Suggestions for lowering my AHI?

[Rabid1]

Am I missing something?

Actually, yes. The lower pressures show fewer apneas because slepr doesn't have constant apnea while sleeping. The APAP doesn't raise pressure until it senses a need for higher pressure. It isn't unusual for an APAP to dwell at a low pressure for hours at a time for some of us. That doesn't happen for everyone, of course, but I see it in my own data all the time, and I presume that's what is happening with slepr.

Based only on the data presented so far, the sweet spot for slepr is indeed around 9 cm and, based on existing data, it looks like he should be able to achieve an overall AHI under 5.0. But, if I were slepr I'd continue to collect data in APAP mode for a while yet. Might want to bring the low end up a little. Also, I'd be suspicious of the apneas showing up at the highest pressure. Those could be centrals. It might be that slepr will need to restrict the upper range to avoid them.

Just my gender biased $0.02 of chart interpretation.

Regards,
Bill

[NightHawkeye]

Rabid1, I spend more than 50% of my time at a pressure of 5 cm. That happens because I am primarily prone to apnea during REM sleep. The rest of the time my airway simply stays open without the need for CPAP. However, when I'm in REM, my airway tends to close and APAP pressure climbs to the needed pressure which is usually around 10 cm.

What I'm saying is that slepr is displaying a pattern which looks very similar to my own. In fact, it is a quite common pattern for apnea. You can search prior posts and find quite a few charts showing this pattern. To be sure, it may not be the most common pattern for apnea, but it is a common pattern.

Just trying to provide a little info, Rabid1. However, I'll agree with you that the data doesn't rule out that 6 cm might be the optimal solution for slepr. It does seem unlikely though, especially given the sharp dip which occurs around 9 cm.

Again, just my gender biased $0.02.

Regards,
Bill

[Snoredog]

The answer "should be" is in your AHI vs. Pressure report. You always want the pressure that puts things on a downward trend, not an upward trend.

But in this case that Report can sometimes be misleading IF (notice I said IF) you have placed a ceiling limit on pressure. In your case you have limited the Maximum pressure to 9.5cm. You should only have to do that if you are at risk of central apnea as seen on your PSG.

As mentioned, 9cm seems to be your ideal pressure (based upon the AHI vs Pressure report). BUT now that I see you have imposed a Maximum ceiling pressure, that report can be misleading and unreliable.

So I look at your Summary Daily Report, and the 90% pressure found. Everything is dumped under 10cm column because you set the limit to 9.5cm. Notice that report only increments by 1cm? There is no 9.5cm column so it dumps everything from 9.0cm to 10cm under that column.

-Your OA indice is too HIGH.
-Your HI indice is excellent.

So my suggestion:

1. Increase the Maximum pressure Limit to 11cm.
2. No change needed to your Minimum pressure setting.
3. Keep an eye on OA indice as Maximum pressure increases (see below).
4. IF after trying 11cm Maximum OA again goes up, then lower Maximum down to 9.0cm.

Sleep another night and observe your new AHI results.

Note: Observe your OA line in the Summary Daily Report, notice that the individual OA indice is INCREASING as pressure increases? It SHOULD be going down not up with increasing pressure if those are obstructive events. If you increase the Maximum to 11cm and the report again shows an increase, then you may have to lower your Maximum ceiling pressure to 9.0cm.

If your HI (Hypopnea) indice was high I'd say increase the Minimum pressure, but at 9.5cm it is only 0.7, you can't get much better than that, so leave the Minimum pressure where it is at. [/u]

[Snoredog]

I agree with RG ... try and post your detailed charts for more detailed info of what is happening during your sleep sessions.

Roberto,

What's your logic? Am I missing something?

what you are missing is the Maximum pressure LIMIT set on his machine.

It is at 9.5cm but all the data gets lumped and thrown under 10cm column. EncorePro rounds up so that can even be more misleading.

So once you spot that error, you toss out the AHI vs. Pressure report and just look at the raw data, since all we have is AHI information, you look at that and break it down.

His HI indice is 0.7 (not 7, big difference). This means the Minimum pressure is just fine. Next you look at the OA indice, it is 8.1, if you add up 8.1 and 0.7 you get the current AHI=8.8 as shown under the 10cm column.

WHENever OA remains high or above 5 it means the Maximum pressure is NOT high enough to stent those events. Then you look back and again there is a LIMIT to Maximum pressure of 9.5. IF one observed the Auto Daily Report as RG suggested you would probably see "flat-lining" in the report. This could be an indicator that the pressure is not high enough (if those OA shown are truly "obstructive" apnea).

So what you do is increase the ceiling say to 11cm or higher and observe what happens to the OA indice. At this point we don't care about Hypopnea, they are already as low as we can get them. Uncleared Obstructive apnea is what you want to eliminate here.

Now, if the user move the Maximum pressure up to 11cm or to 15cm as RG suggested and AGAIN the OA goes UP (vs. down) then you can suspect that the machine is hosed on accurately detecting the correct event (if OA goes up those are most likely central events not "obstructive").

The goal should be to gradually increase the Maximum pressure until those OA's drop below 5.

[Rabid1]

NHE & Snoredog,

I completely understand your logic, and if it were not for one element you left out, I'd agree with it.

