AHI and blood oxgen saturation

[LoQ]

Doctors are trained to save and extend life. People whose oxygen sats are above 90% are considered to be stable. Below that and doctors get concerned that you might decompensate.


However, my own personal journey has revealed that even if my life is not at risk if I'm 94% during the day, I feel better if I'm 97% during the day. Doctors have not been trained to recognize this, I suspect, because they were busy in residency with the seriously sick people, not the chronic fatigue people like me. I asked my pulmonologist if my oxygen level (95% when I asked) could be making me tired, and he responded, "no, you don't have any desaturations." Well, pulmonologists are often the lead doctor in intensive care, so I'm sure he's thinking, "hey, 95% is great. I wish all of my patients had 95%."

[LoQ]

I have a question about bottled oxygen. What I have read is that whether it is oxygen for welding, medical, or aviation, it's all the same stuff (except for the price). Does anyone have a source indicating otherwise? I have previously heard that medical oxygen is superior to welding oxygen and that people should not breathe welding oxygen. I doubt that's true, but I would like to know if anyone knows the answer to that. The only thing I can imagine is that medical oxygen might be 100%, and other grades might be lower than 100%, though still OK to breathe.

[LoQ]

I have a question about bottled oxygen. What I have read is that whether it is oxygen for welding, medical, or aviation, it's all the same stuff (except for the price). Does anyone have a source indicating otherwise? I have previously heard that medical oxygen is superior to welding oxygen and that people should not breathe welding oxygen. I doubt that's true, but I would like to know if anyone knows the answer to that. The only thing I can imagine is that medical oxygen might be 100%, and other grades might be lower than 100%, though still OK to breathe.

Ah, well, I guess the answer might be here:
http://www.pprune.org/archive/index.php/t-376324.html

Oxygen systems for consumption must be purged and evacuated any time pressure is lost in the system, to eliminate contaminates. Welding cylinders are typically emptied, but not evacuated. Without positive pressure to keep contaminates from entering the cylinder, the oxygen in the cylinder can't be considered 100% contaminant free.

Here's another source:
http://www-personal.umich.edu/~lpt/oxlabel.htm

Apparently respiratory grade oxygen will do; that could be diving, aviation, or medical. Only medical requires a prescription.

[LoQ]

However.....I wonder if you allow oxygen from one of those cheap welding tanks to go into the intake port of your cpap machine (lay the tubing right there), if that wouldn't filter out the contaminants? Hmm.....


The problem, of course, is you don't really have control over how much oxygen you're getting that way.


I want to try the oxygen thing, if there is a cheap way to do it. Maybe it would be the final piece of the puzzle for me, and if so, I could ask my dr. about an Rx for it.

[montana user]

I have seen at least 3 people in the sleep lab where there O2 saturations dipped into the 50's! geeze, wonder why they had high blood pressure and morning headaches??? They are feeling much better since there start on CPAP!!!

[M.D.Hosehead]

if he said anything as silly as what your doctor told you I would tell him to quit now and become an accountant

I dunno, I wouldn't want him for my accountant, either.

I'm sure most doctors are conscientious and competent. However, I wish that, like you, I could find incompetent acts by physicians hard to believe. Unfortunately, it's evident they happen too often; they've happened to me.

My guess as to the paradox you cite (that doctors who have not managed a patient's problem correctly, once had enough smarts and logic to get through their training) is that things happen to doctors after their formal training.

Failure to stay current, fatigue, burnout, depression, mental illness, marital problems, substance abuse, financial problems, aging, side-effects of meds taken for physical illnesses, are some of the things that result in a person's trying to get through the day on only one cylinder.

Couple any of those things with a doctor who has trouble saying, "I don't know," or worse yet, fails to keep track of the boundary between what he knows and doesn't know, and you have a dangerous situation.

[torontoCPAPguy]

Guys
I have a question.....
When I went for my first pulmanory test last Nov. the tech said my oxygen levels were at 76. When I had my overnight sleep lab tests in Feb. the tech said my levels went down to 72 at one point. About a month later I was at my doctors office and I was at 96, again a few weeks later and I was at 93. He said those numbers (the 90's) were good and my cpap machine has leveled me off. Was he right?
Nan

Nan, remember this (from my hospital experience):
1. Your SO2 is going to be higher when you are active and breathing deeper (i.e. awake)
2. Your SO2 is going to drop off at night if you are sleeping deeply - hypopnea events that may or may not be detected by your APAP machine will be an indicator of troubles.
3. WITH or WITHOUT those hypopnea/apnea events showing up on the data readings, you CAN have low blood oxygen saturation as I have just discovered. Night before last I was down into the seventies (very bad). Last night I was down into the eighties briefly (still not great but much better) but I felt this morning that I did not have a good night of sleep for whatever reason. I am tired this AM. (Not like I was before CPAP/APAP but nontheless... tired). But my numbers have been lost somehow on my SD Ramcard. Got the summary data which shows AHI under 1 but the detailed data that I would have liked to put up alongside my oximetry data is nowhere to be seen. I am about to fiddle with the card to see if I can find it or redownload it. I am baffled.

