Hertzgog wrote:
My concern now is the number of Central Apneas... could this be brought on by the CPAP itself? How can I lower that number?
While centrals can be brought on by the cpap itself even if this were the case your central index is not even close to being alarming. I don't know that you can do anything about the centrals. We all can have them at various times in the night and they are entirely normal. I have composed an explanation about "centrals" or clear airway events that may help explain things and save my fingers from typing again. Probably goes into more detail than you want but will offer it anyway.
If your central index is pretty much like this report then you have nothing to worry about. In theory if brought on by cpap itself than a reduction in pressure might reduce them but I don't see the need in this case. Though your obstructive component of your AHI seems to be well controlled....up to you if you want to discuss this with your doctor. I doubt it would change the centrals significantly but you do appear to have some wiggle room with your pressure needs because the obstructive hourly index is quite low.
A quick word about "centrals" or "clear airway" events...these are cessation of breathing while the airway is open as flagged by the machine. They may or may not be "true" centrals that warrants concern if we saw a lot of them (and it takes more than a central index of 2.0 to cause concern). Centrals are common at sleep onset and sometimes we even hold our breath (that is open airway cessation of breathing) when turning over in bed and don't know it. The machine only has one dimension to work with when sensing and recording open airway cessation of breathing and that is air flow only. In a sleep lab setting the tech has EEG leads to determine sleep stage and thoracic belts to measure thoracic effort. Some of what our machines report would likely be tossed out the window in a sleep lab setting.
People seem to panic when they see "central" apneas but unless there are a large number of them and presenting with associated desats and can't be blamed on sleep onset or whatever...we have to sort of put them aside and try not to worry about them.
We don't treat centrals with an increase in cpap pressure except in those high level machines that are working sort of like ventilators (another story I won't go into now since it is not needed).
So when evaluating your AHI....and how well things are responding to pressure you need to remove any central index from the equation because we don't try to fix them with cpap machines with an increase in pressure anyway.
The AHI has 3 components..
Central index which is NOT an obstructive component because there is no collapse of the airway to cause an obstruction.
Obstructive Apnea Index...this is an obstructive component because there is either a full or partial collapse of the airway causing the measured reduction in air flow to meet the obstructive apnea definition.
Hyponea Index...these is an obstructive component because there is likely a partial collapse of the airway resulting in the measured reduction in flow to meet hyponea definition.
So when evaluating your night by looking at the AHI....mentally remove the central index from the total and evaluate only the obstructive component index. In your case removing the central index significantly lowers the AHI to obstructive components only and well withing acceptable limits and thus no need for any changes to be made (like a pressure change).
What would we do if the central index was higher than we want? We would first look at the actual reports and the event graphs to see when the centrals were being flagged. If in a cluster at sleep onset..do nothing. If in clusters associated with awakenings..do nothing. I once saw a report where the guy had a central index of 10.0...one might think holy crap...he has central sleep apnea or complex sleep apnea (mix of obstructive and central) but when looking at his reports in detail the centrals were all in huge clusters at sleep onset or in the middle of the night when he was waking up and tossing and turning for an hour or more trying to go back to sleep.
All he did was stop the laying in bed tossing and turning for a few nights and the central index plummeted to less than 1. Once we realized that these "centrals" were awake centrals or semi awake sleep onset centrals that were no cause for alarm he could go back to his normal routine of tossing and turning if he wished because we knew that was the cause of the large number of centrals and not some scary diagnosis.
What do we do if we can't explain away large numbers of centrals? That is a question for another time but we look at a lot of things including history and we suggest that their doctor be alerted for sure.
I may have to RISE but I refuse to SHINE.