AHI low, but events all night

[TalonNYC]

For those following along... I've been under 3 on the AHI numbers for a couple of weeks now, and originally I was just getting a cluster of events at onset and at awakening, but rather flat graphs the rest of the night.

Now, over the last week, I'm seeing small events (less than 20 seconds) throughout the night. My overall AHi is still under 3 (usually hovers around 2.5) but I'm not sure if I need to address the various events or if I should just ignore them.

Here's a representative night:


What advice have you folks got? Feel free to say "this is normal and don't change anything" if that's what I should do =)

Thanks in advance.

[Lizistired]

How did you feel that you slept?
I would check the Flow data. Last night I had more events than usual (CA's), but when looking at the Leak and Flow, all but one event lined up with a leak or an increase in flow prior to the events. So then I remember fiddling with the hose, getting cold and not getting another blanket right away, joint pain because we have another front going through... Tonight is another night.

[TalonNYC]

I'm feeling better overall, but I haven't had a huge benefit from therapy that I've felt. Granted, I can guess that I've had massive benefits, but since they've happened over a 3 month period, I wouldn't have actually felt them since they happened gradually.

Leaks are very well controlled for me, the events don't seem to line up against any particular bumps in the graphs. Could just be what "normal" folks experience when they sleep, I just don't have the baseline from 15 years ago to compare it to =)

[Bodhi]

TalonNY, just from looking and what you said, I'd guess that you are going through a period where you need a bit (not a lot!) more pressure to clear those obstructives. You only have one central and hypo, so a tad more pressure might do the trick.

I haven't been on xPAP long enough to follow any seasonal changes, though I suspect that like this could be from some new environmental factors. I've followed your Blowdown and you've done a great job with the leaks. As I recall, you are on straight CPAP (14?) so even a small increase in pressure could affect leak rate . . .

[TalonNYC]

Yes, I'm at 14 now, up from a titration level of 12. The S9 can do increases in .2 increments, so maybe I should try 14.4 for a couple of nights to see the results?

[AMUW]

Here's a representative night:

Mike, if you were to reduce the OSA durations by just 2 seconds shorter, and igore sleep=onset effects; then you'd hardly have anything peaking above the 10 sec threshold.
Like Liz says, I'd look at the detailed flow curves, zoom in to below a 10 minute scale, see if on other nights you also have some shorter flow interruptions at such near-regular intervals.
In my case such increases in flow restrictions could happen under certain circumstances: body position (i.e. upper airway clearance), air humidity & temperature, mask leaks, gastric reflux, nasal congestion, etc. I don't know yet about the effect of travel and late meals. Do you maybe toss-and-turn every 30 min during sleep; or did your PSG hypnogram show frequent changes in sleep stage?
Many of us have learned that AHIs aren't the only measure of sleep quality, and look at additional measures of sleep fragmentation.

[TalonNYC]

Well, my allergies have kicked into high gear, so there's definitely some congestion on and off through the night. My back has also been acting up, though I do take advil at night before bed, which seems to clear the pain for at least 4-6 hours for me.

[Bodhi]

The S9 can do increases in .2 increments, so maybe I should try 14.4 for a couple of nights to see the results?

I would only increase by .2 because in my case .2 made a huge difference as I closed in on the "sweet spot." YMMV of course. You have 10 (that I can see on the chart) events over 10 sec. each, and 4 (that I can see) at 10 sec. duration. That's why I'd suggest a .2 increment--for maybe a week.

The environmental factors that AMUW mentions (tossing and turning, air and humidity, etc.) can certainly affect AHI. And I agree that AHI isn't the sole criterion for adjusting therapy (how do you feel? as Liz asks). I also correlate the flow restriction / pressure rate changes on my S9 Autoset in auto mode. They correlate very well--more flow restriction= appropriate pressure change. I don't know about straight CPAP. The length of your apneas suggests to me that a tad more pressure (.2) and you may be able to clear them.

(Edit add: IF that clears them AND you feel better, you win! IF that clears them AND you feel worse or the same, you try something else )
Good luck!

[TalonNYC]

Sounds good, I'm going to go up by .2 for a week, to see what happens. Also, the pollen will eventually stop flowing =)

Thanks all!

[bayourest]

Hi Mike,
I have a similar situation. AHI is good (usually below 3) but I seem to have events all night, often seem to be in clusters. In the first half of May my AI scores were almost always below 1, but there has been a clear increase in the 2nd half of this month. Mask leaks are low, and I had not changed the settings. So I feel like, what can I do? I feel ok, but sometimes have very drowsy days. I was thinking that I should raise my minimum pressure (I was titrated at 10, and have the pressure set now on apap 11-20 as the 11 minimum seems to give better results. The max rarely goes above 13) and the responses here make me think that's the way to go for now. So last night I raised the minimum to 11.4
A I was slightly better this am. I do have a few events of 16 - 18 seconds bur also a few of 11-12.
I am in CT and you are in NY so we probably share some regional pollen etc , but I still think that breathing filtered air through the machine should reduce or eliminate the allergy effect...?

[TalonNYC]

Reduce it, yes, but not eliminate it. Plus you're breathing pollen all day, it takes more than a few hours for the histamine response to back down again. either way, it would seem that allergies don't help things LOL

[bayourest]

Here's a long shot (maybe).
Check your filter.
I changed my original S9 filter in march after 4 mos of use and it looked quite good. For some reason I decided to check my filter this a m (even though my AI was a very good 1.2) and let's say that it looked "less than quite good." yuk.
wondering if this may have something to do with rising AHI for the past few weeks.

[TalonNYC]

changed the filter last night, but so far no go, however, it could just be a normal fluctuation in my sleep patterns.

[bayourest]

I raised the minimum pressure from 11 to 11.4 2 nights ago because my ahi and ai had been creeping up....
1st night the ahi was 1.1 and last night it was 0.5
so i guess that small bump in pressure helped
I havent had a chance to look at the graphs yet