CPAPtalk.com

I think your doctor prescribed a great machine for you. I'm interested if he also prescribed the software (silverlining) that goes with the machine. If you have this software, you can get daily feedback on how you are doing. Alternatively, you can periodically bring the machine to him and if he has the software, he can download the information and help you with the settings. If he hasn't said anything about the software, I suggest you ask him about it.

fstanmyre wrote: If this is shown to be a problem during the sleep study it might have been better for the sleep lab or doctor to prescribe the Goodknight which does allow for adjustments to the machines response to apnea, acoustic vibrations(snoring), and flow limitation..

The 420e does not have an adjustment for snore (no "command-on-snore" or "command-on-accoustic-vibration" setting).

It does have all those other adjustments mentioned, though!

fstanmyre wrote:DSM lives in Australia.

Oops. Sorry, DSM, I don't know why I had the impression you lived in Canada.

But you're still right - that is EXACTLY how it should work!

Rol

I haven't used these adjustments as I mentioned. Since you obviously know the machine, can you tell me what exactly does the 1FL2 setting do. It's described as "flow limitation combined with amplitude decrease". This is not a form of snore adjustment?

IFL2 is the trigger for hypopneas---specifically hypopneas that are "concomitant" with flow limited (and therefore obstructive) breathing patterns. IFL2 incorporates this twofold triggering criteria to prevent the 420e from increasing pressure on hypopneas that are central in nature. The hypopnea portion of that triggering criteria is detected via air flow amplitude reduction. The flow limitation portion of that two-fold criteria is detected via certain flow wave shape characteristics. Those characteristics are probability weighted against a likelihood of obstruction.

Perform a search above for "ifl1" and "ifl2" and you will find yet more detail about the 420e. Good luck!

Here ya go, Fred...these are good for starters in the Search:
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Jan 11, 2005 subject: Bman: Spirit Overnight Indices

Topic started by -SWS accidentally logged in as "Guest".

Even though that topic starts out talking about the ResMed Spirit, the topic moves quickly into a very good discussion about the PB 420E's IFL1 and IFL2 triggers. It's a "many pages topic", so keep turning the pages!

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Mar 16 2005 subject: Question to SWS Re: 420E

-SWS discusses turning off IFL1 on the 420E.

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Apr 10 2005 subject: A question (or two if I can remember) about the PBG 420E

-SWS and John discuss PB 420E's IFL1 and IFL2 triggers.

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Feb 14, 2005 subject: APAP and leaky masks?

-SWS discusses the PB 420E's "flow limitation runs".

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May 23, 2005 subject: PB Good Knight 420E and hypopneas

-SWS discusses how the 420E handles hypopneas.

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Fred, you asked about "IFL2"....

It's described as "flow limitation combined with amplitude decrease". This is not a form of snore adjustment?

No, it's not a form of snore adjustment. The "amplitude" the description is speaking about is not about sounds or snoring. It's....as the Guest describes it.

The 420E's "advanced settings" default settings of IFL1 (on), IFL2 (on), and "maximum pressure for command on apnea" (10) shouldn't be changed unless a person thoroughly understands why they are set that way by the manufacturer, and what happens if they are changed. The "advanced settings" that are already in place work fine for the majority of 420E users.

Turning off IFL1 to stop pressure runaway is probably (imho) the most likely tweak some 420E users might need to do...but only if there are pressure runaways with IFL1 "on", as it is by default. Most 420E auto users are fine with the advanced settings left right where they are.

Those characteristics are probability weighted against a likelihood of obstruction.

To further clarify: each wave shape characteristic that is probability weighted implicitly means that algorithm does not deal in certainties (i.e. 100% probabilities). In this example if PB derives its own definition of "flow limitation" from several juxtaposed wave shape characteristics, then a small percentage of flow limited patients will necessarily fall on the short side of that probability weighting, Fred.

That probability-based approach is precisely why an APAP algorithm---any APAP algorithm---is guaranteed to be incompatible for some small percentage of patient breathing patterns.

I continue to be amazed at how many smart and helpful people there are on this site. Thanks all. I think for the time being I won't fiddle with the FL!/2 settings since I don't really understand them too well and the 420E works just fine for me with the defaults. I have the SilverLining manual of course and it really doesn't provide anywhere near the information that I just received on this site.

fstanmyre wrote:I think for the time being I won't fiddle with the FL!/2 settings since I don't really understand them too well and the 420E works just fine for me with the defaults.

If it's not broken, don't fix it! Words to live by.

So is the Remstar Auto better than the 420E for snoring? Why? How good is the 420E at lowering snoring? I have been getting uneven snoring data from my 420S. One night I am way below my average Acoustical Vib and another night I am above. My Accoustical Vib is averaging twice my AHI. I want to lower the snoring so that my wife doesn't complain. My sleep professional told me that I didn't need to tape my mouth to stop snoring if my CPAP is adjusted correctly and he doesn't want to prescribe an APAP so I am going to a second sleep clinic in a couple of weeks.

I have been getting uneven snoring data from my 420S. One night I am way below my average Acoustical Vib and another night I am above.

Your 420S is not able to RESPOND to the acoustical vib. It cannot make any changes in pressure at all. Your numbers can change from night to night for many reasons. If you had alcohol or any other muscle relaxant during the evening, you will likely snore more. Also, if you spend more time on your back, you will likely snore more. All the 420S can do is record the events and report them.

If you had an auto machine, like the 420E, it would respond to the snoring with some increase in pressure. The increased pressure would firm up your airway and the snoring would stop. As it is, your 420S can only tell you what is happening, it cannot change your treatment in any way.