Talk To Me About Resmed's VPAP Pressure Support

Okay. Let's assume an IPAP of 11, EPAP of 6 and Pressure Support of 5 in VPAP Auto mode. That is a spread of 5 cms of pressure support which is governed by the EPAP rather than the IPAP pressure. So half of 5 is 2.5. The Resmeds can't do the odd numbers so lets assume half is 2.4 cms of pressure.

So during the night the Median, 95th Percentile and Maxium pressure reported is 8.4 cms. The Detailed graphs also shows a straight line 8.4 pressure.

Where is the auto adjusting??? Does this make sense to you? Am I thicker than the earth or something?

Slinky wrote:Okay. Let's assume an IPAP of 11, EPAP of 6 and Pressure Support of 5 in VPAP Auto mode. That is a spread of 5 cms of pressure support which is governed by the EPAP rather than the IPAP pressure. So half of 5 is 2.5. The Resmeds can't do the odd numbers so lets assume half is 2.4 cms of pressure.

So during the night the Median, 95th Percentile and Maxium pressure reported is 8.4 cms. The Detailed graphs also shows a straight line 8.4 pressure.

Where is the auto adjusting??? Does this make sense to you? Am I thicker than the earth or something?

Slinky the main issue is what do they mean by Pressure Support on that model. PS means different things betweem manufacturers and between models (i.e. PS on a Resmed Vpap Adapt SV has a very specific meaning that bears little resemblance to PS on a Vpap Auto.

I'll look up their def in the clin manual & post what I find.

Cheers

DSM

Right here is the Vpap Auto def ... (makes challenging reading just see the example for why )

Min EPAP and Max IPAP
====================
(VAuto mode) These settings allow you to restrict the range of pressures in
which the AutoSet algorithm can operate, using the Min EPAP and Max IPAP
settings (see Figure 3, Setting Min EPAP and Max IPAP pressures in VAuto
mode, on page 9 and Figure 4, Pressure Support in VAuto mode, on page 10).
The AutoSet pressure will vary across the session according to the patient’s
needs. It responds to apneas, snoring and flattening of the patient’s flow curve.
Min EPAP and Max IPAP can be adjusted to limit the upper and lower AutoSet
pressure limits.
The pressure range in VAuto mode is 4–20 cm H2O.
Note: The device will stay at Min EPAP (with the selected amount of pressure
support) during the Settling time (if selected) at the beginning of a session.

Example:
Start with the settings Max IPAP = 15 cm H2O, Min EPAP = 10 cm H2O and
Pressure Support = 3 cm H2O. If the Max IPAP setting is readjusted to 11 cm
H2O, the device automatically reduces Pressure Support to 1 cm H2O. Max IPAP
(the highest-priority setting) is preserved.


Pressure Support
==============
(VAuto mode) Pressure Support allows you to set the difference between
inspiratory and expiratory pressure. This value can be adjusted for patient
comfort. A maximum PS value of 10 cm H2O can be selected.
In VAuto mode, if Pressure Support is above 6 cm H2O, treatment efficacy may
be reduced.
Note that the actual delivered pressures will be
AutoSet pressure ± 0.5 x pressure support (as set by the clinician).

NOTE:
=====

Priority is given to the Max IPAP setting, followed by Min EPAP and then
Pressure Support. The device automatically adjusts the lower-priority settings to
ensure the device pressure limits are not exceeded.

**************************************************************************************************

This tells me that if you set epap Min to 8 AND PS to 4 then ipap will start at 12. I also assume from the manual that if Ipap were lifted by the event detection algorithm, then epap will follow by the PS gap.

If you set Ipap Max to say 14, then the machine as set above will only ever raise ipap by 2 CMs before ipap bumps into the ipap Max setting. The priority
of settings means that if you were to drop ipap Max to below 12 (say 11), then PS also gets dropped, in this case to 2 (I think) .

DSM

Slinky wrote: Okay. Let's assume an IPAP of 11, EPAP of 6 and Pressure Support of 5 in VPAP Auto mode.

OK. But I assume you mean, technically, maximum IPAP and minimum EPAP, since we're talking Auto mode.

Slinky wrote:That is a spread of 5 cms of pressure support which is governed by the EPAP rather than the IPAP pressure.

The maximum IPAP and the minimum EPAP don't really govern anything other than the limits. I think I'm still with you, though.

Slinky wrote:So half of 5 is 2.5. The Resmeds can't do the odd numbers so lets assume half is 2.4 cms of pressure.

