New on Bipap ASV, have a few questions

[tcolar]

Hi, I had been on a Abap dreamstation for about a year, first month was rough, but eventually it got better, I never managed to get great AHI but when I was doing well I could get around 4 to 6 (that was with a pressure range of 8-14 or so).

I did feel better (more rested) but eventually started having issues with aerophagia, more and more, eventually every day, unless I kept the pressure under 10 ... but then the AHI was less good (7-10)

Note: I don't really have any medical issues otherwise, normal weight, I play a lot of sports (hockey) etc....

Anyway, did a full sleep study last month and they decided to move me to a Bipap, here is the titration prescription:

-- Prescription --
This was a challenging titration study due to sleep onset and treatment emergent central apneas and aerophagia. Dr. <del>, the attending-interpreting physician, suggests a trial of Bilevel PAP (positive airway pressure) with a pressure setting of 9/6 cm H2O with a back up rate of 12.
----

I picked up the  machine (Dreamstation BiPap ASV advanced) a few days ago, but discovered the tech set it all wrong (it was set to EPAP 6-6 with no BPM)

I've now set it to what I *think* is what the titration says, question1: Do those setting look correct ? 
I set it to this: Press:9, epap+ : 9, epap-: 6, ps+:3, ps-:0, BPM:12, TI:1.2

It seems I had less CA with those settings, however I had a lot flagged as Hypnoeas (much more than usual), not sure what's up with that.

Question2: 
I can't find a clear explanation of "Pat. Trig. Breaths", it seems to be the average of breath triggered by me vs the machine, in which case only 62% by me on avg doesn't sound good, but no idea what a normal range would be here, ditto with "timed breath", what is that about and is that something to worry about ? I think those are new with Bipap.ASV.

Any help appreciated, thank you.

[Gideon]

Unusual settings for an ASV machine
The chart is screaming more pressure support and thus more IPAP max to treat your hypopneas., but those would still be unusual settings for an ASV.
The settings shown are not the ones describes yeither you or the report. Suggest you ask for clarification from the RT or your doctor. You mentioned a trial so I would be more inclined to see where they want to go

[Sleeprider]

tcolar, it would be interesting to see your full sleep study. ASV is normally prescribed for complex and central apnea, but it can be very effective against hypopnea.  As Bonjour mentioned, your pressure support is too low to provide the boost in respiratory volume to overcome the hypopnea.  The way ASV works is your EPAP must be sufficient to prevent OA events.  Pressure support on the ASV is variable for every breath, and its purpose is to maintain tidal volume.  Normally the minimum pressure support is 3.0 and the maximum is 15.0, and the machine uses as much as is needed when it is needed to ensure you take a full breath.  The backup rate of 12 BPM is a timed triggering of IPAP. With 12 BPM inspiratory pressure is triggered every five seconds.  It appears your natural respiration rate is 14 breaths per minute, so we would not expect to see the machine triggering for every breath, but those black hashes above the flow rate chart are triggered breaths, and you have a lot of them.

The fact you are continuing to have CA and H events in abundance, means you need more pressure support.  Your minimum PS is set to 3.0 and maximum at 4.0.  That maximum will have to be increased to what you will tolerate, and that is going to take some experimentation on your part if you want to clear these events.  I would suggest starting with PS max 6.0, then increase it until you reach the threshold where aerophagia is intolerable, and back down to the last setting.   I attached an image showing the usual ASV titration protocol below. It explains the appropriate change to settings for any events.  As you can see, the default settings are EPAP min 4, EPAP max 15, PS min 3, PS max 15, and it is recommended you do not use ramp with ASV.  Basically, EPAP should be increased for obstructive events, and with enough PS, hypopnea and CA will be resolved. In your case, there may be a trade-off between the number of residual events, and your comfort due to aerophagia.

[tcolar]

Thanks for the details, I usually ty to give the prescription a chance before I adjust on my own, even though that's a much slower feedback loop improving things, when I'm getting very poor seep for a week, like now, I lose patience.

I don't have the details of the study, just what the Dr recommended after seeing it (trial) which I included in the original post, can I request the detailed results ?

What I can tell you though:
- I barely slept during the study, I would be surprised if there is more than an hour of data, if that
- I developed aerophagia even during the study, which I think is why they are trying me on lower pressures.

6 months ago I was dong pretty well on my ABAP, I did best with pressures of 14-8 or so, I felt rested and my AHI ,while not perfect, was around 3 to 4.
But eventually started having the aerophagia more and more and it was either, lower pressure, or aerophagia and taking the thing off after a coupe hours.

I was getting CA on bipap too, but it was definitely much less with higher pressures (14 as a high pressure was working well)
I didn't nearly have as many Hypnoeas (2 or 3 score at most, not 9), but that might just be because 6-9 pressure is just to low as you mentined, I was usually using at least 8-11 on Bipap.

