Question about APAP therapy

Flyboy · Post by **Flyboy** » Mon Apr 10, 2006 8:56 am

Good day all!

I just completed my third night on a REMSTAR Auto w/CFlex after several months on a straight CPAP. I have been looking at my data on Encore /My Encore software. My doc put me on an autopap due to wildly fluctuating AHIs from night to night and thought I would benefit from the auto's algorithm.

My question is how to interpret the data and perhaps I don't understand precisely how the machine works. Should the machine be preventing obstructive apnea and hypopnea events entirely, or do they still register as ticks on the reports, but the machine "deals" with them quickly by cranking up the pressure? It seems like I am having just as many events on auto as on straight CPAP. Is there other info I should be looking at?

Auto is set 7-18 with CFlex of 3. Very comfortable therapy.

Ric · Post by **Ric** » Mon Apr 10, 2006 10:10 am

The concept of the "AUTO" is that the pressures are normally lower than necessary to actually "pre-empt" all OA/HI events. Rather, the machine diligently monitors for these events and quickly (and gently) increases the pressure to open the airway such that the OA/HI events are of no consequence "clinically". You will find the tick marks reporting the events, and the data will show the pressure has increased to compensate for the obstructed airway. With the AUTO, the important thing to watch is the detailed report (EncorePro) where it tabulates the "Non-Responsive Apnea/Hypopnea" events. Even some of those tend to be "centrals", which don't bother some people.

Also, if you have Derek's "MyEncore", you can see the "Average Apnea Duration" both on the dailey report and a detailed graph. Most people can hold their breath for, say, 10-15 seconds without consequence. That is about how fast the machine will respond and compensate.

If the upper limit on the AUTO is set too low, then that might become a problem. If the lower limit is set too high, one is not realizing the benefits of having lower operating pressures for "most" of the time.

Flyboy · Post by **Flyboy** » Mon Apr 10, 2006 10:16 am

Ah-ha! Thanks Ric for your explanation. So since I am showing zero non-responsive events and my average duration is about 10 sec (and my total apnea time is lower) I can safely assume that it is doing its job.

Am I correct in my understanding then that the AHI calculated by Encore Pro software is not a very useful measurement for therapy with an auto?

Guest · Post by **Guest** » Mon Apr 10, 2006 10:21 am

Flyboy wrote:Am I correct in my understanding then that the AHI calculated by Encore Pro software is not a very useful measurement for therapy with an auto?

No. The AHI is very useful. You're shooting for an AHI under 5.0 in order to consider your apnea successfully treated.

Flyboy · Post by **Flyboy** » Mon Apr 10, 2006 11:12 am

Guest,

I am confused. I can see that if I was at a titrated CPAP pressure calculated to prevent most apneas from occurring that AHI would matter. but, if the auto doesn't respond with higher pressures until it detects (and software counts toward the AHI) an apnea event occurring, how would my AHI get lower? I thought the software reflects all the detected events and the auto deals with them before they cause disruption in the sleep cycle....

Ric · Post by **Ric** » Mon Apr 10, 2006 11:36 am

Flyboy wrote:I am confused. I can see that if I was at a titrated CPAP pressure calculated to prevent most apneas from occurring that AHI would matter. but, if the auto doesn't respond with higher pressures until it detects (and software counts toward the AHI) an apnea event occurring, how would my AHI get lower? I thought the software reflects all the detected events and the auto deals with them before they cause disruption in the sleep cycle....

Here is a partial answer, If you look at the EncorePro detailed report, you will notice that the pressure rises almost simultaneously with one of the"events". Notice also that it STAYS PUT for quite a while before it starts to "experiment" with dropping your pressure. During that elevated pressure indeed it is "preventing" OA/HI events, and effectively lowering your AHI.

Ric · Post by **Ric** » Mon Apr 10, 2006 11:42 am

Question for you, I will be interested to know if the APAP vs CPAP was of benefit for the issues you described, and if the AHI is indeed lowered. Check back in a few weeks and let us know. I too am still in learning mode about this.

Goofproof · Post by **Goofproof** » Mon Apr 10, 2006 11:49 am

Also what was your AHI on CPAP and what pressure was it running? Also what is you AHI on the Auto and what is your 90% rate. Jim

Guest · Post by **Guest** » Mon Apr 10, 2006 1:18 pm

RIC: My AHI on the auto has been about 2-5 which is better than my results on the CPAP. Not very many data points yet and I will be back in a couple of weeks to report on the progress. I just wanted to make sure I wasn't comparing apples and oranges. Thanks for the info!

Goofproof: My titrated pressure was 10 and the AHI varied from 0 to 7.8 over four weeks (using RemStar Pro 2 w/CFlex of 3). My sleep quality varied in direct relationship to the AHIs. My 90% rate on the auto has been 10-11 over the last few nights.

Goofproof · Post by **Goofproof** » Mon Apr 10, 2006 7:02 pm

Based on those reading I would rein the APAP in a little say a low of 8 and a high of 13 cm. Under those settings the machine should take even better control, less time to respond to your needs. Jim

Guest · Post by **Guest** » Tue Apr 11, 2006 5:45 am

GP: I'll give it a go tonight--makes sense, thanks!

Flyboy · Post by **Flyboy** » Wed Apr 12, 2006 7:35 am

Oops--just noticed I "guested" on my previous two posts...

Last night I tightened up the range on the auto, but I must have had an active night since my mask leaks were really high. Sure wish I could find a FF mask that will stay sealed. Tried Mirage and FP.

rested gal · Post by **rested gal** » Wed Apr 12, 2006 11:21 am

Flyboy wrote:but, if the auto doesn't respond with higher pressures until it detects (and software counts toward the AHI) an apnea event occurring, how would my AHI get lower?

Flyboy, I don't think autopaps are designed to wait for an apnea to actually occur. The auto senses subtle changes in the airflow. As I understand it, ideally the autopap responds to those small, subtle changes before the situation escalates into an "event" worthy of noting with a tick mark on the software charts. When the autopap does its job effectively, there should be very few events marked, resulting in a very low AHI. Preferably an AHI of less than 5.0

The events (apneas, hypopneas, limited flow) that do appear in the software data are events that sneaked through despite the proactive efforts of the machine to prevent them.

I thought the software reflects all the detected events and the auto deals with them before they cause disruption in the sleep cycle....

I may be wrong, but I think the auto responds to subtle changes in airflow before those slight changes become bad enough to qualify as "events" (apneas, hypopneas, flow limitations.) The fewer ticks on the charts for those kinds of events, the better the autopap is doing what it's supposed to do ... preventing those kinds of events from happening.

As for the "NR" line on the software charts... I don't think the absence of "NR" tick marks is meaningful about what kind of treatment the machine is giving. For more understanding about what "NR" (non-responsive) data means, the posts by "-SWS" in this topic are very informative:

Feb 21, 2005 subject: Remstar Auto - Non-responsive events? Three page discussion of Remstar Auto flagging "NR" events.

Guest · Post by **Guest** » Wed Apr 12, 2006 12:30 pm

RG: Thanks for the info and thanks for all the great advice you have offered over more than a few posts to the board! I know you have made it much easier for me to deal with this condition.

What I'm trying to understand is why my AHI is not getting better on auto than it was on straight CPAP. My energy is still lagging.

Flyboy · Post by **Flyboy** » Wed Apr 12, 2006 12:31 pm

Gosh! Did it again--above post is from me--Flyboy.

Question about APAP therapy

Question about APAP therapy

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