can clear your non-central apnea at a pressure lower than 16, it will do so and then lower the pressure, relative to your needs, over the course of the night.

However, if the 420E thinks you are having a central apnea, it will NOT go above 10. Also, if you are at a pressure higher than 10 to treat a hypopnea, and a central apnea starts, it will lower pressure to 10 until it thinks that the central is over.

The default of 10 for 'command on apnea' can be changed through the clinical menu. I would not suggest that you do this without talking with your Dr.

Usually, the range on an autopap is set for 3 below and 3 above the titrated pressure. Your titrated pressure is 14, which means the auto should be set for 11-17. You might find 11 to be a bit high, but I think that your current low pressure setting of 8 is, perhaps, too low. You might try raising this to 9 or 10 and seeing if your AHI reduces.

So, please bear in mind that I am not a Dr., I'm just offering what I have learned about how autopaps work. I would definetly talk with my Dr., and I would not change the 'command on apnea' setting from the default of 10.

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CPAPopedia Keywords Contained In This Post (Click For Definition): 420E, Hypopnea

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CPAPopedia Keywords Contained In This Post (Click For Definition): 420E, AHI, Hypopnea, auto

waikikisnowman · Post by **waikikisnowman** » Wed Sep 14, 2005 3:02 pm

Thank you for your speedy reply.

the max pressure for the Apnea Command' 420E must be set within the range so if the range is 11 - 17 it will need to be set at 11

Is it possible that 420E thinks I am having a central apnea and I am not and therefore ia not responding to Apneas which can account for my high AHI ?

Also I people with non auto CPAPS with high pressure settings say 14 or more may be getting some central apnea and their machines keep punping.

I understood this can be dangerous

Guest · Post by **Guest** » Wed Sep 14, 2005 3:21 pm

the max pressure for the Apnea Command' 420E must be set within the range so if the range is 11 - 17 it will need to be set at 11

No, this is not correct. The 'command on apnea' setting does NOT have to be within the pressure range.

No matter what your range, the 'command on apnea' is best left at the default of 10. There are some circumstances where the 'command on apnea' needs to be changed -if you KNOW that you are not having central apneas induced by pressure AND you know that you require high pressures to prevent hypopneas/apneas, you might want to change the default to something higher than 10. I absolutely would not do this without the direction of your Dr. based on data gained in a sleep study that shows that you need higher pressure to treat apneas, that you are not having central apneas and, that the machine 'thinks' that you are having centrals when, in fact, you are not. This is a very unusual situation -I really would not go changing the 'command on apnea' pressure without your Dr.'s direction.

It is unlikely that the 420E is thinking that you are having central apneas when you are not. Also, be aware that your AHI is more than just the number of apneas.

Your friends with non-autopap machines at a pressure higher than 10 might be having pressure-induced central apneas. Without being studied in the lab, it will be hard to know.

I'm curious to know if you have the Silverlining software. If so, what are the numbers that you are getting?

WillSucceed · Post by **WillSucceed** » Wed Sep 14, 2005 3:22 pm

Sorry! That last post was mine.

neversleeps · Post by **neversleeps** » Wed Sep 14, 2005 3:50 pm

Hello waikikisnowman in Thailand!

Here's part of a post with pertinent information:

-SWS (regarding COMMAND on APNEA) wrote:.... is really best thought of as an AutoPAP pressure-response "safety limit" or "safety cap" to help in the avoidance of pressure induced central apneas (which can easily escalate in some patients, manifesting in a condition referred to as "runaway" central apneas). This "command on apnea" setting is defaulted at 10 cm on the 420e. That 10 cm default limit has very sound statistical basis across the apneic patient population with respect to air pressures at which central apneas are known to manifest in significant numbers. There are only two scenarios that I can think of in which a therapist would need to adjust this "command on apnea" parameter: 1) significant occurences of pressure-induced central apneas at or below 10 cm (in which case the patient might ultimately require a BiLevel machine specifically designed to "treat" central apneas), or 2) a patient requiring more than 10 cm pressure to reactively (not proactively) clear his/her obstructive apneas and that patient shows absolutely no signs of inducing "runaway centrals" at those higher "apnea responsive" pressures.

To read the entire fascinating thread (starts out about the Spirit, but evolves into 420E info too):
Bman: Spirit Overnight Indices

loonlvr · Post by **loonlvr** » Wed Sep 14, 2005 4:17 pm

My AHI was constantly over 10 because I had clusters of apneas every nite.I bought a Remstar Auto and tried everything. The problem was that the Remstar was slowly raising my pressure to combat these clusters. I now have been using the 420e with the command on apnea set very high. It raises the pressure very quickly and seems to be doing a better job of halting these clusters. So basically whereas the Remstar takes it merry time raising the pressure, the 420e shoots right up there,

snork1 · Post by **snork1** » Wed Sep 14, 2005 4:40 pm

I am VERY new using a 420E, but it SEEMS to me to be much faster at responding to events than my Remstar Auto was, even without messing with the command on apnea. I think it might just be that little sensor line does what it advertises.