I don't like the ramp, I'll definitely turn it off, I had turned it of on ABAP too.
The technician did not even know how to do that, she tried. My ARNP seems good, but the company I get the equipment from seems to be very clueless in general .... they really seem to struggle with technology in general :-/

@bonjour you mention my settings are not matching the prescription, could you tell me what to use to match it, I don't think it will work well, but I'd like to start with that, I don't think I'll stay with that long as so far it's been bad (las night even worst, 16 AHI), but I also want to hope there is a reason why the doc wants to start there.

[SarcasticDave94]

Yes, certainly request a copy of your detailed sleep study. It will state what you're working with in regards to Apnea. When you get that, post redacted (black out personal info) screenshots here.

[tcolar]

One more thing I have been wondering about for a while :

I noticed (and that's not new) that my AHI and events are low when my expiration time is low and stable(<1), while it's bad when it gets higher (~2).

As you can see in the attached graph I'll often have say 30mn of good results with my expiration time being low and stable (<1), but then it will be followed by a period (say again 30mn) with much longer and erratic expiration times and much worst results.

Is there anything to that ? what would cause those cycles in my expiration times ?

[Gideon]

-- Prescription --
This was a challenging titration study due to sleep onset and treatment emergent central apneas and aerophagia. Dr. <del>, the attending-interpreting physician, suggests a trial of Bilevel PAP (positive airway pressure) with a pressure setting of 9/6 cm H2O with a back up rate of 12.
----

I picked up the  machine (Dreamstation BiPap ASV advanced) a few days ago, but discovered the tech set it all wrong (it was set to EPAP 6-6 with no BPM)

I've now set it to what I *think* is what the titration says, question1: Do those setting look correct ? 
I set it to this: Press:9, epap+ : 9, epap-: 6, ps+:3, ps-:0, BPM:12, TI:1.2

Per OSCAR (there are issues with setting reporting so verify this) on your charts
Min EPAP   = 5 
Max EPAP  = 6
Min IPAP   = 8
Max IPAP  = 9
PS           = 3-4
 
9/6 Backup 12 unclear on what mode to use
would be 
Min EPAP = Max EPAP = 6
Min IPAP = Max IPAP = 9
PS = 3
Backup = 12
I don't see this working either.  I would call your Dr./RT and discuss.  The fact that you have this machine indicates that your Dr. likely sees an ASV in your future.
I would eventulaly try default ASV settings (see SRs post) but I would give your Dr./RT a chance.

[Sleeprider]

If you want to really get into the weeds, some close-ups of the flow rate (2-minute segments) will let us see the inspriation/expiration wave form. I have no idea if there is anything useful there, but that would help us understand what is going on when you say you have longer vs shorter expiration time. The biggest problem with your settings is the lack of contrast between IPAP and EPAP which is what can cause a breath or change volume. It is fundamental to an adaptive servo ventilator...This isn't just CPAP. Also, you should realize that the pressure support should not be needed every breath, but is provided when needed.

The Resmed machine uses an auto algorithm for backup rate, and your AutoSV also has an auto BPM that you might want to try. You said that shorter expiration time seems to help. You can usually decrease expiratory time by increasing inspiration time. You can do this with a longer Ti Max of 1.8 to 2.0. You should also use a lower BiFlex setting, or disable BiFlex and use a longer rise time of 2 or 3.

[tcolar]

Thanks Bojour, what you said, is exactly what I had set it to:

Min EPAP = Max EPAP = 6
Min IPAP = Max IPAP = 9
PS = 3
Backup = 12

But I noticed the same thing you did, that Osar was reporting slightly different, I had checked the machine yesterday and it was indeed set to what Oscar said, I'm not quite sure why what I set it to didn't stick or what ... 

Worst, yesterday evening it was definitely set to 6/9, I even have a picture of the therapy screen set to that, yet this morning it was back to the (useless) setting the tech had set  (6/6, ps-0, no backup), I had a terrible night (17 AHI) with CA's (4.5) and tons of hypnoeas (12.5), not sure if they reset it remotely or what :-/

I'll make sure it's correct before going to bed tonight ... I might also use 11 instead of 9 (with PS=5), because 9 really doesn't seem to cut it.

@sleepRider, I don't think I explained myself properly sorry, if you look at the last graph I posted, the Exp time graph: forums/attachment.php?aid=15654

You will see periods where my expiration time graph is low and stable and there are barely any events (for example 23:40 to 0:15, 2:30 to 3:25)

On the other hand I have periods where my expiration becomes elevated and unstable and that's when I have tons of events (for example: 0:15 to 0:50, 1:15 to 1:40)

Basically I was wondering id there is anything to that, are those cycles natural ? also not sure if it's a cause or an effect.

[Sleeprider]

The best way to understand the difference between the periods when expiration time is higher or uneven and the quieter time is to look at a closeup of the flow rate As I said, 2-minute snap shots of 01:10-01:12 vs 01:30 to 01:32. The expiration time graph is unreliable as it will be longer during apnea, and we have to see the flow rate to understand the relationship.