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SWS

On refelection, PSmax will never be more than 5 above PSmin. But, as I have been saying the inhale pressure roams between PSmin+EEP & PSmax+EEP banned did say that in an earlier post. So banned is sort of right but didn't spell it out in precise detail but left his subsequent wording open to misinterpretation.

That I can truly have empathy for

DSM

Doug, I agree with Banned that EEP does not roam. But IPAP roams on an as-needed basis according to how MAX PS and MIN PS restrict that fluctuating IPAP.

dsm wrote:On refelection, PSmax will never be more than 5 above PSmin.

I disagree there, Doug. The ASV user manual very specifically states (I'm directly quoting):
"MAX PS minus MIN PS is greater than or equal to 5 at all times."

Unless that's a typo in the part I have underlined and highlighted in bold, Resmed thinks that MAX PS can be more than 5 over MIN PS.

Those two proposed changes I have for Banned include direct quotes from the manual.




But I'll re-quote my proposed changes for Banned since I went back and cleaned up my text on change-proposal two:

-SWS wrote:Banned, would you also mind commenting on these two additional proposed clarifications:

Banned wrote:MAX PS is automatically set by MIN PS and will always be 5cmH2O higher than MIN PS.

The ASV User Manual wrote:Max PS minus Min PS is greater than or equal to 5 at all times

Thus First Proposed Clarification: the ASV design allows for MAX PS to be more than 5cm higher than MIN PS

Banned wrote:You never adjust MAX PS because MIN PS automatically sets MAX PS.

By contrast to the above statement the ASV user manual allows for MAX PS to be manually adjusted between the values of 8cm and 16 cm (with a default value of 10 cm). The ASV manual also goes on to explain that MIN PS automatically adjusts MAX PS whenever it needs to meet these two requirements:

The ASV User Manual wrote: "Max PS minus Min PS is greater than or equal to 5 at all times" [requirement one],

"EEP + MAX PS will not exceed 20cm" [requirement two],

"To satisfy these limits setting Min PS automatically adjusts Max PS" [driven by the above two requirements]

Second Proposed Clarification: MAX PS can be user-adjusted between 8cm and 16cm. However the set-up menu will automatically intercede and adjust MAX PS, but only if the above two requirements are not met by the user during manual set up.

Thanks.

Banned wrote:In the Adapt SV, an EEP of 10cmH2O is one heck of allot easier to exhale against than an EEP of 5cmH2O. EEP 5 would make me choke! Even on my old Vantage S8 it was easier to exhale against EPR 3 than it was EPR 1. Not that EEP equals EPR. Even with my ancient Respironics C-Flex wasn't C-Flex 3 easier to exhale against than C-Flex 1?

Banned, I wonder if you confusing EPR and C-flex settings' "degree" numbers with EEP "cm" numbers? In EPR and C-Flex exhalation relief features, the higher setting numbers do give less pressure when exhaling. So, no wonder you found it easier to exhale WITH (not "against") your EPR pressure set for a higher SETTING number (more cms of drop in pressure) with the Vantage used in cpap mode.

But higher EEP setting numbers in an ASV do not mean more drop in pressure for exhaling. Higher EEP settings means MORE cms of pressure blowing at you. More to have to exhale against.

With both EPR and C-Flex, a setting of 3 gives the "most" drop in exhale pressure coming at you", 2 gives "less drop", and 1 gives the "least" drop in exhale pressure.

It's almost like you're looking at the ASV's EEP pressure setting the same way...thinking that a higher EEP setting number means more drop, more pressure relief, for exhaling. But it doesn't.

"EPR 3" is a setting. EPR (Expiratory Pressure Relief) set at "3" drops the pressure 3 cms when a person exhales when using a resmed cpap machine or using a resmed autopap in cpap mode.

C-Flex 3" is a setting. C-Flex set at 3 gives the most drop in pressure C-flex is capable of, when a person starts to exhale, using a Respironics cpap or autopap. With C-flex, a setting of "3" doesn't drop the pressure an exact number of cms. It doesn't mean the pressure whill drop 3 cms when you start to exhale. How much C-Flex (at any C-Flex setting) will drop the pressure is very dependent on how forceful the beginning of a person's exhalation is.

