From APAP to BIPAP

[Vixoe]

Hi StuartC
Thank you so much for taking the time to give these great advises. - I have been reading your long thread several times to see if i could learn more about this machine.

I bought it thinking it was a bilevel like the Aircurve Vauto or similar. - The reason for doing so is that i cant handle to much pressure without the air going in my stomach. I found out that this issue mostly occur when exhaling with epap pressure higher than around 6 to 7 cmH2O but i need IPAP to be around 11-12 to get rid of the apneas.

I took a screenshot of last night, still in IVAPS mode (just read your post this morning) and i dont feel very great. Dont know if i have been overventilated or something. I feel dizzy and tired. But no air in my stomach :-)

I also posted a screenshot from oktober when using the APAP machine so you can se my RR and Tidal from that night. - I have been using those previous days to guess the target values, and then set them lower to be sure. On the machine the daily report always shows 100% for both trigger and cycle so at least that should be okay.

I will try S mode as you suggest and see i that wil work for me.

BTW, how do you see if there are CA's or Flow limitations with this machine? I guess it is maybe from the flow wave, so i posted a shot that i find odd looking so maybe you can interpret anything from this.

[StuartC]

S mode on the Lumis is like S mode on the VAuto when Easy-Breathe is turned off.  Unfortunately there is no equivalent of VAuto mode.  However, given many people's opinions that CPAP mode is better than APAP mode, S mode should be fine.  It is effectively the BiLevel equivalent of CPAP mode.

IPAP does not get rid of the obstructive apneas - EPAP does.  However, I can believe that you need a lower EPAP than your pressure on the APAP suggests.  For instance, you only had events in two clusters last night.  Outside of thise times, your EPAP was never as high as 6 and you had nothing. 

If those two clusters are obstructive, by the way, a soft cervical collar that prevents positional chin tucking might be the solution you are looking for, not pressure or a more advanced mode of therapy.  Even if you are not sure, a cheap one from a local pharmacist could be good to experiment with.  Positional therapy to stay off you back may also / alternatively be helpful, and I will mention this again later.

Apart from the two clusters, the machine treated you quite gently.  Yes, it can over-ventilate you, as far as I am concerned, because I felt absolutely awful when it did it to me.

The screenshot from October has tidal volume cut off and no minute vent showing.

You need to read the breathing chart to understand OAs vs CAs and flow limitations.  However, CAs should not be possible in ST or iVAPS mode because the mandatory trigger that occurs in less than 10 s should initiate a breath if the airway is clear.  By that measure, all UAs are possibly OAs and all CAs will reduce the Spont. Trigger percentage.  Please understand though that these are my conclusions rather than information I have been able to confirm elsewhere.  

Flow limitations are seen as flat, or sometimes just distinctly non-rounded inspiratory flow.  There is a Wiki article that is worth reading.  In the two minute snip that you included, there are a few inspiratory waves that show some flow imitation.  However the expiratory flow could either indicate mouth exhalation (leak) or, possibly, palatal prolapse.  If it is palatal prolapse, the most successful results I have seen people report involve positional therapy to stay off your back.

[StuartC]

One more thing ...

You would probably be more comfortable if you set Rise Time = 900 ms (max possible setting) and Ti Min = 1.0 s (must be longer then Rise Time).  I don't know if those settings would be either correct or ideal for you, and definitely it is longer than the ResMed default recommendations, but the rise time in APAP would almost certainly have been longer than 900 ms (zoom right in on mask pressure to see).  Providing you do not have COPD (or similar obstructive lung disease) the chances are that there would be no negative therapeutic effect of extending it.

[Vixoe]

Again, thank you for taking the time to view my charts and giving great advise.

I have added a screenshot from last night, where i have disabled Auto EPAP so i am able to lower IPAP Max.

The apneas are a little more scattered but not bad. - I took a snip that i would like your opinion about. - As i can see, i have pauses in breathing in over 20 seconds?
I cant see the machine reacts to that, but maybe thats because IPAP is already at max.

A note: When i was a kid i was afraid to doze off sometimes, because i often forgot to breathe just before sleep took over. - As i got older it went away.
Then 10 years ago i had a stroke at age 49 and after that this same sensation is back. I think i sometimes just forget to breathe. 

I never sleep on my back unless im drunk, and that does not happen very often..

The collar may be a good idea and i will buy one and try it out. - Tonight i will try and increase the pressure a little bit and set rise time to 900 and trigger to 1 sec. as you suggested.

I'm using the F20 full face mask right now. - It is flu season here so my nose is blocked. :-)

[StuartC]

Forget about IPAP.  Increasing EPAP prevents OAs and increases minute vent.  Increasing  PS increases tidal volume, which (according to ResMed) decreases hypopneas (sometimes), snore, respiratory rate and RERAs, which we see as reduction in flow limitations (on machines that report that).  IPAP = EPAP + PS, so it is simply a consequence of the two settings that do something.

Lat night was interesting because your tidal volume was already around 530 ml with PS = 3.6.  I wonder if you need a BiLevel or if EPR = 3 is sufficient?  However, increasing Rise Time might reduce tidal volume a little, so that will be interesting to see.  If so, Easy-Breathe on the AirSense, or on the VAuto, would possibly reduce that further, requiring PS to be higher.

The OAs last night, because that is what they were, are clustered.  The collar should resolve those.

By the way, I have worked out how to make the Lumis work (almost) like a VAuto.  It turns out that AutoEPAP can be turned on when Max PS = 8 even if Min PS is greater than 0.  So if you set Min PS = 4, for example, the consequence of the iVAPS mode increasing PS is not as severe as if Max PS needed to be set to 12 (PS Range = 8) in order to enable AutoEPAP.  But you can mostly prevent PS from increasing by setting target VA to 1 L (minimum setting).  This should keep PS at the Min PS setting in all but the most severe reduction in minute vent.