ASV as a Non-ASV device - an experiment

As part of an experiment to provide some data to Jedimark concerning SleepyHead, I did an experiment this morning.
I tried to set up my Respironics ASV machine to be in straight BiPap mode.
Edit:
Apparently I got into APAP mode and not BiPap mode - sorry for the labeling error
End Edit:

Here are the parameters:

Then I did two experiments:
1. I held my breath while keeping my airway closed to simulate an OSA event.
2. I held my breath while keeping my airway open to simulate a CSA event.

The simulated OSA event shows on the WaveForm chart but doesn't have the usually expected pressure pulses.
Neither does it show up on the Daily Details page as an OSA event.
The simulated CSA event shows also but does show the pressure pulses.

Here is the appropriate section of the WaveForm Graph:

Very Curious.

I may do another experiment in which the Min EPAP and Max EPAP are set to the same value and see if anything else changes.

An interesting experiment using an ASV as a BiPap... I hope it works when your testing is done. Keep us informed

The purpose of the experiment was to see if the internal coding for pressure pulses could be determined and Jedimark could make some changes in SleepyHead. I'm sorry that I wasn't clear about the purpose. These ASV machines are really complicated and hacking at the reporting stuff with no documentation is a real bear. Hats off to Jedimark for all the really good work he has done.

if pressure support is 0, then it's not a bipap/bilevel.

MY ASV was set up exactly as a BIPAP when I first received it from my DME, that was the prescription pressure that I had on file from my sleep study.. I went 4 days with it and had the same crappy results as my old BIPAP machine... then IAN and Pugsy stepped in and helped me setup the ASV as it should have been if a had an ASV sleep study...

Jedimark now has my data from that unintentional experiment..

Cowboy Casey wrote:MY ASV was set up exactly as a BIPAP when I first received it from my DME, that was the prescription pressure that I had on file from my sleep study.. I went 4 days with it and had the same crappy results as my old BIPAP machine... then IAN and Pugsy stepped in and helped me setup the ASV as it should have been if a had an ASV sleep study...

Jedimark now has my data from that unintentional experiment..

sure, if you set it at say, min ps 5 and max ps5, then it's a bilevel

did you ever go further in your experiment with the wireless cards?

JDS74 wrote:As part of an experiment to provide some data to Jedimark concerning SleepyHead, I did an experiment this morning.
I tried to set up my Respironics ASV machine to be in straight BiPap mode.
Here are the parameters:

Sorry to disagree with you on this one JDS74 but Palerider is correct and these settings are APAP mode and not BIPAP. Fixed BiPAP can be set on the 960 by setting the PS MIN and MAX to the same value but not zero. If they were both set at 5 a fixed bilevel of 5 cm (without ASV) would be applied.

As regards to your different breath holds, I am interested as to how you did them differently. I will then have a go at working out why the different machine response.
Ian

igdoc wrote:As regards to your different breath holds, I am interested as to how you did them differently. I will then have a go at working out why the different machine response.
Ian

Ian
Its relatively easy to simulate an OSA event.
In my case, simply using the tongue to block the airway did it.
Remember, I'm using an oral mask so the issue of the nasal passageway doesn't apply.
Similarly, simulating an CSA event means just stop breathing, don't block anything.
Does that explanation help?

I thought the difference in responses was interesting also.

With a FFM, simulating an OSA event while still wearing the mask would be more tricky.

My guess would be to disconnect the mask hose and just block it. The disconnect would have to be on the mask side of the anti-asphyxiation valve in order for the machine to still see "normal leakage" in the air flow.

Whoops, that wouldn't work either. What needs to be simulated is the vent at the mask remaining open, not the anti-asphyxiation valve being open.

Blocking at the end of the hose would get a condition that could not happen to a patient's airway but might be an interesting experiment anyway since it is likely that the firmware developers never considered the possibility. That would be a condition in which something happened and the hose was crushed flat blocking the air flow.

So, I'm not sure how it could be done with a FFM.
With a nasal mask that had the vent built in to an external device that was disconnectible, the making the break on the mask side of that device and blocking might do it. Just speculating here since I don't have either mask style to experiment with.

If I were the firmware developer for this machine and I intended it to be usable as a CPAP, Auto BiPap, or an ASV machine, I would make those menu choices and not depend on mode selection by guessing from the other settings.
But that's just me.

In ASV mode, logically there would never be a pressure pulse as is seen in other models. The machine switches immediately into ventilator mode when it detects a loss of air flow to the patient. That either opens the airway for an obstructive event or provides ventilation for a central event. it would be easy to tell the difference and should be flagged as such (and my recollection is that it does mark obstructive events.) Therefore there is no need for the pressure pulses in that circumstance. I haven't had any OSA events in many months so they don't show up on my charts.

BTW I placed an edit in the OP noting the "Bi-Level" error.

I am able to simulate an OSA event by jamming the base of my tongue back into my throat which blocks air from both my mouth and my nose.

photonic wrote:I am able to simulate an OSA event by jamming the base of my tongue back into my throat which blocks air from both my mouth and my nose.

