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Can anyone shed some light as to why these resp rate spikes are not evident when the machine runs at a lower pressure with EPR 3 as in the first sh attachment?

garyjack wrote: ↑

Tue Jan 08, 2019 2:16 am

Can anyone shed some light as to why these resp rate spikes are not evident when the machine runs at a lower pressure with EPR 3 as in the first sh attachment?

Not without doing a lot more detailed examination of your data on a breath by breath basis than I'm interested in doing for something that's inconsequential.

I think I'm content to leave it then. Thanks everyone for your help.

Sometimes we don't always get the answers to why something happens or shows up in the data because the answer just isn't in the data in the first place. We can make educated guesses and maybes...but still not know for sure why.
We used to have a forum member Dave (who had so many aliases that I lost count) and he could explain the "whys" better because he was a sleep tech and ran a sleep lab in a major hospital....he could maybe explain it better and sometimes even he couldn't explain a why with the data that we have from the machines. To really know "why" additional data is needed that we just don't have on hand from these machines.

When the end result to anything is "it's not a big deal one way or the other" anyway...we shrug our shoulders and move on to stuff that we have control over and actually matter in the big picture. If you can't do anything about it...and it doesn't matter anyway...might as well shrug the shoulders and move on. I don't expend much energy on anything that doesn't really matter or if I can't do anything about it anyway.
Some battles aren't worth fighting. No sense in wasting time and energy on those battles when we have zero control over the outcome anyway.

From above:

Jay Aitchsee wrote: ↑

Mon Jan 07, 2019 4:43 pm

Ballistocardiographic artifacts
Alternatively:Cardioballistic

Here's a link to a discusion by Dave (Delta Dave, Muffy, Not Muffy), -SWS(another heavy hitter), and a couple others including Pugsy from 2011 about Respiration Rate, central apneas, and Ballistocardiographic artifacts among other things. This is after the introduction of the S9 and the increased data availability that came with it. ResScan Software had been hacked to display Respiratory Rate. The link jumps into the middle of the thread. viewtopic/t61466/Central-Apneas-and-Res ... 45#p576919

For those not inclined to follow the the above links, here's an excerpt that graphically depicts ballistococardiographic artifacts and the resultant skew of Respiration Rate. This comes up quite often and maybe this graphic would be helpful in future explanations. I think it is worthy of note that ResMed did not and does not intend for Respiration Rate to be used with non-ventilator type machines. ResScan does not display Respiration Rate for machines of less than bi-level capability. SleepyHead does, however, and sometimes does so erroneously leading to undue concern by the user.

-SWS wrote: ↑

Tue Mar 15, 2011 9:58 pm

NotMuffy wrote:

... and the ballistocardiographic artifact at 3A has contaminated the RR calculation.

Similarly, while respiratory rate should have slowed at Breath 6, another ballistocardiographic artifact at 5A (although without simultaneous EKG tracing, we can debate the the actual origin of the artifact) artificially maintains the high RR.

In this context, ballistocardiographic artifacts refer to "heartbeat pulsations" sitting in the flow channel as signal noise. They are also referred to as "cardiac oscillations" or "cardiogenic oscillations".

Dr. Rapoport, the 420e's designer, intentionally used those heartbeat signals (sitting in the flow channel) to differentiate central from obstructive apneas:
http://chestjournal.chestpubs.org/content/116/3/660

But in the S9 chart above, they appear to skew RR calculations as signal noise.

Jay Aitchsee wrote: ↑

Wed Jan 09, 2019 4:05 pm

ResScan does not display Respiration Rate for machines of less than bi-level capability. SleepyHead does, however, and sometimes does so erroneously leading to undue concern by the user.

Another sad instance of a bad side effect of Mark Watkin's propensity to throw everything he possibly can into the program, just because he can... (vs2, anybody?) no matter how it may confuse the user.