Max Ipap/epap values reached but no AHI's recorded

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
ittiandro
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Max Ipap/epap values reached but no AHI's recorded

Post by ittiandro » Wed Sep 21, 2022 8:57 am

The Ipap/Epap pressure values go up and down through the night, which is normal. THey reach periodically the max set values ( in my case 14-18), but when they do there are no AHI's recorded on the graph on the corresponding timeline. I am just curious. Normally I would expect pressure peaking when the machine senses a decrease in the air flow due to a narrowing or obstruction of the airway . In other words, I would expect to see either an H or a an OA in the the event flag graphic. Does it mean that the machine did sense a decrease ( or an obstruction) in the air flow, but the pressure increase restored the air flow too quickly for an AHI to be recorded?

Thanks

Ittiandro

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Pugsy
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Re: Max Ipap/epap values reached but no AHI's recorded

Post by Pugsy » Wed Sep 21, 2022 9:08 am

These auto adjusting machines will also increase the pressure when it senses flow limitations and/or snoring.
It's not just about the OAs and hyponeas.
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robysue1
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Re: Max Ipap/epap values reached but no AHI's recorded

Post by robysue1 » Wed Sep 21, 2022 9:32 am

And it's worth adding to Pugsy's reply:

The reason the auto machines respond to flow limitations and snoring is to prevent apneas and hypopneas from happening in the first place. Flow limitations and snoring both indicate the airway is in some danger of collapsing, so the machine increases the pressure in order to make it more difficult for the airway to collapse and cause an apena or hypopnea event to occur.

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ittiandro
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Re: Max Ipap/epap values reached but no AHI's recorded

Post by ittiandro » Wed Sep 21, 2022 12:20 pm

Pugsy wrote:
Wed Sep 21, 2022 9:08 am
These auto adjusting machines will also increase the pressure when it senses flow limitations and/or snoring.
It's not just about the OAs and hyponeas.
Thanks

You are absolutely right. Looking at the graphs, I see that these pressure spikes correspond to snoring and/or FL events of about 0.30, Usually my FL readings are about 0.10-0.15, though, but this doesn't bother me, as long as my AHI's keep in the 0.30-0.80 range, as they usually do.
Also, I guess that I can't get yhe FL down to 0 because my upper airway, the doctor found, is narrower than the average person, which impedes a fuller flow of air.
I don't feel it, because I'm physically active and I run, but the machine picks it up when asleep.

My doctore had originally set the pressure settings to 8-15 cmH2O . My AHI's had already dramatically decreased to well under 5 since I started the CPAP therapytwo years ago, but I wanted to see if I could bring them further down, by increasung the min EPAP setting from 8 to around 14., while keeping the IPAP setting to around 18.
It worked, because the AHI's consistently dropped to under 1, keeping at an average of approximately 0.60, sometimes even 0, albeit rarely.

Ittiandro

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ChicagoGranny
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Re: Max Ipap/epap values reached but no AHI's recorded

Post by ChicagoGranny » Wed Sep 21, 2022 1:52 pm

ittiandro wrote:
Wed Sep 21, 2022 12:20 pm
my upper airway, the doctor found, is narrower than the average person
All of us are here because of that.