With both of those features (EPR and C-flex) the higher setting number means "more drop" in pressure. The degree of drop in pressure. The higher the number for those settings, yes...the more drop in pressure when you exhale.

But the EPAP setting in bilevel machines and the EEP setting in the ASV machine is stating specific cm's of pressure that will be blowing at you when you exhale. A Higher EEP number does not mean more drop in pressure. EEP is stating how many cms pressure will blow at you when you exhale.

If EEP or EPAP (EEP in the ASV machine; EPAP in a bilevel machine) is set at 10 cm, you're going to have 10 cms of pressure blowing at you when you exhale.

If EEP or EPAP (in the respective machines) is set at 5 cm, you're going to have 5 cms of pressure blowing at you when you exhale.


As for your feeling that you breathe more comfortably with your ASV set for EEP 9 or 10: Perhaps it's that you absolutely need 9 or 10 cms of pressure to keep your throat open "enough" during exhaling so that you can even BEGIN to draw in a new breath when you start to inhale again. If a pressure of only 5 (EEP set at 5) allows your throat to collapse after you've finished exhaling, and didn't allow you to even begin to inhale again, certainly you'd breathe easier with EEP set at 9 or 10. That seems to be the case for you. Would be for me, too.

However, that doesn't mean (as you seem to have been saying) that an EEP setting of 10 means LESS pressure to exhale against than an EEP setting of of 5.

The lower the EEP setting, the less cms of pressure blowing at you when you are exhaling.

At least, that's the way I understand "EEP" (and "EPAP") settings.

-SWS wrote:

dsm wrote:On refelection, PSmax will never be more than 5 above PSmin.

I disagree there, Doug. The ASV user manual very specifically states (I'm directly quoting):
"MAX PS minus MIN PS is greater than or equal to 5 at all times."

Unless that's a typo in the part I have underlined and highlighted in bold, Resmed thinks that MAX PS can be more than 5 over MIN PS.

Those two proposed changes I have for Banned include direct quotes from the manual.

Agreed that C-Flex EPR=3 entails less water column pressure than C-Flex EPR=1. And that ASV EEP=10cm entails more water column pressure than ASV EEP=5cm. Those two machines use numerically inverted pressure-relief scales when compared against each other.

An EEP of 10cm is way more pressure to exhale against than an EEP of 5cm.

If Banned truly has an easier time exhaling against an EEP setting of 10cm than an EEP setting of 5cm, then he has something strange going on in either perception or anatomy.


[on edit: corrected 4cm EEP references to lowest possible setting of 5cm]

Banned wrote:That's what frustrated clinicians with the first versions of the Adapt SV. The machine was so automatic there were no dials to spin. With no dials to spin the clinician's complained they couldn't pay the rent.

I mistakenly thought you were going it alone, Banned. Curious how you managed to garner that juicy inside track.

rested gal wrote:
With both EPR and C-Flex, a setting of 3 gives the "most" drop in exhale pressure coming at you", 2 gives "less drop", and 1 gives the "least" drop in exhale pressure.

It's almost like you're looking at the ASV's EEP pressure setting the same way...thinking that a higher EEP setting number means more drop, more pressure relief, for exhaling. But it doesn't.

WOW RG, that is so weird but you maybe right! I figured since an EEP of 9cmH2O felt good for me, it would feel good for everybody! So you're saying my great EEP of 9cmH2O may feel awful to someone else? No wonder I've been confusing the hell out of everyone. I've never known how to state it. Using your wording as described above with an EPR and C-Flex setting of 3 (which I always used), an EEP of 9cmH2O would feel equivalent for me (i.e. give the most drop in exhale pressure coming at you?). So, now that I'm beginning to understand that EEP, EPR, and C-Flex may effect different people differently, would my EEP of 9cmH2O be considered high or low pressure? Or how would be the correct way to describe it?

Thank you for the enlightening moment!