I pondered that setting and also came to the conclusion to back away from the very thought of messing with it, after reading the manual and reading a few posts on the subject. It seems to be a very complex thing going on with that setting.

I just started looking at the software readouts last night though, so I am still figuring this out myself.

FMichael4 · Post by **FMichael4** » Wed Sep 14, 2005 5:54 pm

Anonymous wrote:
the max pressure for the Apnea Command' 420E must be set within the range so if the range is 11 - 17 it will need to be set at 11
No, this is not correct. The 'command on apnea' setting does NOT have to be within the pressure range.

I haven't actually tried applying this setting but when I raise the minimum pressure using Silverlining, it also moves the "max pressure for command on Apnea"

I just checked that again and the "on Apnea" bar moves with the minimum pressure setting when the minimum pressure goes over 10.

Is this just a software issue?

WillSucceed · Post by **WillSucceed** » Wed Sep 14, 2005 6:28 pm

FMichael4, I believe that you are right about the 'command on apnea' being within the range -I've misled the original poster.
I received an e-mail today from -SWS. He knows a whole lot more about the 420E than I; I've included the body of the e-mail that he sent:

Hello, Paul! Haven't chatted in a while. Every now and
then I find time to spot check the apnea boards. I'm absolutely
delighted to see that you are doing so well with xPAP
and that you are helping so many people! You do us
hoseheads proud!

I did spot one of your posts about "command on apnea"
and wanted to give you some more insight into that
parameter and why it is so important. First a little gem
of information that I recently learned myself: fixed pressure
tends NOT to induce central apneas so much as PRESSURE
ON THE RISE can induce centrals (in "pressure sensitive"
patients). That little tidbit of central-apnea related "pressure
reality" is why autoPAP algorithms spend so much time being
very careful about avoiding the induction of central apneas.
AutoPAPs introduce PRESSURE ON THE RISE to patients
throughout the night. Indeed, even sleep technicians note that
they must increase pressures slowly (especially for "pressure
sensitive" patients) when trying to titrate a fixed pressure.

With that tidbit of information, you might also be interested in
knowing that "command on apnea" will limit pressure response
even on obstructive apneas (not just centrals!). Otherwise
that parameter would have been called "command on central
apnea". Recall even the Spirit is hard-coded to limit a pressure
response to only 10 cm for any and all apneas as well. That 10
cm limit has to do with the likelihood of rising pressures inducing
runaway central apneas in sensitive patients.

Regarding the 420e's apnea detection accuracy:

central apnea sensitivity=62%
central apnea specificity=100%

The above meaning that 38% of all central apneas, unfortunately,
do not get properly detected as central by the 420e. Yet when an
apnea does get detected as a central, it is virtually guaranteed
to be a central apnea (versus obstructive).

(combined) apnea sensitivity=100%
(combined) apnea specificity=99.8%

The above two specs speak of central and obstructive apneas
as if they were a single or combined category. Those
(obstructive and central combined) apnea specs mean that
the 420e at least recognizes an apnea as an apnea (versus
missing it all together or even misrecognizing it as another sleep
event type). No separate specs are explicitly given for obstructive
apneas

Hope this helps and sorry for the mis-information that I gave you earlier!

Janelle · Post by **Janelle** » Wed Sep 14, 2005 7:42 pm

Been away for a while from the Forum, but this topic really caught my attention. As some might already know I've been questioning the multitude of Centrals showing up nearly every night on my 420E, but I have had only 1 central recorded in a total of 3 sleep studies. The Dr. is telling me that the amount of centrals recorded on my software is not significant, and this is why the third test was ordered.

So if the sensitivity of the 420E is 100%, shouldn't the sensitivity of all those wires, etc. we wear during a sleep test be just as sensitive, and if so, why aren't they showing up anywhere except on my software?

Have an appointment tomorrow afternoon and will AGAIN ask what the heck is going on.

My treatment is otherwise going well, and I'm losing weight like crazy (25 pounds since July) and I feel great, but this still worries me.

ozij · Post by **ozij** » Wed Sep 14, 2005 10:20 pm

Janelle,
While we call it "central" apnea, I think we should remember that it could also mean "holding you breath".