Fair enough.

Slinky wrote:So during the night the Median, 95th Percentile and Maxium pressure reported is 8.4 cms. The Detailed graphs also shows a straight line 8.4 pressure.

Where is the auto adjusting???

If that line ain't squigglin', it ain't adjustin' nothin'.

Slinky wrote: Does this make sense to you?

Well, yeah, I guess, as much as anything makes sense to my O2-deprived head. If you are getting effective treatment at that pressure, it's not going to raise the pressure just for fun. That pressure line represents the midpoint exactly between what your true experienced IPAP and true experienced EPAP was at any given moment. So if the so-called "AutoSet pressure" didn't move, IPAP and EPAP never moved. You stayed at the exact same two pressures all night.

Slinky wrote:Am I thicker than the earth or something?

Slinky, I consider you to be the smartest woman I've never met.

NO. YOU ARE NOT DENSE!! ResMed apparently paid someone to make the way our machine reports pressures about as confusing as it can possibly be! I respect your logical approach to it. So please don't be mad at yourself for ResMed's convoluted way of labeling things.

In my opinion, if your AHI is doing OK, and if you keep your pressure support on 5, you are following your prescribed treatment as well as anyone on the planet could arrange it--you, a doctor, an RT, ANYBODY!

I like it when you vent, though.

jeff

I agree with DSM, the Resmed VPAP Auto manual definitely makes for challenging reading.

jnk wrote:

Slinky wrote: Okay. Let's assume an IPAP of 11, EPAP of 6 and Pressure Support of 5 in VPAP Auto mode.

OK. But I assume you mean, technically, maximum IPAP and minimum EPAP, since we're talking Auto mode.

Slinky wrote:That is a spread of 5 cms of pressure support which is governed by the EPAP rather than the IPAP pressure.

The maximum IPAP and the minimum EPAP don't really govern anything other than the limits. I think I'm still with you, though.

Slinky wrote:So half of 5 is 2.5. The Resmeds can't do the odd numbers so lets assume half is 2.4 cms of pressure.

Fair enough.

Slinky wrote:So during the night the Median, 95th Percentile and Maxium pressure reported is 8.4 cms. The Detailed graphs also shows a straight line 8.4 pressure.

Where is the auto adjusting???

If that line ain't squigglin', it ain't adjustin' nothin'.

Slinky wrote: Does this make sense to you?

Well, yeah, I guess, as much as anything makes sense to my O2-deprived head. If you are getting effective treatment at that pressure, it's not going to raise the pressure just for fun. That pressure line represents the midpoint exactly between what your true experienced IPAP and true experienced EPAP was at any given moment. So if the so-called "AutoSet pressure" didn't move, IPAP and EPAP never moved. You stayed at the exact same two pressures all night.

This makes sense in theory, but my results don't appear that way.

I'm on the VPAP Auto 25. As far as I can tell, the only difference between my unit and Slinky's is mine goes up to 25 as a Max Pressure. I think Slinky's goes up to 20 as a Max, correct?

My current settings are IPAP 25, EPAP 15 with a Pressure Support of 4. My Pressure Line stays on 19 most of the night, every night. It never drops below 19. Here's a report I posted in another thread where the pressure never wavered from 19 (no squigglin' at all! ):

http://www.box.net/shared/303nstsdi8

19 is exactly 4 points above my EPAP of 15 and 4 is my pressure support. Why isn't my pressure line at the midpoint between my true experienced IPAP and true experienced EPAP? I can't imagine the pressure line would be that straight and flat if the unit raised my pressure and found that to be the optimal pressure to prevent events.

Am I missing something???

I'm suspecitng something "ain't" exactly right or kosher w/my VPAP Auto unless I flat out am NOT understanding something. (Which is ENTIRELY possible!!!)

So let's try this one: IPAP 11, EPAP 6, Pressure Support 5 and reported Median, 95th Percentile and Maxium pressures are 11.

Leaks are all w/in acceptable limits in both examples.

Take a look at what BlueBonnetGal is running into. WHAT ARE WE MISSING or what is going on? BlueBonnetGal's reported pressures and pressure line graph makes sense to me - mine don't. Duh!

Slinky wrote:I'm suspecitng something "ain't" exactly right or kosher w/my VPAP Auto unless I flat out am NOT understanding something. (Which is ENTIRELY possible!!!)

