ASV - Cheyne-Stokes Episode Treated

Entering month two of my new ASV machine and I noticed this sequence of ventilator activity. I think it shows a 15 minute episode of Cheyne-Stokes breathing starting at 1:56 AM and ending about 2:11 AM being treated. Needless to say, I slept through the whole thing.



A question on pressure settings: If the Pressure Support + EPAP total remains the same, will there be a bigger switch in pressure when the machine goes into ventilator mode if the EPAP is raised or if the Pressure Support is raised?

I am assuming that the larger the change in pressure, the more air exchange takes place and the better the distribution of Oxygen will be during a ventilator period.

I don't know exactly how the ASV's work but what I've found is that they tend to take the 'where you're now' pressure and the 'max pressure' and split it up into segments.

Look at your first line. The first timed breaths' pressure start out say at 1/3 of the difference then it goes to 2/3 and then up to the full max pressure (the red line).

My original max pressure setting was too low and those first timed breaths didn't do much to stabilize my breathing. Setting the Max Pressure to 25 allows that first blast to be rather high and my body responds better to that.

I also think the machine takes into account flow rates and elapsed time. If you haven't had a full breath for a while it hits you with close to Max Pressure on the first timed breath (look at the 6th timed breath in the first line where the CA occurs).

Is that sequence CSR? In this case, I have a lot of CSR as well. Maybe need to call a sleep doctor.

Are you confusing Cheyne-Stokes with clear airways - because they're not interchangeable CS respiration is quite serious - were you diagnosed with it?

I don't see any CSR breathing there. I think if there was there would be a turquoise line showing it all.

JDS74 wrote: A question on pressure settings: If the Pressure Support + EPAP total remains the same, will there be a bigger switch in pressure when the machine goes into ventilator mode if the EPAP is raised or if the Pressure Support is raised?

Asking for some clarification here.

First: Your signature shows your machine as an PR System One Series 60 BiPAP AutoSV Advanced. Are you using it in fixed BiPAP mode or auto adjusting BiPAP mode?

Next: I need some mathematical clarification about what you are asking. You say you want to hold

• Pressure Support + EPAP = CONSTANT

but you also want to increase ONE of (Pressure support, EPAP), but the only way to do this is to increase one of the two settings and decrease the other one by exactly the same amount. In other words, if you chose to increase EPAP by 3 cm, you must decrease PS by 3 cm if you want PS + EPAP to remain the same. Likewise, if you choose to increase PS by 3 cm, you must decrease PS by 3 cm if you want PS + EPAP to remain the same. Is this really what you're talking about???

Finally, if you are running in fixed EPAP mode, my understanding is that in "ventilator mode" (when the machine is triggering inhalations), the IPAP is allowed to go to MAX IPAP. Hence the maximum difference in pressure between inhalation and exhalation will be: MAX IPAP - EPAP in fixed EPAP mode. I believe the PS setting simply sets up the "usual" difference between IPAP and EPAP on "normal" inhalations---i.e., when the machine is not triggering an inhalation for you, IPAP = EPAP + PS, but I'm not sure of this. Perhaps you could give me a list of all the pressure settings? That would make it easier to figure out what you're talking about in terms of how the PS setting would affect things.

robysue

I'm running in auto mode.
Both pressure Support and EPAP are allowed to vary.

I'm having excess hypopneas even though OSA = 0.0, and CSA's are being treated just fine.
So, with the approval of my sleep doctor, I'm exploring small changes in either Pressure Support or Min EPAP or both.
Since getting this new machine, I've had a couple of times when the machine was in ventilator mode for more than one hour. I'm concerned with maximizing the air exchange during these periods. So I don't want to change pressure settings to reduce hypopneas and end up reducing air exchange effectiveness.

Since I've had CSR episodes lasting 16 minutes or so recorded on my 750P Auto BiPap machine before getting this 960P and this sequence looks similar except from the pressure swings that treat the CSR lows, I concluded that it was the same, just treated.

