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Correlation between AHI and Low Sp02
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MAPnea Offline

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Post: #1
Correlation between AHI and Low Sp02
Last night I had to sleep part of the night without my oxygenator "off" because of an intense lightning storm. DME told me not to use the oxygenator when lightning was happening.

I slept 4 hours, then woke up because I felt I couldn't breathe (like before I started using my CPAP) and decided to turn the oxygenator back "on" and slept another 4 hours. I was wearing my CMS50D+ and was shocked to see what a difference oxygen made. I live at an elevation of 5,600'.

Anyway... when I checked my AHI for last night I was surprised to see the largest number I've seen since starting CPAP therapy last October. I've been getting AHI of less than 1.0 per night and last night I had 5.0. Sure, I know that isn't bad at all, but here are my questions:

Is there a correlation between low Sp02 (my lowest was 76) and AHI events?

Should I turn the oxygenator "on" even if there is a lightning storm? Or was my DME just trying to scare me?

Thanks
08-18-2013 10:50 PM
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Paptillian Offline

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Post: #2
RE: Correlation between AHI and Low Sp02
(08-18-2013 10:50 PM)MAPnea Wrote:  Is there a correlation between low Sp02 (my lowest was 76) and AHI events?

Absolutely, yes. The more difficulty you have breathing (higher AHI) the lower your blood oxygen levels can be. Sub-optimal oxygen levels are what put our bodies into distress and cause fragmented sleep, increased blood pressure, and long term health problems. Doctors tell us that an AHI of 5 or less is sufficient to keep this in check, assuming there aren't other issues at play.

What was the difference in SpO2% that you saw on your oximeter without the supplemental oxygen?

Your AHI of 5 was okay but if you're waking up and feeling like you aren't getting enough air then the DME could be giving bad advice by telling you not to use it. I would take the doctor's advice over the DME's any day of the week. Ask them if it's a personal safety issue or an equipment damage issue. If they're only concerned about the equipment then maybe it can be solved with a good quality surge protector. It's a good idea to have your CPAP machine on one as well.
(This post was last modified: 08-19-2013 12:27 AM by Paptillian.)
08-19-2013 12:20 AM
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vsheline Offline

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Post: #3
RE: Correlation between AHI and Low Sp02
(08-18-2013 10:50 PM)MAPnea Wrote:  Is there a correlation between low Sp02 (my lowest was 76) and AHI events?

Should I turn the oxygenator "on" even if there is a lightning storm? Or was my DME just trying to scare me?

Hi MAPnea,

Clearly, AHI events do cause low SpO2, but I think you are asking whether low SpO2 can cause AHI events.

I know supplemental O2 is one of the treatments for central sleep apnea. For some people supplemental O2 eliminates or reduces centrals. So in the case of centrals, yes, low O2 can contribute to AHI.

Who knows, perhaps low O2 also increases relaxation of the airway and increases obstructive events, too. But I haven't read that anywhere.

Where your extra events mostly centrals?

Of course, it could very well have been just a coincidence. Perhaps the weather or something else was affecting your sleep.

O2 is very combustible - explosive really. Your DME was probably just trying to prevent getting sued by your survivors in case lightning were ever to hit a power line near your house and cause a spark and explosion in your O2 concentrator. He is safe now: he has warned you.

Take care,
--- Vaughn

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
(This post was last modified: 08-19-2013 03:19 AM by vsheline.)
08-19-2013 03:10 AM
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MAPnea Offline

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Machine: ResMed S9 AutoSet - currently "set" on CPAP mode
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Other Comments: New Sleep Doc + New DME = Trying new approach to PAP therapy.

Sex: Female
Location: near Great Basin National Park, Nevada

Post: #4
RE: Correlation between AHI and Low Sp02
What was the difference in SpO2% that you saw on your oximeter without the supplemental oxygen?
_____________
Without the supplemental oxygen my average low Sp02 was 84.6 with the most dramatic drops below 88 and longest cluster of Sp02 "events" happening in the last 90 minutes (of the 4 hours) of sleep with a corresponding increase in heart rate. I'm just learning, but the "visual" really helps me understand that a lack of oxygen equals a big increase in heart rate (as high as 119 right before I woke up).

After I turned the oxygen concentrator "on" for the final four hours of sleep, my Sp02 never went below 88. It took about 15 minutes for my pulse rate to drop back below 80 bpm and the rest of the night my heart rate was in the 60 range.

I hope you (and others) don't mind, but I have another question I'd like to ask about "Total Events" data. This particular night I had 90 Sp02 "events" and 119 Pulse "events". Is this, on average, "normal"? As with AHI total events (ideally below 5.0 every night), are there "normals" one should have with total Sp02 and Pulse events every night?

Thank you so much for your explanations and questions. You've no idea how helpful this is for me.

Margaret
(This post was last modified: 08-19-2013 01:03 PM by MAPnea.)
08-19-2013 12:42 PM
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MAPnea Offline

Advisory Members

Posts: 182
Joined: May 2013

Machine: ResMed S9 AutoSet - currently "set" on CPAP mode
Mask Type: Other
Mask Make & Model: ResMed AirFit F10 and P10 - varies
Humidifier: ResMed H5i
CPAP Pressure: 8
CPAP Software: SleepyHead

Other Comments: New Sleep Doc + New DME = Trying new approach to PAP therapy.

