How do resmed machines adapt pressure to AIH events

[Pierre]

Hello,

I have now quite stabilized my AI around 1.0.
I also have now the Rescan sotware.

But last night, my AI went up to 2.6 and AH up to 4.6. Actually nothing special that I see happended...
There is a dozen of apnea between 2:30 and 3:30 AM.
If I look at the pressure data, it remains stable during the same period, between 10 and 11.8 (NB the machine is set with a min pressure at 8.4 and a max at 20).

The question I have : Is it normal that the machine didn't go up to higher pressures during this episod which let to an AI (on 1 hour) of 12? I actually don't know how the machine reacts to thse events/

Thanks for your feedbacks

Pierre

PS : I have a copy of my report (picture), but don't know how to get it into my post

[Snoredog]

obviously they don't

[Slinky]

I don't know the answer.

But come on, SnoreDog, have you not accused the Resmeds of chasing the pressures too high???

How about I trade you in on a goat and shoot the goat?

SnoreDog is ticked off at Resmed for their 01 Oct 06 minimum online pricing policy and attempted restricting of their software sales to patients. None of us like that policy but that doesn't reflect or affect the quality of the Resmed products.

[Billyboy]

I have experienced the same situation with a resmed malibu. My dr. does not know why the vpap won't increase to a higher level and I don't know why the pressure won't increase if you haven't reached or come close to the max pressure setting. I ask almost the same question here last night and have not recieved any responces.

[Pierre]

Hello,

I still have the same question, triggered by one bad night without any reason I can see.

Last night, I went up to an AI of 2.9, and the pressure remained stable around 11.5, event when the events were very dense.

Maybe it is normal, if the machine adapts based on a long period and does not react on immediate events. Maybe it is not. And I need to know.

So my question is : does someone know (or can tell me where to search) how Resmed machine S8 autoset spririt are programmed to adapt to the events?

Thanks

Pierre

[Slinky]

Go to this URL and read the entire thread. Some excellent links there that will explain your question. Basically, your pulse is responding to the lowered oxygen in your blood.

viewtopic/t25644/THIS-Should-Be-A-Sticky-.html

[ozij]

Resmed machines in automatic mode areprogrammed not to respond to apenas that occur above a pressure of 10.

Resmed machine cannot distinguish between a obstructive apnea, and one the may be induced by the pressure. So in order to be on the safe side, Resmed's in automatic mode will ignore any apneas that appear when the pressure is above 10.

If your doctor knows for a fact that you have obstructive events above a pressure of 10, you can't trust a Resmed machine on automatic mode to handle them. You either need to switch to fixed mode on the Resmed, or get a kind of machine that handles the problem of "this might be a non-obstructive apnea" differently.

Respironics and Puritan Bennett have automatic machines with a different approach to apneas at higher pressures.

Moderated chat transcript on talkaboutsleep

The A10 algorithm increases pressure in response to Flow Limitation, Snore, and Apnea up to 10cm H2O. Above 10cm H2O, pressure response to Flow Limitation and Snore continues, but there is no response to Apnea. AutoSet Spirit and AutoSet T do not differentiate between obstructive and central apneas. Increasing pressures above 10cm H2O in response to apnea can lead to "runaway" central apneas.

Resmed keeps the same algorithm for the Vantage.
My emphasis.
O.

[Snoredog]

Resmed machines in automatic mode areprogrammed not to respond to apenas that occur above a pressure of 10.

Resmed machine cannot distinguish between a obstructive apnea, and one the may be induced by the pressure. So in order to be on the safe side, Resmed's in automatic mode will ignore any apneas that appear when the pressure is above 10.

If your doctor knows for a fact that you have obstructive events above a pressure of 10, you can't trust a Resmed machine on automatic mode to handle them. You either need to switch to fixed mode on the Resmed, or get a kind of machine that handles the problem of "this might be a non-obstructive apnea" differently.

