Btw the No. 1 reason why we measure low SpO2 values in clinical settings is that the finger clips are no longer correctly placed.
But as you say, if you get this repeatedly, it points to a different problem. I am curious if you get different values on different fingers.
FWIW, blood pressure is about 3/3 higher on the left arm, too.
MedEwok wrote:
Btw the No. 1 reason why we measure low SpO2 values in clinical settings is that the finger clips are no longer correctly placed.But as you say, if you get this repeatedly, it points to a different problem. I am curious if you get different values on different fingers.
The figures seem to be the same on all fingers on one hand (within 1% as there is always some variation) but lower (1-2%) on the left hand fingers compared to the right hand fingers. Should I be worried? 
1-2% lower on the left hand and no other symptoms? No, I wouldn’t be worried.
Reviving this thread with a question: what minimum saturation level should be maintained? Or is this so dependent from the physical condition of each individual that it’s not possible to say, e.g., minimum 90% is fine?
And additionally, I’ve seen some trouble in measuring SpO2 on my finger when flying, no difference whether measured with a cheap amazon product or with a 100€ sensor. I have to try a lot of times, and don’t know in the end if the result is reliable. Several consecutive measurements can range say from 87 to 97, even had one in the 70ies. I then repeat the measurement until a value in the 90ies appears and stop measuring. But it’s not really satisfying that way. Not so on the ground, where the 98 or 99 on my finger just pop out and don’t change. Any idea on how to improve measurement reliability up there?
Bearing in mind that you consistantly have good and reliable readings on the ground, and assuming that you are using exactly the same technique in the air with the figures you are getting I would firstly check both my CO2 and CO monitors and if they are okay I would consult a doctor. Something strange is going on anf its better to be safe tjan sorry.
UdoR wrote:
Reviving this thread with a question: what minimum saturation level should be maintained? Or is this so dependent from the physical condition of each individual that it’s not possible to say, e.g., minimum 90% is fine?
I am sure +95% is fine and can happen on the ground, +90% is ok, beyond that you get into hypoxia but why not go with another pilot him on O2 and you without O2 and test how far you can go?
Ibra wrote:
but why not go with another pilot him on O2 and you without O2 and test how far you can go?
I did that and have experienced that. But that was not my question, because you only see short-term effects.
gallois wrote:
assuming that you are using exactly the same technique in the air
Well that may be part of the problem. The ground is not vibrating like a big-bore engine, I don’t have a big table to rest my arm on and so on. So it’s not exactly same technique. But maybe I was exaggerating a bit in the former posting. Most of the measurements work fine, but from time to time it doesn’t work and mostly refuses to give out any value. It’s just that any time that a value of below 90 pops up I get uncomfortable, and it’s annoying to find out that prob99 it’s not the saturation, it’s the oximeter. Well I haven’t found that thread before, because if not I wouldn’t have asked. So according to that other thread I’m not the only one to experience this kind of trouble. I’ll go and check for another oximeter.
The other question regarding minimum O2 saturation level would still be interesting to have some more input, if anyone can contribute here. If, say, to just introduce some numbers, having 88% for hours may provoke long-term damage, or anything. Or if it’s all recoverable until a certain threshold, like 80%.
I’d look at high altitude climbing medical publications for a steer. Twenty years I did a bit in the eight thousands and there was a study of bloodox then. They were highly bemused why we were able to fully function with 55%. In fact they couldn’t understand why we weren’t dead. Yet there we were. As it happened I got cerebral edema before the summit but that’s a whole other story. I never saw or heard of their conclusions but I suspect it may be out there somewhere. May 1999.
The thing is, that the reaction to low O2 is highly individual. A few years ago the FAA brought their oxygen depletion chamber to L.A. and one could sign up for the ride. This thing does not change the pressure inside the chamber, but ‘only’ simulates O2 levels at FL260. We went inside in groups of 5 or 6 and were given some simple tasks. The really interesting takeaway was that age had nothing to do with performance. The best was a guy in his 70s, one of the worst a young FI who worked for the FBO I rented from at the time. Smoking was a big factor, as was physical fitness in general – the old cha(m)p was an avoid mountain hiker (nowhere near as extreme as @Pig, though, but L.A. being surrounded by terrain that goes up to 11k ft, still something).
Personally I go on 02 if flying for extended periods above 10k ft, although my 02 levels tend to be in the low 90s all the way up to about 12k. I just feel better after a few hours up there if I’ve had the additional 02.
