HOW PULSE OXIMETERY WORKS AND IDEAL LEVELS (NB!)

[torontoCPAPguy]

Usually, levels of SpO2 range from 96 to 99% in healthy individuals.
However, when patients have pulmonary or cardiovascular chronic diseases at the same time as a common cold or pneumonia, the level of SpO2 may drop rapidly. SpO2 lower than 90% is defined as acute respiratory failure. When SpO2 drops by 3 to 4% from its usual level, even if it is not less than 90%, an acute disease may be suspected.
In some patients, usual levels of SpO2 may be below 90%. Most other individuals will have fluctuations of 3 to 4%.
Depending on individual pulmonary or cardiovascular conditions, the level of SpO2 may be relatively higher at rest, even though the level drops considerably during exercise or sleep.
As with “normal” body temperature, the level of SpO2 varies from person to person. Since pulse oximeters may produce errors, there is no “correct” or “incorrect” result.
Therefore, it is best to record the individual’s level of SpO2 over a long period, and determine their typical range at rest and at various levels of activity so that abnormal decreases can be detected.
In the book “Manual of Elderly Home Care by Individual Illnesses,” published by Kinpodo Inc., two key insights into SpO2 rates are provided:
** The ideal range of oxygen saturation is 96 to 98%. However, since some patients may have lower levels, the person's normal levels should be determined.
** If the level is lower than normal, first measure another finger. If the level is 3 to 5% lower than the usual stable level, or lower than 90%, consult your personal physician.

For the full report go to:
http://www.maxtecinc.com/docs/pulsox/ab ... imetry.pdf

[torontoCPAPguy]

http://books.google.com/books?id=rfwYul ... &ct=result

This is a portion of a paramedic handbook previously posted back in February I believe. It suggests that oxygen be administered when SpO2 falls below 96% and that at under 90% the patient is in acute respiratory distress. Jeez.

How many of us drop down into the 80's and even into the 70's on a regular basis? And either don't even know it because we do not own a pulse oximeter or know it and ignore it because our doctor(s) haven't picked up on it?

I know that at my own sleep study I was down in the 70's, was prescribed a CPAP machine with a magical pressure of 4cm H2O and never had a follow up booked to ensure that my SpO2 was adequate! How many of us?

SpO2 is the fifth most vital of the body's vital signs in determining one's condition. Mine has been dropping down below 90% for the last 20 years I am sure; and down into the 70's since I have started measuring and tracking almost every other night.

God bless the guys that have come out with inexpensive oximeters; you may drive your doctors crazy, but you are for sure going to live a longer, healthier and more comfortable life. Since starting oxygen infusion therapy (of my own volition I might add) I have had three doctors essentially say 'go for it, bravo' and I have a meeting with a top pulmonologist next week.... and will be anxious to hear what the reaction is and where we go from here.

I am presently infusing 3L into the APAP line and getting SaO2 readings that do not drop below 90% and are generally above 96%. I was going to shoot for 95% consistently but I think after reading all that I have read over he past day or two I am going to leave my settings exactly where they are and just continue to monitor my SpO2 during the night.

During the day, when upright and on the move my SpO2 runs in the high 90's without any supplemental O2.... it is the nightime that appears to hold the key to the magic bullet and it is an essential part, unless I am gravely mistaken, of an overall clinical evaluation of OSA, along with all of the other essential body readings including EEG readings to see how much REM sleep we are getting and what is happening during that REM sleep.

There are much more educated folks on here than I.... any comments?

[brain_cloud]

Usually, levels of SpO2 range from 96 to 99% in healthy individuals.

I'm sure that's waking normal levels, not sleeping.

[torontoCPAPguy]

They made no distinction although I would have thought that sleeping SpO2 levels would be lower, especially during REM sleep. I can tell you this for a fact though, and that is that with SpO2 running 96-97% all night I slept like a bloody log to the extent that when I awoke (groggy) I was shortly thereafter energized, but it took the whole day for the aches in my spine and bones to wear off with the help of some Tylenol. I don't think I budged more than maybe once during the night. I'm heading off to bed shortly after checking my blood sugar one last time (the O2 also improves the efficacy of my diabetes meds, as does the loss of a few teeth this week). Mind, I am feeling like I could go to the movies right now and grab a beer afterwards. Once I lay down though with the APAP/O2 infused I will be out like a light in 2 minutes. And wake up to the alarm clock on my Blackberry at 8 a.m. (ain't semi retirement great? I used to get up at 6 a.m. every morning).

