Understanding Pressure Sup. on my P.R.S.O Bipap AutoSV adv.

I am still trying to understand the role of Pressure Support MINIMUM on my Phillips Respironics System One Bipap AutoSV Advanced.

On my ResMed S9 Autoset my 95% pressure is 14.88
Max 15.86.
AHI usually below 2. I do not have excessive mask leaks.

I have set the following on my Bipap AutoSV Advanced:
EPAP min 8
EPAP max 15
PS min 2
PS max 20
Max pressure 25
Rate auto

The first couple of nights I had the pressure support MIN set on 0. My AHI on Bipap AutoSV Ad. is usually around 0.59 or less.

I find going to sleep Bipap AutoSV Advanced very easy, in fact amazingly so, as I do not have to breath against the high pressures that I usually have to breath against within just a few minutes of going to bed, on my Resmed autoset.

However On the Bipap AutoSV Advanced I then find myself being woken up every couple of hours by something..... possibly a massive burst of air, I am not sure what though.

So my question is, in very simple terms, if I set the pressure support minimum to 2 will it make a difference to these huge sudden bursts of air that I am experiencing? What difference will I feel, if the machine is set to PS min 0 or PS min 2?

I am still finding difficult to understand how PS min is going to affect the over all automatic functioning of this machine.
Any input would be greatly appreciated.

Others with much more experience than me will surely chip in with comments.

I have set the following on my Bipap AutoSV Advanced:
EPAP min 8
EPAP max 15
PS min 2
PS max 20
Max pressure 25
Rate auto

Setting EPAP Min to 8 and Max Pressure to 25, limits the variation of the Pressure Support parameter to the range of 2-17 not 2-20 as the parameters suggest.

Setting EPAP min to 8 and PS min to 2 means your initial pressure starts out at 10cm H2O, quite a bit less than the about 15cm H2O from your previous machine.

I suspect that the 'burst of air" you are experiencing is a rapid increase from the start of 10cm H2O to the max pressure of 25cm H2O, a pressure change of 15cm H2O probably over a period of 5 to perhaps 20 seconds. The machine detecting a central apnea could cause it to respond in this manner.

How did you come to these numbers? Did you have a titration or sleep study that set them for you?
One caution, I don't suggest that it is safe to fiddle with the numbers without the guidance of your sleep doctor.
The reason that there is a significant difference between EPAP min and Max Pressure is to ensure that if your machine goes into ventilator mode and breathes for you for any significant period of time, the tidal volume as a result will be sufficient to provide oxygen to you until you begin to breathe on your own again.

As JohnB has mentioned, getting used to this type of machine can be quite a struggle.

Do you have any reports indicating what percent of patient initiated breaths you are experiencing?
Since starting on this same machine myself, I have had as few as 67% patient initiated breaths (about 1 hour and 20 minutes in ventilator mode).

Hi JDS

Thank you for your kind input. I have pasted some of my SH results,first time I have managed to post results,which I am really pleased about thanks to Pugsy's excellent post of how to do that here:viewtopic.php?f=1&t=81072&p=737779#p737779. I have been wondering how to do this for years!

If I am interpreting the results correctly I am having 100% patient initiated breaths which is good, so machine does not seem to be going into ventilator mode, unless I am very much mistaken of course.

Your patient triggered breaths shows a min of 64% and you have a few instances of pretty sudden rises in pressure.
I don't know with the version of SleepyHead you are using, but I think the Pat. Trig. Breaths is a rate per minute number rather than the overall number reported by Encore Pro.

In any event, your numbers look good.
Keep up the good work.

Hi JDS

The version of sleepy head that I am using is the 0.9.0.3-0. so I am not sure if it is 'breaths per minute'. How could I find out?

With reference to my 'patient triggered breaths showing a min of 64%' does that mean that my autosv goes into ventilator mode 36% of the time? Or not necessarily?

Will my raising the Pressure support MIn to 2 from 0, as I have done, affect the massive bursts of air that I am getting during the night? Perhaps by decreasing them slightly?

I am considering increasing the PS to a Min of 4 to see what difference it would make. I would again, really appreciate any thoughts.

I am surprised that I am having these slight 'awakenings' on the AutoSv because my auto pap, for years, used to regularly,swing from pressure 7 to 15 and more often than not up to 19 or 20 and I slept right through it, however, then finding myself being woken by an excruciating tummy ache in the early hours of the morning,as a result of having swallowed tons of air and feeling I was very close to bursting point! At that time though, I used to have enormous mask leaks which I now, hopefully, have sorted out and am no longer plagued with.