Exactly. Just another advantage of the Oracle 2 mask

New thought:
In answer to a different post, it occurred to me that using an Oracle 2 nasal plug would allow a FFM user to simulate an OSA event. A use for these noticeably unusable devices. If one didn't have access to these, then a pair of soft ear plugs might do as well. Plugging the nose in this way would, in effect, convert the FFM to an oral mask. Except for experimentation and/or training purposes, I have no idea why one would want to do so on a regular basis.

palerider wrote:

Cowboy Casey wrote:MY ASV was set up exactly as a BIPAP when I first received it from my DME, that was the prescription pressure that I had on file from my sleep study.. I went 4 days with it and had the same crappy results as my old BIPAP machine... then IAN and Pugsy stepped in and helped me setup the ASV as it should have been if a had an ASV sleep study...

Jedimark now has my data from that unintentional experiment..

sure, if you set it at say, min ps 5 and max ps5, then it's a bilevel

did you ever go further in your experiment with the wireless cards?

I did, I was able to get a connection from my machine and the WIFI with a range extender and could see the data on the card inside the machine... I could never get the data off as data unless i went to each and every file and downloaded it... The cards are set up thinking "ALL" data on the SD card are pictures and treats it all the same... Untill someone "hacks" a card and turns it into "data" its to much work to get the data off the card....

JDS74,
Based on my very limited experience with Respironics ASV 960 (I have been testing it during last two weeks):
(1). In order to use Respironics ASV as a Non-ASV device, BPM (backup rate) should be set to “Off” not “Auto”. This way you completely eliminate “machine triggered breaths”
(2). My SH reports show both CA and OA apneas in ASV mode. Respironics ASV 960 uses pressure pulses to distinguish between them (Sleepy Head shows many “Pressure Pulse” events).
So Respironics ASV 960 has both “machine triggered breaths” and “Pressure Pulses”. Thus, one need to use two different types of event flags.

Corrections:
1. Actually BPM=“Auto” is a Non-ASV mode, but it is not APAP or BiPAP also. It is more like BiPAP S/T.
2. I realized that Sleepy Head “Pressure Pulse” events could be in fact “machine triggered breaths” (due to current SH implementation). However, SH still shows OA and CA separately. So it can distinguish them somehow.

buran wrote:JDS74,
Based on my very limited experience with Respironics ASV 960 (I have been testing it during last two weeks):
(1). In order to use Respironics ASV as a Non-ASV device, BPM (backup rate) should be set to “Off” not “Auto”. This way you completely eliminate “machine triggered breaths”
That suggests an experiment to see if this is indeed the case. It does seem likely, though, on the face of it.
(2). My SH reports show both CA and OA apneas in ASV mode. Respironics ASV 960 uses pressure pulses to distinguish between them (Sleepy Head shows many “Pressure Pulse” events).
My comment was meant to explain why, in ASV mode, the machine does not need to generate pressure pulses to distinguish. Failure to breathe on time generates a giant pressure pulse (ventilation mode) and the machine can easily tell the difference. It is quite likely that Jedimark has flagged Triggered Breaths as Pressure Pulses. He is looking into this issue currently.
So Respironics ASV 960 has both “machine triggered breaths” and “Pressure Pulses”. Thus, one need to use two different types of event flags.
Its not clear if the machine actually does have a separate flag it uses in ASV mode. JediMark is looking into the data to make that determination. When not in "normal" ASV mode, it does generate pressure pulses as my data illustrated.

Corrections:
1. Actually BPM=“Auto” is a Non-ASV mode, but it is not APAP or BiPAP also. It is more like BiPAP S/T.
I think I'll have to differ on this point since my machine is normally very much in ASV mode and the BPM is set to Auto.
I did do a short experiment of setting BPM to 10 which might be the equivalent of BiPap S/T mode to look at what happens to my breathing before the triggered breaths occurs. I found out that my breathing is very irregular in terms of timing of breaths. Having found that out, I switched back to Auto where I remain.
2. I realized that Sleepy Head “Pressure Pulse” events could be in fact “machine triggered breaths” (due to current SH implementation). However, SH still shows OA and CA separately. So it can distinguish them somehow.

Thank you very much for your observations and welcome to the Respironics ASV club.

JDSL thanks for the information about obstructing the airway, I will have to use this in future.

Just a couple of points regarding all the above, firstly the 960 disables the BPM automatically when the PS Max is set to 0 for APAP or CPAP mode.

When breath holding (without physically obstructing the airway) which is by definition a central event, the machine may register an 'obstructive' apnea because there may be no flow change in response to the small 2cm H2O pressure pulses. In a way this is an example of a falsely classified event but can occur when awake and turning over in bed.

With regard to the different machine responses for the two different breath holds, my only thought is whether the first breath hold occurred soon after the machine had been activated and there will probably be a short lead in time of a minute or two before it starts responding. It might be worth repeating the experiment to see if this is the case.
Ian