What you've left out of the equation is his titrated pressure of 7cm. Shouldn't that be considered?

[DreamStalker]

NHE & Snoredog,

I completely understand your logic, and if it were not for one element you left out, I'd agree with it.

What you've left out of the equation is his titrated pressure of 7cm. Shouldn't that be considered?

Of course it should ... but only if it is correct.

I was titrated at 10cm and managed an average AHI of about 4 ranging between 2 and 15 -- but after learning how to tweak my machine with the help from the great folks of this forum, I have had an average AHI under 1 for the past 4 months and an AHI under 0.5 for the past 3 months. It turns out my “sweet spot” is between 11 and 12 cm.

Sure it is only off by 1 or 2 cm from my titrated … but it made the difference between an average AHI of 4 and 0.4 (last 30 days). So the lab titrated pressure does provide a good guide … assuming it is correct. But if you read some of the other posts on this forum, there are many that are incorrect … add to that the percent difference between pressure settings and AHI numbers and the lab titration number is NOT the most important aspect to be considered.

[NightHawkeye]

I completely understand your logic, and if it were not for one element you left out, I'd agree with it.

What you've left out of the equation is his titrated pressure of 7cm. Shouldn't that be considered?

You could be absolutely right, Rabid1, and I mean that seriously. The data is not totally convincing that a higher pressure will help, but neither does the data show convincingly that a lower pressure will help. There are plenty of variables here. I look at slepr's data and see similarities with my own apnea patterns. I'm pretty sure that Snoredog sees similarities with patterns he's experienced. As for RG's and Linda's interpretations (notice the segregation by gender here), well, they've both seen and experienced quite a lot, and have displayed excellent judgement (often better than my own, actually). We're all just offering opinions though, based on our own experiences.

Fortunately for slepr, it's easy enough to change pressure and discover what works the best. While it may be frustrating to slepr to have to work this through in trial-and-error fashion, it will be worth it. As you suggest, slepr may find out that the sleep lab titration value may be the best of all (but I doubt it).

Regards,
Bill ( . . . thinking this is cpaptalk at its best; the sharing of possible explanations for aomalies)

[Catnapper]

When my doctor couldn't explain something on my sleep study, he called them artifacts. How do you like that explanation?

[Rabid1]

Reading back through this thread, Linda made a good observation that we should also explore; leaks.

We should also consider mouth-breathing as a culprit in this case.

Slepr, do you have your leak data?

[slepr]

First, I have to give a big thanks to everyone who has weighed in on my question. I really appreciate the time taken, and I am learning a lot. I was away overnight for a quick trip and upon return I showed my wife all the responses this morning. She was AMAZED.

Leaks: Here is a chart from the same date range. I got my Opus working well about 2 weeks ago and really like it. The leaks fall well within the values for that mask/pressure. I'm not sure how it would do at higher than 11 cm pressure (maybe I'll play with that) but at what I've been using, it works well.



If I can provide other info please let me know.

Thanks again

[slepr]

Sleep Therapy Daily Details for 3/16/07 , which I think is fairly representative of the past week. I split it into two images from the screen capture.

Part A


Part B

[WNJ]

slepr,

I see nothing in the charts to suggest that your APAP is set incorrectly.

Rather than fuss about the pressure range of your APAP, and since you said you were a back sleeper, I suspect that you would make a bigger dent in improving your AHI if you worked on teaching yourself to sleep on your side. I know it has made a huge difference for me. It is worth a try anyway.

Then there are the other usual non-xPAP considerations, e.g., losing weight, avoiding alcoholic beverages in the hours before bedtime, etc. I’m not sure what may apply to you.

I think the AHI vs. Pressure chart is the most misleading information you can look at. It is too easy to conclude that a higher AHI and a higher pressure means that if you could avoid that pressure you will avoid apneas or hypopneas. Not necessarily! It is more likely that the pressure is going up in response to apneas or hypopneas. If so, preventing your APAP from going to those higher pressures will result in higher, not lower AHI.

The ONLY way to know for sure what your AHI at a given pressure will be is to set your APAP at each constant pressure for several nights and analyze those results.

Wayne

[Snoredog]

Sleep Therapy Daily Details for 3/16/07 , which I think is fairly representative of the past week. I split it into two images from the screen capture.

Part A


Part B

Between therapy hours 4-5 and 6-7 you are flat-lining, that means your pressure ceiling is NOT high enough, that is why your AHI is so high. Increase the ceiling to 11 or 12cm.

[Wulfman]

I agree with Snoredog.
And, the bottom pressure isn't high enough to keep the number of hypopneas minimized.

Den

[slepr]

Given all the good feedback over the past two days I think I am going to proceed methodically. Yes, it may take a bit of time but as in many others here, it seems to be time well spent 'dialing in' the individual pressure. I will shoot for each course to be a week in length.

Course 1: APAP from 8.5 to 18 cm pressure - lets see how this higher range works, does it stem the OAI.
Course 2: CPAP at 9 cm
Course 3: CPAP at 6 cm

The feedback is much appreciated and certainly helps me move forward with some logical choices.

Thanks very much, and I'll post some results in a week.

Mike