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.
See my Guide to SleepyHead