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AHI help
#1
AHI help
So, I'm only a few weeks into this odyssey, and I finally figured out last night by pushing the machine buttons right and left --- how to find the AHI number. If I understand correctly, the AHI is the number of non- or low-breathing events per hour?

During my sleep study, my number was 33. Last night and the night before my AHI was 16 and 15. Those two nights, incidentally, were the first two nights I have slept completely through the night with the mask; no waking up and no getting up for the bathroom.

So, it sounds better ... but not by much. What are these numbers telling me? Should I be increasing the air pressure?

Thanks for any help with this.
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#2
RE: AHI help
You should be looking at why you are at 15 by using software.
That will tell you:
What type of events?
How long are the events?
Are they clustered?
What does the machine do in response?
What are your min, mean, 95th percentile, and max pressures running?

Information is power. AHI does not tell the whole story.
Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#3
RE: AHI help
(07-23-2014, 08:57 AM)Clementine Wrote: If I understand correctly, the AHI is the number of non- or low-breathing events per hour?
Yes, that's correct.

Quote:Last night and the night before my AHI was 16 and 15.
...
So, it sounds better ... but not by much. What are these numbers telling me? Should I be increasing the air pressure?
Without a lot more information, it's impossible to make a blanket recommendation about whether you need to increase the pressure or not.

What is the breakdown of events by type?

When are the events occurring?

And are the leaks under control?


Answers to all of those questions are needed before you can answer the question: Should I be increasing the air pressure?

Questions about SleepyHead?  
See my Guide to SleepyHead
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#4
RE: AHI help
okay -- I'm not using software, so that's the next step, I take it. My hubby will have to help me with getting that all into place; I'm a Computer Idjit.
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#5
RE: AHI help
Okay --- I think I have the software in place. I think. Here's what came up. I hope this is clear to someone. It doesn't look good to me. Keep in mind that I have only completed two nights of wearing the mask the whole night (the last two nights). I hope someone can look at this and help me to understand it.

CPAP Statistics
16 days of CPAP Data, between Mon Jul 7 2014 and Tue Jul 22 2014
Details Most Recent Last Week Last 30 Days Last 6 Months Last Year
CPAP Usage
Average Hours per Night 08:16 06:15 04:40 04:40 04:40
Compliance 100% 100% 69% 69% 69%
Therapy Efficiacy
AHI 14.98 10.90 10.58 10.58 10.58
Obstructive Apnea Index 12.44 9.07 8.80 8.80 8.80
Hypopnea Index 0.48 0.23 0.16 0.16 0.16
Clear Airway Apnea Index 1.93 1.58 1.57 1.57 1.57
Leak Statistics
Average Leak Rate 1.22 0.67 0.71 0.71 0.71
90% Leak Rate 2.40 2.40 2.40 2.40 2.40
% of time above Leak Rate threshold 0.31% 0.06% 0.03% 0.03% 0.03%
Pressure Statistics
Average IPAP 10.00 9.99 9.93 9.93 9.93
90% IPAP 10.00 10.00 10.00 10.00 10.00
Min IPAP 9.16 9.14 9.02 9.02 9.02
Max IPAP 10.00 10.00 10.00 10.00 10.00
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#6
RE: AHI help
Actually that doesn't look all that bad. It does suggest you are bumping up against the max pressure most of the time. So that would suggest a pressure increase would be beneficial. If it were my machine, I'd probably increase both the minimum and the maximum a small/modest amount. Say to about 6/12. That sort of thing.

Wait until Robysue comes back around. She may see something I'm missing.
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#7
RE: AHI help
Okay, I will wait and see what RobySue says ...
I also will give my DME a call and talk with them at some point.

I am wondering what the clear airway apnea means --- clearing my throat? Or is that more like the central apnea/brain thing?
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#8
RE: AHI help
CA is the brain thing. Sometimes it'll increase a little when you first start doing something new, or increasing your pressure, or whatever. But with your numbers it is not a concern at this point. It's also often reported by the machine erroneously. I had a couple last night that definitely coincided with the puppy licking my face causing me to eject the mask.
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#9
RE: AHI help
Clear airway apnea is often referred to as a Central Apnea. Your machine sends out a pressure wave, after 4 seconds of no flow, and looks at the reflection in the flow data. ResMed calls it their FOT algorithm. It scores the apnea as obstructive or central.

You posted summary data, graphic data would be better.

It does appear that you are running up against the max pressure.
Maybe a pressure increase is called for; however, pressure induced central apneas may containdicate that.

More data please!
Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#10
RE: AHI help
Clemintine,

The lines of data that stand out are:

(07-23-2014, 11:07 AM)Clementine Wrote: Most Recent Last Week Last 30 Days Last 6 Months Last Year
AHI 14.98 10.90 10.58 10.58 10.58
Obstructive Apnea Index 12.44 9.07 8.80 8.80 8.80
Hypopnea Index 0.48 0.23 0.16 0.16 0.16
Clear Airway Apnea Index 1.93 1.58 1.57 1.57 1.57
Leak Statistics
Average Leak Rate 1.22 0.67 0.71 0.71 0.71
90% Leak Rate 2.40 2.40 2.40 2.40 2.40
% of time above Leak Rate threshold 0.31% 0.06% 0.03% 0.03% 0.03%
Your leaks are under control. So you don't need to worry about that.

But your AHI is still WAY too high. The goal of PAP is to get the total AHI < 5.0 consistently night after night. Your AHI last night is almost 3 times too high and the longer term AHI's are also way too high. On a diagnostic sleep test, an AHI = 14.98 = 15.0, would land you with a diagnosis of mild-to-moderate OSA.

Moreover, the thing that is making your AHI way too high is your Obstructive Apnea Index (OAI). Your OAI is still WAY too high at 12.44 (last night) and 8.80 for the whole time you've used the machine. This indicates that your airway is still completely collapsing way too often. And it probably means that the current pressure setting is not quite high enough to properly manage your obstructive sleep apnea.

Last night's AHI may be higher than the previous nights simply because you did sleep all night with the mask. REM sleep tends to increase as the night goes on, and so it's not uncommon to have more events in the second half of the night. Of course, if you were sleeping without the mask for the second half of the night, your real AHI would reflect the 30+ AHI on the diagnostic sleep study.

What to do: I'd report this problem to the sleep doc if I were you. I think you are still way too new to PAP to be messing around with your therapy settings all on your own. But the sleep doc needs to know that the total AHI reported by your machine is still very high. My guess is that the sleep doc will either authorize a (slight) increase in pressure or perhaps a switch from straight CPAP to an APAP with a pressure range.


Questions about SleepyHead?  
See my Guide to SleepyHead
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