AHI, Centrals

I have a new Airsense 11, replacing the 10 I have had for about 10 years. With my old CPAP, my central apneas accounted for about half of my events. With the new machine they were close to 90%. Overall AHI stayed about the same, just below 1 event per hour. I was told to turn off EPR, and centrals should go down. Indeed, they did, but AHI went up to 3 per hour average. So, 2 questions. Can anyone explain why EPR affects the central apneas? And am I better off with lower AHI, with the high % of centrals, or the higher AHI and almost no central apneas?

First, did you use OSCAR to track your results on your A10 machine. If you did then you can just add the A11 data to your old A10 results. That would be the best way to see what has happened. If you did not use OSCAR and still have the SD card from that machine you can load the A10 data in first and then update it with the A11.

With respect to your A11 was it set up exactly the same as the A10? If not what was changed. I cannot think of any reason if the setup was the same that the results would significantly change. A while back my wife switched from the S9 to the A10. I used exactly the same settings and 0.57 down to 0.53, and insignificant difference. Since that time I increased her EPR from 2 cm to 3 cm, and AHI has dropped to 0.49.

I have not seen any clear evidence that EPR increases CA events in my experience. What I have seen is that it can make a big reduction in hypopnea events. I went for a long time with EPR set for ramp only and was off during the rest of the sleep. My AHI was about 2.1 and CA events was the large portion of the total events. Then I switched to full time EPR and my AHI immediately dropped to about 0.8. The reduction was almost entirely hypopnea. And CA events did not change.

My experience is that CA events can be caused by higher pressure, and my strategy to deal with them is to keep pressure as low as possible and I have switched to a fixed CPAP pressure. Since EPR reduces pressure it really should not cause more CA. But EPR can affect everyone differently.

If the increase in your AHI is largely due to hypopnea events I do not think they are as serious as OA and CA events because it is a flow reduction not a full stoppage. However, I think I would go with the total AHI number and use the settings that give the lowest AHI.

In any case I would encourage you to use OSCAR if you are not. It would clearly show what happened. It is a free download but requires a SD card reader and PC or Mac.

OSCAR CPAP Monitoring Software

Thank you. I was puzzled when my clinician said EPR could affect CAs. My thinking, perhaps wrong, is breathing happens, and machine tracks that, and that the appropriate pressure just keeps the air flowing. Changing EPR now.

Not using OSCAR because I have no computer, just iPad.