AHI has dropped

This isn't really a big concern to me; just a curiosity. I've been on my BiPAP Auto SV for about 30 months now. Once I was settled in to using it I would have AHI readings on my data card of about 2.5 to 3. Over a 6 month period my average rose from about 2.8 to about 3.8, so my doctor adjusted my pressure upward, changing the EPAP from 10 to 12. For the past 10-12 months my AHI was about 3. I would have a rather large cluster of events in my first 45 minutes of sleep. I never really worried about this since my sleep study AHI was 46 and I knew that 3 was workable. It's curious to me that over the past 3 or 4 months my AHI has fallen from 3 to 1. I don't have these clusters of events lately. There have been no changes to any machine settings.

As I said, I'm not complaining. I'm just curious why these numbers would drop off so significantly. Any ideas?

Thanks,
Tony

Are your events mostly obstructive or clear airway or hypopneas? On my ASV I have mostly hypopneas. But I would love to have an AHI as low as 3. Good Luck finding your answer. I'm too new at this to even guess!

I am on auto cpap not BIPAP. My AHI has dropped to <1 each night and some nights is recorded at zero. I started cpap in July 2011 and I have noticed a very gradual decrease in AHI over these months. Seems for me, it is a "settling in" effect. I think now that the external and internal factors are under control, the therapy is doing it's job and I think there may be some cumulative positive effects of therapy when you are able to stick with it.

teknomom wrote:Are your events mostly obstructive or clear airway or hypopneas? On my ASV I have mostly hypopneas. But I would love to have an AHI as low as 3. Good Luck finding your answer. I'm too new at this to even guess!

There are typically more hypopneas than apneas. Lately a typical 7 hour sleep session will show a single apnea somewhere and 2 or 3 hypos scattered throughout the night.