AHI vs. Snore

[Jcochran]

Does it make sense when a small change in pressure (from 9 to 9.5) would cause your AHI to go from around 6 to 11.5-12? My vibratory snore was lower with the higher pressure, but the AHI is higher. The mask leak rate is very similiar between the two. Thanks in advance.

[Wulfman]

How long did you have it at the higher pressure? If it was a short time, there could be a some possibilities. It's not really "logical", but I have seen reports that had "curves" in the AHI lines. At another, slightly higher pressure, it might take another drop.

Den

[turbosnore]

By the way, What is that snore number?

For my sleep study there was no index but these:
Snoring Time: 167.2 min
Relative Snoring Time: 34.0 %
Number of Snoring Episodes: 330
Average Snoring Episode Duration: 0.5 min
Longest Snoring Episode: 11.8 min
The total monitored sleeping time was : 8 hours 12 minutes ( 492 minutes )

This suggests that snoring event is different from apnea event.
Apnea event only lasts seconds but snoring event may take hours, so number of events per hour
doesn't sound informative. If average is 1 event per hour lasting 1 hour...

[DreamStalker]

It is a snoring index .... divide the number of snores by the time in hours.

[turbosnore]

Number of snores?
There is just number of snoring episodes longest of which is 11.8 mins.
I don't think that could be it. If I snored through the whole night, number of snoring episode would be closer to 1/8.
As if I didn't snore at all.

[ozij]

How long did you have it at the higher pressure? If it was a short time, there could be a some possibilities. It's not really "logical", but I have seen reports that had "curves" in the AHI lines. At another, slightly higher pressure, it might take another drop.

Den

That's the main point: how long did you have it at the higher pressure?

O.

[DreamStalker]

Number of snores?
There is just number of snoring episodes longest of which is 11.8 mins.
I don't think that could be it. If I snored through the whole night, number of snoring episode would be closer to 1/8.
As if I didn't snore at all.

Correct. Number of snoring episodes divided by time (in hours) is 330 / 167 min = 118 snore index ... but think whatever you want.

[turbosnore]

So one 7 hour episode gives SNI 1/7?
Such a person is better off than 7 different episodes, say 1 min each = 7/7min = 60?

[DreamStalker]

So one 7 hour episode gives SNI 1/7?
Such a person is better off than 7 different episodes, say 1 min each = 7/7min = 60?

Sorry for the confusion ... 167 min = 2.78 hours ... 330 episodes / 2.78 hours = 118 index for snoring (episodes per hour).

[Jcochran]

I have only been at the higher pressure for two nights now. Just that both nights were consistent at the AHI of 12 range where pressure of 9 gave me fluctuation of an AHI between 4-8. I stayed at 9cm for 1 full week, and figured that was long enough to see I needed to change it a little. ???

[Wulfman]

I have only been at the higher pressure for two nights now. Just that both nights were consistent at the AHI of 12 range where pressure of 9 gave me fluctuation of an AHI between 4-8. I stayed at 9cm for 1 full week, and figured that was long enough to see I needed to change it a little. ???

If you take it to 10 or 11......and it gets even worse......then you'll get a good idea that you're going in the wrong direction.

By the way......what became of this discussion......about Centrals. I don't have a whole lot of time to re-read some of the threads, but did see this one.....since it may be an/the issue.

viewtopic/t36336/viewtopic.php?f=1&t=36 ... 66#p310966


Den

[Jcochran]

After everyones advice from this board, I got a copy of my PSG from the doctor. I only had 2 centrals. Before seeing the report, I was just trying to figure out why I could not get my AHI down. The doc says I have Rera's, and was changing my pressure to much instead of trying it for a bit. I was originally titrated at 6cm, but the AHI were up in the double digits at that pressure too. Should I stay at 9.5 for a few more nights, or go ahead and bump it up to 10?

[Wulfman]

I'd go up to 10. There have been a few people who were able to split the difference on some pressures when doing the fine tuning , but this way you'll find out sooner rather than later.

Good luck.

Den

[echo]

There have been some discussions on change-induced centrals - that is, until your body stabilizes and accepts the new pressure, you might have some CA's here and there for a few nights. This happened to me during the titration - at 10cm I was getting CA's just because it the was first time I was using CPAP ever, but now I can easily go up to 12cm w/o any CA's.
There's been quite a few threads on this phenomenon but I can't remember which ones at the moment (something about "settling" maybe?).

I hadn't heard about the AHI curve concept that Den mentions, but I guess it's possible. In any case if they're true CA's I guess you will hit them at 10cm as well as 9.5cm so you'll have your answer regardless of which one you use. Just go with your intuition.

[ozij]

I don't see a vibratory snore problem at 9 on this, taken from the other thread.



Your AHI is 3.6 here, your snore index 0.2.
You've got at an automatic machine, and you're running it on fixed pressure.
You were titrated at 6.

I don't understand your reasoning - a short recap of what pressures you've tried and why would help.

O.