Optimum O2 percentage

[RockyBob]

Got an unusual question, I think. I started using a CPAP more than ten years ago and benefitted enormously. Then, in 2010, after losing 30 pounds, I tried using an oral appliance and got very good results. Naturally, I preferred using the oral appliance to hauling around a very heavy CPAP device and using a mask every night. Then, about six months ago I began to notice I wasn't waking as refreshed in the morning. I bought an oximeter for my iPhone, and the results were very interesting. With the CPAP, of course, my O2 level stays very high, typically 95-96%. Sure enough, with the oral appliance my average number is about 2% lower, And there are a very small number of apneas during the night, less than five, typically. Although I'm not quite as refreshed in the morning, the ease of just using a mouth appliance certainly predispose me to wanting to use that rather than the CPAP. I asked my apnea doctor if he knew of any long-term consequences from lower numbers like this, and he knew of none. I did find one article looking at the Wisconsin apnea study, and it suggested that apnea associates with increased risk of cancer.
Does anybody have any information about the effects of small deficits in oxygen over the long-term?
Thanks!

[PaulaO2]

I personally (and as a non-medical professional) would not consider it a concern. As long as the O2 stays above 90, preferably over 92, then all is well.

You'd probably find better "effects of small deficits in oxygen over the long-term" studies if you looked into the COPD or other lung issues vs limiting it to sleep apnea.

Let us know what else you find! It would be interesting to know so we can help others later.

[trish6hundred]

Hi RockyBob,
WELCOME! to the forum.!
Hang in there for more responses to your post.

[Airstream]

I agree with Paula that at over 90% you should be ok. Also, I have not heard of cancer being attributed to apnea. I do know, however, that deficits in oxygen levels during sleep over a long period of time can lead to congestive heart failure (CHF). Patients who already have been diagnosed with CHF and apnea should probably be on CPAP. I don't know what oxygen levels are too low over the long term, but I would think you are fine. Of course, it's always best to ask your doctor.
There are many articles on this subject (CHF/apnea) available on the net. I have included one below on this subject from The Ohio Sleep Medicine Institute. I think it's ok for me to post it.
http://sleepmedicine.com/blog/archives.c...rt-failure
/Jeff/

[RockyBob]

I personally (and as a non-medical professional) would not consider it a concern. As long as the O2 stays above 90, preferably over 92, then all is well.

You'd probably find better "effects of small deficits in oxygen over the long-term" studies if you looked into the COPD or other lung issues vs limiting it to sleep apnea.

Let us know what else you find! It would be interesting to know so we can help others later.

Thanks for the response, Paula. I've been googling for long term oxygen deficits and no one considers the numbers I've mentioned to be a problem. But then, no one tracks this kind of issue. In the scheme of respiratory issues this is undoubtedly not something medical research could possibly focus on. However, I sure notice a small effect on waking and can certainly imagine a cumulative effect on mental acuity over many years. Who knows what spending one third of one's life with mild oxygen deprivation does for disease and overall aging?
If anything ever come up, I'll post for sure.

If anyone else wants to monitor their own O2 periodically, I can highly recommend the Masimo oximeter for the iPhone. It's pricey ($250+) but it is reported to be very accurate.

[RockyBob]

I agree with Paula that at over 90% you should be ok. Also, I have not heard of cancer being attributed to apnea. I do know, however, that deficits in oxygen levels during sleep over a long period of time can lead to congestive heart failure (CHF). Patients who already have been diagnosed with CHF and apnea should probably be on CPAP. I don't know what oxygen levels are too low over the long term, but I would think you are fine. Of course, it's always best to ask your doctor.
There are many articles on this subject (CHF/apnea) available on the net. I have included one below on this subject from The Ohio Sleep Medicine Institute. I think it's ok for me to post it.

/Jeff/

Thanks Airstream. Conventional wisdom says that 90% or thereabouts is enough to avoid acute problems, but nobody is looking for long term effects. I sure can tell the difference between a night of 92-94 (a little fuzzy, maybe a little headache) versus 94-96 (really, really feels good). I'm not worried about heart failure or other fairly sudden effects, just worried about slowly losing mental acuity (or cancer) in the next decade or two. OK, I'm already 67, but if I'm still here in 15+ years I don't want to be unnecessarily debilitated...
The cancer paper, besides showing that those diagnosed with severe apnea had a 4.8 times greater incidence of cancers over the next 22 years (length of the study, presumably), it also posited a reasonable mechanism. A real problem for cancer tumors, from a tumor's point of view, is they do not have well organized vascularization to support their rapid growth. This "problem" is even used as an avenue to defeat some tumors. Unfortunately, the body responds to apnea (oxygen inadequacy) by stimulating vascularization (angiogenesis). This seems to be just what the cancer tumors need. Interesting idea...

