What is considered a real central?

[dolppl]

I watched the lanky lefty video that talked about centrals that are right after a period of instability when you are maybe rolling over as not being true centrals.  Are there any other indicators that what is flagged as a central is truly a central.  I know this isn't perfect but just looking for some thoughts.

I have had a quite a few of what I have attached throughout my night of sleeping which looks like i am going along just fine and then it looks like a i take a deep breath and then a central is right after that.  Could that be an indicator of a false central that maybe i took such a deep breath i could hold it for a while without an arousal and then continue breathing just fine?

   

[Crimson Nape]

Yep! Your graph is a prime example. You took a deep breath prior this CA being flagged. I would term that a false positive. If your flow rate had remained constant prior to the event, then that would have been a real CA.

[SarcasticDave94]

Others may add a better answer as for signs to view, etc. I suppose. I can tell you what a central apnea is and a few components that make one up.

First, to be an apnea, it is a 10 or more second time period where you're not breathing. An obstructive apnea is where you're attempting to breathe but airflow has been blocked. A central apnea is where no breathing effort takes place with no accompanying blockage to airflow.

Signals to breathe are not present during CA, and one reason is a carbon dioxide to oxygen imbalance, where carbon dioxide is unnaturally lowered as in cases of treatment emergent CA. This is typically caused by being on CPAP where carbon dioxide is washed out too thoroughly.

Another form of CA can have the oxygen sensors think carbon dioxide is too low to require breathing, as might be the case in pre-existing and/or idiopathic CA.

PS in your chart, as Crimson Nape mentions as well, you're breathing in a bit more deeply probably just before say you change sleep positions. Then during position changes, you're holding your breath.

[Gideon]

The other tell is to look for a recovery breath following the apnea. A Central Apnea usually has a diminished breath and subsequent breaths building in amplitude.

[Dormeo]

In your zoomed flow-rate graph, you aren't actually holding your breath. First you inhale deeply, then you exhale deeply, and then you pause for a while before you inhale again. (Dave gave a good explanation for how this happens.) After the pause, your next breath is fairly normal, then you have several deeper breaths, followed by breaths of decreasing shallowness, and then it looks like you get back on track.

I'm not sure I'd use the term "false positive." I can see why people do: if the arousal before the CA is really a wake-up, then you aren't having a sleep apnea. But it can be unclear whether the breathing beforehand comes from a wake-up or just an arousal that kicks you out of a deeper sleep stage into a lighter one. All of that is just by the by' it's just something I've been thinking about.

It's hard to tell, but it looks as though your breathing in this segment may have had some flow limitations.* I'm not sure, but I sometimes have the suspicion that a stretch of flow-limited breathing can bring about a deep breath.

Flow limitations are like baby hypopneas -- they reflect some restriction within the airway, but not as much restriction as an hypopnea. In addition to the flags for FLs, you can see them when you zoom in. The curve of your inhalation -- the part above the zero line -- should be nice and smooth, but FLs show up as plateaus, dents, or pointy peaks.