Duration of hypopnea events

My SH output designates the duration of my hyponea events all as 10 seconds (I admit I haven't looked at all of them) this sort of suggests some lack of distinction and perhaps some lack of consequence. It's hard to see that such an event could have serious implications on oxygen saturation. And yet Pugsy reminds us that they must not be discounted?? In looking closely at the flow rate during most of my hyponea events I can hardly detect anything out of the ordinary. Comments?

A random hyponea of 10 second duration isn't likely going to do much in terms of desats.
It's when we might have a whole bunch of them back to back so that the cumulative effect could potentially add up and cause desats that they become more important.
I don't worry about a random anything that is so brief.
It's when I see a dense cluster of something that I sit up and take more notice. So how many and how close together comes into play.

Hypopnea's are basically baby Apneas. Something restricts your breathing, but not enough that the machine considers it a full apnea. If you get enough of them, they can cause sleep issues the same as full-blown apneas.

For instance, years ago I had turbinate reduction, septoplasty, and UPPP surgery. As a result, I have very few full Apnea's, compared to Hypopnea's. Because it's so open all the way down, yet something still restricts a bit. I do know my tongue tends to slip back, but I absolutely refused the surgery that advances the whole palette. I had a friend that had all the same surgery, and the palette/tongue advancement, and he ended up in ICU and died.

Anyway, my cpap machine all these years was nothing but a no-data brick, so hard to tell anything. However, I did/do for sure still need one. In the last month I just bought an Airsense 10 Autoset, and am now getting data with Sleepyhead to tweak things.

I can tell you that even with mostly Hyponea's, I do NOT feel completely normal, even with treatment. But as I said, no telling how well the old machine worked. So, basically even though I've been on cpap for 20 years, I'm starting over from scratch, with nearly all the same "getting used to" issues I had in the very beginning.

It's something to with the way Resmed machines report hypopneas. They're obviously not all 10 seconds, but perhaps someone could elaborate further.

Hypopnoeas should never be discounted and their impact underestimated. Not only can they cause the blood oxygen levels to drop into the low 80% range, but they cause as many sleep interuptions and full apnoeas.
I am not familiar with the algorithms in the Airsense machines. It may be that there is a default where by the machine recognizes that a breathing problems is occurring but is unable to measure it so scores it as 10 seconds, which is the minimum duration of a valid breathing obstruction/blockage.
People with severe sleep apnoea can have hundreds of hypopnoeas recorded on their diagnostic sleep study, with no apnoeas. Their overall AHI can easily be over 30 breathing blockages per hour. These people have no less a form of sleep apnoea compared to someone who has hundreds of full breathing passage blockages [apnoeas]. Both people will have hundreds of episodes where their sleep is disturbed. It is likely that the person with the apnoeas will have greater drops in the blood oxygen levels.
Information generated by a CPAP machine provide some insight into what is occurring, but is only a reasonable guide and cannot tell the full story. So no matter how much you pull the data apart, it only means so much, and is not a polysomnogram.

I've spent a lot of time staring at highly magnified SH Flow Rate graphs corresponding to ResMed designated Hyponeas and frankly a lot their designations look pretty arbitrary. Anyone an expert of interpreting Flow Rate graphs?
















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Josiah wrote:I've spent a lot of time staring at highly magnified SH Flow Rate graphs corresponding to ResMed designated Hyponeas and frankly a lot their designations look pretty arbitrary. Anyone an expert of interpreting Flow Rate graphs?

Sorry I'm not . I do agree with your assessment in general. I've zoomed in on Dreamstation flow rate graph and some things flagged as hypopnea or apnea look slightly less then normal. Where as I can have something look funky and be ignored.

Check out this link for general helpful information including some info on flow rate graph.



http://www.apneaboard.com/wiki/index.ph ... SleepyHead

I see stuff flagged sometimes that I sit here and scratch my head and wonder what the heck but I have to tell myself that some of this stuff involves minute differences in flow rate that we may or may not be able to see with the data we have available.

I don't get many hyponeas. Never have no matter what machine I might be using but I happened to stumble on this little example.
Shows all 3 in close proximity to each other....rare for me.

USMCVet wrote:Where as I can have something look funky and be ignored.

Funky doesn't begin to describe some of my Flow Rate graphs

I just looked at Pugsy's flow rate graph. What I am seeing is typical flow after an arousal. I respect that Pugsy is very knowledgeable. But what I am seeing is classic for an awake-to-sleep breathing transition. They do look like breathing events. Yes they do look like 2 central apnoeas followed by one hypopnoea [I see that the machine interprets them as CA, OA, OH]. They are not true obstructive or central apnoeas. fI we had an oximeter attached to a person you would likely not see much if any drop in blood oxygen assocated with these events. I see this all of the time after an arousal or a disturbance to the person's sleep pattern. They are not true breathing events or problems. They will typically comprise 2 CA and 1 OH event as a pattern They are not usually scored by sleep scientists a true breathing events if they are seen in a full polysomnogram. Another awake/sleep transitional breathing pattern will comprise around 6 consecutive CA events. These occur when first falling asleep, or if a person has been awake for a while during the night and is then returning to sleep. This is all about the body transitioning itself from one system of breathing triggers to another.
I admire Josiah's interest in trying to understand the flow rate information. There are other things I could say to explain how to read it, but just to say that I think you are trying to understand something but the machine is not designed to give the whole picture. If it could provide oxygen levels and EEG patterns it would make more sense. As one might say, it is like trying to look at a landscape view through a keyhole. You can see that something is there, but you only get part of the picture, and no more. That can be frustrating.

TerrificSoporific wrote: ↑

Sun Feb 25, 2018 12:41 pm

But what I am seeing is classic for an awake-to-sleep breathing transition.

Yeah, they do look at bit like post arousal breathing events don't they?
They were just a couple that I had handy stored for easy showing of how the machine flags the breathing.
I didn't go looking for just hyponeas because I just have them flagged so rarely I didn't want to spend the time looking for something that was obviously asleep vs post arousal breathing.

What do you think of this one?