How to reduce AHI? (New user)

[Dan9463]

I started on APAP about 6 weeks ago.  Tried ResMed nasal and facial masks but had trouble getting comfortable night's sleep.  Bleep Dreamports worked better, and for the past couple of weeks I have been using Bleep Halos.  Both of the Bleep systems seem to work better for me than the headgear masks.

The attached data from last night is fairly typical for what I've been experiencing over the past couple of weeks.  AHI is typically between 4 and 5.  I know less than 5 is OK, but I'm wondering if there are changes I could or should make to reduce AHI further.  (EPR is set to 3).
 
In general during the past couple of weeks the majority of event flags seem to be CA, and the frequency is typically increased in the 3 am to 5 am period.  Sometimes I am awake during that time, but lying in bed.

Is there a good strategy to try to figure out what is likely causing the CAs?  Are they most likely due to positional changes? 
Last night I believe I was awake during the 4am to 5 am period, which is when there was a cluster of CA.  In retrospect I don't think I was very restless or active while lying in bed during this time, so I was surprised to see the cluster of events.  And there's also a cluster of OAs during that period.  I'm surprised there would be trouble with OA while lying awake.

Any suggestions for improvements? 
Thank you

[SarcasticDave94]

The Central Apnea/CA issue can be 1 of 2 things. The common first, CA are fundamentally a breath pause. To be flagged, the pause is 10 plus seconds. The most common cause of CA will be the CPAP usage itself. Remember, it's foreign to your respiratory system, it's got a slight pressure which will cause more CO2 to be exhaled then your brain has been programmed to accept as your "normal". To compensate, your breath trigger is suppressed/paused.

To help this type CA, some need to minimize pressure swings, like EPR and/or the Min Max pressure separation. Ramp also can disrupt things and add another area for pressure swings.

The second less common CA source, predominant Central Apnea which shows in the diagnostic sleep study/PSG. This Central Apnea, if existing as roughly half the total events might indicate need to get a specialized bilevel called ASV. It's not a universal machine. Note, some CA can be avoided in VAuto via the Trigger setting to High or Very High. If the case is more difficult, only ASV helps.

[Dan9463]

Thank you for this information.
So, it sounds like it might be worthwhile for me change the EPR from 3 to 2 and see what happens? (Ramp is off).

[SarcasticDave94]

Yes, you can trial a lower EPR. Watch the OSCAR chart events. Ask "did CA reduce?" Yes, OK great. Run this for a week or so. Then trial the higher EPR a night. See if CA return. Because the thought is eventually your brain reprograms itself on breathing with CPAP. Then that lowers the probability of this treatment emergent Central Apnea.

BTW any CA are consistently inconsistent. They'll be up, down, absent then suddenly returning. But treatment emergent CA should mostly reduce with time on CPAP.