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BiPAP vs EPR/Flex etc?
Out of interest, what is the difference between a BiPAP machine and the various exhale pressure relief systems?

As I understand it BiPAP is 2 different levels of pressure, one for inhale and one for exhale.

The various "comfort" systems available on Auto PAP machines reduce the pressure on exhale by a specified amount (In the case of my Devilbiss by up to 3cm).

I could understand in the past you had a simple mechanically pressure set machine for CPAP and a more complex machine with variable pressures etc for BiPAP.

But now the pressure setting is done by a feedback loop to a blower motor, and AutoPAP machine must have some sort of flow measurement sensor anyway, what is the difference?Huhsign
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The biggest difference is the bilevel (generic term) can have a pressure split between IPAP and EPAP that exceeds 3 cm-water. Like mine is 5.
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I was just doing some searches in the Wiki, and it seems these terms are not covered very well.
EPR http://www.apneaboard.com/wiki/index.php?title=EPR
A-Flex http://www.apneaboard.com/wiki/index.php?title=A-Flex
Bilevel, BPAP or BiPAP http://www.apneaboard.com/wiki/index.php?title=BiPAP

I may have to add some to those. Resmed EPR and your machine both provide a form a limited bilevel. It is a true 0-3 cm pressure reduction during exhale, and the IPAP pressure does not resume until you initiate an inhale.

The Respironics C-Flex and A-Flex provide up to 2-cm pressure relief, but it is at the end of inspiration as exhalation begins. By the time exhale is complete, the CPAP pressure is restored before inhale begins.

In bilevel, the Resmed and Respironics auto bilevel is a bit different, but the "S" models are the same providing fixed IPAP and EPAP. Resmed Vauto uses a range of EPAP pressures with a fixed pressure support, so the difference between IPAP and EPAP is constant. With Respironics BiPAP Auto, the minimum EPAP is set with a range of pressure support, and a maximum IPAP is set. This gives a range of EPAP and IPAP with variable pressure support.
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thanks for that!SmileThanks

I was just wondering why we persist with these labels. it sounds like a modern auto CPAP machine could cover everything from constant pressure to fixed inhale and exhale pressure (bipap) to varying constant pressure to varying either or both inhale and exhale pressures and anything in between.

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The auto CPAP, especially the Resmed version, is getting much closer to bilevel than traditional CPAP. Bilevel has always been considerably more expensive than CPAP, and they all treat the same obstructive sleep apnea. Bilevel has usually only been approved for insurance reimbursement when the patient does not tolerate CPAP or the bilevel is medically necessary. The bottom line is bilevel is actually more comfortable for many people. I can't say what accounts for the price difference. The machines are nearly identical inside, with the same flow generators and circuit boards. It seems the different operation is mainly in software and firmware. I think it is interesting that Resmed, and perhaps Devilbiss are using a bilevel approach in CPAP. This could eventually really cut down the number of true bilevels dispensed. Very few people require more than 3-cm pressure support.
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I suspect you're right.

I can see that, back in the days of mechanical or open loop pressure control BiPAP would be considerably more expensive than a simple fixed pressure (constant) PAP.

As you said, the Auto PAP machines have all the required hardware, it's the software that makes the difference.

I guess manufacturers know they n sell the same machine with a different sticker and slightly different parameters in the software, and stick an extra couple of hundred $ on the price.Smile

money for old rope!
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The basic blower, air path, and sensors are nearly the same across the different platforms from a manufacturer.
The big difference is in the firmware for the processor that controls the machine.

A big advance was made when advanced, low inertia, multi-phase, electronically controlled blower motors were designed in.
That permits the machine to adjust pressure quickly and/or, maintain pressure against a varying flow pattern.
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(11-13-2016, 08:51 AM)SleepyBee Wrote: thanks for that!SmileThanks

I was just wondering why we persist with these labels. it sounds like a modern auto CPAP machine could cover everything from constant pressure to fixed inhale and exhale pressure (bipap) to varying constant pressure to varying either or both inhale and exhale pressures and anything in between.

Labels = $$$, that's apparently why they persist. Was at the supermarket butcher the other day, they had "Shell Steaks", "NY Strip Steaks", and "Strip Steaks", all priced differently, all obviously the same cuts. When I asked the difference I was told "Price".

I started at 19 fixed pressure CPAP when I got my machine. It was pretty awful. When I met this forum much was explained to me and I wished I'd found it before I accepted my machine. Unfortunately I couldn't get another unless I paid for it. They wanted some ridiculous amount of $$$. I bought a 40 hour machine off Craigs List for $300 and never looked back. My original machine sits in a draw gathering dust. The differences between fixed and BiPap were night and day for me. Sad that they make $$$ the priority to patient treatment.

If everyone thinks alike, then someone isn't thinking.
Everyone knows something, together we could know everything.
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