If anyone has anything else to contribute in the way of data as to the ideal SpO2 range awake/asleep, please chime right in. I can't see that 96-97% is doing any harm. Quite the contrary it would appear at first blush.

[elena88]

What I dont understand is why is the red line at eighty eight percent, and but events are counted as happening below ninety four percent.

Then I hear you will be given oxygen in the hospital if you fall below ninety, but some docs wont prescribe oxygren for cpap unless youre in the
high eighties?

So if you spend all your night in the low nineties, you are having events all night, but its not low enough to be prescribed oxygen?

Is there a type of "reichter scale" for oxygen levels.. or red, yellow, and green zones ?

[Goofproof]

What I dont understand is why is the red line at eighty eight percent, and but events are counted as happening below ninety four percent.

Then I hear you will be given oxygen in the hospital if you fall below ninety, but some docs wont prescribe oxygren for cpap unless youre in the
high eighties?

So if you spend all your night in the low nineties, you are having events all night, but its not low enough to be prescribed oxygen?

Is there a type of "reichter scale" for oxygen levels.. or red, yellow, and green zones ?

In the software, that number can be changed from 88 to whatever. Jim

[elena88]

Oh cool, thanks Jim!

I think I found that when I was messing around with it today..

Maybe my husband set it eighty eight or it came programmed that way..

[montana user]

http://books.google.com/books?id=rfwYul ... &ct=result

This is a portion of a paramedic handbook previously posted back in February I believe. It suggests that oxygen be administered when SpO2 falls below 96% and that at under 90% the patient is in acute respiratory distress. Jeez.

How many of us drop down into the 80's and even into the 70's on a regular basis? And either don't even know it because we do not own a pulse oximeter or know it and ignore it because our doctor(s) haven't picked up on it?

I know that at my own sleep study I was down in the 70's, was prescribed a CPAP machine with a magical pressure of 4cm H2O and never had a follow up booked to ensure that my SpO2 was adequate! How many of us?

SpO2 is the fifth most vital of the body's vital signs in determining one's condition. Mine has been dropping down below 90% for the last 20 years I am sure; and down into the 70's since I have started measuring and tracking almost every other night.

God bless the guys that have come out with inexpensive oximeters; you may drive your doctors crazy, but you are for sure going to live a longer, healthier and more comfortable life. Since starting oxygen infusion therapy (of my own volition I might add) I have had three doctors essentially say 'go for it, bravo' and I have a meeting with a top pulmonologist next week.... and will be anxious to hear what the reaction is and where we go from here.

I am presently infusing 3L into the APAP line and getting SaO2 readings that do not drop below 90% and are generally above 96%. I was going to shoot for 95% consistently but I think after reading all that I have read over he past day or two I am going to leave my settings exactly where they are and just continue to monitor my SpO2 during the night.

During the day, when upright and on the move my SpO2 runs in the high 90's without any supplemental O2.... it is the nightime that appears to hold the key to the magic bullet and it is an essential part, unless I am gravely mistaken, of an overall clinical evaluation of OSA, along with all of the other essential body readings including EEG readings to see how much REM sleep we are getting and what is happening during that REM sleep.

There are much more educated folks on here than I.... any comments?

Im also an EMT, as well as sleep tech, and on the ambulance we add O2 to anything below 90%. I see O2 in the 50's in the lab all the time. Amazing these people even function at all!

[torontoCPAPguy]

We have a good friend whose daughter has Cystic Fibrosis and deminished lung function as a result. Very diminished. And she functions fairly well although there are good days and bad. She is a pit bull and is tenacious as heck.

[LoQ]

Im also an EMT, as well as sleep tech, and on the ambulance we add O2 to anything below 90%. I see O2 in the 50's in the lab all the time. Amazing these people even function at all!

Interesting jobs! At what point in the lab do you add O2?

At my diagnostic sleep test, I went well below 80 for a considerable period of time, and they did not start oxygen.

