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VPAP Machine Pressure Settings - me50 - 01-21-2014

This is for those that use Bi-level machines. Are you using your machine on a set pressure or do you have an Auto machine? If you have a set pressure, what is that pressure? If you have a pressure range (auto) what is that pressure range?

Trying to learn about this new machine.

Thanks.


RE: VPAP Machine Pressure Settings - me50 - 01-21-2014

I found out today that my pressure settings are 18/8. I am having a hard time understanding how this can be a range on my machine (with my CPAP auto, I knew it was a range...as an example, 12 to 16). Can someone explain this to me please?


RE: VPAP Machine Pressure Settings - DeepBreathing - 01-21-2014

Hi me50. I have a VPAP Adapt, which has variable EPAP (exhale pressure) and variable PS (pressure support), which effectively also gives variable IPAP (inhale pressure). For these machines IPAP = EPAP + PS. So the EPAP varies to maintain a patent airway and the pressure support does up and down (on a breath by breath basis) to manage apneas and hypopneas.

I'm not familiar with your machine, but reading the ResMed information sheet leads me to believe it can work the same way.
http://www.resmed.com/us/assets/documents/product/s9_vpap_auto/info_guide/368432_s9-vpap-auto-st-s-h5i_information-guide_amer_eng.pdf Page 8

It looks like the machine can be configured as straight CPAP, in S, ST and T modes and VAuto mode. In S, ST and T, it looks like you can set an EPAP of 3 to 25 cm H2O, and an IPAP of 4 to 25. Whether the machine can vary these pressures I don't know. In the VAuto mode it looks more like the VPAP Adapt I described above. I suspect that the VPAP Auto can be used in any of these modes, but your prescription seems to be for one of the non-auto modes.

Vaugn seems to know a lot of detail about these machines, so maybe he can chime in. I just wish Resmed would make their literature a bit less ambiguous.


RE: VPAP Machine Pressure Settings - vsheline - 01-22-2014

(01-21-2014, 10:27 PM)me50 Wrote: I found out today that my pressure settings are 18/8. I am having a hard time understanding how this can be a range on my machine (with my CPAP auto, I knew it was a range...as an example, 12 to 16). Can someone explain this to me please?

Hi me50,

In its Auto mode, the S9 VPAP Auto automatically-adjusts EPAP (within a manually-adjusted range) and has a fixed (manually-adjusted) Pressure Support.

The S9 VPAP Auto is much like the S9 AutoSet except on the VPAP Auto the max pressure (max IPAP) can be 25 instead of 20 on the AutoSet, and on the VPAP Auto the max Pressure Support (PS) can be 10 (I think) instead of the max Exhalation Pressure Relief (EPR) being limited to 3 on the AutoSet. Plus, the VPAP Auto has a few more adjustable settings than the AutoSet. The VPAP Auto can adjust how early or late it triggers into IPAP and how early or late it cycles back to EPAP.

Both PS and EPR represent the pressure difference between EPAP and IPAP. On the VPAP Auto the inhalation pressure IPAP is calculated as IPAP = automatically adjusted EPAP + fixed PS. On the AutoSet the exhalation pressure EPAP is calculated as EPAP = automatically adjusted Pressure - fixed EPR, where the AutoSet setting called Pressure represents IPAP pressure.

The S9 VPAP Auto does not not have a backup rate to treat centrals, so no T mode (Timed mode) or ST mode (Synchronous Timed mode). "Synchronous" just means the machine is doing its best to synchronize its changes between IPAP and EPAP to match our own natural breathing; these days all CPAP machines with PS or EPR or Flex synchronize to our natural breathing rate, but long ago this was a new feature.

If you View Settings (by pushing at the same time on both rectangular buttons for about 5 seconds to enter the Advanced Info menu, and then turn or push the round knob to navigate) you should be able to navigate to all the machine's settings.

What are the EPAP Min, EPAP Max, PS and Max Pressure (max IPAP) set to?

