Difference between BiPAP and ASV

[raisedfist]

Thankyou everyone who has taken the trouble to post these detailed explanations.

It seems clear that the consensus is:

(a) My machine can work for me but needs to be set up just right
(b) It is more sophisticated than some Bi-Levels but not as sophisticated as the ASV

I think this will take time and a patience and I have another appointment in early May for review.

What exact issues are you having? Aside from us explaining what the ASV is and does, people can help you optimize your therapy as best as they can if you provide the data.

[Chalkie]

The issues are erratic but often moderate to high AHI scores and quite a high leak rate.

As has been outlined on other threads, Sleepyhead is incompatible with my machine and I have had a hell of a time installing Encore Pro.

I am indebted to a fellow forum member for running my data through Encore Pro for me. They give me pretty good feedback.

[Pugsy]

IPAP does seem to vary a wee bit but EPAP doesn't and PS is for all practical purposes at 10cm....and that's all the time with every breath. I don't know if that high of a PS is causing the centrals or helping with them. There is an apparent forced back up rate being used of some sort.
I don't have access to any of the old sleep study results to know what the original problem was or is.

There are truckloads of both OAs and centrals when the leaks aren't bad. When leaks are bad they are so bad that I think that is why the lower AHI night....the machine can't sense what is going on because the leaks are so bad.
I have yet to see a report with a low AHI and it not have massive prolonged large leaks.

Here's a report that Chalkie gave me permission to share in the past so you all can see what is going on.
How to fix it...that is the million dollar question. I don't know the original problem nor do I know what the hell they were trying to do with this machine.
Plus I am just not familiar enough with this machine to know where to start. My gut tells me EPAP for the obstructive stuff but again I am just not comfortable offering specifics in this situation.

This was the old settings...EPAP at roughly 4.



This was with the new EPAP setting...roughly 6 but they kept PS god awful high..
The numbers have reduced but not enough to suit me. Centrals not nearly so bad. Maybe when they were bad they were post arousal centrals and not real. Meaning maybe the OAs and hyponeas caused arousals and the central was an arousal central and not real.
Unfortunately this machine doesn't give us flow rate to look at to see if maybe he was awake or not.
It also doesn't officially flag large leak but my past experience with Respironics machines...anything over 100 L/min total leak seriously compromises the machine's ability to sense and record anything.

[JDS74]

This is applicable to the Respironics 960 ASV and may or not be applicable to the BiPap S/T machine.

On my machine, in consultation with my pulmonologist, I have titrated the pressures and achieved better numbers (lower AHI) and somewhat better sleep.
However, because the machine max IPAP is 25 cm H2O, my base EPAP can never be above 15 cmH2O so that in the case of a prolonged central (my longest was 2.5 hours), the machine in ventilator mode could manage a swing in pressure from 10 cmH2O to 25 cmH2O to deal with the problem. My pulmonologist would like that range to be bigger but realizes that the OSAs weren't being treated adequately, hence the compromise.

It is possible that on the BiPap S/T the PS of 10 cmH2O is doing the same thing; i.e., preserving the ability to effectively ventilate. Without a proper manual, it is impossible to tell how this machine reacts to a central event - it certainly does it differently from the ASV machine with which I am familiar.

A this point, a long heart-to-heart with the prescribing physician seems called for so the OP can get an understanding of what the settings actually do and how the machine behaves in the presence of an extended central event. It may be that it can be tuned up with better results. Since it was prescribed at a time that an ASV was an available alternative (is this timing correct???), There may be some underlying reason for selecting the S/T instead of the ASV and it would be helpful to the OP to understand that reasoning.

[raisedfist]

I am pretty positive such a high constant pressure support is causing over ventilation, resulting in centrals because so much CO2 is being washed out. I would keep the IPAP the same and just raise EPAP to clear out obstructives and also reduce the pressure support. You should be able to tell within a night or two if that is helping or hurting.

The only time I've seen an EPAP of 4 is when someone doesn't really have OSA and are just using bi-level to help with ventilation. As far as I can tell here, complex sleep apnea is the issue.

Aside from the settings, it's clear that the mask used is not working at all. Those pressures are not very high and there should be little to no leaking honestly. Unfortunately finding the right mask requires some trial and error.

[palerider]

I am pretty positive such a high constant pressure support is causing over ventilation, resulting in centrals because so much CO2 is being washed out. I would keep the IPAP the same and just raise EPAP to clear out obstructives and also reduce the pressure support. You should be able to tell within a night or two if that is helping or hurting.

The only time I've seen an EPAP of 4 is when someone doesn't really have OSA and are just using bi-level to help with ventilation. As far as I can tell here, complex sleep apnea is the issue.

Aside from the settings, it's clear that the mask used is not working at all. Those pressures are not very high and there should be little to no leaking honestly. Unfortunately finding the right mask requires some trial and error.

what he said +1

[Chalkie]

I am pretty positive such a high constant pressure support is causing over ventilation, resulting in centrals because so much CO2 is being washed out. I would keep the IPAP the same and just raise EPAP to clear out obstructives and also reduce the pressure support. You should be able to tell within a night or two if that is helping or hurting.

