Questions about flow rate data

[Pap365]

Hello,
Last night I had my best night ever on apap...or so I thought. Even though my AHI was zero and I slept around 8 hours I woke up feeling groggy and felt sleepy all day. I looked at my data and found something I haven't seen before. I have very little experience interpreting data and apologize in advance if this is something common. I do not recall being awake or rolling over during this time frame.
Thanks!
G


Sorry the top picture doesn't show the full event.

[Pugsy]

That little fuzzy looking part?
That's the S9 FOT doing its job. FOT is ResMed's way of determining what to call an event when it isn't sure.
If the event has lasted long enough to be called something FOT helps the machine decide what to call it.

FOT
http://www.resmed.com/us/products/s9_se ... nc=dealers

[Lizistired]

That's funny. I didn't know Mark smiled at you if you had a 0.0 AHI!

On your graph, I always consider the increase in inspiration and expiration prior to an apnea a good thing, as opposed to those that just taper off to nothing. But what do I know?

[kaiasgram]

Pugsy, looking at the flow limitation graph right below the flow line graph, would it be fair to assume this would have been flagged as an obstructive apnea or a hypopnea if it had lasted 10 seconds?

[Pap365]

Thanks for the link Pugsy. So if I understand the information correctly, the fuzzy lines are caused by the pulses the machine puts out to figure out what, if any type of event I’m having? So I could have several of these events and still have an AHI of 0? Could these almost apneas be the cause of my daytime sleepiness?

[Pugsy]

would it be fair to assume this would have been flagged as an obstructive apnea or a hypopnea if it had lasted 10 seconds?

Would have been flagged as something if it had lasted 10 seconds and the reduction in airflow was within criteria which is sure appears to be. I don't know enough about the flow itself to have an idea if it would have been central, obstructive or hyponea though. I just haven't studied the minute differences under a microscope.

So I could have several of these events and still have an AHI of 0? Could these almost apneas be the cause of my daytime sleepiness?

Yes, you could in theory have a lot of these "sort of" events and if they don't meet criteria (which is at least 10 seconds and a certain amount of reduction in airflow) you could have AHI of 0.0.
Could these "almost" apneas be responsible for daytime sleepiness? I suppose they could but I would think it doubtful that they all by themselves were the problem. If they are the problem then I would think that something else going along with them would be maybe factoring into the mix. Like maybe some sort of mini arousal or something.
Maybe if you had a whole bunch of them within a relative short period of time.
I don't see a random "almost" event being totally responsible though.

[Pap365]

Thanks Pugsy. I agree one random event is not enough to draw any conclusions. I’m just looking for a starting point. I think I’m going to go back through my data and see how many “sort of” events I have. I know things like rolling over in bed can cause blips in the data. Any suggestions for identifying a “sort of” event from rolling over?

@Lizistired The smile is very encouraging I didn’t think to look at the inspiration/ expiration rate thanks!

@Kaiasgram I think before all is said and done, we will be flow limit experts !

[Pugsy]

Any suggestions for identifying a “sort of” event from rolling over?

No suggestions that I can think of other than just zoom in on flow line like you did when you spotted the FOT thing and get familiar with what appears to be a pattern that you might see.
You might notice some sort of pattern. It really takes a lot of looking to get an idea what might be a pattern.
Like for me I almost always see a big gulp of air (sharply increased flow line on the graph) before a "central". I assume it is a turning over in bed "central" and I am holding my breath briefly but I really don't know that is for sure what is happening.
It takes a lot of zooming in and looking and to be honest...just more work than I really am inclined to do because I don't know for sure if I am right and even if I am right...what would I do about it?

[kaiasgram]

@Kaiasgram I think before all is said and done, we will be flow limit experts !

When is graduation?
I'm glad you posted your question because I do have a lot of 'almost-events' like the one you posted. And I can't blame it on rolling around because for whatever reason I lay as still as a statue at night (like my mother who never even had to make her bed in the morning, just slid out from under the covers and you'd never know someone had slept in it!).