AHI Went Up After Switching to New Machine - Help?

[CapnLoki]

On the other hand, blowing the the mask off and causing major leaks can hardly be considered a "success."

People who have pressures in the high teens, and indeed into the twenties would laugh at your hyperbole of "blowing the mask off".

No Hyperbole - if you set the straps so that the leaks start at pressure 13, then pressure 18 will quite literally lift the mask off your face. Its basic physics. I'm sure that most people who need a high pressure would be happy if they could loosen the straps a bit. Perhaps some of them really only need to raise their minimum pressure to avoid the ResMed overshoot.

[Dog Slobber]

On the other hand, blowing the the mask off and causing major leaks can hardly be considered a "success."

People who have pressures in the high teens, and indeed into the twenties would laugh at your hyperbole of "blowing the mask off".

No Hyperbole - if you set the straps so that the leaks start at pressure 13, then pressure 18 will quite literally lift the mask off your face. Its basic physics. I'm sure that most people who need a high pressure would be happy if they could loosen the straps a bit. Perhaps some of them really only need to raise their minimum pressure to avoid the ResMed overshoot.

If one used a ResMed and their ResMed routinely "overshot" delivering a pressure of 18, why would they set their straps at 13 instead of the 18 they regularly receive?

[CapnLoki]

On the other hand, blowing the the mask off and causing major leaks can hardly be considered a "success."

People who have pressures in the high teens, and indeed into the twenties would laugh at your hyperbole of "blowing the mask off".

No Hyperbole - if you set the straps so that the leaks start at pressure 13, then pressure 18 will quite literally lift the mask off your face. Its basic physics. I'm sure that most people who need a high pressure would be happy if they could loosen the straps a bit. Perhaps some of them really only need to raise their minimum pressure to avoid the ResMed overshoot.

If one used a ResMed and their ResMed routinely "overshot" delivering a pressure of 18, why would they set their straps at 13 instead of the 18 they regularly receive?

I'm guessing that most people don't bother to formally titrate the strap tension. I did it when I realized that on my side the pressure was never above 12, but on my back it went to 16 or more. By tensioning to just over 12, if I rolled on my back the pressure would climb to the point where the large leaks would lift the mask and wake me up. After a few weeks I essentially trained myself to avoid sleeping on my back - maybe once or twice a year I wake up and realize I somehow got supine, but it was never bad enough to cause a cluster of events. When I set up new straps I just make them very loose so they leak, then tighten just a bit.

I can only assume that most people simply tighten enough to stop major leaks, but I wonder how many people suffer with very tight straps because they get too much overshoot on the pressure.

[jimbud]

Maybe I need more knowledge to understand but:

If you need 18 to prevent events, that would not be overshoot. Tighten your mask to that pressure.
If you are overshooting because of false events or some other reason (on a regular basis) why would you not just cap the pressure to a level you are comfortable with, and will prevent most events. Then tighten your mask to that pressure.

That is what I have done and will do.

JPB

[palerider]

Maybe I need more knowledge to understand but:

If you need 18 to prevent events, that would not be overshoot. Tighten your mask to that pressure.
If you are overshooting because of false events or some other reason (on a regular basis) why would you not just cap the pressure to a level you are comfortable with, and will prevent most events. Then tighten your mask to that pressure.

That is what I have done and will do.

JPB

Either that, or desperately try and figure out something to criticize the better performing machine... *shrug* Even if it makes no sense and nobody else interprets things that way. *shrugs*

[CapnLoki]

If you need 18 to prevent events, that would not be overshoot. Tighten your mask to that pressure.
If you are overshooting because of false events or some other reason (on a regular basis) why would you not just cap the pressure to a level you are comfortable with, and will prevent most events. Then tighten your mask to that pressure.

You are correct on both counts. But there are two other possibilities:
You could raise the minimum pressure to reduce the tendency to overshoot and have a more constant experience.
Or, as I chose to do, use a machine that does not overshoot, raise the min pressure as above, and leave the max pressure high and allow the (now very rare) supine events to trigger large leaks and wake me up. Since I found that I don't like the pressure too low, and I prefer a relatively constant pressure, and I want the mask as loose as possible, and supine sleeping puts me in a whole different place that I want to avoid, this works out best for me. Since my long term AHI is about 0.1 its hard to see how I could improve on that.

Add to that the the DreamStation is much better for battery use, better for travel if humidity is not needed, and my second (out of pocket) machine was much cheaper I still claim its a reasonable option for some people.

[CapnLoki]

Either that, or desperately try and figure out something to criticize the better performing machine... *shrug* Even if it makes no sense and nobody else interprets things that way. *shrugs*

You've got it all wrong PR. I was simply trying to understand want you meant when you talked about the "fast response" of the Resmed. What I found was that the research backed up your claim but it also leads to overshoot, which has to be dealt with. I never said it was a flaw, I only said it was a property that had to be accounted for. If you want to start with a low pressure and have a fast response that reacts quickly with some overshoot, then clearly the ResMed is the machine for you. If you want to stay within a narrower range then the DreamSation is a reasonable choice since it obviously works for some people.

Your insistence that any attempt to understand the real differences in the machines is "desperate bashing" of your personal favorite puts in doubt your ability to give impartial advice here - perhaps you should stick to something you know about.

[Pugsy]

I just haven't seen the response by ResMed machines being nearly the negative that CapnLoki thinks it is.
In real life people use (and not machines that the test he wants to keep bringing up used to simulate breathing) using the machine doesn't seem to cause nearly the problems that he thinks it could cause with leaks. I have seen bad leaks at baseline starting pressures more than with higher pressures on hundreds of reports from people here. Overall mask fit or mouth opening seems to be the primary cause of most leaks.

I think you boys need to agree to disagree and move on and quit beating this dead horse to death over and over again in other people's threads.

Either that or start a thread entirely devoted to this difference of opinion and you guys can discuss it to your hearts content in that thread.

[palerider]

I think you boys need to agree to disagree and move on and quit beating this dead horse to death over and over again in other people's threads.

There's no talking sense with someone that has an ax to grind, I gave up a while ago.

[zorki1c]

I changed to the Dreamstation after five years on the S9. With the S9 my AHI was normally below 1.0. The the Dreamstation it was all over the place--sometimes over 15! (same mask -- the P10). So I went to the A10. It too a few days but soon my AHI reading settled down to around the same as with the S9.
PS: I run at a fixed pressure rather than auto