High AHI on APAP?

Hi all,

I'm a 30 y/o who has been on APAP for about a year now, and CPAP for 5+ years before this. I'm healthy, normal weight (170 pounds, 6' tall) and have a non-snoring sleep apnea (likely due to my cleft palate repair). My AHI at my first sleep study was 2.5 on on my stomach and 15 on my back. My doctor prescribed cpap at 8cm H20 and this left me with an AHI consistently above 5.

After several years we switched to APAP and my current setting is 5-11 cmH20. I have a F&P Icon+ Auto. My problem is that I'm still waking up many times a night. My leak rate is low, my 90th percentile pressure is low (typically ~ 8cmH20), and I'm still having many hypopneas (5-8 per hour).

How can I eliminate hypopneas if my machine isn't increasing to the maximum range? I'm chronically fatigued but definitely compliant. I'm thinking I might have UARS or something...

5 is pretty low for the lower pressure - have you tried raising it by a few cms?

Have you also succeeded in staying off your back all night by wearing a backpk, or using foam wedges behind you, or ??

Have you gained any weight lately?

Do you use Sleepyhead software to see what's going on overnight?

Are you on any meds?

No weight gain, no meds, no alcohol even. I do use sleepyhead and it shows almost no events for the first several hours, and then huge clusters of hypopneas after that. My apneas are limited to one or two per night. My biggest concern is why my pressure doesn't increase to eliminate hypopneas. If my 90th percentile pressure was up near 10 or 11 I would definitely increase the range.

Can you post the graphs on Imgur.com and leave a link to them here? We can't comment well without getting a look.

Your lower pressure should be closer to 8. An APAP doesn't chase events like people think it does. It should have a minimum close to where it is needed to prevent events.

buddy88 wrote:I do use sleepyhead and it shows almost no events for the first several hours, and then huge clusters of hypopneas after that. My apneas are limited to one or two per night. My biggest concern is why my pressure doesn't increase to eliminate hypopneas. If my 90th percentile pressure was up near 10 or 11 I would definitely increase the range.

Your machine does NOT increase the pressure for each and every event that it scores. Typically APAPs will only increase the pressure if two or more events occur within 2 minutes or so of each other. If the events are spaced further apart than that, there won't be a pressure increase because of the events.

Your min pressure is set to 5 your max pressure is set to 11, but your 90th percentile pressure is around 8. You also say that you have "huge clusters" of Hypopneas are occuring.

Without seeing the actual data, it's hard to say exactly what is going on. My own speculation is that one of the following is happening:

• Once the pressure reaches 8cm, the "clusters" of Hs break up enough to the point where the remaining Hs are occuring at least 2 minutes apart, and that prevents the machine from increasing the pressure ant further.
• The clusters actually do clear up by the time the pressure reaches 8cm, but they're thickly clustered while the machine is increasing the pressure from 5 to 8.

Without seeing the data, it's impossible for us to tell you which of these two scenarios best describes what is happening to you. But in either case, raising the minimum pressure from 5cm to 7 or 8 cm is a reasonable thing to consider. Leave the max pressure at 11 for the time being.

buddy88 wrote:No weight gain, no meds, no alcohol even. I do use sleepyhead and it shows almost no events for the first several hours, and then huge clusters of hypopneas after that. My apneas are limited to one or two per night. My biggest concern is why my pressure doesn't increase to eliminate hypopneas. If my 90th percentile pressure was up near 10 or 11 I would definitely increase the range.

APAPs primarily increase pressures on Flow Limitations and/or Snores.
You're having the same problem with the range of pressures that I had......and consequently found that I did better with straight pressure (although at a somewhat higher pressure). I also found that the pressure changes disturbed my sleep.

When using ranges of pressures, the minimum pressure is the most important. It needs to be set where it eliminates the vast majority of events.

I would also suggest filling in your profile with the exact equipment and settings you're using.


Den

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Thank you guys SO much. I didn't appreciate the significance of the minimum pressure. I'm having trouble with getting decent pics, but I think I have enough to go on. If I have to post again I'll make sure I have pics beforehand.

Thanks!

I'm dubious about how good the F&P Icon Auto is.

It was my first machine and no matter what I did I couldn't get my AHI much under 10. After researching on this forum I convinced my DME to change to a Resmed S9. The improvement was instantaneous. I guess that the algorithm used by F&P just didn't work for me but the Resmed certainly has. I also notice very few folks on this board use an F&P. So maybe try a different machine and see what happens.