I got some odd data last night.
The first thing that hit me was the gap I don't remember. That would be the first gap in red below. Oximetry shows that the gap exists, yet, I must have just been sitting doing nothing in bed. I think I would have remembered that. I do remember the second gap in green. I wonder if this has anything to do with daylight savings time -- except there's the oximetry. I watched tv for about 20 minutes at the second gap so my apneas would be less pronounced when I got back to sleep.
When you look at a closeup split of the gap, the data match up as to height and delta. That's weird.
This was an example apnea, 14 second duration.
This apnea appeared in the events graph, but not in the flow pane. Nada. This is the first time I've actually seen one graph not completely agreeing with another graph.
For this night, there is a thirty second lag between pressure and flow at the beginning of each mask event as denoted by the red shading...
And consequently at the end of each mask event (also red shading). So the system isn't perfect.
Part 2 - central apnea deconstruction...
In an effort to understand when an apnea starts and stops visually, I set up an example measuring stick for a 25 second apnea. Once I had a yard-stick to work with in pixel width, I did a ratio to get the correct size width for other apneas. I set the yardstick at the very center of the apnea event, as shown by the crosshair.
This is a similar example for a fifteen second apnea.
What I'm calling an 'ideal' example of a central apnea.
Another ideal example. Sorry - i don't get obstructive apneas, so I can't show you those!
This one is less than ten seconds, so it doesn't count here.
This one is either darn close, or the system just didn't pick it up.
This one looks like the event is shifted from the flow data.
This one looks like it should count, except there is the tiniest bump of flow in the center. Go figure.
Pulling back to a one-minute time frame, this is a view two near apneas with one software-acknowledged apnea.
Getting closer again, here's an 11 second central with the measurable quantity in green.
Another 11 second central with the measurable quantity in green.
That's pretty much what I'm looking for in a central. So when I apply understanding that to other areas, I'm sometimes finding clumps of 'almost' apneas. I'm not really sure what all of this means, but it does show a few things. One of them is that the system is not perfect. A ten-second limit as to what counts as an apnea could miss a whole night of nine-second apneas. Some centrals show up for no apparent reason in this software. Others don't seem to be picked up. Hypopneas still somewhat elude me in terms of picking them out in a graph, even if I get the gist of a verbal definition.
That's all my musings for this time. Hope it helps somebody.
