Sleep report anomalies and their causes.

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
dataq1
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Re: Sleep report anomalies and their causes.

Post by dataq1 » Thu Nov 24, 2022 11:11 pm

ejbpesca wrote:
Mon Nov 14, 2022 12:04 pm
lynninnj wrote:
Wed Nov 23, 2022 8:53 pm
Have you tried holding your breath as long as you can and see how low it goes and in what time frame?
I can't locate it now, but a research study was done to determine the response time of desaturations to respiratory interruption.
To the best of my recollection something like 30 healthy adults were monitored for oxygen saturation while awake for several minutes sufficient to establish a base line.
Each subject was told to hold their breath for as long as possible, while oximeter readings were recorded each second.

IIRC, the oxygen saturation dropped (on average) approximately 16 seconds after breathing ceased (I honestly don't remember if the threshold was a 3% desaturation or 4%)

That sets up an interesting question: IF the brain reacts (is aroused) by a low blood oxygen level (caused by apnea), but the blood oxygen level is slow to respond to the apnea, there is some period time that passes before the brain reacts to an apnea*

I've found it interesting, in observing my own oximeter recording that very often my oximeter might record a 3% desaturation that takes 1-2 seconds to drop from a steady baseline. (At first I thought that these might be artifacts) But then the recovery to return to baseline would take 10 seconds or more. (I suspect if the initial drop were actually a "positional" or "contact" artifact, then the restoration back to baseline should also be abrupt -

* as different from the brain reacting to excess CO2.

UPDATE: Just found similar information on "Emergency Medicine Update" website where they demonstrated "pulse-ox lag" to breathing.
Here the physician begins with a 100% O2 and STARTS by holding his breath.
After 37 seconds the O2 level BEGINS to drop.
"THE INFORMATION PROVIDED ON CPAPTALK.COM IS NOT INTENDED NOR RECOMMENDED AS A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE."

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ejbpesca
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Re: Sleep report anomalies and their causes.

Post by ejbpesca » Fri Nov 25, 2022 8:45 am

lynninnj wrote:
Wed Nov 23, 2022 8:53 pm
ejbpesca wrote:
Wed Nov 23, 2022 9:27 am
Rubicon wrote:
Mon Nov 21, 2022 5:34 am
Yeah probably a back roller. Probably too long and sustained to be (entirely) REM. Surrounding breaths are significantly flow-limited:

Image

Major snoring registered.

Didn't we have this same conversation a month ago?
Similar conversation was held but in different context. In this thread I am pursuing the possibility of sleep reports containing anomalies and their causes. The question is, "Is this cluster an anomaly or is it real? If anomaly, what can cause it?" From responses, I gather that it is the opinion here that a tightly packed cluster is a correct indication of apneas, not an anomaly. The cluster in question appeared so severe I was hoping it may be an anomaly, that is, a failure of the system to report properly.

Another example of a possible anomaly is coming from my O2 ring. It will show at times, in a 30 minute cluster, O2 saturations go from 97 to 75 in 20 seconds, then back to 97 in 12 seconds, repeating the oscillation about 60 times in 30 minutes. One poster here suggested that was caused by movement claiming the saturation to desaturation and back time is too close to be possible. The pulse rate on that segment of the graph also jumped up and down from 60bpm to 90bpm in a similar fashion, but not quite as dramatic. The motion graph was near empty of events for the same period of time so I have no evidence of me shaking up the oximeter in my sleep. Perhaps I rolled around putting pressure on the ring that made it fail. Maybe blood O2 can change that rapidly. Do you think it can?

That incident got me wondering if the CPAP data also can have clusters of data that are not accurate, and maybe caused by some input the software is misreading. When a number of events happen so rapidly, it does not seem physically possible to be occurring. Could it be incorrect data, or are these packed clusters of events concise data that should be taken as an alarm bell to change something, get medical help, etc.? I see these clusters intermittently on my sleep reports. I would like to dismiss them as mistakes by the machines, not rough spots on my cpap therapy, but I don't know enough to do that. I guess I need to read articles about the accuracy of sleep and oximeter reports, and opinions here are most appreciated.
Have you tried holding your breath as long as you can and see how low it goes and in what time frame?

I know that isn’t scientific but it’s a start and may answer part of your question.

My other curiosity comes from the threads about diffusers and breathing in your own co2 if diffusers are blocked. Any chance that could be happening ie bed sheets blocking?

gl
Holding my breath does not produce a dramatic drop in oxygen as shown in the report. The only return of exhaled co2 would come from the cpap mask. I'm pretty sure the O2 Ring data is flawed by sensing failures at times. Now to determine how and when can cpap sleep report data be flawed, I am sure it is not perfect. I understand SWJ readings, but I'm wondering about such a rapid succession of OA's as indicated on some reports, if that is even possible or if, and how those could be a false readings. I have no sleep therapist to ask so I'm seeking opinions on the net.

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robysue1
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Re: Sleep report anomalies and their causes.

Post by robysue1 » Fri Nov 25, 2022 8:55 am

ejbpesca wrote:
Fri Nov 25, 2022 8:45 am
Holding my breath does not produce a dramatic drop in oxygen as shown in the report. The only return of exhaled co2 would come from the cpap mask. I'm pretty sure O2 Ring data is flawed by sensing failure. Now to determine how and when can cpap sleep report data be flawed. I understand the SWJ, I think, readings but I'm wondering mainly about such a rapid succession of OA's as indicated on some reports. If, and how that could be a false reading.
As others have pointed out, those clusters of events are most likely real and most likely being caused by your rolling onto your back combined with the fact that you have capped your Max Pressure at a setting where the machine is not allowed to increase the pressure any further in order to prevent subsequent events from happening after the first couple of events happen

If you were also experiencing large, long leaks at the time these events were flagged, then it could be reasonably asked whether the size and lengths of the leaks were causing the machine to have trouble tracking the airflow into and out of your upper airway. But that's not the case here.

Yes, you are dealing with aerophagia issues. So just opening up the Max Pressure to 20cm is probably not what you want to do. But you could start by increasing the Max Pressure by 0.2cm once a week or so in an effort to find out how much you can safely increase Max Pressure so that your machine has the ability to try to prevent these clusters from getting started in the first place.
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ejbpesca
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Re: Sleep report anomalies and their causes.

Post by ejbpesca » Fri Nov 25, 2022 9:02 am

[quote=ozij
Weren't you much better off - obstruction-wise - when your minimum pressure was not lower than 9?
[/quote]

Yes. At years of Min 12 Max 20 I had few OAs. With help here, and Youtube advice I think I may have found a decent Min at 8 and I'm tapping Max up to get therapy without aerophagia. All sorts of things are being learned and questioned along the way.

Thank you.

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