Getting my AHI down

I've been on my machine for 4 weeks now. My AHI average over those 4 weeks is 5.75. At first, I was ecstatic, as that is a huge reduction from the 60 I was tested at. When I look at the graphs, I can see the on a normal night my AHI is considerably lower for much of the night, but a few episodes where it rises to 15 or 20 over a short period of time - often towards the morning - cause the average to go up.

My pressure range is set at 6-16. Last night, for instance, AHI 6.2, the pressure was running at a median of 13.02, 95% at 14.56, max at 15.16. The questions are these:

1. If I'm not maxing out at 16, would raising the top permissible pressure produce any results at all?
2. Would raising the upper pressure do anything towards reducing my AHI? I'm thinking it might respond better to the episodes where I am experiencing 15 or 20 during the night.

Thanks all.

Paul

Actually it is the minimum pressure that is the most critical pressure and not the maximum. The minimum pressure needs to be set optimally so it can do a better job preventing the collapse of the airway in the first place.

Also...when evaluating AHI for possible pressure needs you need to look at the event categories and not just the total AHI.
If your AHI is primarily obstructive in nature (Obstructive Apneas and hyponeas) then more minimum pressure might be indicated but if it is primarily Central (Clear Airway) in nature we don't/can't fix centrals with more pressure anywhere with regular cpap/apap machines.

More events in the wee hours of the morning sounds like REM stage sleep. It's common for people to have more events and/or need more pressure in REM stage sleep. It might also be supine sleeping...or a combination of supine sleeping and REM stage sleep. REM stage sleep normally starts out about 90 minutes after sleep onset and becomes longer in duration and more frequent as the night goes on with the greatest amount of REM normally occurring in those wee hours of the morning before we wake up.

Also if the minimum pressure is set more optimally often the machine won't have the need to go up near that maximum.
I see it all the time...increase the minimum pressure so the airway is held open a little better to start with and the pressure line doesn't go to maximum as often or for as long.
Auto adjusting pressure mode has its limitations and the main one is the machine can't respond quickly enough to the warning signs that the airway is trying to collapse. So while it is trying to respond...the collapse happens and the event gets scored. Using a little more minimum pressure helps keep the airway open better and gives the machine a head start on increasing when an increase is needed.
All this is if the events are obstructive in nature.
If they are mainly Central in nature we have a different discussion
So what is the event category breakdown of the AHI?

Hi Pugsy:

You are the guru of the forum! Thanks for sharing your time and knowledge.

The majority of my events are OA's and H's. Normally a few "Clear Airway's," but on some nights none at all. For example, last night reported Clear Airway - 7 events, Hypopnea - 11 events, and Obstructive Apnea - 26 events, Unspecified Apnea - 1 event. As I said, on some nights there are no Clear Airway events at all. Obstructive Apnea is always by far the largest category.

Raising the minimum pressure sounds logical, the way you have described it. I think I will leave it for two weeks, anyway, until I have visited my respirologist. That will be the first time I will see him since starting on the machine.

Regards,

Paul

Sounds like a good plan. No rush or urgent need to go changing things at the moment. Your doc may even suggest it if he looks at the data.
I happen to have the REM sleep makes OSA worse thing myself. I would see little clusters of events within a time frame that REM is likely to happen...plus on my sleep study it was documented much worse in REM sleep like 53 per hour vs 12 per hour in Non REM sleep. I would have parts of the night where nothing was flagged and then little clusters of OAs...then nothing....then another cluster. The machine would try to get up there (you can watch the increasing pressure) but it just couldn't get there soon enough. Once I increased the pressure a little the clusters were broken up and the pressure itself wasn't nearly as erratic. Most of the time it doesn't take much to break up those little clusters anyway. 1 to 2 cm increase in the minimum will usually get the job done if the AHI is in the single digits like yours is.

You can see the hypnogram here to get an idea when REM sleep normally occurs.
http://en.wikipedia.org/wiki/Sleep
just scroll down the page a little and it is on the right side.