Auto M series question

jnorris · Post by **jnorris** » Thu Jun 26, 2008 2:29 pm

Does an Auto M series with A-Flex use the same algorithms to determine sleep events when it is used in CPAP mode as it does when it is in APAP mode?

When using the Auto M series in APAP mode what is the minimum difference between the low pressure setting and the high pressure setting?

Thanks

John

Guest · Post by **Guest** » Thu Jun 26, 2008 2:41 pm

There is no algorithym in CPAP mode!
2 cm of difference.

jnorris · Post by **jnorris** » Thu Jun 26, 2008 2:55 pm

[quote="Anonymous"]There is no algorithym in CPAP mode!
2 cm of difference.

Wulfman · Post by **Wulfman** » Thu Jun 26, 2008 8:00 pm

jnorris wrote:
Anonymous wrote:There is no algorithym in CPAP mode!
2 cm of difference.

Then how does it count the AHI and SI events that Encore reports on?

The "algorithm" in an Auto actually tells the program what to do with the machine's pressure when it detects events......while the CPAP machine (or mode) only records the events as they take place.

Den

Guest · Post by **Guest** » Fri Jun 27, 2008 6:42 am

Thanks for the feedback. I understand the functional differences between the APAP and the CPAP.
I will rephrase my question.

Does an Auto M series operating in APAP mode identify sleep events differently than when it is operating in CPAP mode? Does it use different criteria to peg an apnea event or does it use the same criteria but only acts on it in APAP mode?

I ask because my AHI components are always higher when I use the machine in APAP mode with a range of 8-10 than when operating in CPAP mode with a constant pressure of 9. My 90% pressure is 9.

Thanks

DreamStalker · Post by **DreamStalker** » Fri Jun 27, 2008 7:06 am

Both modes use same criteria to peg an apnea event.

In any case, one reason for seeing higher AHI components in APAP compared to CPAP is that you are starting out at 8 cm when your 90% value of 9 cm is what takes care of most of your events. That period while your APAP is at 8 cm allows a few extra events to slip by before the APAP has a chance to ramp up to required pressure.

Are you using exhalation relief? If you are, that may also have an effect too.

Try setting your min APAP pressure to 90% (9 cm) ... if you use exhalation relief, add another cm for each unit of exhalation relief that you are using to both min and max pressure settings.

About only reasons to use less than 90% for APAP min pressure is if you are trying to mitigate aerophagia (stomach gas) or if you sleep mostly on your side but want that extra security of using APAP in case you roll over on your back for a prolonged period of time.

jnorris · Post by **jnorris** » Fri Jun 27, 2008 7:37 am

Good information DreamStalker.

I am a back sleeper and I have no problems XPAP induced stomach gas problems.

I currently have exhalation relief set at 3 and APAP set at 8-10 cm. I will try APAP at 9-11 cm for a while and see how it works.

Thanks

John

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