Getting back to SnoozeBlues original theme.
The Bipap AutoSV in SV mode can essentially can do the following ...
1. Can set a base epap (titrated to remove blocking apneas)
2. Can set a Min Ipap (what the pressure goes up to on inhale)
3. Can set a Max Ipap (what the pressure can go up to if flow is not being maintained)
The Bipap AutoSV does not make use of a mask pressure sensing airline (i.e. Proximal line) like the Vpap Adapt SV does. It does all its estimations back at the machine. The approach of sampling only the flow (and rate) allows them to avoid use of the a mask pressure sensing airline line.
The Bipap AutoSV then uses its sampling of flow as determined at the machine end of the airhose and using internal pressure sensors and flow rate sensors, to drive the IpapMax such as to maintain a particular flow target.
The shape of the waveform is set by a risetime setting similar to the Bipap S/T. The breathing rate can be set to Auto or to a specific number. If set to a specific number the machine will work to keep that rate the same.
***************************************************
The Vpap Adapt SV in SV mode can do the following
1. Can set a base eep (=epap - titrated to remove blocking apneas)
2. Can set a MinPS starting at 3 CMS above eep (eep + minps = Ipap - what the pressure goes up to on inhale)
3. Set a MaxPS starting at 5 above MinPS (what the pressure can go up to if user drops below 90% of last 3 mins MV & breating rate and the machine uses PS to correct this)
The Vpap Adapt SV uses a sensing air line (the Proximal Sensor tube) that samples pressure in the mask as the user breathes. This sampling is in conjunction with flow & pressure sensors in the machine itself.
The Learning Circuit process appears to be the Vpap Adapt SV building an internal 'mask fixed leak' rate table for the mask being used (vs the other models from Resmed that all have a set of tables based on Resmed masks). Using internal 'mask fixed leak' tables has been done by Resmed & Puritan Bennett for years on some of their models but not all.
***************************************************
The major difference between the machines is the data each samples.
The Bipap AutoSV samples flow & (if activated) rate.
The Vpap Adapt SV samples 90% of the users Minute Ventilation and Rate.
***************************************************
The remaining question then is how effective either machine is for a specific target user base.
If we look at users with centrals, the Adapt SV appears to be more precise (due to its ability to sense mask pressure vs delivered pressure based on the proximal line) while the Bipap AutoSV appears to be a lot more like a Bilevel but with added ipap pressure support if the machine determines the user is having a central. How the Bipap SV determines if the user is having a central is the open question. Lack of mask sensing suggests it does a best guess, but if it gets this right most of the time, that may be ok.
My impression is that the Vpap Adapt SV in terms of irregular breathing, is tuned like a high-performance F1 sports car.
The Bipap AutoSV is more like a NASCAR racer.
I think each type can do a good job in its own type of race & race track
DSM
_________________
CPAPopedia Keywords Contained In This Post (Click For Definition):
resmed,
bipap,
Puritan Bennett,
auto