Think of pressure support as the IPAP of the moment. So the ASV unit adds the current PS value to the current EPAP value to give you your current IPAP value. Increasing PSmin to 4 should have minimal impact other than making it easier to breathe and exhale. It will feel more like a BiPAP machine.

Hope that helps.

If you go to the statistics section (left side) on the daily detailed graphs and hover your mouse over each value you will see a little box pop up that will give you units of measurement for each value.
Percent of patient triggered breaths...the higher the better. The detailed graph should show you when you were at the minimum if it is significant. Often the "minimum" value reported by SleepyHead is just a brief scoring time and not often bears any significance.
Same as it is shown in Encore.
EncoreGuide link this will show you examples of what you will see.
http://www.healthcare.philips.com/pwc_h ... _Guide.pdf

Did we ever get your Encore up and running or are you one of the ones who had problems installing it?

I notice several of you are using Sleepyhead with PRS One ASV Auto machines, yet it does not yet seem to work with my new DS960 ASV. Why can you al use SH and I can not?

bwexler wrote:I notice several of you are using Sleepyhead with PRS One ASV Auto machines, yet it does not yet seem to work with my new DS960 ASV. Why can you al use SH and I can not?

SleepyHead works with some of the 950 models but not all. I don't know why it works for some and not others who have the 950 model. Right now it won't work at all with the 960 model.
The 960 was released after the main work on SleepyHead was done so Mark didn't have a chance to dig into the file structure of the 960. Even the original Patch file wasn't made to work with the 960 because that model's data was available for study. The 960 is really relatively new and apparently Respironics changed a lot of the files because it wasn't until recently that Encore would even support it and then only the Pro 2.12 version.. even though Pro 2.11 worked with the other 60 series models very well.
Mark...SleepyHead's creator...is working on trying to get SH compatible with the 960 but it takes time and work and access to data from SD cards from that machine.

Would it help Mark, and all of us if I were to forward additional data fills from my 960?

bwexler wrote:Would it help Mark, and all of us if I were to forward additional data fills from my 960?

I think that he already has some SD card data from 960 users but I don't know if he has enough or not.
I do know it takes time and a lot of work and there are other issues he is trying to sort out with SleepyHead at the same time.
Software development takes time and Mark is one person doing this. Plus he has to have a life outside of SleepyHead as he has his own health issues that have created some road blocks.

I would love to be able to help more than I do but what I know about coding you can fit on the head of a straight pin and I just can't wrap my brain around it enough to help in that manner.

Thanks Pugsy for the info on encore interesting guide, I had not seen that before.
Useful to know how to find out units of measurements.

I did have encore on my laptop but I no longer have the card reader for it.
I do not think that I have tried installing it on my main computer which is a 64 bit Windows Vista, so I would very much like having a go at trying to install it.

Back ground info about myself:
I do not have any underlying other condition like heart etc.
All been checked out by having a full health screen, therefore not on any meds, thankfully.People on the forum have kindly expressed concern, so thought it was worth clarifying.

Last night Turned the Min Pressure Support up from 2 to 3 and my readings are worse. My AHI up from 0.5 to 1.66.

Is it just coincidence or could turning up Min Pressure Support make my AHI go up?

I shall continue another night without changing anything.

sleepinglass wrote:... Last night Turned the Min Pressure Support up from 2 to 3 and my readings are worse. My AHI up from 0.5 to 1.66.

Is it just coincidence or could turning up Min Pressure Support make my AHI go up?

I shall continue another night without changing anything. ...

Is it a coincidence or a trend? You chose the correct cup! ...

There's an old saying you will hear repeated on the forum. One night a trend does not make!

Typically you need to see the data over several nights. Oh, if the AHI had gone from 0.5 to 50, we could be pretty certain it was not a good setting for you. But a bump from 0.5 to 1.66 is quite possibly statistical noise. That is, you might have awakened one or two extra times during the night. See what happens after a week or so.

Hope that helps.

Thank you John for your input, I very much appreciate it.

I must be patient, only problem is, even though the numbers look good, I do not feel at all rested and do not feel that I am sleeping soundly, in fact, I am falling asleep in the day.

I have one question, I read somewhere trawling through the internet that the PS Min must always be equal to EPAP. I am not sure if that applies just to bipaps or to the auto asv as well, or if that is just nonsense.

So if my EPAP Min is 7 because my auto pap my pressure 95% cm H20 is often 15.28.

I am just wondering if the Pressure Support should also be 7 to match the EPAP Min?

I do not have difficult falling asleep,have never used or tolerated ramp, or bipap, I do not get up during the night, however on the AutoSV wake up after 5,6 or 7 hours, feeling absolutely shattered.

Something is not right! I welcome thoughts or suggestions.