[jgjones1972]

I remember reading a journal artical about the correlation between OSA and Alzheimer's disease/dementia; but, If I remember right, they didn't mention much if anything about the mechanism. They were looking at untreated OSA though, so I'm sure the subjects with OSA they included were probably having significant desaturations.

The problem is that there are so many things that could be researched concerning significant desaturation, I mean doctors still argue over whether or not OSA can cause edema because there hasn't been a definitive study done, that finding out the long-term effects of slightly lower than normal SpO2 probably isn't even on the back burner.

[PaulaO2]

There are so many factors that go into a good or bad night of sleep. Unless every factor but the oximeter readings were exactly the same, there's really no way to say "I feel bad because of x".

I am assuming the numbers you mention is average vs it staying put all night. You need to look at whenever it is below what you consider optimum. How many times? How often? Any patterns?

Then, have someone else who does not have sleep apnea nor a lung issue to do the same thing.

To be brutally honest, you are nitpicking a little detail among a plethora of other details. If your O2 meter says you have only 5 events a night, then consider yourself one of the very few that actually gets positive results from an oral appliance only. Your blood oxygen saturation levels are what many folks can only dream of reaching.

[DocWils]

O2 sats are, according to the book, to kept above 92% on the average for a "healthy" oxygenation level. Ideal median is 95%. There is no real evidence that a person with a constant level in the low 90s would suffer any ill effects long term. However the point about vascularisation increase is noted in several papers, but hard levels have not been determined or the trigger levels. O2 sats are lower for people living higher up in the mountains, but there is no correlated increase in cancers from the thinner oxygen levels amongst the mountain folk due to the lowered air pressure (and we Swiss know a thing or two about that).

On the whole, mild deprivation might cause symptoms of the type you mention (fuzzy head, tiredness) and people with strongly deviated septums might experience O2 sats around 2% lower than the ideal over the entire day (and night). Usually, the lung capacity increases in response to that problem.

If your AHI is 5 or lower with the oral device, then you are smiling, but if your overnights are averaging, say, 90% to 92% you would of course feel the effects of the slightly lowered Os saturation in various ways, and if your events show massive drops (higher drops than your events on the CPAP) you may still consider returning to the CPAP when you are not travelling. What you really need is a differentiated sleep study, to see how you are without any device and with both the oral device and the CPAP, to determine where you are at. It is possible that even throat toning exercises are all you need now, since if your AHI is 5 or lower I would suspect that you are close to "cured" anyway (meaning I don't have a lot of faith in oral appliances).

[RockyBob]

O2 sats are, according to the book, to kept above 92% on the average for a "healthy" oxygenation level. Ideal median is 95%. There is no real evidence that a person with a constant level in the low 90s would suffer any ill effects long term. However the point about vascularisation increase is noted in several papers, but hard levels have not been determined or the trigger levels. O2 sats are lower for people living higher up in the mountains, but there is no correlated increase in cancers from the thinner oxygen levels amongst the mountain folk due to the lowered air pressure (and we Swiss know a thing or two about that).

On the whole, mild deprivation might cause symptoms of the type you mention (fuzzy head, tiredness) and people with strongly deviated septums might experience O2 sats around 2% lower than the ideal over the entire day (and night). Usually, the lung capacity increases in response to that problem.

If your AHI is 5 or lower with the oral device, then you are smiling, but if your overnights are averaging, say, 90% to 92% you would of course feel the effects of the slightly lowered Os saturation in various ways, and if your events show massive drops (higher drops than your events on the CPAP) you may still consider returning to the CPAP when you are not travelling. What you really need is a differentiated sleep study, to see how you are without any device and with both the oral device and the CPAP, to determine where you are at. It is possible that even throat toning exercises are all you need now, since if your AHI is 5 or lower I would suspect that you are close to "cured" anyway (meaning I don't have a lot of faith in oral appliances).

Thank you for a very thoughtful response. I think you've summed it up nicely. My only added thoughts are 1) I think we can all agree that apnea studies are never designed to parse any small, long term effects, when there are much more pressing issues regarding apnea; therefore, the question of long term overnight 92 vs. 95 has to remain open rather than "no problem", 2) I wonder if continuous exposure to somewhat lower absolute atmospheric pressure (in Switzerland) might have a different effect on vascularization phenomenon than nightly episodic anoxic events, and 3) even today, if I forget my appliance, I almost always wake up with a splitting headache, so I'm pretty convinced that the appliance is helping considerably. The first time I was tested (approx. age 50, overweight, but not close to obese), I had 71 apneas per hour on my back, I went 90 seconds without breathing, and my O2 dropped to 80%. I was told the staff was on their way to wake me as I started breathing again. The really amazing thing was that during the day I never fell asleep at work, didn't fall asleep driving and only got tested because my wife absolutely insisted.