CSR can be a serious condition normally associated with some pretty bad heart conditions, for example.
In my case, it's idiopathic CSR not related to anyhing the doc's have found. BTW, I'm getting really tired of repeated echocardiograms each time a new doctor sees CSR in my medical records.

Lazer1234 wrote:Is that sequence CSR? In this case, I have a lot of CSR as well. Maybe need to call a sleep doctor.

CSR breathing patterns look like this.



Nothing in the graph first posted appears to be CSR to me...and certainly didn't appear so to the machine or it would be highlighted in green. The PR System One machines will flag CSR because CSR is a form of Periodic Breathing. Not all PB is CSR though.
Your S9 doesn't flag PB so nothing to point to but if you will post the series of breaths that appear questionable to you someone had maybe help you decide for sure.

I have made ​​custom flags, apnea between 5 and 10 seconds. It is U1. That's a typical night.

The problem in looking for a CSR episode in an ASV waveform recording is that the ASV machine reacts immediately and changes the wave form dramatically. It won't look anything like an untreated episode.

In this case, the machine initiated sequences are spaced at the same intervals, etc. of prior episodes I have had.

Lazer1234 wrote:Is that sequence CSR? In this case, I have a lot of CSR as well. Maybe need to call a sleep doctor.

Your machine reports but does not treat CSR events.
It is very unlikely that what you show is related to CSR so you should relax.

Cheers

JDS74 wrote:robysue

I'm running in auto mode.
Both pressure Support and EPAP are allowed to vary.

So your machine has the following pressure settings?

Min EPAP
Min PS
Max PS
Max IPAP

And EPAP gets raised in response to obstructive events (OAs, snores, etc).

And the ASV kicks in when the machine is not happy with the respiratory rate or the minute volume or both and starts triggering breaths. And the ASV involves a hefty increase in IPAP as the way to trigger the inhalations.

And by the way, do you know if EPAP or IPAP is raised when clusters of Hs, clusters of RERAs, or FLs, are detected? I ask because on a System One BiPAP Auto, it's the IPAP that gets increased for H's, clusters of RERAs, or FLs if there's no snoring or OAs occurring at the same time. So I'm wondering how the Auto EPAP algorithm on the System One ASV Advanced works.

Now my understanding is that on your machine, the Max EPAP and Min IPAP are not set directly, but rather they are determined by the other settings as follows:

Min IPAP = Min EPAP + Min PS
Max EPAP = Max IPAP - Min PS

And out of curiosity, is Max IPAP = Min EPAP + Max PS?

And now asking for more clarification about your original question, which was:

JDS74 wrote:A question on pressure settings: If the Pressure Support + EPAP total remains the same, will there be a bigger switch in pressure when the machine goes into ventilator mode if the EPAP is raised or if the Pressure Support is raised?

Are you talking about leaving:

• min PS + min EPAP = Constant
• max PS + min EPAP = Constant

and are you talking about raising min EPAP, min PS, or max PS?

Lazer1234 wrote:I have made ​​custom flags, apnea between 5 and 10 seconds. It is U1. That's a typical night.

Those don't look anything like CSR to me. Also you are using custom flagging which doesn't meet real apnea criteria anyway.

This is probably the closest I have seen on mine that looks CSR ish and it isn't and even if it were it's short lived and extremely rare.

Pugsy wrote:

Lazer1234 wrote:I have made ​​custom flags, apnea between 5 and 10 seconds. It is U1. That's a typical night.

Those don't look anything like CSR to me. Also you are using custom flagging which doesn't meet real apnea criteria anyway.

Lazer,

I have to agree with pugsy. This doesn't really look like CSR to me because it doesn't really look like periodic breathing in the first place, and CSR is a special type of period breathing. Like pugsy, I don't often get periodic breathing flagged by my System One, and when I do, it's pretty minimal in both the sense of not lasting very long and in barely meeting the criteria for being scored as periodic breathing by the System One. However, this little stretch from 10/3 does nicely show the waxing and waning pattern present in periodic breathing, even though at the minimum of the cycle, the airflow is (just barely) strong enough to not get flagged as an H by my machine:



Notice how the breaths are clearly getting larger and then they get smaller and smaller for several breaths, before "bottoming out" in the (near) hypopnea and start to grow again.

