Can you set Aircurve VAuto Bipap to run as an Auto Cpap?

[bluemom51]

I met with my new Sleep Doctor about 3 weeks ago - didn't really make any headway with anything.  But when I told her I was still struggling with getting restful sleep with the Bipap (started it about November 2017), she asked "do you want us to set it to run like an Airsense 10 Auto?".  My pressure needs are not high - it runs about 11-14 and I don't have many centrals or other extraordinary issues, so I've always wondered about the reason for the Bipap (prescribed by previous doctor).

The Bipap is set at 11-20 with a PS of 2.  I wake up and toss and turn all night and never feel relaxed.  Have tried full face, nasal, and pillows masks - same result.

Is is possible to set an Aircurve VAuto Bipap to run like an Auto Cpap - my settings on the Auto were 11-17 with EPR of 1.  I just wonder sometimes about the other settings on the Bipap like the trigger, etc. (all set to factory settings) and how they may or may not be affecting my breathing.  Like almost all Sleep Doctors, she just looks at the AHIs and pronounces everything "fine".  My AHIs are running about 2-2.5, but if they went be how I feel, they would be 10-15 or more.

Just wondering - thanks for any input.

[Walla Walla]

Yes it you can set it up like your old Auto CPAP. Set EPAP to 10cm, set PS to 1cm and set Max IPAP to 17cm. That will give you the same pressures you had on your CPAP.

[bluemom51]

What about the other settings like Trigger etc?

[Walla Walla]

Since there's no place to adjust those settings on the Auto CPAP I'd guess just using the default settings on the VAUTO would work fine.

[Gideon]

Another way to look at is VAuto settings (EPAP) are CPAP settings (IPAP) - EPR.   VAuto PS = CPAP EPR


Fred

[bluemom51]

Yes those 3 are comparable, but the Bipap has some other settings that cause it to function differently than an Auto - TI Max, TI Min, Trigger, and Cycle - when I tried to set those to zero or off, you can't.  There are certain ranges that TI can go to and the Trigger and Cycle can be set low to high, etc. 

These aren't on an Autosene 10, and are additional settings on the BiPap.  I was thinking if you could turn those "off" maybe it would be identical to an Auto, but since you can't, I really don't know how they could set it to function Exactly like an Auto, because you would always have those other settings that affect how the Bipap operates.

Her Sleep Lab person had suggested I try setting the Trigger and Cycle to Low to improve comfort, and it had a Significant impact on the air flow - not in a good way, so I know they do influence how the Bipap is operating.

[Gideon]

The long answer

VAuto mode
In VAuto mode, the AutoSet algorithm automatically adjusts pressure in response to flow limitation,
snore and obstructive apneas.
Min EPAP, Max IPAP and pressure support in VAuto mode
Pressure support allows you to set the difference between inspiratory and expiratory pressure and
is fixed throughout the night. Min EPAP and Max IPAP settings allow you to restrict the delivered
pressure ranges in which the AutoSet algorithm can operate.
The EPAP and IPAP will vary across the session according to the patient’s needs. It responds to
snoring, apneas and flow limitation of the patient’s flow curve.
Min EPAP and Max IPAP can be adjusted to limit the upper and lower delivered pressure limits.


Triggering and cycling
VAuto, S and ST modes only
The device has adjustable trigger/cycle sensitivity to optimize the sensing level according to patient
conditions.
Under normal conditions, the device triggers (initiates IPAP) and cycles (terminates IPAP and
changes to EPAP) as it senses the change in patient flow. Patient breath detection is enhanced by
ResMed's VSync automatic leak management.

   


TiControl - Inspiratory time control
VAuto, S and ST modes only
Unique to ResMed bilevel devices, TiControl™ allows the clinician to set minimum and maximum
limits on the time the device spends in IPAP. The minimum and maximum time limits are set at
either side of the patient’s ideal spontaneous inspiratory time, providing a ’window of opportunity’
for the patient to spontaneously cycle to EPAP.
The minimum time limit is set via the Ti Min parameter and the maximum time limit is set via the Ti
Max parameter.
TiControl’s Ti Max and Ti Min parameters play a significant role in maximizing synchronization by
effectively intervening to limit or prolong the inspiratory time when required. This ensures
synchronization even in the presence of significant mouth and/or mask leak.

   

The following table is a guide to selecting the Ti Max and Ti Min values that best correspond to the
patient’s respiratory rate and inspiration and expiration ratio, depending on the respiratory
conditions.
Examples:

• I:E = 1:1 – Ti Min prevents the premature cycling to EPAP for patients whose inspiratory effort is extremely weak.
  
• I:E = 1:3 – Ti Max limits the inspiration time for patients who require a longer expiration time.
  

   


The Triggering and cycling and TiControl - Inspiratory time control are not available in an AutoSet and apparently they cannot be disabled, only set up do do what they were designed to do, help trigger breathing for the user when needed and adjusted properly.

Fred

[Sleeprider]

Fred, looks like you just wrote another Wiki.

[bluemom51]

Thanks for the info and explanations.  I guess since they cannot be disabled, there is no way to set a VAuto Bipap to work Exactly like an Auto Cpap.  So I really don't know what the doctor meant when she said they could set it that way.......

It would seem that the extra settings on the Bipap would make the whole process more comfortable, and I'm sure that is the intention, but for me, it doesn't seem to be working that way.

And the Sleep Doctors don't seem to know much about those extra settings, which makes it even more fun.  My previous Doctor didn't even know they existed.....

Your explanation ended with the perfect summary/puzzle - "when needed and adjusted properly".  I wonder how that affects our sleep when the doctors/sleep technicians don't know how to do that and leave everything on factory settings that may or may not be right for everyone?

[Gideon]

One of the things we do here is adjust to comfort.  Post your dailies and settings and we should be able to help with that.
The basic VAuto AutoSet (hint, hint) algorithm is the same algorithm as the AutoSet, but acting on EPAP and adding PS instead of acting on IPAP and subtracting the EPR.

I've never heard of anyone detecting the difference except that PS can be much higher than the AutoSet EPR.   The impact of Timing can be minimized by setting to values compatible with your breathing.  That is by setting to timings that would rarely occur.

On the Sensitivity, Medium would be the default, if you wish try something else (you did) and if it didn't work, set it back or try something else.

The bottom line is that we cannot help you with your settings unless we know your settings and see your daily charts.

Fred