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Event Duration, O2 Level, Lag, Vib. [Chart Review Request]
#1
Event Duration, O2 Level, Lag, Vib. [Chart Review Request]
Newbie here so still learning.  Just installed OSCAR so not enough data to share yet, though my questions are more generic in nature anyway.

I understand there is a time lag between a given apnea event and the effect of that event from a measurable O2 saturation perspective.
Does anyone know the average range (in seconds) of that time lag?

The reason I ask is that I wear a finger pulse oximeter that has a vibration alarm feature to associate with an O2 level threshold.
The idea being to wake me up if I may be in the midst of a non-breathing event so that I can consciously breath, change position, etc., to remedy.
I'm thinking that this alarm is only going to be helpful if the duration of the apnea event is greater than the time lag... is this right?
Because I also struggle with intermittent wake-ups (and more to the point, difficulty falling back to sleep... perhaps sleep-maintenance insomnia?), I'm not sure if I should be using the alarm vibration threshold at all.  Or if so, what to set it to for improved odds of it being worthwhile (vs. essentially being alerted to the fact that something happened in the recent past that I can't do anything about now, if that makes sense.)

At my overnight sleep study at the lab, I had 53 total events... 36 of which were central, the longest central duration being 37 seconds... and the longest obstructive duration being 57 seconds... with lowest SpO2 level of 69%.  Over the past month of in-home results, I typically have at least one (typically 2-3 or more) SpO2 level drops into the high 70s to low 80s.  I've been experimenting with an alarm threshold level of 81% since there's also a time lag between being alarmed, doing something about it (deep breaths and changing position), then seeing the level come back up over the alarm threshold.  (Even after the alarm goes off, I think the level can continue to drop before rebounding.)  I've found that if I set the alarm threshold very much higher, then it goes off too often (especially when first trying to get to sleep).

Bit more background if helpful.  My original diagnosis was 49.5 AHI.  After a couple months of struggle against mask fitting, I found a good full-face and have since been improving with CPAP (current pressure levels tinkered to 4-10) over the past 6-7 weeks, so I'm generally encouraged (and with decreasing aerophagia too).  But while my AHI is indeed better (I'm generally under 10 now... and had my best night last night at 1.5... though my actual sleep on any night is probably just 5-6 hours... twice as good as before CPAP though... )... and though I no longer suffer from GERT... and though my bathroom visits at night are now 0-1... I'm still concerned about the effects of potentially "long" apnea events (especially CSA)... so I'm also interested in understanding what is considered "long" enough to warrant concern.  Given my blend of OSA/CSA, I'm wondering if BiPAP might be better than CPAP.  I seem to be an edge-case though, as the sleep lab results noted (poorly worded sentences theirs, not mine):

(1) This CPAP and BiPAP titration showed an initial decent response to 10 to 12 cm H2O with an AHI of no higher than 5 with no significant hypoxemia.  When the patient transitioned to higher pressure settings for minimal residual apneas started to develop some increase in the AHI with findings consistent with complex sleep apneas on 14/9 cm H2O.  Nevertheless the patient did have an adequate response at 10 and 12 cm H2O.  BiPAP was not tested at lower pressure settings.

(2) Sleep efficiency was normal as was the sleep latency.  The REM latency was slightly shortened to 57 minutes.

(3) Cardiac data showed sinus rhythm with no evidence of rhythm disorders.

(4)  Mild elevation the periodic limb movement index.

... followed by recommendations, in which is noted:

"... one could consider return to the sleep lab for consideration of lower BiPAP starting pressures vs. an ASV titration.  Patient does not clearly need either of those pressure changes though."

Per (4) above, my PA thinks this could be the culprit behind my intermittent wake-ups in the night... and so we're now experimenting with 0.25mg Pramipexole.  Hard to say if this is helping or not, just given all the other variables that go into getting a good night's sleep that I'm also trying to fine-tune in parallel (diet, exercise, timing of both, good bed-time habits, blue-light filtering, sleeping position, etc.).  

To recap my questions (sorry for the long post here): 

What is the average range (in seconds) of the time lag between an apnea event and the measurable effect of that event in Sp02%?
What is considered "long" (significant enough to be of potential concern) when it comes to an apnea event (especially CSA)?
What SpO2% alarm threshold, if any, would be advised for someone wanting to "arrest" a significant event in progress without after-the-fact alarms?

