[Equipment] New to Bilevel Therapy

[Titchcat]

Hello

I've just been switched from CPAP to a Resmed S9 Lumis 150 ST machine to treat hypoventilation caused by a spinal curvature. Its taken about three years of unsuccessful CPAP therapy and being told I was fine when I wasn't to get to this point but that's another story
My problem is that I am struggling with the new machine, frequently waking with a start in the night, feeling like it's trying to breathe for me etc. and the inspiratory pressure delivery  feels very abrupt.  I've been having a twiddle with the settings to try and calm it down a bit and currently have it set as follows;
Machine is set in ST mode. Ipap = 12; EPap =6 
TiMax 2.7s
TiMin 0.5 
iBR off
Backup rate 10
Rise time 350ms
Trigger - Med
Cycle -Med
I use a nasal mask with mouth tape and a chinstrap.
Looking at Oscar, my flow rate has gone from a smooth sinusoidal pattern to something sharper and more "spiky", often with double spikes for each breath . My O2 drops have improved but I'm still waking in the morning feeling like death warmed up. I've only had the machine for a couple of weeks so maybe I just need to be patient and give myself more time to adjust but I must confess, it does feel like it's a bit too much for where I'm at but maybe I'm just overthinking this. 
I'm attaching a couple of screenshots from Oscar. The first is a general overview, the second a more detailed view showing some of the double spikes . Any thoughts anyone may have would be very much appreciated, please, 
Many thanks.

[gainerfull]

was the backup rate prescribed as 10 or is that the default setting? Most adults are breathing around 14 and I think you set BUR to your breathing rate minus 2 so it should be set to 12. This is likely why you have the double peaks.

[Jay51]

I have been diagnosed with hypoventilation as well.  I have trialed many different ventilators.  

The settings need to be "just right" or goldilocks.  It took a lot of time and patience to get my settings just right.  Lots of tweaking.  

The pressure seemed too high and like the machine was breathing for me in the beginning as well.  The strategy has been to back settings down a bit to get used to sleeping with the machine and gain some confidence.  Then can always increase pressure(s) in the future very slowly.  The timing settings are a very individual thing IMO.  

Hang in there.  Gainerfull is spot on with his analysis also IMO.  The back up rate needs to be trialed at different rates to prevent quick, double peaks to get in better rhythm and sync with the ventilator.  

Try to relax as much as possible and not fight the machine.  Try to get in rhythm with it as long as you can just before you fall asleep.

[SarcasticDave94]

I could get away with backup rate 10 to 12, but I'm COPD and a slow breather. It's a shame this probably doesn't have the auto learn an ST-A would have.

What modes will this 150 ST have for you?

[Titchcat]

Thank you for your reply, Gainerfull. The machine was initially set at 12 but when I mentioned the fact it seemed to be breathing for me, it was suggested at the clinic that the rate be lowered to 10. Once I get more used to it, I will step it back up again. Thank you for the information, it is appreciated.

[Titchcat]

Thank you Jay51 for your reply and suggestions, I'm glad I'm not the only one who's struggled
Last night was a little better as I changed my TiMin to match my Rise Time - 400ms - and that seemed to smooth things out a bit.(Unless it was my imagination!) You are quite right, though, it is like Goldilocks with these machines and lots of little, gradual tweaks does seem to be the way to go. You are also right in that I was fighting the machine to start with, as it felt so different to my usual CPAP but then I thought back to how I struggled with that at first, too! I find the pressure is ok for me but see from the replies I've had that I need to address the Back up Rate, so will give it a few days for the latest changes to bed in and then start tweaking that.

Thank you again for your help.

[Titchcat]

Thank you for your reply, SarcasticDave. The modes available on the machine are:

CPAP; S; ST and iVAPS. 

The clinic have it set on ST mode at present. You are correct, I'm not aware it has any auto-learn feature.

[SarcasticDave94]

OK. Hmmm, iVAPS would introduce pressure range selections. Depending on the unit, it might have IPAP range. Probably no EPAP range in the S9 though.

The ResMed AirCurve 10 series ST-A I borrowed some time ago has Auto learning backup breath rate. It guessed too high for me, but it was an easy edit.

Sounds like this is similar to our US version of ResMed AirCurve ST-A, at least partially.

I'm not certain how your choices to edit are handled. But iVAPS mode would likely give more flexibility.

If you can at some point, look into the clinical menu and set it to iVAPS mode then note the setting options available.

[gainerfull]

One thing that I found helped me when I was trialing ASV was using a 30-45 min ramp and focusing on not breathing too deeply when I got in bed so I could prepare myself to catch on to the ASV timed breath train. Good luck

[Titchcat]

Thank you for your further thoughts, SarcasticDave, they are appreciated. I hear what you're saying about iVAPS giving more flexibility and I have made a note of that. I don't think I can change things at the moment as I've only had this machine for just under three weeks now and the NHS Clinic I'm under have set it up in ST mode. The Sleep Tech was ok about me tweaking the settings to a degree, to try and find something more comfortable for me but didn't seem keen on the idea of switching to a different mode. I'll persevere with it for now but keep the iVAPS option in mind to run past them again if I really can't get on with it in ST mode.

Thank you again for your help with this.