So let's try this one: IPAP 11, EPAP 6, Pressure Support 5 and reported Median, 95th Percentile and Maxium pressures are 11.

Leaks are all w/in acceptable limits in both examples.

Take a look at what BlueBonnetGal is running into. WHAT ARE WE MISSING or what is going on? BlueBonnetGal's reported pressures and pressure line graph makes sense to me - mine don't. Duh!

Slinky

This is what makes more sense to me

Min Epap = 6
Max Ipap = ? (this shd be set to above 11 if you want VAuto to work)
PS = 5 (which sets Ipap = 6+5 being 11)
IF the machine is in VAuto mode AND If the machine detects no events & doesn't shift Ipap then the 95th % pressure should be somewhere between the 2 settings of 5 & 11. I can't see it being stuck at one or the other, it *has* to be just below ipap.

But as a side comment PS= 5 goes against my good judgment as a valid setting esp with your Min Epap set as low as it is. I would hope the RT thought very carefully about such a wide spread between epap & ipap when epap is set so low.

Good luck

DSM

Slinky wrote:I'm suspecitng something "ain't" exactly right or kosher w/my VPAP Auto unless I flat out am NOT understanding something. (Which is ENTIRELY possible!!!)

So let's try this one: IPAP 11, EPAP 6, Pressure Support 5 and reported Median, 95th Percentile and Maxium pressures are 11.

Leaks are all w/in acceptable limits in both examples.

Take a look at what BlueBonnetGal is running into. WHAT ARE WE MISSING or what is going on? BlueBonnetGal's reported pressures and pressure line graph makes sense to me - mine don't. Duh!

Slinky

Are you quite confident you have set the machine for VAuto mode & have Ipap Max above 11 CMs.

In your posts you keep mentioning :- epap-Min (yes you set that) PS = 5 (yes you set that) BUT ipap = 11 is set automatically from setting epap-Min & PS. If *you* are entering 11 for Ipap then I don't think the machine is in VAuto mode. Restating IPAP gets set automatically by setting epap Min & PS & also making sure to not set Ipap-Max to 11 or less (doing that forces PS to go lower). Ipap itself is a product of epap Min + PS.

Good luck

DSM

Well, I was titrated at IPAP 13, EPAP 8 at the bi-level titration when I was originally switched to a bi-level. I was doing just fine in auto mode at those pressures (the pressure support was set at 4). My Leak rate was bad but I still did the best I've done on bi-level. At least as far as how I was feeling.

Then the joker insisted that I should stay at those pressure but in Spontaneous mode. That was when I would get the "puff" between inhalation and exhalation. THAT was NOT working for me.

So then I had the second bi-level titration. That resulted in IPAP 10, EPAP 5, pressure support 5. That wasn't cutting the mustard either.

I was using the S8 ResLink, it started cycling thru the menus on the LCD screen and wouldn't stop. Sent it in to Resmed. Decision was it was a corrupted card. S8 ResLink returned - but no new SmartMedia card so am waiting its arrival before I can use the S8 ResLink again.

So the next step was lets try this IPAP 11, EPAP 6, Pressure Support 5 - and these weird flat line pressure reports. I'm wondering if what is going on is normal or if when the S8 ResLink blew its mind something also went on w/the VPAP Auto.

Doug, with the VPAP Auto when you go into Settings the first thing up is the Mode. I select VPAP (auto). The next thing up is IPAP, I set it at 11 cms. The next thing up is EPAP, I select 6. The next thing up is Pressure Suppot, I set that at 5. The next thing up is Ti Maximum, that is set at Default of 4.0s, Next thing up is Ti Minimum, that is set to Default 0.5s. Next thing up is Exhalation Sensitivity, that is set at Default Medium. Next up is SmartStop, that is set to Off. Last up is Mask, which is set to Standard since I am using the Respironics Simplicity simple nasal cushion.

The next main menu is Advanced Settings (or options, I forget which). The first thing up is LeakAlert which is turned to Off. Next up is Trigger Sensitivity, that is set to Medium. Next up is Cycle Sensitivity, that is set to Medium. Next up Tube Length, set at Defualt 2m. Last up is Maximum Settling, that is set at Off.

The software version in my VPAP Auto is SX4430200. You'll find that in the Servicing Menu. So what software version is in your VPAP Auto 25, BlueBonnetGal? And what software version is in your VPAP Auto 25, Jeff?