Respironics and Puritan Bennett have automatic machines with a different approach to apneas at higher pressures.

Moderated chat transcript on talkaboutsleep

The A10 algorithm increases pressure in response to Flow Limitation, Snore, and Apnea up to 10cm H2O. Above 10cm H2O, pressure response to Flow Limitation and Snore continues, but there is no response to Apnea. AutoSet Spirit and AutoSet T do not differentiate between obstructive and central apneas. Increasing pressures above 10cm H2O in response to apnea can lead to "runaway" central apneas.

Resmed keeps the same algorithm for the Vantage.
My emphasis.
O.

[Slinky]

But, SnoreDog, I "ain't" no techie. I've only got a high school eddykashun and one college course of Medical Terminology.

[Moby]

Pierre, I found the same thing with a wide setting (12-20)

I took my average median (ie the mean of the recent relevant medians) and set the auto on one under and two over that, and the past two nights have done very well on the resulting 12-6 - 15.6.

I am also on top of the leak problem for the time being.

The machine has been much more responsive.

My energy has bounced up like one of the super bouncy little balls.

Di

[Moby]

Another really good night - three consecutive nights with these settings.

8hrs 30 mins use, AI 0.2, HI 1.9, leaks negligible, pressure set 12.6-15.6, pressure median 12.8, max 15.6 (I think when I readjusted my mask at one point) 95th percentile 14.2

The pressure moves around more responsively within these tight settings.

I wouldn't know that without the software, so glad I've got it.


di

[Pierre]

Hello Moby, hello to all,

I read that you see that your resmed machines are reacting with perssure, even with ranges set with a minimum presssure at 12 (or let's say above 10).

I also read that Resmed machine do not react to apenae when pressure is above 10.

In my case, and for all my nights, what happens is that few minutes after starting, the pressure goes up from its minimum set to a level (depending on the range set) and gets very stable around this value, whatever eventes happen (Apena, Hypo). It basically seems that the machine does not react anymore, even with a lot of apnea or a lot of hypo.

Note that my average AI duration is around 20 sec, but I often have apnea of 1 min.

I tried, on long periods, 3 settings :
1) Min 4 - Max 20
-Pressure gets established and stable around 10.9
-Average IA is at 2.4
-Average total time per night in apnea is 5 min
-Worst night : IA = 4.6
-Best night : 1

2) Min 8 - Max 20
-Pressure gets established and stable around 11.4
-Average IA is at 1.3
-Average total time per night in apnea is 3 min
-Worst night : IA = 1.9
-Best night : 0.4

3) Min 11.4 - Max 20
-Pressure gets established and stable around 12.7
-Average IA is at 1.5
-Average total time per night in apnea is 3 min
-Worst night : IA = 3.5
-Best night : 0.5

For sure, when I get to AI around 0.5, I feel in a great shape, and when I get above 1.5, I feel quite bad.


So my remaining questions are :
-Can I consider that my Resmed machine works well? Even if I understand that it should not react when pressure is above 10, I still wonder why no event manages to get my machine use its full range, and why it stays so stable around a pressure (like a constant pressure setting!)
-My main problem is that my machine has for sure improved my apnea issue, but my key problem is that, whatever the setting I use, the results are not stable, and my energy still much depending wether I get an AI at 0.5 or 2, which I do not control, and I only discover in the morning.


Thank you for your feedbacks.

Pierre

[Slinky]

Are you looking at your Leak rate during these events?

[Moby]

I'm doing the same sort of "tweaking" Pierre.

The last poster is right, check whether the events are because of mask leaks.

Another point: Do you need the top level of 20? If I had your numbers I would reduce the top level from 20 to just above my 95th percentile number.

Keep posting!

regards

Di

[Moby]

I notice you use the Ultra Mirage full face mask.

Is your machine working in the "ultra mirage" option?

The ultra mirage has a high leak rate, so the machine might not be compensating adequately for this if it doesn't know you're using the ultra.

Di