Clusters of hypopneas with no flow limitation

[mannsch]

I am getting big clusters of hypopneas throughout the night where the breathing pattern on the flow rate gets much smaller, then followed by a big breath. Then repeat several times.

See here: https://prnt.sc/p7o5le
And here: https://prnt.sc/p7o32i

There is no flow limitation shown on the charts that correlates with these patterns.

Anyone else get these? Any tips to deal with them?

I am using the Resmed Aircurve 10 ASV.

[Pugsy]

Are you for sure solidly asleep when things seem to go off?.
You do extremely well for a little over half the sleep session and then things get wacky. That makes me wonder what changed?
Awake tossing and turning? Sleep position change?

[mannsch]

I can't say for sure if I was awake or not. I feel like I did manage to have a long stretch of uninterrupted sleep last night and a lot of these events are within that I think.

Maybe I should try to record myself on video for a few nights and see if I can correlate these events with any sleep positions or disturbances.

[Pugsy]

The two variables that I can think of
not quite asleep or a change in sleep position.
Your breathing pattern during the bulk of the ugly stuff that you show doesn't look like asleep breathing to me.
Looks like tossing and turning breathing to me.

Learn how to zoom in on your flow rate to get an idea of awake breathing vs asleep breathing and you can see what I mean.
The vidoes here explain how to do it.
http://freecpapadvice.com/sleepyhead-free-software

If you were asleep....
It is of course entirely possible that those hyponeas aren't obstructive in nature and if that's the case the absence of any FLs doesn't mean much because we wouldn't expect to see them with central in nature events. Hyponeas aren't always obstructive in nature.

If you can video yourself to rule in or out the sleeping on your back thing...that would help with your detective work figuring out what is happening here if you are indeed asleep.

[Jay Aitchsee]

Hypopneas and Obstructive apneas are not necessarily accompanied by Flow Limitations.
Hypopneas and Apneas are a reductions in flow while Flow Limitations generally refer to the shape of the flow wave. Flow LImitations generally result in a flattened inspiration wave top. Flows can be diminished without being flattened resulting in a hypopnea without a corresponding Flow Limitation.
Hypopneas can be "central" in nature where breathing becomes shallow resulting in reduced flow amplitude without exhibiting the characteristic flattening of Flow Limitations.

[pouetance]

That's REM sleep hypopnea I believe (look like central hypopneas actually if such things exist). Looks at the timing of the clusters. They are all almost ninety minutes apart and as the night progress, you get more events.

[palerider]

I am getting big clusters of hypopneas throughout the night where the breathing pattern on the flow rate gets much smaller, then followed by a big breath. Then repeat several times.

See here: https://prnt.sc/p7o5le
And here: https://prnt.sc/p7o32i

There is no flow limitation shown on the charts that correlates with these patterns.

Anyone else get these? Any tips to deal with them?

I am using the Resmed Aircurve 10 ASV.

Flow limitation and hypopnea are not related, you can easily have one without the other.

https://www.youtube.com/watch?v=-gie2dhqP2c

[Jay Aitchsee]

(look like central hypopneas actually if such things exist)

http://jcsm.aasm.org/ViewAbstract.aspx?pid=31260
The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications (AASM Scoring Manual) provides the option of scoring hypopneas as obstructive or central.1,2 Obstructive hypopneas are those with evidence of increased airflow flattening, chest/ abdominal effort belt paradox, or snoring during the event. If none of these are present the hypopnea is classified as central.

Hypopneas can be "central" in nature where breathing becomes shallow resulting in reduced flow amplitude without exhibiting the characteristic flattening of Flow Limitations.

[raisedfist]

The clinical guide for ResMed under the ASV section says to raise the EPAP:

"Any obstructive apneas, hypopneas or RERAs? Increase EPAP by 1 cm H2O every 20 minutes until obstructive events are eliminated"


Not all cases are textbook, but worth a shot to raise the EPAP min and see what happens to the hypopneas. It won't cause any harm either way.

[Jas_williams]

They don’t look obstructive to me but centrally based as the amplitude goes down although the ASV is blowing too it’s max settings to encourage the small breath that’s there. I would raise the max PS to its max setting.


Beyond that not sure what else you can do.

[mannsch]

Thanks for the help, everyone.

I tried raising the PS Max to the maximum setting of 19, so the pressure was going up to 25 during these shallow breaths.

Here's last night, full chart: https://prnt.sc/p8nk5a

Here's a zoom-in one of the hypopnea clusters: https://prnt.sc/p8nlgn

The machine clearly ramps up to the maximum pressure of 25, but it still doesn't suffice to force breaths.

I'll try raising the min EPAP next, although I'm not sure how that would help if these hypopneas are central in nature.

I do feel like I am sleeping better with the ASV, though. I'm not waking up nearly as much during the night and I am having clear, vivid dreams every night.

[idlewire]

I would lower your PS Min to the default of 3. A min PS of 6 is enough to actually induce centrals in someone who doesn't normally have them. If your machine is over-ventilating you at baseline, you'll be more likely to have central events.

[mannsch]

I would lower your PS Min to the default of 3. A min PS of 6 is enough to actually induce centrals in someone who doesn't normally have them. If your machine is over-ventilating you at baseline, you'll be more likely to have central events.

That's interesting, thanks!

I tried lowering the min EPAP and min PS settings:

Min EPAP: 4
Max EPAP: 15
Min PS: 3
Max PS: 20

Last night, I had an AHI of 1.59 which is the lowest since I started the therapy! See here: https://prnt.sc/p906il

Maybe it was excessive ventilation that was causing these central events. Looks like the ASV easily handles the obstructive apneas as needed as I have zero of them now.

[Pugsy]

ResMed ASV machines won't ever flag an OA because they don't differentiate between OA and central.
Instead they dump them in the UA basket.
It's just what they do.

You've got a handful of UAs....probably obstructive. Not enough to worry about.

Give yourself more nights at these new settings and see what happens.

[mannsch]

Still doing really well with the lower pressures -- AHI is consistently much lower than before: https://prnt.sc/p9tzw4

The pressure support now seems to be sufficiently powerful to eliminate most of the hypopneas from before.

However, I am wondering if the big pressure spikes themselves could also be causing me to wake up.

See here: https://prnt.sc/p9u1ee
And here: https://prnt.sc/p9u1se

Anyone know how to deal with this?