Remember this too. OSA/Apnea events/Hypopnea events... they are all symptoms and NOT issues. The issues are what kills you. The issues are things like dropping blood oxygen saturation that causes skyrocketing blood pressure as your body tries to keep all of its parts supplied with oxygen and that skyrocketing blood pressure is what causes heart attacks, strokes and Lord knows what else. The lack of deep sleep is also known to cause reduced liver function which in and of itself will create grief for you if you are on medications... what was prescribed for your condition(s) is not being processed as expected; drug interactions in the liver are now going to be different than what was expected as well and your success with things like Metformin for your diabetes is going to be all over the place.... so the importance of getting OSA under control is just as important from that aspect as it is from the aspect of maintaining a good level of blood oxygenation (above 90% is acceptable... anything under 90% sets off the alarms when you are being closely monitored inthe hospital, literally), and generally gets you poked during the night to breathe deeply or it gets you put on a small amount of oxygen to allow you to maintain 90+% and to sleep better if you are able to.

All appears to be intertwined and I can now see why respirologists and other cardiopulmonary specialists spend years learning this stuff intensively. Problem is that they see so very much of it they become jaded and tend not to concentrate on the minutia of your particular situation, rather prescribing a pill or two, or a machine and out the door asap with a handful of tests requested for follow up three months down the road. NOT GOOD ENOUGH FOR ME and it should not be for you. I am not advocating that one be their own doctor but I am advocating that one be their own spokesperson and work with their doctors to obtain optimal results. It will make you feel better, operate better and will definitely extend your life significantly.

Keep at it. It is important.

[sleepmba]

Good thread so far. I thought this would be a good place to throw in "tales from the sleep center". As Montana mentioned, we (sleep tech's) are used to seeing people's oxygen level go down who have sleep apnea. It is common amongst people with sleep apnea. Anyway, when somebody has an apnea, their air is cut off for the moment. While your body is continuously using oxygen, the oxygen is not being replenished at the moment. The available oxygen in your system is being used up, making your oxygen level going down. Once you take a recovery breath, the oxygen is replenished and your oxygen level goes back to "normal". Enough with the logic and on to an example.

The bottom line is when somebody has an apnea or hypopnea, their oxygen level will go down within seconds. When that somebody takes their recovery breath or gasps, the oxygen level will bounce back up within seconds. What we see from somebody with sleep apnea is an unstable oxygen level while they are having events (apneas and hypopneas). Some people desaturate worse than others. Some people desaturate longer than others. But usually it is only for a moment.

nanwilson posted here (thanks for posting) that her oxygen level went to 72% during a sleep study. That probably happened when her sleep apnea was at its worst. That time is usually in REM or while on her back.

[torontoCPAPguy]

Good thread so far. I thought this would be a good place to throw in "tales from the sleep center". As Montana mentioned, we (sleep tech's) are used to seeing people's oxygen level go down who have sleep apnea. It is common amongst people with sleep apnea. Anyway, when somebody has an apnea, their air is cut off for the moment. While your body is continuously using oxygen, the oxygen is not being replenished at the moment. The available oxygen in your system is being used up, making your oxygen level going down. Once you take a recovery breath, the oxygen is replenished and your oxygen level goes back to "normal". Enough with the logic and on to an example.

The bottom line is when somebody has an apnea or hypopnea, their oxygen level will go down within seconds. When that somebody takes their recovery breath or gasps, the oxygen level will bounce back up within seconds. What we see from somebody with sleep apnea is an unstable oxygen level while they are having events (apneas and hypopneas). Some people desaturate worse than others. Some people desaturate longer than others. But usually it is only for a moment.

nanwilson posted here (thanks for posting) that her oxygen level went to 72% during a sleep study. That probably happened when her sleep apnea was at its worst. That time is usually in REM or while on her back.

