Variance in AHI readings

[NotMuffy]

Avi123 has foe'd me for not usually agreeing with him...

As Donald Rumsfeld once said:

Avi123 doesn't know what he knows.

[NotMuffy]

I am so disappointed that bandnuts took down his image. That was going to be a key to this discussion.

There's only a shadow left:



"Drive-bys".

Honestly.

[Pugsy]

OK, I have confusion between these 2 posts:

My comment about EPR being comfort feature that you highlighted was directed at avi123 who likes to blast what I say and insinuate that I am playing doctor. He seems to think that changing EPR is a great sin. Not that he will pay any attention to what I say. Rested gal feels more comfortable being a wee bit more aggressive in suggesting change. I was not questioning Rested Gal. I was trying to hit avi123 over the head with a 2 X 4 and get his attention but I know it is fruitless. While he won't respond to what I post, he must be reading them because he always seems to interject some nasty little comment about not listening to anyone here because we are playing doctors and he doesn't trust us.. Usually after I have made an observation or suggestion. Then proudly displays his numbers which are obviously less than optimal....

I have no problem with Rested Gal offering her thoughts. I just was being a little extra cautious and in my head I was thinking along those same lines but I just hesitate to offer it because I tend to be a bit more cautious when I see centrals until I am sure the doctor is also on board or we aren't making things worse.

[avi123]

sleeptiger, I went back to an earlier topic you had posted...to refresh my swiss cheese memory about what you might have already tried, settings-wise.
viewtopic.php?p=569045#p569045

If 9 was the pressure prescribed from a PSG sleep study, and if I liked using EPR full time (and I would), I think I'd give these settings a try with a straight CPAP machine:

If I were going to use EPR "1" -- I'd set the CPAP pressure for 10.

If I were going to use EPR "2" -- I'd set the CPAP pressure for 11.

If I were going to use EPR "3" -- I'd set the CPAP pressure for 12.

If I turned EPR off or used it only during ramp, I'd leave the pressure set at 9.

If one of those combos didn't seem to reduce the high number of obstructive apneas you're seeing fairly often on your data, I'd raise the CPAP pressure another full cm or two, for any of those EPR settings.

And if raising the pressure more didn't take care of it, I'd start thinking that GERD, or allergies, or something that could cause inflammation/swelling of some area of the airway on some nights might be causing a problem that CPAP has difficulty pushing aside at all. Then, I'd get a good ENT to scope it out.

And if that ENT carried out on you a uvulectomy, nasal reconstruction, adenotonsillectomy, and palatal implants. Or, uvulopalatopharyngoplasty (UPPP or UP3) and genioglossal advancement with hyoid myotomy. Or even, a maxillary-mandibular advancement, bimaxillary advancement, palatal advancement and tongue-base surgery (midline glossectomy), and tracheostomy.

And if it did not work as you expected, then please do not come complaining to us!

But still, RG is super.

[avi123]

to be re-edited

[NotMuffy]

...I tend to be a bit more cautious when I see centrals...

OK, but what you think about when the ResMed algorithm is running a FOT scout (specifically, as it relates to EPR)?

[Pugsy]

OK, but what you think about when the ResMed algorithm is running a FOT scout (specifically, as it relates to EPR)?

To be honest, my eyes glaze over at this point. I get some of the meaning but I haven't been able to assimilate all these very intricate details. I took a vacation from the forum for about a year and I am way behind on this stuff with the way the newer machines are reporting all this waveform stuff and FOTs and.....

I am trying to grasp it but I know that I am lagging way in the rear. Is there somewhere that I could read up on this starting from nearer the beginning so that I can understand what each of these different terms are, what they do, how they relate to these reports? I find it immensely interesting and I know I can learn but I learn best by doing or example and I don't have a machine that offers anything for me to compare to. I guess what I am trying to say is that I don't have a good basic understanding of it all to enable me to grasp any implications. I just have bits and pieces in my head and they haven't gelled yet.