Take care,
--- Vaughn



RE: VPAP Machine Pressure Settings - me50 - 01-22-2014

(01-22-2014, 12:08 PM)vsheline Wrote:
(01-21-2014, 10:27 PM)me50 Wrote: I found out today that my pressure settings are 18/8. I am having a hard time understanding how this can be a range on my machine (with my CPAP auto, I knew it was a range...as an example, 12 to 16). Can someone explain this to me please?

Hi me50,

In its Auto mode, the S9 VPAP Auto automatically-adjusts EPAP (within a manually-adjusted range) and has a fixed (manually-adjusted) Pressure Support.

The S9 VPAP Auto is much like the S9 AutoSet except on the VPAP Auto the max pressure (max IPAP) can be 25 instead of 20 on the AutoSet, and on the VPAP Auto the max Pressure Support (PS) can be 10 (I think) instead of the max Exhalation Pressure Relief (EPR) being limited to 3 on the AutoSet. Plus, the VPAP Auto has a few more adjustable settings than the AutoSet. The VPAP Auto can adjust how early or late it triggers into IPAP and how early or late it cycles back to EPAP.

Both PS and EPR represent the pressure difference between EPAP and IPAP. On the VPAP Auto the inhalation pressure IPAP is calculated as IPAP = automatically adjusted EPAP + fixed PS. On the AutoSet the exhalation pressure EPAP is calculated as EPAP = automatically adjusted Pressure - fixed EPR, where the AutoSet setting called Pressure represents IPAP pressure.

The S9 VPAP Auto does not not have a backup rate to treat centrals, so no T mode (Timed mode) or ST mode (Synchronous Timed mode). "Synchronous" just means the machine is doing its best to synchronize its changes between IPAP and EPAP to match our own natural breathing; these days all CPAP machines with PS or EPR or Flex synchronize to our natural breathing rate, but long ago this was a new feature.

If you View Settings (by pushing at the same time on both rectangular buttons for about 5 seconds to enter the Advanced Info menu, and then turn or push the round knob to navigate) you should be able to navigate to all the machine's settings.

What are the EPAP Min, EPAP Max, PS and Max Pressure (max IPAP) set to?

Take care,
--- Vaughn

Max IPAP 18
Min EPAP 8
PS 4.0
TI Max 2
TI Min 0.3
Trigger Med
Cycle Med
Start EPAP 4.0
Mask Nasal Ultra (I use the wisp nasal mask)

Thanks for any help you can give me to understand this. Am I using my machine in auto mode or straight VPAP.


RE: VPAP Machine Pressure Settings - Peter_C - 01-22-2014

Looks like Auto mode to me.

Remember, PS=pressure support, or EPAP+PS=IPAP

My machine 'was' on set mode, and a few months back I changed mine to auto mode.
MIN EPAP=8
PS=
MAX IPAP=25
No ramp for me, I need the air ASAP!


RE: VPAP Machine Pressure Settings - robysue - 01-23-2014

(01-22-2014, 02:02 PM)me50 Wrote: Max IPAP 18
Min EPAP 8
PS 4.0
...
Start EPAP 4.0

Thanks for any help you can give me to understand this. Am I using my machine in auto mode or straight VPAP.
You are running in VPAP Auto mode. You are also using the Ramp since Start EPAP is not equal to Min EPAP. Every time you turn the machine on, the machine enters RAMP mode. Your pressures start at:

Starting EPAP = Start EPAP = 4
Starting IPAP = Start EPAP + PS = 8

So when you first put the mask on, the pressures are at 8/4. The pressures ramps up linearly during the Ramp period until your minimum therapeutic pressure settings are reached. Your minimum therapeutic pressures are:

minimum therapeutic EPAP = Min EPAP = 8cm
minimum therapeutic IPAP = Min EPAP + PS = 8 + 4 = 12cm

When the machine detects snoring, flow limitations or records two or more OAs or Hypopneas in about a 5 minute period, it will increase both the EPAP and IPAP by the exact same amount because you are using a Resmed S9 VPAP. (The PR System One BiPAP's auto algorithm is different and allows IPAP and EPAP to increase independently of each other.)

