(04-11-2012, 04:47 PM)shutterbug sue Wrote: Good to know. I got the feeling she was just giving me a very short answer to get rid of me. What is a clear airway then if it's not a central apnea? How can you tell if you are having central apneas from the S9 readings in the SleepyHead software? How are central apneas treated?
I don't think she was being insincere. Here's the thing. When you stop breathing, that's an apnea. The machine then sends a pressure pulse to try to determine if your airway is obstructed. If it is obstructed, it counts it as an obstructive apnea (OA). If the airway is not obstructed, then it counts it as a CA. What's a CA?
It could be a true central apnea, or it could be just a clear-airway apnea. (You'd need the gear they use in a sleep study -- e.g. a chest belt to show no effort to breathe -- to tell for sure if it's a true central apnea).
The point here is that it probably doesn't matter for a patient who was diagnosed with obstructive sleep apnea. If the machine shows too many OA's, and the pressure can be raised to reduce that number, we conclude that raising the pressure reduces the number of OA's.
Likewise, if the machine shows too many CA's, and the pressure can be lowered to reduce that number, we conclude that lowering the pressure reduces the number of CA's.
Who cares what you call them?! They are periods of time where you're not breathing while asleep. Lowering the pressure reduces the number of those events that you experience.
So, I think the techs just use the jargon. They say too high of a pressure induces centrals, because they know that in many patients reducing the pressure reduces the number of centrals recorded by the machine.
What do they mean by a central? It's the thing recorded by the machine, called a CA. Resmed calls a CA a central apnea, Respironics calls a CA a clear-airway apnea.
A rose by any other name smells as sweet. Lowering the pressure reduces, in many patients with OSA, the number of CA events. A reduction in the number of CA's, by any other name, feels as sweet.
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