Is there a "Understanding Sleep Analysis for Dummies, the In Depth Stuff"?

[sleeptiger]

Hiya,

Last night my S9 was set to 9.0 with EPR 2.0...after 5 hrs of sleep, i put the machine on standby and had a toilet break, read the AHI off the LCD screen. It read 3.3. After this, I put the mask back on and resumed the S9. Could not sleep for the next 2 hrs, read the machine again, AHI was reading 7.5. It looks like I register higher AHIs while I'm awake! There were also a lot more centrals during the 2 hr period when I wasn't asleep.

[Pugsy]

Could not sleep for the next 2 hrs, read the machine again, AHI was reading 7.5. It looks like I register higher AHIs while I'm awake! There were also a lot more centrals during the 2 hr period when I wasn't asleep.

I think this is a common occurrence. While awake our breathing is much more erratic than we realize but the machine doesn't know that you are awake.

What did the first part of the night look like on the report? Have you checked it yet? We toss the awake time out the window..

[NotMuffy]

OK, but what you think about when the ResMed algorithm is running a FOT scout (specifically, as it relates to EPR)?

To be honest, my eyes glaze over at this point. I get some of the meaning but I haven't been able to assimilate all these very intricate details. I took a vacation from the forum for about a year and I am way behind on this stuff with the way the newer machines are reporting all this waveform stuff and FOTs and.....

OK, lemme get a cran and draw in the pressure of what people think they're getting while on ResMed with EPR:

[sleeptiger]

Hi Pugsy,

If we discount the awake time, then my AHI would be 3.3 and I think the centrals would be spaced quite far apart. Don't have the data on me as I'm in the office. Will upload it later when I'm home.
Regards,

[NotMuffy]

OK, but what you think about when the ResMed algorithm is running a FOT scout (specifically, as it relates to EPR)?

To be honest, my eyes glaze over at this point. I get some of the meaning but I haven't been able to assimilate all these very intricate details. I took a vacation from the forum for about a year and I am way behind on this stuff with the way the newer machines are reporting all this waveform stuff and FOTs and.....

OK, lemme get a cran and draw in the pressure of what people think they're getting while on ResMed with EPR:

And even more importanter, what pressure FOT is analyzing at:

[sleeptiger]

Still on the sbject, can someone tell me what the following "terms" mean and what's being measured?
Flow,
Flow limitation,
Minute ventilation and
Snore index

How can the S9 measure snore when there's no microphone or audio in it?

[Pugsy]

And even more importanter, what pressure FOT is analyzing at:

Gonna make a stab here. Since this example shows EPR of 3 and the FOT probe is actually testing the waters during the exhale reduction phase instead of during the full pressure phase? Is this APAP since minor increase in pressure? So if FOT is probing at lower pressures it is sort of testing things at a lower pressure and thus able to respond to what it feels needs responding to and if this is the case, lowering EPR doesn't necessarily let more events slip past the guards? God I hate being so thick headed.

[NotMuffy]

Since this example shows EPR of 3 and the FOT probe is actually testing the waters during the exhale reduction phase instead of during the full pressure phase?

Bingo.

Is this APAP since minor increase in pressure?

Correct.

So if FOT is probing at lower pressures it is sort of testing things at a lower pressure...

Stop there.

If pressure drops by 3 cmH2O at EPR 3, then the airway may close. If that's where FOT is probing for centrals, it may now register a closed airway. I think that may be an explanation all of bandnut's "obstructive" apneas. In summary, if S9 says it's a central, then it is near certain to be so, but if it says it's an obstructive, I think measuring airway patency at 3 cmH2O lower than therapeutic pressure is going to miss a ton of events if there's an element of obstruction. However, I suppose if it's a case of pure centrals, then wingin' the pressure around like that may not make a difference in the yield.

A good test in bandnut's case would be to assess those chain events at EPR 0.