At my titration test, they were able to clear all obstructive events (though I had 4 central events during REM) and my oxygen was below 90% for about 18% of the night. They did not recommend oxygen.


Just trying to understand why doctors are so miserly with oxygen. Some of us think it might help us a lot.

[-SWS]

Just trying to understand why doctors are so miserly with oxygen.

I think the status-quo medical treatment paradigm for supplemental O2, to date, has been largely about: 1) avoiding hypoxemia at the cellular level, or 2) stabilizing central respiration. I'm unaware of medical studies/literature supporting a reasonable-sounding hypothesis that supplemental O2 might be able to enhance sleep architecture by means unrelated to those two objectives (eg. supplemental O2 addressing hyper-reactive chemoreceptor-based sleep disturbances in at least some highly arousable patients).

Here are a couple links that discuss the benefits of using supplemental O2 as well as contraindications and a few other non-medical complications:

LONG TERM OXYGEN THERAPY IN ADULTS
-and-
SUPPLEMENTAL LOW FLOW OXYGEN TITRATION IN POLYSOMNOGRAPHIC TECHNOLOGY
(an Adobe PDF document)

[LoQ]

I think the status-quo medical treatment paradigm for supplemental O2, to date, has been largely about: 1) avoiding hypoxemia at the cellular level, or 2) stabilizing central respiration.

That was my suspicion. Most pulmonologists are on the front line in intensive care. So it would be pretty hard to get my pulmonologist to jump at supplying O2 for 90% SpO2. He probably think that looks pretty darn good compared to most of his patients.

But in my case, I'm not on a quest to save my life, which 90% is sufficient to do. I'm trying to improve the quality of my life, and my guess is that 90% is way too low for good quality of life.

Doctors are primarily trained to save and extend lives. If they can keep your O2 above 90%, they've done their job.

[M.D.Hosehead]

Thanks, SWS. You are a treasure trove of useful information.

Like LoQ, I suspect there hasn't been sufficient consideration, in the sleep literature, of the possibility that the conventional threshold for O2 supplementation in OSA has been lower than ideal (if it's even been considered at all). I don't think anyone has researched whether the cognitive symptoms in people with SA would improve if their average SpO2 during the night was maintained (just picking a number for illustration) above 96%.

If anyone has seen that kind of study, I'd love to know about it.

[torontoCPAPguy]

Just trying to understand why doctors are so miserly with oxygen.

I think the status-quo medical treatment paradigm for supplemental O2, to date, has been largely about: 1) avoiding hypoxemia at the cellular level, or 2) stabilizing central respiration. I'm unaware of medical studies/literature supporting a reasonable-sounding hypothesis that supplemental O2 might be able to enhance sleep architecture by means unrelated to those two objectives (eg. supplemental O2 addressing hyper-reactive chemoreceptor-based sleep disturbances in at least some highly arousable patients).

Here are a couple links that discuss the benefits of using supplemental O2 as well as contraindications and a few other non-medical complications:

LONG TERM OXYGEN THERAPY IN ADULTS
-and-
SUPPLEMENTAL LOW FLOW OXYGEN TITRATION IN POLYSOMNOGRAPHIC TECHNOLOGY
(an Adobe PDF document)

A little confusing but right on the money essentially. In my case I have TWO clinical indicators; first treat me for my OSA. Done, my AHI is pretty much zero now. Oooops! Hey, check out this guy's SpO2 - even with OSA corrected it is still dropping into the 80's during sleep and into the 70's during REM sleep. Let's try infusing some O2 into the CPAP line. At 2L/M patient's SpO2 at rest remains in the 90's all the time now and never drops into the 80's or heaven forbid, into the 70's. Make sure the patient understands that "more is not better" as suppression of the CO2 response can result, associated with reduced respiration (like a dog chasing its tale sorta).


I feel better and more alert during the day to be sure; but it will take several days or weeks to get a good solid handle on this as I am also dealing with medication changes, etc. at the same time. And the efficacy of those medications as well as interactions of same are also changing as a result of a properly functioning liver, etc.

[Slinky]

When asking all these "whys" of the medical profession keep in mind the COST of supplemental 02 - especially if Medicare is paying for the supplemental 02.