Data handling for VERY low SpO2 reading on Viatom product.

[Ratchick]

So, I just wanted to mention that (at least for me) the Viatom seems to bottom out at around 61% SpO2. I don't expect this to be a common issue for almost everyone else, but when oxygen saturation drops that low, the sensor fails to fill in a valid data point.

The byte that stores the SpO2 value records FF instead. This is currently handled for sensor removal by not reporting a measurement when the value is FF in the first three bytes of each five-byte data "packet". However, when it's due to the inability to measure just the SpO2 because of hypoxia, only the first byte is recorded as FF, with an accurate value for the other four bytes and so it is displayed on the SpO2 graph as a value of 254 instead. 

I'm not sure whether the best idea is to blank it the same way that it would for a sensor-off event? I don't know for sure if that option would prematurely end a SpO2 drop at that point, rather than when the SpO2 has risen above the necessary drop criteria, though.

I can supply a file with the low SpO2 if needed.

[Crimson Nape]

So a decimal output of a sample would be something like, 255  70  0  0  0?  Hex would be, ff  46  0  0  0.

Edit:
A personal sidenote: If you are recording an SpO2 that low, you need to be talking to your doctor and not us!

I just checked the OSCAR loader code, and it is only looking at the 3rd column, oximetry validation bit. If good, it records a 0 (zero), if bad then ff (255). The oximetry value currently doesn't have validation logic. You are the first to have anything that low to even know this scenario exists.

Thanks!

[Ratchick]

LOL Yep you have it. So the actual values for mine for the last time were as follows (in hex):

3D 56 00 01 00
FF 56 00 01 00
40 57 00 00 00

It's happened way too often (and yes, my doctors DO know this, but absolutely agree, this is not something anyone SHOULD be seeing!)

61/3D is the cut off based on all the times I've seen this. Usually, I just go in and change it manually to 60 or whatever, but yep, some validation would be nice.

[Crimson Nape]

Wow!  Not only a low O2, but an elevated pulse too.  Oddly, the 3rd column should be reporting a 255 also. H-m-m-m-m!    Initially looking at the code, it shouldn't be a major task to add logic to this field.  Just what to put there to replace it is now the question.

Take care!!!

- Red

[Ratchick]

I usually manually edit the file to just drop it a little below 61 , even if it's just to 60 (one night I had 3 readings below 61 but that's still nowhere near the 45 I recorded on my Contec LOL). Either that or maybe whatever the previous value is? I'd be ok, personally, with it bottoming out at 60 but OSCAR isn't just for me. LOL

[sawinglogz]

Ratchick, could you upload your files so that we have samples demonstrating this? That will helps us (eventually) support this scenario.

https://www.dropbox.com/request/6VeFzBXa4qZ37EgphL5b

Thanks!

p.s. If you can also provide PDFs from Viatom's software showing how it reports these (or screenshots if on mobile), that would be a huge help as well.

[Ratchick]

I can post screenshots, but the Viatom software doesn't actually show the graphed results below a SpO2 of 70. It just cuts it off. Beyond that, it only reports the lowest value that it records above that point in the summary table (average, lowest, highest etc) - usually, that is 61 on one side or the other, but it might be a few points higher. If I export the data to CSV, it simply reports it as having a SpO2 value of 255. So basically it ignores everything below 70 for the graphing and anything below 61 gets marked "out of range" as it were.

However, I will create a zip with some of the files with super low values and a sample PDF so you can take a look.

[staceyburke]

I am on oxygen 24/7 - why do you NOT want to have supplemental Oxygen?  It really is not a big deal to sleep with O2 hooked up to the cpap.  Keep the Oxygen generator in another room with a tube running into the bedroom.  60% is just nothing to continue to have during your sleep.

[Ratchick]

OK I uploaded a rar file with 2 files from the last couple of weeks, plus one from 6th August... That one is crazy - There was a 36 second stretch where my SpO2 bottomed out and then later in the night, there was a shorter and then another longer dip below 61 right after each other. I also included the PDF and CSV exports for the 6th August file.

[Ratchick]

Stacey, I assume this was meant to go in my other post? It's more a case of I don't want to be fobbed off with O2 and CPAP/APAP because then even if I have apneas, my oxygen levels are okay and also because it's one of those things... I guess because I have SO much else wrong with me, and I just... I'm tired, you know? I'm tired of being sick, of being bedbound since my mid-thirties. To have been too sick to work since my twenties. I already have a laundry list of things that are wrong with me, and honestly, not only do I not want to need oxygen, but I would genuinely feel like a fraud. I've had to fight tooth and nail for every single diagnosis, and even then, I've had my symptoms brushed aside or minimised, by toxic family, condescending a-hole doctors who think women are nothing by hysterical attention whores, so-called friends, etc... So yeah. I'm just tired and don't want just to have oxygen thrown at me without proper therapy with ASV or whatnot. That's all.