Sex: Female
Location: near Great Basin National Park, Nevada

Post: #5
RE: Correlation between AHI and Low Sp02
Clearly, AHI events do cause low SpO2, but I think you are asking whether low SpO2 can cause AHI events.

I know supplemental O2 is one of the treatments for central sleep apnea. For some people supplemental O2 eliminates or reduces centrals. So in the case of centrals, yes, low O2 can contribute to AHI.

Where your extra events mostly centrals?

O2 is very combustible - explosive really. Your DME was probably just trying to prevent getting sued by your survivors in case lightning were ever to hit a power line near your house and cause a spark and explosion in your O2 concentrator. He is safe now: he has warned you.
________________

Thank you Vaughn for deciphering my question! Yes, I did wonder if low levels of Sp02 caused higher AHI events. My sleep doctor did not mention my having central sleep apnea. In fact, in both of my sleep studies I did not have enough "events" to merit having a titration study, but - because of my afib that was getting worse - he qualified me for the CPAP machine. In addition to the increasing afib events, I developed a chronic cough (which went away about two months after I started CPAP therapy). I have not had an afib episode since starting CPAP therapy. And now my cardiologist is starting to reduce my dijoxin and blood pressure meds. At my last visit he said there was a possibility I might be able to get off the supplemental oxygen in a few more months. After I see what happened when I was "off" oxygen for four hours, I think not!

I'm ashamed to say that - even though I've downloaded the ResMed software - I have not been brave enough to try to "figure it out" yet. I have an entire week "off" and plan to spend many hours figuring out the ResMed software. So - to answer your question about whether or not I had more centrals without oxygen, I don't know. This was just two nights ago and when I read the information on my ResMed S9 I only saw the increased (for me) AHI "events" and did not scroll down the menu to see if they were central or not. I plan to be able to "go back" and re-visit that night with the ResMed software within the next few days.

And, yes, my DME has now covered his you-know-what!
(This post was last modified: 08-19-2013 01:04 PM by MAPnea.)
08-19-2013 12:58 PM
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RonWessels Offline

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Post: #6
RE: Correlation between AHI and Low Sp02
(08-19-2013 03:10 AM)vsheline Wrote:  O2 is very combustible - explosive really.

Technically, that is not true. From a pure chemistry point of view, oxygen does not burn at all. Oxygen is the element that allows other things to burn.

The danger with pure oxygen is that the behavior of flame in an enriched oxygen environment is far more violent that people are used to. People "know" what happens when you strike a match. But strike a match in an enriched oxygen environment and people will be shocked at the size of the flame and the speed at which the match burns. Which probably causes them to drop the match. Which will cause the rug to catch on fire. Normally, there would be plenty of time to put out the fire before it gets out of control. But in an enriched oxygen environment, unless you react _immediately_ (rather than still being surprised by the size of the flame), it's too late.
08-20-2013 01:53 PM
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jgjones1972 Offline

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Post: #7
RE: Correlation between AHI and Low Sp02
Just a thought here; but, it seems to me that low SpO2 could increase AHI and more specifically, obstructive events.

I could be wrong here, but imagine this: If low oxygen saturation stimulates one's body to increase respiration (rate and/or tidal volume), then would it not be reasonable to assume that this may increase events due to the increased effort/force in breathing?

In other words; it seems that obstructive apneas and hypopneas are generally caused by a collapse of the airway while inhaling - so it seems to me that the airway, in simple terms, is being sucked closed while inhaling. If this is more or less the case ,in simple terms, then wouldn't increasing the force of inhale increase the frequency/severity of the airway collapsing?

The above is all just a guess...
08-20-2013 05:06 PM
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MAPnea Offline

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Machine: ResMed S9 AutoSet - currently "set" on CPAP mode
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Mask Make & Model: ResMed AirFit F10 and P10 - varies
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Other Comments: New Sleep Doc + New DME = Trying new approach to PAP therapy.

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Location: near Great Basin National Park, Nevada

Post: #8
RE: Correlation between AHI and Low Sp02
OK, I finally worked up enough courage to open up ResScan to take a detailed look at the night I "slept" four hours without supplemental oxygen. ...which led me to the next night and, then, last night. All three nights I had increased AHIs and this morning I woke up feeling like I couldn't get out of bed. So what did I discover? Three nights ago when my AHI started creeping up - I not only slept four hours without supplemental oxygen because of a thunderstorm, but I had also inadvertently set my machine to CPAP mode with a pressure of 9. It was so obvious when I could see the detailed ResScan charts! A double whammy.

I carefully re-set my S9 to what the doctor ordered (Auto Set; 6-11) and I vow to be more careful in the future and to double check my machine before I crawl into bed. I'm also going to sleep with the oxygenator huffing and puffing (in another room - I can't stand the noise that thing makes!) even if there is a thunderstorm. I've planned my escape route ..

Thanks to everyone who responded with thoughts and helpful information. I would have never figured this out without your help and encouragement. Now I'm off to donate to Apnea Board!
08-21-2013 12:53 AM
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