Thanks for any thoughts or insights... love this forum!
Bob
51 yrs
6'1", 215 lbs
ResMed Air Sense 10
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#2
Help... long OSA event and low oxygen saturation
I wear two pulse ox readers (CONTEC CMS50F and also ViATOM Wearable) and both recorded a major SP02% drop last night... to 53%.  In looking at the ResMed data in OSCAR, I see an OSA event of 120 seconds just a bit beforehand.  Oddly, there is then a gap in the ResMed data before it resumes again (image attached).  Is there a 120-second time-out or something in the ResMed device that causes this gap?  There was no leak at the time either.  AHI was 14.8 (has been all over the map since starting CPAP late June) and seems to be trending to more of a mixture of CA and OSA, which leads me to wonder if BiPAP should be next step.  Over the past 5 nights, I've been averaging 12 minutes per night at below 88% saturation with total apnea per night averaging just over 20 minutes.  CPAP set to 11 (following lab titration recommending 12, as we've been tweaking a bit to try and reduce aerophagia).  Am wondering if my response to CPAP (more emergence of CA?) might now have rendered what was previously somewhat effective settings as useless.  Also curious if anyone has a study that speaks to length of individual events... like a severity categorization table or something... or maybe it's just all about the related desaturation effect per person?  Dunno... PA keeps saying my CPAP is "adequately" treating my apnea (originally identified as 49.5 AHI)... I guess she thinks "adequate" since AHI is lower than it was (?)... though we all know that AHI is only part of the story and it seems my PA really isn't that interested in getting into the data like I am.  Am I over-reacting to these long OSA events or over-assuming the importance of SP02% data?  Sorry for all the questions... lots more... struggling and concerned... 


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#3
RE: Help... long OSA event and low oxygen saturation
There is no standard for length of events other than the 10 seconds to be considered an event.  Many short events may also be bad.

The two biggest events are sleep disturbance and desats.  Both are measured during a sleep test.

You should be concerned about long events that end in DeSats.  The level of desats that you stated are a concern that requires supplemental oxygen.

It's hard to give advice without viewing the data.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#4
RE: Event Duration, O2 Level, Lag, Vibration Alarm
If anyone interested... I overlaid my SP02 chart on top of my apnea chart and manually aligned the timestamps (stretched the SP02 image) for an isolated 91-second OSA event (screenshot below).  No doubt many variables that could cause different differentials from one person to the next, but at least for me in this one case, I found about a 3.5 - 4 minute lag between OSA event Start and resultant downstream effect (below 88% SP02), though obviously depends on your saturation to begin with too, etc.  Just thought was kinda interesting as thought perhaps the lag would be much less.  Surely someone somewhere knows more about this and has done an actual study... haven't found... so just my own back-of-the-napkin here.


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#5
Charts Review Request: Discouraged and Concerned
Not feeling like CPAP is doing me any good, while my PA notes as "adequately treating", seemingly based on AHI alone (though has FINALLY agreed to doing a nocturnal oximetry study after I've repeatedly pushed my data and concerns... guessing another month before actually happens).  Regardless of AHI, I'm continuing to struggle with wake-ups, fatigue, and worries about longer-term effects already accrued over pre-diagnosis decades as we keep twiddling with pressure settings and dragging out what surely must be a need for supplemental oxygen (if not also BiPAP (?), as I seem to have sporadic CA/OSA nights).  I didn't happen to show a need for oxygen during my sleep lab test night several weeks ago... just a lucky night I guess, or maybe my body is now behaving/responding differently to CPAP?  I voiced concern about basing decisions or discarding possibilities just upon a single night's worth of data... on deaf ears it seems.

Re: my oxygen concerns (since limited on attachments)... over the past week I've averaged 15 minutes per night (42 minutes last night!) at < 88% with average ODI per night of 18 and bottoming at 53% SPO2.  Over this same span, my AHI has averaged just under 10 (+/- 4) (hence "adequate"?)... but total apnea per night has averaged 21 minutes (seems like this should matter to someone) with a few long OSA events in the 1-minute to 2-minutes range (since I can't find any other definition of "long") combined with dozens of smaller OSA and CA events every night.  So I'm fragmented, tired, frustrated, and concerned.  (But gee ain't it just swell that my AHI has averaged under 10!?)

I've tried to follow all of Bonjour's guidelines re: chart organization.  Hopefully something can be gleaned here.  Really appreciate your time to review and offer any insights/guidance.