The highest your pressures are allowed to get are:
Max EPAP = Max IPAP - PS = 18 - 4 = 14cm
Max IPAP = 18.

So at any point in the night EXCEPT during the Ramp time(s), your pressures are in the following ranges:
8 < EPAP < 14
12 < IPAP < 18
And IPAP - EPAP = 4 at all times.

NOTE: Every time you turn the machine off and back on, the machine enters Ramp mode, and the pressures go back down to 8/4 and ramp up linearly to 12/8 during the Ramp time. It's important to know that the Resmed machines do NOT flag any events that happen during the RAMP time. In other words, if your ramp time is set to 45 minutes any OAs, Hs, or CAs that happen within 45 minutes of the machine being turned on are simply ignored and not flagged. Obviously if your ramp time is 45 minutes, but you fall asleep in 15-20 minutes, that could be a real problem. So its important to make sure that the ramp time is pretty close to the time it typically takes you to fall asleep.

And recall that every time you press the Off/On button (or you use Auto On/Off and the machine turns itself Off and then back One), the machine goes back to the ramp settings and no events will be flagged until the ramp time is once again over. If the ramp time is short, that's not usually a problem, but if your ramp time is 30-45 minutes long and you're turning the machine off and on repeatedly during brief 5-10 minutes wakes, that's a lot of time when the machine is not flagging events even if they are occurring.

Now lets look at the rest of those settings:
Quote:TI Max 2
TI Min 0.3
TI Max and TI min control how long the pressure will be held at IPAP. I believe those settings are in seconds. (If someone knows this is wrong, PLEASE correct me.)

TI min = 0.3 seconds means that once the machine changes to IPAP pressure, it will NOT go back to EPAP regardless of what you're doing breathing wise for at least 0.3 seconds.

TI max = 2 seconds means that machine will drop the pressure to EPAP 2 seconds after it switched to IPAP even if the machine has not yet detected the beginning of an exhale. In other words, the switch from IPAP to EPAP is done when any of the following is true:
  • It's 0.3 seconds after the switch to IPAP and the machine detected the beginning of an exhalation before 0.3 second elapsed since the beginning of the inhalation.
  • It's between 0.3 seconds and 2 seconds after the beginning of the inhalation and the machine detects the start of the exhalation.
  • It's 2 seconds after the beginning of the exhalation.

Quote:Trigger Med
Cycle Med
If I recall correctly:

Trigger Med sets the sensitivity for detecting the beginning of an inhalation; hence it determines how "hard" you have to inhale before the switch to IPAP happens.

Cycle Med sets the amount of time it takes to ramp the pressure up from EPAP to IPAP at the beginning of each exhalation.

If anybody knows I'm wrong, please post a correction.



RE: VPAP Machine Pressure Settings - me50 - 01-23-2014

Thanks Vaughn and robysue. I turned the ramp off. I don't need it as I have been using some machine for about 3 years now.

I will read your posts again and see what I get from it.

Thanks again for both of your posts.


RE: VPAP Machine Pressure Settings - vsheline - 01-24-2014

(01-23-2014, 04:14 PM)robysue Wrote:
Quote:Trigger Med
Cycle Med

If I recall correctly:

Trigger Med sets the sensitivity for detecting the beginning of an inhalation; hence it determines how "hard" you have to inhale before the switch to IPAP happens.

Yes, when Trigger sensitivity is High (instead of Medium as it presently is) it means the machine will trigger the start of the higher IPAP earlier, with less delay after you start inhaling, helping you to inhale by advancing the start of higher pressure.

The Cycle setting controls how early or late IPAP ends. When Cycle sensitivity is Low (instead of Medium as it presently is) it means the pressure will cycle back into the lower EPAP pressure later, with more delay, allowing you to more completely finish inhaling before the higher IPAP pressure ends.

I think it is Rise Time which sets how abrupt or gradual is the transition from EPAP to IPAP. The larger the Rise Time value, the longer it takes for pressure to increase from EPAP to IPAP. People who are slow breathers may prefer a longer Rise Time.

Take care,
--- Vaughn