Sleepmba: Wonder if you would comment on the results, generally, of sleep studies AFTER CPAP/APAP begins; AND, why, generally, do we not see more folks being prescribed supplemental O2 during the night when their SaO2 drops below the 90% mark? My SaO2, for example, regularly drops down into the 80's and sometimes into the 70's and although my APAP seems to have reduced my incidence of apnea/hypopnea to nearly nil, I still awaken somewhat tired and with a feeling of 'anxiety' albeit mild. Here it is 10:54 a.m. and the anxiety feelings are gone and I am feeling good to go for the day now. Wondering if that wee 'spritz' of O2 into my mask would make a difference in the type and quantity of deep sleep I was getting. Do they ever try that during the sleep studies? (i.e. note low SaO2, suggest minor O2 being added, redo the sleep study and find amazing changes in sleep quality according to the EEG?)

Thanks for participating. Every bit helps all of us understand and strive for a better life. What the heck did I ever do before CPAP? I know I did not have a dream for 40 years for one thing and I now dream regularly - very few if any are nightmares for some reason. But the change is noticeable for me. I am thinking very seriously of trying an injection into my air line of 2 or 3L of O2 for a few days. I was on a whole lot more than this at the hospital and I have no hesitation in plopping that 2L into my face. Fact is, I hung up my O2 canulas at about 3L and just sucked in air on my own.... they never bothered me except if I dropped below 90% SaO2 and then they would poke me and tell me to breathe deeply. Made for a great night of sleep being poked all night.

[frh]

Nan, I was going to post this a couple of days ago, but got sidetracked. My wife was diagnosed with mild to moderate COPD. She was prescribed O2 after the doctor had her wear an oximeter overnight that put her SO2 level in the low 60's. (The diagnosis was confirmed by xrays, ct scan, lung function studies, etc.) Without 2-1/2 to 3 liters, her S02 would be 93 to 94 while watching TV. But it would fall to 84 to 86 by the time she climbed to the top of the stairs. She uses it most of the time because it makes her feel better and she gets tired more easily if she doesn't.

Her sleep doc (pulmonologist) tried to tell her she does not need O2 at night. The pulmonologist she trusts doesn't care if she uses CPAP, but thinks the other guy is an idiot for telling her she doesn't need oxygen. I think they're both wrong, she should be using her CPAP machine and she should be bleeding oxygen into it. I suggest trying to talk your doc into letting you try O2 at night. If he won't let you try it, find a new doc or start watching craigslist for an oxygen concentrator.

LoQ, I agree with you about Doctors. Between my wife and I we have seen a dozen of them in the last 6 months. They all seem to be stuck in their own narrow focus and don't seem to want to see anything outside of that area of expertise. The more doctor visits we go to, the less I trust any of them.

What you posted about oxygen is interesting, but I don't buy the part about evacuating the cylinders. After going through 18 tanks in her first week, the DME supplier sent out a home fill system. We have been re-filling the same tanks for 8 months. We keep an 18" or so tall tank in the back seat of the car, and she carries around one that is about 12" tall. Sometimes they run out before she tops them off, but we usually just put them on the machine when we come home to keep them topped off.

toronto, my average AHI for the last 30 days is 3.3. Under 2 is not unusual. Most nights I have several hypopneas and a couple of centrals and obstructive apneas. Supplemental O2 at night does not seem to change those numbers, but it sure makes me feel better and more functional the following day (even after a night with crappy numbers like those I posted).

Sleepmba: Wonder if you would comment on the results, generally, of sleep studies AFTER CPAP/APAP begins; AND, why, generally, do we not see more folks being prescribed supplemental O2 during the night when their SaO2 drops below the 90% mark?

That's what I want to know. Why does there seem to be a reluctance to recommend Supplemental O2 with CPAP?

Going into my 5th month of CPAP, I am still looking for my magic bullet. I am better than before CPAP, but still have chronic short term memory loss, chronic fatigue (and several other symptoms associated with untreated OSA). Without O2 I wake up exhausted with no desire or ability to do anything mentally or physically challenging. My business has gone down the tubes. Even with the O2, I still feel powerless to accomplish seemingly simple things like updating my website. But after a week and a half with O2 bled into the mask, then two nights without it (then two nights with it again), I am feeling a lot closer to that magic bullet.

I am totally freaked out the sleep study I have scheduled for Sunday night will not say I need Supplemental O2 bled into the CPAP machine. (I do not want to give up this feeling of better mental clarity and energy.) Is there anything I can say to the sleep tech that might influence his recommendations to the doc? (Or for that matter is there anything I can say to the doc?)