- Bob


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#6
RE: Event Duration, O2 Level, Lag, Vib. Alarm, Chart Review Request
Hello rbellamy,
I have combined your two therapy threads into one thread here.  
See the PM I sent you. Smile
OpalRose
Apnea Board Administrator
www.ApneaBoard.com
Dreaming


https://www.sleepfiles.com/OSCAR
OSCAR Chart Organization
Using Attachments to Post ScreenShots.
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE.  ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA.  INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#7
RE: Event Duration, O2 Level, Lag, Vib. Alarm, Chart Review Request
You have very strong evidence of chin tucking causing positional apnea. You recognize this because you provided close up zoomed views of these events. These are indicated by clusters of obstructive events.

I would like you to try a soft cervical collar loose fitting or a anti snoring collar (no back foam) sufficiently tight to keep your chin from tucking inside. I haven't heard of any doctor recognizing this yet, but it works. Ask your doctor if you can get an ASV trial or titration study since it was mentioned by your sleep tech in the report. The fact that it was mentioned is extremely unusual.

On the charts we want the left sidebar minus the calendar and piechart because it gives us good information to help you.

Your desats are severe enough to require Oxygen supplement overnight. Ask for it.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

Download OSCAR
New to Apnea? Helpful tips to ensure success
Soft Cervical Collar
Mask Primer
Dealing with a DME
Organize Charts
Attaching Charts

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#8
RE: Event Duration, O2 Level, Lag, Vib. [Chart Review Request]
Mr. Bonjour.... I can't thank you enough for taking the time to share your insights.  It has been a frustrating ride so far, but now I'm encouraged by your recommendations and will follow up later as resultant data and sleep quality (hopefully) improve.

- Bob
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#9
RE: Event Duration, O2 Level, Lag, Vib. [Chart Review Request]
As follow-up to earlier cervical collar recommendation upon reiew of charts... thank you again Mr. Bonjour!  You're recommendation has made a HUGE difference on my AHI (and also on the desats that were leading me down the path towards supplemental oxygen).  I've been plotting all related data over the past 4 weeks... first two weeks being pre-collar for comparison against most recent two seeks w/ collar... chart below speaks for itself.  The collar has been so effective that I'm now questioning if CPAP even needs to be part of the ongoing plan, and so have been looking into how I could use just oximetry (ODI and minutes below 88%) as indicators of likely AHI as I suspect CPAP may be disrupting more than helping... hard to say.  Think I may alternate nights with and without CPAP and see what happens to oximetry data.  Anyone else tried this approach with CPAP weaning in mind?  (If all I'm getting out CPAP is ability to get AHI data, then would rather bypass and just have some other rough way to indirecctly keep an eye on it.)

From what I've read, there's evidence of decent correlation between ODI and AHI when AHI < 5.  In my case, ODI generally correlates from a pattern perspective, but I've only once ever had an ODI less than 10 despite AHI consistently under 3.  What are others seeing w/ ODI averages and relationship to AHI?  Despite the drastically improved AHI, active daily exercise (5-10 miles walking daily), improved diet and related weight loss of 25 lbs over past 8 weeks (BMI 26.3 and continuing to drop), low life stress, no alcohol, no drugs, no other health issues, consistent sleep hygiene, etc., I still wake up every hour or so through the night and once I get to 3:00a, it's rare to get back to sleep (after starting about 10:00p)... and so I still have fragmented sleep and daytime fatigue.  I think I'm probably still only getting 4-5 hours of actual sleep per night.  Could my consistently >10 ODI be playing some role w/ awakenings?  Have also read elsewhere that EPR can be another potentially bothersome contributor... so I've changed from default of FULL TIME to RAMP ONLY and reduced from 3 to 1 to see if that does anything for me.

Any guidance / suggestions re: ODI and ongoing awakenings?  Thank you all so much for this community... soooooo very helpful.


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#10
RE: Event Duration, O2 Level, Lag, Vib. [Chart Review Request]
Great, we solved one problem. I'd like to see your sleep studies, full copies w personal information redacted. And current OSCAR charts. I'm especially interested in your flow limitations. Is something that can restrict your breathing by up to 50%important to you.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

Download OSCAR
New to Apnea? Helpful tips to ensure success
Soft Cervical Collar
Mask Primer
Dealing with a DME
Organize Charts
Attaching Charts

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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