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Lowering Pressure, same AHI - Printable Version

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Lowering Pressure, same AHI - zzbert - 11-10-2014

I have Resmed S9 Auto. I have have been "experimenting" with VERY SLOWLY lowering the highest pressure over a long period of time. I started out with range of 6.0-16.0 (my sleep study result was 12.0). After a year of careful monitoring I am now at 6.0-7.6. My AHI has actually slowly DECREASED. Started around 3.5 typically and is now <1.5 consistently.

At any setting the mean pressure rides close to the max setting all the time but I have almost no events all night. Along with this I have lost a very large amount of weight.

So, what does this mean? I am going to continue to reduce the pressure all the way down to 6.0 then if AHI is still so low, stop CPAP. The strangest thing about my study is how the median pressure always rides close to the max. You would think if I didn't need CPAP it would drop to a level near the min.

I know the best answer would be another sleep study but I plan to wait until I lose another 10-20 lbs to give it my best shot.


RE: Lowering Pressure, same AHI - retired_guy - 11-10-2014


(11-10-2014, 03:56 PM)zzbert Wrote: I am going to continue to reduce the pressure all the way down to 6.0 then if AHI is still so low, stop CPAP.

Not sure that would be your best idea.

Losing the weight is great! Congrats on that. But you do still have apnea events. 1.5 is a good score, but that's with treatment. You don't know what it would be without treatment until or unless you have another sleep study. Rather than continuing to reduce the pressure which is already pretty darn low, I think I would be more inclined to raise the bottom to say 6.5 for instance. Like I said, 1.5 is good, but it's not zero. Stopping therapy could be snatching defeat from the jaws of victory, so if it were me, I don't think I'd want to do that.



RE: Lowering Pressure, same AHI - zonk - 11-10-2014

Hi zzbert and welcome
First of all, which S9 Auto is it? AutoSet or Escape Auto

You say "At any setting the mean pressure rides close to the max setting all the time but I have almost no events all night"

It means the machine not allowed to do its job as intended ... the machine strikes early to prevent apnea as it increase pressure in response to snoring and flow limitation (FL), FL are not classified as apnea but nevertheless are airways obstruction somewhat. Zero AHI means the machine prevented apnea events and does not mean there was no apnea event in the first place, the machine only flag the events that slip through

Weight loss and avoid sleeping on your back might be useful but as you summed up correctly
"I know the best answer would be another sleep study"



RE: Lowering Pressure, same AHI - DocWils - 11-10-2014

Raise up the pressure - if it is an autoset, it will find the right pressure to do the job for the time it needs to be at that pressure. You are limited the effectiveness of the support the CPAP gives you. The 95% pressure you are experiencing as lowered is indeed most likely from your weight loss, but I do not think you are doing yourself a favour by lowering the top pressure - it is not the pressure the machine takes you up to, but rather the pressure past which it is not allowed to go - the machines senses your needs and responds accordingly.

And when time allows and your weight has hit a plateau and will not lower or raise, do another sleep study.


RE: Lowering Pressure, same AHI - PaulaO2 - 11-10-2014

I agree. You lowering the Autoset and the dropping of the AHI is most likely pure coincidence with the weight loss. The Autoset will only use what you need. If the mean is as high as the max, yeah, you are setting the max too low.

As for discontinuing the CPAP, you are not really seeing this the correct way.

It is like taking insulin for diabetes. You take insulin, your blood sugar levels out. You eat right, lose weight, you can lower your insulin dose. You know everything is working because you use a glucose meter. If you stop using the insulin, you can see the results.

The same with your sleep apnea. The CPAP is your insulin. It is just like any other medication. You've been able to lower the dose/pressure, which is good, but more than likely you still are going to need it. Your CPAP is also your "glucose meter". It is saying you have AHI of 1.5 with treatment.


RE: Lowering Pressure, same AHI - trish6hundred - 11-10-2014

Hi zzbert,
WELCOME! to the forum.!
CONGRATULATIONS! on your weight loss.
I don't think it's a good idea to stop CPAP therapy though. While it is great that you are losing weight, ( that doesn't necessarily mean you still don't have sleep apnea.
Best of luck to you with your CPAP therapy and I hope you will continue with it.


RE: Lowering Pressure, same AHI - surferdude2 - 11-10-2014

One of the most revealing tests you can perform in the privacy of your own home bed is to get one of the small inexpensive (<$40) digital audio recorders. Tape it to your tee shirt with the mike end right at the top of your chest for a night's recording session and play it back the next day. Hearing all those sounds will tell you a lot about how well you sleep and how well you breathe. It will also go a long way in helping you decide whether to get further help or continue with your present treatment.

You can even do this same test using a laptop computer that has a built in microphone. Those are very sensitive and need not be any closer than your nightstand. The resident Windows Recorder will suffice for the software.

I did it both ways (prefer the small recorder) and it gave me sufficient proof that I needed help with my night time breathing problems. You too may be surprised at what you hear.

It's not a complete sleep study but the price is right and if it moves you to get a more professional evaluation, so much the better.

Google Olympus VN-7200 and you'll see what I used. It worked OK but if buying one again, I'd opt for the Olympus VN-722PC since it has PC connection capability. You can copy the file to a PC with that unit and use a software to view the entire waveform string for the sleep session so you easily locate the areas of concern without having spend the time playing it all back and listening.


RE: Lowering Pressure, same AHI - Galactus - 11-10-2014

Everything everyone else has said makes sense, but no one has mentioned the most obvious thing.... Let's just say for arguments sake that you get all the way down to 6, and your AHI remains at 5 or lower, or even at your current less than 1.5, so that's wonderful, BUT how does that equate to stopping cpap? Are you aware that people out there are titrated and prescribed at 6 on straight cpap? What makes you think just because you get to 6 you can be at 0 and still get a low AHI? You could get to 6 and stop only to have an AHI of say 20. How would you know without a sleep study?