Different machines Different AHIs

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iainza
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Different machines Different AHIs

Post by iainza » Sat Jan 21, 2023 4:25 am

I used a Devilbiss Autocube AutoPlus for a number years. The last time for a new machine I was pressure sold a Fisher Paykel Sleepstyle as a design with bluetooth on promotion. I wasnt too happy with it and so I bought myself a new DeVilbiss Autocube AutoPlus. Because it had a heated tube on the Fisher and Paykel I used it during the first winter.
What surprised me were the fantastic AHI readings I got on the F&P - between 1.7 and 2.5. In all the years of using both the earlier and more recently bought DeVilbiss my AHIs were always between 7 and 10.
I have now been testing both machines over the past weeks using the same min and max pressures and the same and the same nasal pillow mask. F&P gives a 1 -2.5 AHI and the Devilbiss 9 -10AHI. Often after using the F&P I don't wake up with full energy. Using the De Vilbiss I do wake up with full energy.
My first thought was F&P set their algorithms differently to give a positive sales pitch on its efficiency.
Could someone explain what is going on to explain this large difference?

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LSAT
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Re: Different machines Different AHIs

Post by LSAT » Sat Jan 21, 2023 10:12 am

Unless you were using both machines at exactly the same time there is not a valid comparison.

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iainza
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Re: Different machines Different AHIs

Post by iainza » Mon Jan 23, 2023 1:38 am

No. I used each machine separately on different nights within same week.

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ozij
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Re: Different machines Different AHIs

Post by ozij » Mon Jan 23, 2023 7:12 am

You seem to be comparing trends - which I do consider a basically valid comparison.
You'd have to find out the descriptions of both algorithm to find out how they differ.

I don't think the makers intend to "miscount" the events in order to raise sale. Note that you yourself report sleeping better / feeling better with the machine that reports higher AHI for you.

Some of us benefit more from some algorithms than from others.

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jas32
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Re: Different machines Different AHIs

Post by jas32 » Wed Jan 25, 2023 4:36 pm

Not surprised about you're seeing different AHI numbers, after all they are different machines. Sorry I cannot offer an analysis just my own experience.

I've used a Philips DS1 and a ResMed AS10 this past year and found the Philips to consistently show 50-100% higher AHI, with machine settings as comparable as possible (e.g. 2 for ResMed vs 3-4 for Philips). I've also seen the same difference when using my recently received DS2. Most important is that I generally feel the same after using either machine.

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ChicagoGranny
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Re: Different machines Different AHIs

Post by ChicagoGranny » Wed Jan 25, 2023 5:05 pm

iainza wrote:
Sat Jan 21, 2023 4:25 am
In all the years of using both the earlier and more recently bought DeVilbiss my AHIs were always between 7 and 10.
Goodness gracious! These are considered unacceptably high numbers. In hindsight, you should have joined here and found out what was going on ----> Could the settings have been changed to get lower AHIs? Or were the events primarily SWJ caused by other factors than sleep apnea? Etc.

If you want to optimize your therapy now, read some of the educational posts (The first three announcements at the top of the index page for sure.) and then ask again for help in this same thread.