By the way, I think my SO2 issues are more neurological than physical. My lungs are great. I recently wore a heart monitor for 3 weeks. It reported that my heartrate normally stays in the low 50s at night. The doc said I do not have bradycardia. He said I might need a pacemaker someday, but not right now. If I am reading the ResScan data correctly, my breathing also becomes very shallow at night. I could easily be wrong, but I seem to see a lot of episodes that don't quite qualify as hypopneas. I have no way of proving this, but unlike toronto, my gut feeling is these episodes of shallow breathing do not seem to be accompanied by high blood pressure. Is CPAP is the right kind of machine for someone with shallow breathing?

I do not know if this has anything to do with anything, but increasing the pressure does not work for me. It causes centrals. Also, without Ambien I don't really sleep at night. Instead I just lay there drifting in and out of consciousness. My leak rate winds up being zero but I forget to breathe a lot and have a lot of apneas. After reviewing ResScan reports with it and without ambien, the sleep doc told me to keep taking it. But I have been wondering if it contributes to the shallow breathing? Should I leave the ambien at home the night of the sleep study? (I used it at the last sleep study.)

[msudawg]

In my first sleep study, my AHI was 99 and my O2 sats dropped in the low 60's. I was put on CPAP and O2 concentrator until my next sleep study. After the last study they removed the O2 because with CPAP my O2 sats looked good all night (stayed above 95%) I could not tell a difference when the O2 was removed in the way i felt the next morning.

[slaaplekker]

[quote="M.D.Hosehead"
I dunno, I wouldn't want him for my accountant, either.

I'm sure most doctors are conscientious and competent.[/quote]


Having worked directly with doctors for 11years and indirectly with them for another 22 years, I've heard and seen a lot of strange things. Most of the time I can just point out the error and most doctors pick up on it. There are some who don't and won't those are the ones to stay away from. I think most as say are doing the best they can but they can get a bit lackadaisical so it pays to have enough knowledge to push them to think beyond the obvious. They see a lot of patients and for many of them the easy answer is the best answer but when it isn't the best answer they often don't have time or energy to work through what needs to be done. That is where the patient who has primary responsibility for their own health needs to help guide the doctor. But I won't put up with any doctor who replies that I don't need something done when I suggest that it might be a good idea to have it done. Then it is time to find a new doctor.

regards
John

[LoQ]

What you posted about oxygen is interesting, but I don't buy the part about evacuating the cylinders. After going through 18 tanks in her first week, the DME supplier sent out a home fill system. We have been re-filling the same tanks for 8 months. We keep an 18" or so tall tank in the back seat of the car, and she carries around one that is about 12" tall. Sometimes they run out before she tops them off, but we usually just put them on the machine when we come home to keep them topped off.

That's a good point. I think the one thing that I see that is different from just buying oxygen at a welder's supply is that typically you take the tank in and they give you another tank that was already filled earlier. You don't really have knowledge or control over how that other tank has been stored or kept before or after being filled, so you don't really know for sure what the environment has been.

If it weren't for that, if I could just get them to fill my tank and return the same to me, I'd be good with getting it done at the welder's supply place.


frh, your story is so similar to mine. I'm really wanting to find an easy way to try the oxygen and see how I feel. I'm sorry about your struggle. I know how it feels. My current sleep doctor thinks it's all about depression. It's hard to deny depression, but when you are fatigued for years at a time, depression goes with the territory.

[M.D.Hosehead]

Is there any forseeable harm from trying supplemental O2?

Can you think of any reason that, if, during a titration, the O2 sat fell below 90%, they could not turn on some oxygen and see what happens?

Like frh, I cannot fathom the reluctance to consider trying O2 supplement. "We don't think you need it" isn't a rational explanation.

[LoQ]

Is there any forseeable harm from trying supplemental O2?

Can you think of any reason that, if, during a titration, the O2 sat fell below 90%, they could not turn on some oxygen and see what happens?

Like frh, I cannot fathom the reluctance to consider trying O2 supplement. "We don't think you need it" isn't a rational explanation.

Yes, there can be harm. People with obstructive lung disease, for reasons I don't entirely understand, can stop breathing when the oxygen content in the air they breathe is too high. Clearly people with obstructive lung disease are often put on O2 supplementation, but I would think that a doctor needs to determine how much they need without it being too much. I don't think a sleep tech should make that decision independently of a doctor's order.


The reluctance may come from several fronts. One may be that they are trained to save and extend lives, not necessarily to improve the quality of life, so O2 supplementation is probably geared towards that. Second may be that if a doctor goes outside of the diagnostic criteria for supplemental O2, insurance may not pay for it, or the doctor may not want to open himself up to the charge of practicing bad medicine.

Medicine is no longer practiced as an art as it was before high tech. Now it is far more dictated by the "books."