S9 Autoset goes to Max pressure with N30i mask

[elliotg]

I have been using my Resmed S9 Autoset machine for some years with nasal masks (currently a Mirage Activa LT).  While this mask works well, I would prefer a more transportable one.  So I purchased a new  Resmed N30i today.  It fitted well and was very comfortable to wear.  But I have a big problem.

When I put it on, once the ramp time is over, it goes very quickly to its maximum pressure and seems to stay there. The machine is set to the range 6 to 12.  Within 5 minutes it will be sitting on 12 and blowing hard. I haven't even gone to sleep! Trying the same thing with my Mirage Activa, it will be just a fraction over 6.  I did change the mask type in the S9 from Nasal to Pillows but this did not help. I seem to recall that the same thing happened a little while back when I tried another pillows type mask.

Is their some secret setting I have missed on the S9? Or is the machine somehow defective?  Or is it just me? (Perhaps my wide awake breathing is too much like an apnea?). When I am using the Mirage Activa even the sleeping pressure rarely goes much over 10, though it has reached 11.5 on a bad Apnea night.

Any guidance would be appreciated.  I really would like to us this mask, but not unless this issue can be resolved.

[OpalRose]

The ResMed N30i is also a Nasal mask, not a Nasal Pillows mask, so the setting should be left on the Nasal setting for both masks.

[Dog Slobber]

The ResMed N30i is also a Nasal mask, not a Nasal Pillows mask, so the setting should be left on the Nasal setting for both masks.

The correct setting for the N30i is Pillows, not Nasal.

From the N30i manual.


   

https://www.resmed.com/us/dam/documents/...ac_eng.pdf

[elliotg]

I have tried both settings but the problem remains the same.  I would be very interested if anyone out there has used the S9 auto with the n30i.  Did you see the same problem?

I think the problem is that the S9 sees large flow limitations when I use this mask (as seen in ResScan).  This does not seem to occur with my older nasal mask. I have not managed to actually sleep with this mask as the high pressure is just too annoying.

I may have to take this mask back as I cannot fall asleep when being hit by the full pressure.  I know about using a ramping period but this would be of limited use to me as I often take an hour or so to get to sleep.

[Gideon]

Welcome to the forum.

Could you upload Sleepyhead charts for the night.  Seeing them would indicate what is raising the pressure beyond your activa mask.

[elliotg]

I don't have sleepyhead but I am happy to put it on my computer. I will be out for most of this weekend but will do this by Monday.

[elliotg]

Welcome to the forum.

Could you upload Sleepyhead charts for the night.  Seeing them would indicate what is raising the pressure beyond your activa mask.

I haven't got around to installing Sleepyhead yet, but I think there screen shots from ResScan tell the story.  Last night I slept with my Mirage Activa mask.  It was a good night's sleep.  A few hours later I switched to the N30i mask to do a teat run (with a a 5 minute ramp time).  I lay in a sleeping position though I did not fall asleep).  The first page of the file shows most of the previous sleep and the 25 minute teat run.  On the second page I show an expanded view of the test itself.

A few things jump out:
1  The n30i run led a rapid rise to my maximum pressure of 12.  It then showed no sign  of dropping.  At no time during the Mirage Activa sleep did the pressure even get close to 10 (on other occasions I have seen it rise briefly to a little over 11). The last bit of the night run shows a period when I was actually awake you can see the pressure was sitting at just over 6.  So being awake is not the problem!
2  The reason for the N30i jumping to the max pressure seems to be that it perceived a strong "flow limitation".
3  Leak was not the problem.  The leak from the N30i was smaller than for the Activa.

Not shown here, i also ran a trial with a N20 that I had bought last year but gave up on when I could not get to sleep with it.  When a ran this trial the outcome was very similar to that shown for the N30i.

So it would seem that neither the N20 or N30i works for me but the larger mask does.  I am not sure if this is a fault with the S9 Autoset, or perhaps with my nose!

[jaswilliams]

It seems that with the n30i mask for you it causes excessive flow limitations, why I do not know but it is the flow limitations that causes the pressure on your machine to rise. The only answer is to limit the max pressure on your machine to say 10

[Coffee Man]

I have an Airsense 10 Autoset and it started to have the same issue. Really high pressures initially. (Mask was DreamWear but had been fine for 6 months).

So, I reduced the max pressure and also decreased the minimum pressure by 0.2 cmH2O. I also unplugged the machine and then rebooted it. After I made those changes I haven’t had any issues. I don’t know what the problem was or which of the changes I made resolved the issue, but it was just as described by the OP.

By the way, I have been using the N30i without any pressure issues.

[Sleeprider]

Elliot, are you using EPR. While you may think Resscan is giving you the information needed to identify the problem of increasing pressure, I can assure you Sleepyhead is a much better tool. I agree with Jaswilliams that it is flow limitation that is causing the pressure increase, and we can reduce FL with the use of EPR.