[split] Confusion over PS equation (Discussion)

[Rubicon]

Clearly you think ...

I get by.

Unfortunately, this thread was split off from another for some odd reason, so now it is out of context.  In that thread, the original poster had asked:

"Everywhere you look the formula for determining the Pressure Support setting is  (PS) ≈ IPAP – EPAP, so if IPAP is 15, EPAP is 9 then PS 'should' be 6 according to that. Or IPAP 20, EPAP 10 then PS 10. But you don't really see anyone setting the PS higher than 5...most of the time 3 or 4 regardless of what the IPAP/EPAP settings are. I just don't get why that formula is what it is if people don't actually set the machine that way. Even when I first got my machine is was set IPAP 25 EPAP 5 PS 5...I don't actually know how high the PS can be set, I've never tried turning it up past 6."

Consequently, the above explanation was offered to provide clarity for the apparent disparity pointed out by the OP.  In that scenario, what the EPAP:IPAP Gradient was is academic:  PS operates within that window.  EPAP:IPAP does not define treatment, it defines limits.

Granted, if the PS function is not employed; all breaths are provided by set EPAP/IPAP; and breath termination is flow-based, in that case those breaths would indeed be pressure support breaths.

The exception would be if the inspiratory time limits were active, in which that would technically be Pressure Control, not Pressure Support.

[Rubicon]

I suppose these are interesting observations and opinions, but to me there's no real weight to them if you don't have any working knowledge by not using a PAP yourself.

In this case, "having a working knowledge" and "not using a PAP yourself" are mutually exclusive.


But hey, you're certainly allowed your opinion.

[Rubicon]

Clearly you think you know more than everyone else including the doctors, researchers and equipment manufacturers that all refer to pressure support as being the difference between IPAP and EPAP. Please get your facts straight especially if you are going to be aggressive like this.

For example maybe you should inform Resmed they don't know anything about pressure support or positive airway pressure equipment. 

https://www.resmed.com/en-us/healthcare-...-10-vauto/

"The device works by adjusting the baseline pressure to hold the airway open while maintaining a fixed pressure support."

Two additional points:

1.  I hardly think that quoting the sales brochure offers proof of anything.  That said, I think for the layman that explanation is fine.

2.  Your statement "Clearly you think you know more than everyone else including the doctors, researchers and equipment manufacturers" is unfounded, since (a) you don't know what I think, and (b) you don't know if I, in fact, do know more than the doctors, researchers and equipment manufacturers.  Frankly, from what I've read here, if you guys' collective opinion of the doctors is even close to correct, then it wouldn't seem to take a lot for that to be true.

[Rubicon]

Pressure support (PS) also known as pressure support level is not a machine mode, it is a the level of support provided by a ventilation machine and it is equal to driving pressure - PEEP which are the equivalents to a PAP machine IPAP - EPAP.

Pressure support ventilation on the other hand is the mode of ventilation (not a bilevel operating mode) that many bilevel PAP device uses.

Bilevel is a type of machine and it just means the machine has two pressure levels (IPAP and EPAP). Bilevel is not the difference between IPAP and EPAP. The difference is PS.

Since it's Easter, I will refrain from my usual response, which would be

"WTF are you talking about!?"

But as previously noted, I will "restrain myself..."

[David Clark]

Rubicon:
"EPAP:IPAP does not define treatment, it defines limits." it is exactly that I was confused about. I don't know if I was having a bad day or what but I completely took it the wrong way when I read it and it stuck with me and I ran with it.
No worries Gideon I'm not confused about it anymore.

[Geer1]

Thanks but I don't actually use a machine,

We can tell. For future reference if you had a machine this is the setting to adjust the pressure difference between EPAP and IPAP. 

   

[Rubicon]

Rubicon:
"EPAP:IPAP does not define treatment, it defines limits." it is exactly that I was confused about. I don't know if I was having a bad day or what but I completely took it the wrong way when I read it and it stuck with me and I ran with it.
No worries Gideon I'm not confused about it anymore.

Glad it worked out!

[Rubicon]

We can tell. For future reference if you had a machine this is the setting to adjust the pressure difference between EPAP and IPAP. 

And actually TOUCH the machine??

Ewwww!

There are other ways to turn the dials:


l
Just because I don't "use" the machine, it doesn't mean that I don't "use" the machine...