The only time I've seen an EPAP of 4 is when someone doesn't really have OSA and are just using bi-level to help with ventilation. As far as I can tell here, complex sleep apnea is the issue.

Aside from the settings, it's clear that the mask used is not working at all. Those pressures are not very high and there should be little to no leaking honestly. Unfortunately finding the right mask requires some trial and error.

Thanks for the replies but feeling confused here. Just googled IPAP and EPAP but these are new terms to me. Ther is a lot to get my head around.

So should the pressures have been raised? Feeling lost here.

The technician just whacked the pressure up, with no discussion, and sent me packing with a new mask and a ticking off for admitting to using the forums.

[Pugsy]

What are the educational qualifications of the "technician" and when was the last time you actually saw a real doctor who knows about this stuff?

[palerider]

Thanks for the replies but feeling confused here. Just googled IPAP and EPAP but these are new terms to me. Ther is a lot to get my head around.

ipap = pressure while inhaling
epap = pressure while exhaling/pausing between breaths.
PS (Pressure support) = difference between the two.

The technician just whacked the pressure up, with no discussion, and sent me packing with a new mask and a ticking off for admitting to using the forums.

Some people are just too full of themselves. They want to be "in control" and want you to be ignorant and dependent on them.

[raisedfist]

So should the pressures have been raised? Feeling lost here.

The technician just whacked the pressure up, with no discussion, and sent me packing with a new mask and a ticking off for admitting to using the forums.

I think you're better off starting from scratch and using the forums help to get you some better settings. Either the technician doesn't know what they are doing, or they are just not interested in helping you. Or both.

Since you have the BiPAP S/T, I would switch it to Spontaneous "S" therapy mode, and set your pressures at something like IPAP 8 and EPAP 6 and see what happens. You should get less mask leaks, and with the lower pressures, especially less pressure support, there is less chance of the pressures themselves causing centrals. If you still have a ton of centrals, we can trial switching back to S/T mode with a low backup rate, and see if that helps. If that doesn't help the centrals, then probably off to ASV land you will need to go.

[Barb (Seattle)]

ASV is a 'ventilor' pap system. They told me bipap OR cpap won't force me to breathe..it waits for me.

ASV forces you to take a breath.

There are bipaps/bilevel machines that will act like ventilators and force you to breathe whether you do it or not.
They are special bipaps/bilevel machines though...they have what is called a back up rate that will time the breaths whether you do it or not.

So think of it this way...bipaps without a back up rate (what I call plain bilevels) and bipaps with a back up rate that will force a person to breathe and thus do act like a ventilator.

ASV isn't the only type of machine that has a back up rate and will force a person to breathe. What happens with the ASV machine is the machine only forces the breath if needed and the patient isn't breathing enough on their own.
ASV machines will auto adjust as needed....those other bilevels with a back up rate are fixed rates...nothing auto adjusting about it and they will make you breathe per whatever back up rate has been set.

So people need to understand that not all bilevel devices will act like ventilators...some will and some won't....and not all are auto adjusting of those that will act like ventilators.

I'm learning every day! thanks for the clarification

[Chalkie]

So should the pressures have been raised? Feeling lost here.

The technician just whacked the pressure up, with no discussion, and sent me packing with a new mask and a ticking off for admitting to using the forums.

I think you're better off starting from scratch and using the forums help to get you some better settings. Either the technician doesn't know what they are doing, or they are just not interested in helping you. Or both.

Since you have the BiPAP S/T, I would switch it to Spontaneous "S" therapy mode, and set your pressures at something like IPAP 8 and EPAP 6 and see what happens. You should get less mask leaks, and with the lower pressures, especially less pressure support, there is less chance of the pressures themselves causing centrals. If you still have a ton of centrals, we can trial switching back to S/T mode with a low backup rate, and see if that helps. If that doesn't help the centrals, then probably off to ASV land you will need to go.

All sounds eminently sensible. However, with the NHS they don't want you messing around with the settings.

What I COULD do is use the backup machine they have given me (and probably forgotten I have) and learn how to tweak the setting on that.

I reckon another sleep study is called for tbh. I agree I need to start from scratch.

[Jas_williams]

Chalkie

I am with the NHS I tweaked my settings the nurse asked why i had made the changes i explained my reasoning she was happy. Thus was in the furst 30 days of gaving the machine. As long as it helps your sleep AHI then i fobt see an issue.

[Pugsy]

I am with the NHS I tweaked my settings the nurse asked why i had made the changes i explained my reasoning she was happy. Thus was in the furst 30 days of gaving the machine. As long as it helps your sleep AHI then i fobt see an issue.

Chalkie's nurse/tech doesn't even want him coming here on this forum...we are a bad influence.
He got his hands slapped for just mentioning coming here. That's the kind of person he is dealing with.

[chunkyfrog]

If possible, a change in providers is due.
Health is too precious to trust to someone who DOES NOT CARE.