Right,

Some clarifications are emerging

Rested Gal has the handle on pressure relief & SWS has clarified the fact that PSmax can be more than 5 CMS above PSmin.

Also we have it that EEP stays the same (banned observing his machine & SWS observing the manual )

But I have to say, I just can't picture EEP acting like an epap in staying fixed at its set CMS when inhale pressure roams as high as say 16 CMS - that makes no sense to me at all. That could mean the machine if EEP=4CMS, going 16CMS-4CMS-16CMS-4CMS-16CMS-4CMS etc: - my imagination has that patient being ventilate to death

As previously mentioned neither the Malibu or Vpap Auto behave that way (hold exhale pressure constant) - there has to be another explanation for the exhale pressure on the Vpap SV.

Really need to think that out.

Cheers

DSM

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Banned wrote:So you're saying my great EEP of 9cmH2O may feel awful to someone else?

It could. However, even an EEP of 10 probably wouldn't feel awful, because any exhale pressure that's lower than the inhale pressure is usually going to feel pretty darn good to most people.

That same 9 that feels like a lot to try to exhale against when using a straight CPAP, feels like breathing out into an empty hose when using a traditional bilevel machine, set at, say, IPAP (inhale) 13, EPAP (exhale) 9. Same with the ASV's EEP pressure... ANY EEP setting is going to be lower than the pressure the IPAP (inhale) pressure the ASV is using.

EEP isn't just a comfort feature, like EPR and C-flex are. The EEP (exhale) setting -- and the EPAP (exhale) setting in traditional bilevel machines -- while they do make breathing out more comfortable, are supposed to be set to serve a very important treatment purpose. That purpose being.... to prevent an OBSTRUCTIVE apnea from happening after or near the end of your exhalation.

EEP (and EPAP) are to hold the throat open "enough" so that you are able to START to breathe in again.

EEP (or EPAP) of 9 cmH2O might be what someone NEEDS to keep the throat open "enough" at, or near the end, of exhaling, in order to be able to START the next exhalation. The exhale pressure needs to be high enough to prevent an apnea from slamming the throat shut after a person has finished (or has almost finished) exhaling.

An EEP pressure of 5 cms might be enough to keep someone else's throat open when they've finished, or almost finished, exhaling.

If EEP of 6 or 7 cms were allowing your throat to collapse near the end of your exhalation, that could have been why you felt those low EEP settings were choking you, Banned. Apparently you need 9 cms of pressure to keep yours open. EEP of 9 cms apparently prevents obstructive apneas for you so that you can breathe in again.

Banned wrote:No wonder I've been confusing the hell out of everyone. I've never known how to state it.

LOL!!! We're all here trying to learn. It was ages before I understood that a C-Flex setting of 1 doesn't mean 1 cm drop in pressure, etc.

Banned wrote:So, now that I'm beginning to understand that EEP, EPR, and C-Flex may effect different people differently, would my EEP of 9cmH2O be considered high or low pressure? Or how would be the correct way to describe it?

Your EEP of 9 is a high pressure for exhaling, compared to EEP of only 5 or 6.

I'd describe what you've done this way... "I've set my EEP at a pressure of 9, which is a higher pressure to exhale against than the default EEP of only 5 cms of pressure. I have to keep EEP at a high pressure because at, or near, the end of my exhalation, my throat seems to collapse, and I feel like I'm choking when I try to take the next breath."

Or, to put it another way, "It seems to take a pressure of 9 cm H2O to prevent most obstructive apneas for me, so I have to set my EEP at 9 instead of the default of only 5 cms."

Gotta remember -- the resmed ASV machine was really designed for people who have a lot of central apneas and central hypopneas, as opposed to people who have mostly obstructive events.

If:

1. a person's main problem is obstructive apneas with very few centrals...

and

2. using cpap or bilevel doesn't cause centrals...

That person doesn't really need an Adaptive Servo Ventilator machine.

If a person does need an ASV, but:

A. they have a significant obstructive sleep apnea problem in addition to the centrals problem....

and

B. 10 cms of pressure (EEP set at the most it can be set for -- 10 ) is not enough pressure at the end of exhalation to keep the throat open enough for that person to even START to take another breath...

