I was going to say that the best advice about iVAPS is ... don't do it! It is highly unlikely that you need it (To tell whether it might help you, you need to post a chart showing minute vent in a mode other than iVAPS).
But you did! And with Auto EPAP so you had PS range > 8! How are you feeling? I don't know what settings you are using for height, Target Va or Target Pt Rate, but it looks to me as though the targets were low and so the machine did not try to blow you away - much.
If you really want to use iVAPS, do the following over a period of several nights, or even weeks:
- Convert from APAP to S mode. Based on 6 November, maybe use use EPAP = 8 and IPAP = 11 . Take time in this mode to refine EPAP and IPAP and to work out your settings for Rise Time, Ti Min and Max, Trigger and Cycle.
- Switch to ST mode. This is just S mode with a backup rate. Best is to turn iBR on and set Target Pt Rate to 13, your median respiratory rate. Note that you could possibly combine this and the previous step because your min RR on 6 November was 9.6 compared to the background backup rate of 8.7 (2/3 of 13), so it would have had no effect anyway.
- Switch to iVAPS mode (Auto EPAP off). This is ST mode but with a range for PS (IPAP - EPAP) instead of a fixed IPAP, and a target volume that the machine will attempt to maintain by varying PS. My suggestion is to set Min PS to the same PS as you were using in ST mode, initially set Max PS to Min PS + 2. Set Target VA such that Target Mv is about 10 to 15% lower than your median Mv achieved while using ST mode.
- If you get that working, your first adjustment will be to max PS to give it enough range to work with.
- Next you might increase your Target VA, eventually up to where the Target Mv is approximately your median Mv achieved while using ST mode. As you do so you will most likely need to both reduce Min PS and increase Max PS.
- If your PS range is > 8, you could consider auto EPAP again
When I look at my charts for iVAPS, I focus on:
- Flow rate
- SpO2 (if you record that)
- Pressure
- Resp. Rate
- Tidal Volume
- Minute Vent
I don't look at Event flags because I have few, and they show on the breathing chart. I don't show leaks because I use an Evora Full and seldom have any. Either or both of these may be useful to you.
Other useful indications are the Spontaneous Trigger and Cycle values. These are
only available in the sleep report of your machine, Be sure to change the report period to 1 Day (and do this after any power disruption to the machine). I keep a record of these daily values in a spreadsheet so that I can use them to assess the impact of settings changes. Spont. Trigger, in particular, may provide a proxy for the CA index, since backup rate should prevent CAs from occurring by initiating a mandatory (non-spontaneous) Trigger.
Final word, the smart thing to do is only Step 1 of the process described above (S mode). Step 2 (ST mode) should also be "harmless" if you really wanted to do that, but it should also be unnecessary unless you increase PS to the point of causing CAs. As I said, I think it is unlikely that you will need iVAPS.