Contrast my clear waxing and waning pattern to your pattern:

All the breaths in your pattern are about the same size; the only "odd" thing is the slightly longer pause between inhalations that you've had SH flag with the custom flagging option as "apneas lasting between 5 and 10 seconds". My guess is those things are only about 5 seconds long and they probably don't represent anything "real" even though there's a lot of them.

robysue wrote:

JDS74 wrote:robysue
I'm running in auto mode.
Both pressure Support and EPAP are allowed to vary.

So your machine has the following pressure settings?
Min EPAP
Min PS
Max PS
Max IPAP

My Settings
Min EPAP: 9.5
Max EPAP: 15.0
Min Pressure Support: 7.0
Max Pressure Support: 15.0
Max Pressure: 25.0
Backup Rate: Auto
Flex Setting: 1
Humidification Mode: System One
Humidifier Setting: 5

robysue wrote:And EPAP gets raised in response to obstructive events (OAs, snores, etc).
And the ASV kicks in when the machine is not happy with the respiratory rate or the minute volume or both and starts triggering breaths. And the ASV involves a hefty increase in IPAP as the way to trigger the inhalations.

It also drops the Pressure support entirely so if the current calculated IPAP is 20 in my case with my parameters, then in ventilator mode (ASV acting up), the EPAP pressure drops to 9.5, a pressure change of 11.5 cmH2O. When this happens, normal relaxation of the chest causes an exhale.
Normal biflex pressure changes are around 3 or so depending on the particular machine and the settings. Biflex doesn't change enough to affect the lung air mixture so if you were depending on biflex to breathe in the absence of patient effort, shortly the CO2 level would be quite high and the O2 level quite low. Not a good place to be.

robysue wrote:And by the way, do you know if EPAP or IPAP is raised when clusters of Hs, clusters of RERAs, or FLs, are detected? I ask because on a System One BiPAP Auto, it's the IPAP that gets increased for H's, clusters of RERAs, or FLs if there's no snoring or OAs occurring at the same time. So I'm wondering how the Auto EPAP algorithm on the System One ASV Advanced works.

Now my understanding is that on your machine, the Max EPAP and Min IPAP are not set directly, but rather they are determined by the other settings as follows:

Min IPAP = Min EPAP + Min PS
Max EPAP = Max IPAP - Min PS

And out of curiosity, is Max IPAP = Min EPAP + Max PS?

I don't think so. I think maxIPAP = Max Pressure but that can arrive in different ways. If there are obstructives, then EPAP is raised until EPAP + PS = Max Pressure. If there are CSA's, restriction in tidal volume, etc. then PS is raised. The amount of increase is governed by Max Pressure. There is no IPAP setting, either min or max. IPAP is a calculated quantity depending on the current EPAP and the current Pressure Support. It's hard to get my head around all of this since it seems that the various parameters interact with each other.

If I had the B-Flex turned off, then there would be another parameter: rise time that controls the rate at which the pressure changes between EPAP and "IPAP".

robysue wrote:And now asking for more clarification about your original question, which was:

JDS74 wrote:A question on pressure settings: If the Pressure Support + EPAP total remains the same, will there be a bigger switch in pressure when the machine goes into ventilator mode if the EPAP is raised or if the Pressure Support is raised?

Are you talking about leaving:

• min PS + min EPAP = Constant
• max PS + min EPAP = Constant

and are you talking about raising min EPAP, min PS, or max PS?

I'm talking about minPS+min EPAP being held constant. Absent any apnea events, this results in the same value for EPAP and for "IPAP" but allows for a different pressure swing (the point of my question) when a central type event occurs. My question is "Is the preceding statement true."