Patient triggered breaths - do these stats suggest I need ASV?

I have an appointment with the sleep doc tomorrow.

It has bee suggested by several people that I need ASV to treat my centrals as it is breathing for me.

But if you look at the Patient Triggered Breaths Section in the image below, there was a sudden plummet from invariably being 100 per cent to as low as the 30s...that coincided with the pressure increase from 6-17 to 10-20. So this suggests to me that my current machine is adequate as long as the p5ressure i snot too high. Or have I misunderstood something and could ASV be a better bet after all?

Do you have the correct machine listed? If you have a BiPAP S/T, I have no idea how you are using a pressure range?

Please list your exact machine, and all your prescription and machine settings so we can make better sense. There are a lot of different reasons for PTB % changing.

OP is in the UK
He does indeed have the PR S1 BiPap S/T 30 model 1061
and these were his settings last June....his nurse and/or doctor wants to use some big PS numbers.
I have no idea what they are now but it is indeed a fixed bilevel machine with a back up rate of some sort and probably even bigger PS numbers

The combination of large pressure support (PS) and fast rise time means you are being hyperventilated to hell and back most likely. That is pretty easily confirmed by your high tidal volumes and minute volumes.

The low backup rate of 8bpm pretty much rules out the backup rate as being a culprit for PTB % change (meaning you aren't fighting the backup rate with your own spontaneous rate).

I don't think the machine is the culprit - the settings are though for sure.

Are you able to alter the settings? If the IPAP and EPAP being altered would get you in trouble, I would at least increase the rise time to 2 or 3 and see if that helps a bit.

raisedfist wrote: ↑

Tue Jan 22, 2019 6:35 pm

The combination of large pressure support (PS) and fast rise time means you are being hyperventilated to hell and back most likely.

Which would *cause* centrals, and fewer patient triggered breaths.

I do wish we could disallow people who make threads and then abandon them...see it time and time again here.

raisedfist wrote: ↑

Thu Jan 24, 2019 10:20 am

I do wish we could disallow people who make threads and then abandon them...see it time and time again here.

Thank you for the replies. The stats that Pugusy posted (for which, thankyou also) were from when the pressures were at their highest.

I have not abandoned the thread. I was in bed all day after the hospital visit as I felt so lousy.

Pressures are now back at 6-17, as I cannot even tolerate 10-20. They just set that PS as standard for the clinic.

To my surprise, the doctor was amenable to the idea of my getting ASV. As Respironics had failed to supply my latest data download, I am seeing her again soon.

They freak out if you alter the settings yourself (which I know how to do if I want). Duty of care...

If I wete starting out and not going to have titration done (which I have not anyway), would anyone recommend starting therapy at 6-17?

If not, what would be more sensible settings, as I do not have COPD (which is what they generally treat at this clinic).

Chalkie wrote: ↑

Thu Jan 24, 2019 12:02 pm

would anyone recommend starting therapy at 6-17?

No.

And you need to be more specific with your settings.
6 to 17 tells us nothing.

And if you do get an ASV machine...doesn't matter what we think would be good starting settings anyway.
Your doctor will set it up and you won't change it.

Take a picture of your settings and post them here. The S/T machine does not have an auto-range capabilities. Honestly, who cares if they freak out about you changing the settings. The settings they seemingly set are stupid and harmful. If this has been longstanding, you are better off finding a new physician (one who knows what the hell they are doing) or buying your own gently used machine and gaining control over your own therapy and health.

When you tell us the settings...we need to know EPAP and IPAP and the back up rate.

If your EPAP is 6 and your IPAP is 17....it's very likely causing central apneas...not fixing them.

Yup...the opposite of "Do No Harm" ...ignorance isn't an excuse in law, it shouldn't be in medicine either!

Chalkie wrote: ↑

Thu Jan 24, 2019 12:02 pm

raisedfist wrote: ↑

Thu Jan 24, 2019 10:20 am

I do wish we could disallow people who make threads and then abandon them...see it time and time again here.

Thank you for the replies. The stats that Pugusy posted (for which, thankyou also) were from when the pressures were at their highest.

I have not abandoned the thread. I was in bed all day after the hospital visit as I felt so lousy.

Pressures are now back at 6-17, as I cannot even tolerate 10-20. They just set that PS as standard for the clinic.

To my surprise, the doctor was amenable to the idea of my getting ASV. As Respironics had failed to supply my latest data download, I am seeing her again soon.

They freak out if you alter the settings yourself (which I know how to do if I want). Duty of care...

If I wete starting out and not going to have titration done (which I have not anyway), would anyone recommend starting therapy at 6-17?

If not, what would be more sensible settings, as I do not have COPD (which is what they generally treat at this clinic).

6-17 suggests a pressure RANGE, which an S/T machine is unable to do, a S/T machine offers a set inhale and exhale pressure, and those bilevel pressures are written as 17/6, 17 inhale, 6 exhale. or EPAP 6 and a PS of 11, that's a *lot* of PS.

When I Trialled an ST I had PS of 8 to treat the Central apnoea it was not helpful/comfortable and did not improve my numbers the CA remained untreated most of the time.

Just in case someone here reading this is using ASV and realizes that their machine will sometimes do 10 to even 15 PS when dealing with centrals....yes it will do that but the key is sometimes and only when needed. When no centrals are happening the PS goes down to whatever minimum it is set at and usually that's 3ish to around 5.
So you ASV users....don't freak out here.

The ST machine does it with each and every breath and the ASV does it only when needed. Big difference in what is happening here.
Too much PS all night long can cause Carbon Dioxide wash out or reduced levels and that's when the brain sits by and says to itself "CO2O levels are low...no need to send the signal to breath" and we get centrals.

So PS is good in the ASV use of it because it is on an as needed basis and not all night long with each and every breath.
Not so good in high numbers with the ST machine because it's doing it whether it is needed or not and creating a hyperventilation situation where it can actually cause low CO20.

Now there are probably some medical situations where continued ventilation is needed for some reason or other but that's going to involve some very special respiratory issues.
It is unclear if OP has anything special going on to cause him to need ventilation on an each and every breath situation.
From what I saw in the past with sleep study results that I saw....he started out with OSA and a few centrals with cpap use. Never saw the diagnostic sleep study that I remember anyway. He might have had a mixture even on the diagnostic study so they decided to put him on the ST.
Problem with that is he still needs adequate EPAP to deal with the obstructive stuff....and the 6 isn't adequate.
And the constant high PS is probably causing more centrals than it is fixing by breathing for him.

It's painfully obvious that this way isn't working but no one seems to know what else to do or they are unwilling to do anything except increase PS.
The ST could maybe be used to treat both OSA and the central apnea...but with careful use of the options available.
It's really best used for central apnea only and even then when there are other medical issues involved causing the lack of breathing....like neuromuscular kind of stuff where the person simply can't move the air themselves.

OP needs a new medical care team or he needs to take charge and at least try something different with this machine (and event then I don't know if he could have success).....both of which he simply is unwilling or unable to do.

Why not just take one single night, and change the settings drastically, and see what happens. The CPAP Police are not gonna kick down your door and arrest you, and take your machine away.

Just say this out loud: Your medical team, professionally obligated to work on behalf of your health, are actively causing you harm instead.

The ASV may be of benefit. Until then - I would take the wheel.