The 420E lists an "apnea with cardiac oscillation" each time it senses the heartbeat causing oscillations in the airflow. Those oscillations are an indication of an open (unobstructed) airway. I can even hear them sometimes in the outflow from the Breeze. They might be "real" central apneas - but they don't have to be:

We sometimes hold our breath while tossing and turning in bed - for instance, I'm pretty sure that that in my case, I will get more "apneas with cardiac oscillation" on nights when my back hurts - I toss and turn more, and catch my breath as I wince. Catching you breath when you wait for the pain to subside is also an apnea with cardiac oscillation. The SL3 doesn't know why you're not breathing, it just reports it is so.

I remember you reporting on back and knee pains - could that have to do with those apneas with cardiac oscillation that you're getting?

O.

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CPAPopedia Keywords Contained In This Post (Click For Definition): 420E, breeze

WillSucceed · Post by **WillSucceed** » Thu Sep 15, 2005 8:02 am

The 420E lists an "apnea with cardiac oscillation" each time it senses the heartbeat causing oscillations in the airflow. Those oscillations are an indication of an open (unobstructed) airway

We sometimes hold our breath while tossing and turning in bed - for instance, I'm pretty sure that that in my case, I will get more "apneas with cardiac oscillation" on nights when my back hurts - I toss and turn more, and catch my breath as I wince. Catching you breath when you wait for the pain to subside is also an apnea with cardiac oscillation. The SL3 doesn't know why you're not breathing, it just reports it is so.

Ozij: These are great observations and make alot of sense. One thing that comes to mind is that the 420E is known to be somewhat aggressive. I believe that in comparison, it is more aggressive than the RemStar Auto and I suspect that this is why I did not get great treatment from the RemStar even though it delivered essentially the same pressures as did the 420E.

I have noticed that since I changed the 420E to work in .5 increments instead of the default of 1.0 increments, I seem to sleep more soundly. I know that micro-arousals can be caused by the change in pressure that the auto delivers if you happen to be really sensitive to pressure change. By setting the 420E to make .5 increment changes, the amount of pressure change is lessened while the aggressiveness of the 420E algorithm still tries to quickly stop the obstructive event that is happening.

Also, as -SWS pointed out

fixed pressure
tends NOT to induce central apneas so much as PRESSURE
ON THE RISE can induce centrals (in "pressure sensitive"
patients). That little tidbit of central-apnea related "pressure
reality" is why autoPAP algorithms spend so much time being
very careful about avoiding the induction of central apneas.
AutoPAPs introduce PRESSURE ON THE RISE to patients
throughout the night. Indeed, even sleep technicians note that
they must increase pressures slowly (especially for "pressure
sensitive" patients) when trying to titrate a fixed pressure.

So, in line with this thinking, perhaps the aggressiveness of the 420E does trigger some centrals. I honestly don't know if changing the pressure change increment from 1.0 to .5 helps prevent this, but it does seem to be helpful to me. Without changing my pressure range, the increment change seems to be giving me 'gentler' treatment and I'm not aware of waking at all during the night whereas, when the increment was set at 1.0, I did wake several times during the night.

ozij · Post by **ozij** » Thu Sep 15, 2005 8:33 am

WillSucceed wrote:I have noticed that since I changed the 420E to work in .5 increments instead of the default of 1.0 increments, I seem to sleep more soundly. I know that micro-arousals can be caused by the change in pressure that the auto delivers if you happen to be really sensitive to pressure change. By setting the 420E to make .5 increment changes, the amount of pressure change is lessened while the aggressiveness of the 420E algorithm still tries to quickly stop the obstructive event that is happening.

I have the same experience (but wake up slightly once or twice a night), and agree with your thinking.

As for the impact of pressure changes - I seem to get hypopneas frequently just when the pressure goes down. I tried two weeks of higher low pressure (6 instead of 5.5), my hypopneas were worse, I didn't sleep as well, and I'm back to a 5.5 minimum.

O.

Janelle · Post by **Janelle** » Sat Oct 15, 2005 7:33 am

Apologies to all for being away so long. In the interim I had a visit with my Sleep Dr. and took in a 96 hour report. He too noticed that I seemed to have a lot of central apneas and regular apneas associated with major leaks. Now I know that some have said they have not noticed this phenomenon with their 420Es, but I have on several occasions, but not on others going back through my readouts.

Anyway, my dr. did say he doesn't like to use the 420s just because they are SO aggressive and SO sensitive because he feels they make people worry more about their condition. He prefers the Resmed APAPs. I told him I did not get good treatment with the S7 and felt I was getting much better treatment with the 420E. He lauded the new Escape as an alternative to my frequent traveling and I pointed out it was actually taller and more clumsy than the 420E and weighed exactly the same.

He did not feel that my centrals were anything to worry about and did point out that during a leak I might be holding my breath.

"the max pressure for the Apenea Command' 420E

"the max pressure for the Apenea Command' 420E

the max pressure for the Apenea Command' 420E

"central" apnea in silverlining.