Slinky wrote:
The software version in my VPAP Auto is SX4430200. You'll find that in the Servicing Menu. So what software version is in your VPAP Auto 25, BlueBonnetGal? And what software version is in your VPAP Auto 25, Jeff?

My SW Version is SX4590103

The difference is that Slinky's machine and software are showing her a line for her "AutoSet pressure," whereas Bluebonnet_Gal's machine and software are showing her the experienced IPAP pressure. Bluebonnet_Gal's machine is doing the math for her. The VPAP Auto is requiring Slinky and me to do our own math to find our experienced pressures.

The experienced IPAP pressure graph line (what Bluebonnet_Gal is seeing) will always be the FULL pressure support distance above experienced EPAP, since that is what pressure support is: the distance between experienced IPAP and EPAP (NOT the distance between maximum IPAP and minimum EPAP limits). The so-called "AutoSet pressure" graph line (which is what Slinky is seeing, and which, oddly enough, is not a real pressure at all), will always be ONE HALF the pressure support number above experienced EPAP. (Another way of saying the same thing is that it will be one half the pressure support number below experienced IPAP,' because that is the same thing mathematically.)

The thing to keep in mind is that IPAP pressure and EPAP pressure (not the maximum and minumum) are pressures you actually experience. The distance between those experienced pressures is the "pressure support." The "AutoSet pressure" is not really a pressure at all. It is an imaginary point midway between experienced IPAP and experienced EPAP. That AutoSet pressure is merely a number that the AutoSet algorithm uses because that one number tells the algorithm (originally written for an auto CPAP, not an auto bilevel) all it needs to know. If we human VPAP Auto users know the AutoSet pressure, though, we can figure out our real IPAP and real EPAP by adding one half our pressure support number to get the real IPAP, and subracting one half our pressure support number to get the real EPAP.

jeff

Sorry, jnk. What software version is in your Resmed VPAP Auto??

Okay. I can grasp that, jnk. But it doesn't explain the fluctuation I got early on in my Statistics and my Detailed graph lines - unless I've selected AutoSet Pressure to be reported and NOT Pressure to be reported in the Customize Reports. I'm going in to check that this morning. That just might be the explanation 'cause I vaguely remember seeing the options of both Pressure and AutoSet Pressure.

NOPE. That isn't it. If I select just Pressure and not AutoPressure in the Report creation section then no graph is included showing Pressure at all. It is reported in the Statistics, of course, but no graph for it.

Slinky wrote:Okay. I can grasp that, jnk. But it doesn't explain the fluctuation I got early on in my Statistics and my Detailed graph lines - unless I've selected AutoSet Pressure to be reported and NOT Pressure to be reported in the Customize Reports. I'm going in to check that this morning. That just might be the explanation 'cause I vaguely remember seeing the options of both Pressure and AutoSet Pressure.

Just a note that my pressure is usually not a straight line all night. Some nights, I have a straight line all night, but most nights, there is some slight fluctuation. Since I got my EPAP up to closer to where it needs to be, I see a LOT LESS fluctuation in the pressure through the night.

Let us know what you find on the options of pressure and autoset pressure. It sounds vaguely familiar to me too, but I'm at work now so I can't check my machine for those options until this evening.

Thanks for your explanation Jeff. That makes sense. Thanks for the "plain English" which ResMed doesn't seem to be able to use!

Slinky wrote: Sorry, jnk. What software version is in your Resmed VPAP Auto??

I'll check when I get home. I didn't read these posts till I got here to work. Sorry.

Slinky wrote:Okay. I can grasp that, jnk. But it doesn't explain the fluctuation I got early on in my Statistics and my Detailed graph lines - unless I've selected AutoSet Pressure to be reported and NOT Pressure to be reported in the Customize Reports. I'm going in to check that this morning. That just might be the explanation 'cause I vaguely remember seeing the options of both Pressure and AutoSet Pressure.

I have not found any way that my VPAP Auto and ResScan software can show me IPAP and EPAP on a graph. The only graph I've been able to get is an AutoSet pressure graph. (A user of ResLink may be able to get an IPAP or EPAP graph out of the VPAP Auto/ResScan combination, I don't know. But I can't.) That's no biggie though. When I look at my AutoSet pressure graph, I just imagine two other lines--one line above it and one line below it, each one-half of pressure support away, and the full pressure support distance away from each other. That is where the lines would be if they were there, since on a Resmed autobilevel (NOT a Respironics autobilevel) pressure support remains the same all night long.