That person may need to use a different brand of SV machine ... one that allows the exhale pressure EEP to be set higher than 10. Like, ummm.. the one you think of as mediocre.

Because it's the EXHALE pressure...the fixed "EEP" setting in an ASV machine, and the fixed "EPAP" in a bilevel machine or the varying "minimum EPAP" in an autotitrating bilevel machine... that prevents full obstructive apneas.

RG

Well said!

DSM

Banned wrote:If I'm hearing you correctly sws by all means MAX PS can be more than 5cmH2O over the MIN PS. In fact it can be substantially more. When I was telling Ceasea how to set-up her Adapt SV I was trying to hit the highlites without the detail to confuse her. I personally never touch MAX PS. But I mess with EEP and MIN PS all the time. There is no requirement to even touch MIN PS because, "Setting EEP automatically adjusts MIN PS then MAX PS. That's what frustrated clinicians with the first versions of the Adapt SV. With no dials to spin the clinician's complained they couldn't pay the rent.

Well, first of all, there were always dials to spin. EEP needed to be manually set, and MAX PS needed to be set high enough to insure that Target Ventilation was being reached (remember SAG's concept of IEA - "Incomplete Event Attack"?)

Banned wrote:That's what frustrated clinicians with the first versions of the Adapt SV.

Actually, the biggest concern of technicians concerned the duration of the "Floating Window". In another post, pjd noted

pjd wrote:This may be redundant and inconsequential, but as I understand, the Adapt algorithm measures and adjusts over a 100 second traveling interval, so the proximal tube data is averaged and not reactive specifically to an individual event other than maintaining ventilation within the 90 percentile range for a perceived central event. Sort of a 90 percentile ventilation based on an average of an average taken over the previous 100 seconds of data collection.

which was from the patent, yet all of the other literature says the window is 3 minutes. This can have a substantial effect on determining Target if the window is 180 seconds:



or 100 seconds:



The additional dial that needs to be spun is the duration of the Floating Window, because the Average Minute Ventilation and consequently Target Ventilation could be considerably underestimated in a patient with long central apneas. And why a flow-based machine like BiPAP AutoSV might be a better choice in those cases.

Further, while how AdaptSV (or AutoSV, really) addresses central apneas needs consideration, of equal importance is how the machine addresses normal breathing. The trigger and perpetuation for CSA and CSDB is hyperventilation, and overventilating during normal breathing (by arbitrarily wingin' the dials around because, oh, 9 feels like a good number today) will create far more problems than it will fix.

fjd2006 - Guested wrote:If person A says a dozen times that such and such is true. Someone asks if it's really true. Then person B says "no it's not" and with no further explanation, i would call that a glib! response. I don't care if he is in charge of 100 sleep labs.

Well, you believe who you wanna believe. If Person A says the Earth is Flat, it doesn't matter how many times he says it.

SAG

Casiesea wrote:Physical -

PFT - normal
O2 sats - normal
Chest xray - negative

Thyroid (tsh, t3, t4)- normal - from last week
CBC - normal
BMP - normal

EKG - Not completely normal (or what he would expect for a 39 yr old) but the doctor said he wouldn't call it abnormal. Scheduling Echo for next week with a cardiologist.

He feels like he is sleeping very well now (past 2-3 nights), but still feels like he could sleep all day every day.

That's good news so far, Casie. Continue to update, don't worry about this mumbo-jumbo, all threads eventually get 'jacked, anyway.

BTW, what's the elevation where you live?

SAG

Well, thank you everyone for putting me on the path of light. My apologies to the guest who so nicely defended my repeated misconceptions of how EEP was working. I'm going to see my cardiologist this morning and drag my Adapt SV along. Hopefully she can script a titration on an Adapt SV from my Bombay trained, "No I will not treat your gasping issues", sleep-lab doctor. They have been using two Adapt SVs in the lab for 6 months now.

Casiesea, now that I understand your husband may actually be breathing more naturally at 6-4 then 7-3. When you get a chance, can you casually ask him which setting 'feels' most natural for him? Thanks!

Banned