08-11-2019, 12:00 PM
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
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
