New paper on CPAPs for tech-geeks and data-hounds

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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robysue
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New paper on CPAPs for tech-geeks and data-hounds

Post by robysue » Mon Apr 25, 2016 12:37 am

This evening I wound up stumbling on a paper published in Oct. 2015 on an NIH web site called Treatment of sleep-disordered breathing with positive airway pressure devices: technology update. The paper's url is
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629962/

It's a fascinating paper with a lot of technical details about how modern day CPAPs, APAPs, and BiPAPs go about their business of treating our OSA.

You will find this paper of interest if you've ever wondered about such things as:
  • How does a PAP know or estimate the pressure at the mask end?
  • How does a PAP compensate for leaks?
  • How does a PAP determine the breathing pattern? How does a PAP know when the inhalations and exhalations start?
  • What criteria are used to score hypopneas, apneas, flow limitations, snoring, etc? And how do these vary between manufacturers? And how is the "AutoSet for Her" mode different from the "AutoSet" mode on Resmed A10 AutoSets?
  • How do Auto machines from different manufacturers respond to events? When do they increase pressure? When do they decrease pressure?
  • How bilevels actually transition between EPAP and IPAP
  • How COPD and neuromuscular conditions can cause problems with a bilevel transitioning between IPAP and EPAP at inappropriate times in the breath cycle
  • How do the ASV algorithms work? How do they differ between manufacturers? And what's the difference between ASV and (AVAPS or iVAPS)? [AVAPS = PR lingo and iVAPS = Resmed lingo for the same thing.]
  • What's the difference between PR's AVAPS and Resmed's iVAPS algorithms?
*********
Some interesting technical details:

Table 1 shows that ResMed machines do indeed start to (slowly) increase the pressure before the very end of the exhalation.

Table 2 is chock-full of all kinds of details about the criteria various machines use to score apneas, hypopneas, and flow limitations. It also contains information about how each machine is programmed to respond to events and under what conditions the APAP will start to decrease the pressure and how fast it will decrease the pressure. Interesting factoid: The "For Her" algorithm is slower to decrease the pressure than the regular AutoSet algorithm is.

There are also detailed tables comparing the Resmed and PR ASV machines' algorithms and their VPAP machine's algorithms.

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palerider
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Re: New paper on CPAPs for tech-geeks and data-hounds

Post by palerider » Mon Apr 25, 2016 12:55 am

robysue wrote:Some interesting technical details:

Table 1 shows that ResMed machines do indeed start to (slowly) increase the pressure before the very end of the exhalation.
The way I read it, it's not referring to what the machine does with pressure, it's referring to how the machine figures out what phase of the respiration cycle you're in.

I assume you're talking about the line: "Small negative Increasing slowly Late expiration"

but what follows that is a zero respiratory flow, not change, end of expiratory phase... waiting for the next inspiration to start.

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rick blaine
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Re: New paper on CPAPs for tech-geeks and data-hounds

Post by rick blaine » Mon Apr 25, 2016 2:38 am

Great read. Thanks for finding it and posting the link. And thanks for your remarks and on-going wisdom too.

klv329
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Re: New paper on CPAPs for tech-geeks and data-hounds

Post by klv329 » Sun Apr 16, 2017 12:26 pm

Good info indeed.

Been messing around with different CA/OA machines and it appears that i may soon have to come to the conclusion that the resmed asv is the one that helps my type of apnea problems without parallel.....and that bothers me a bit.

One manufacturer's one line of machines...eeks, I feel cornered.

But I have to be glad 'cause that resmed asv makes a huge difference to me. Thanks resmed.

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JDS74
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Re: New paper on CPAPs for tech-geeks and data-hounds

Post by JDS74 » Mon Apr 17, 2017 9:26 am

+1 Robysue

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