Synch Wellue SPO2 data time with CPAP in Oscar

[Liteheart1]

1. I just updated MACOS Oscar to V1.4.0 Using Wellue O2 ring just purchased and Viatom O2_Insight_Pro. While I finally successfully imported date file that was renamed per forum instructions, the SPO2 data is not displayed in Oscar at the proper timing.
   
2. In reading on forum later it is suggested that CPAP session and O2 Ring should be started as close in time to each other as possible. I did NOT do that as I often read with mask on for a while before sleeping so in case I not out then therapy is in place. Instructions for O2 ring to start it when your head hits pillow and your intention is to fall asleep as starting prior to that will make the ODI and other stats less correct as it includes longer awake time in the data.
   
3. I started CPAP 23:16:25 on Sept 19th but didn't start Oring til the 20th at 00:21:??  so about 45 minute mismatch. Per forum instructions I renamed a copy of the O2 ring data file as 20220919231625 and upon import to Oscar it is shown in first file attachment below.
   

Questions:
A) What is the best timing and sequence for starting CPAP machine and Ring? Both have a slight time delay (from pushing machine button or from putting ring on) til when the device starts recording.
B) The Ring report in software only shows start time and end in hours and minutes. I assume that the file data is actually time stamping things to nearest second, correct? (I know that RIng does not actually sample SPO2 @ second.) More important am I correct in assuming that while CPAP data and O2RIng data might on occasion actually completely align as "picture" of what happened at that moment in real time, in actuality the Oscar display might be misaligned (versus reality clock time) by at least several seconds? If indeed that is the case then I assume that in analyzing the data (especially around some AH event of interest) that one should have a bit of flexibility in one's view of the sequence of what was going on as the Oscar data alignment might be off slightly.

2nd file attachment is of just part of the O2 ring data.

Thanks for the support in getting me up and running. The Wellue tech support is non existant, and the user manual, and FAQ are inaccurate in places - thank goodness for this forum, grateful.
       

[Jeff8356]

Question A:  I always start both as close to the same time as possible, even if I am going to read for a little while.  There can be delays of several seconds with the oximeter starting.  Then if you have apneas the desats may lag behind what OSCAR shows by a little.  A desat does not show on the oximeter the exact instance an apnea might start.  It may take some seconds for it to show (up 20).  As an experiment put your oximeter on then hold your breath for as long as you can (safely).  Watch how long it takes for the oximeter to drop that 3% or 4%.  Do that a couple of times throughout the day and you can use that as a baseline for how long it might take a desat to show up in OSCAR with an apnea occurring.  Also, desats do not necessariky correspnd to actual apneas.  I get plenty of desats where there are no events present in the graphs.  For me, other health issues can also casue desats.

Question B:  The time stamp on the oximeter file is HH:MMs so yes, the oximeter is using the nearest second (at least for the time stamp).  There will almost always be some variation in the time between the machine and oximeter so a little flexibility is necessary.  Your cpap is also prone to clock drift over time.  As an example, I leave my xPAP on standard time (winter) so my SleepU is always about an hour off.  No big deal, just change the time in the file befor importing it.
 If I'm not mistaken the wellue models only sample data every 4 seconds anyway.  They may say it's done every 2 seconds but users have discoverd that it just repeats the previous reading again, then takes a new sample.

Look at the whole picture, not just a few seconds in time.  There will be good nights and bad, so see what you get over a few days worth of data.

Also, in your SpO2 printout it shows you below 90% for almost 8:28 minutes.  Might be worth keeping an eye on that to see if it is a regular occurance.  If it happens frequently then discuss it with your Dr.

[Liteheart1]

@Jeff8356 much thanks for the details and very helpful especially "A" some of which might be good for wiki on Wellue. Yes I realize that Wellue ring only samples @ 4 seconds.

I will going forward start CPAP and Ring as close to same time as possible.

I live at slight elevation 3,100' and also given my age (77) my sleep Dr considers 93% to be an OK rested sitting SPO2; and that during sleep would not be overly concerned about O2 as 88% or higher. While personally I want to get as good O2 as possible while asleep to benefit from its healing and restorative aspects, I was surprised to read an article and confirmed by my recent ? to sleep Dr. I had inquired about whether it would be worthwhile for me to add an oxygen concentrator to treatment and her answer was No. She indicated that there is an optimal range for any individual and that not only is more not always better, but that it can lead to downsides e.g. with eyes. Since I already have thyroid eye disease as separate but related to the Graves (thyroid auto immune) disease she definitely is cautious.

The more I read about O2 the more I realize that many articles and forum posts etc. often are written assuming sea level and for those under <60; and that modifications for elevation and age are really important. In addition there is also rarely good clarity on distinguishing what is normal/typical from what is optimal. It is the latter that is my target.