UdoR wrote:
Any idea on how to improve measurement reliability up there?
You could try with a disposable SPO2 Sensor that is not clipped but taped own the finger. This might be out of the budget you have in mind, though …
UdoR wrote:
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?
Most clinical guidelines (including the most recent ones for treatment of Covid patients) indicate corrective actions if the SpO2 level of the patient drops below 92%. So if you would be in hospital or in any other form of controlled medical setting, you would receive additional oxygen if you are below that level. I guess this is a good yardstick.
Obviously that doesn’t mean that you will immediately die if your SpO2 is just at 90% or even below for some time. Difference between 92 and 90 is within the margin of error for most pusloxis anyways.
But on the flip side we are not talking about keeping sick people alive but about keeping healthy people healthy – so personally I would add some margin to the point where medical intervention is indicated and target at 95% SpO2 on longer flights…
Malibuflyer wrote:
Most clinical guidelines (including the most recent ones for treatment of Covid patients) indicate corrective actions if the SpO2 level of the patient drops below 92%. So if you would be in hospital or in any other form of controlled medical setting, you would receive additional oxygen if you are below that level. I guess this is a good yardstick.
Yes, but that’s not a temporary low saturation caused by external factors like it is on a flight.
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.
I read a few years ago that there is a correlation with age and hypoxia. Younger people show worse effects than older ones. Something with the body „being perfectly synced“ at around 30 and reacting adversely to changes, whereas this isn’t the case for old people.
Snoopy wrote:
Younger people show worse effects than older ones.
There might be also a significant “training effect” involved in that: A surprisingly high percentage of elderly people (esp. male) suffer from some form of sleep apnea (often undiagnosed) that leads to alarmingly low levels of SpO2 during some phases of the night. If your body is used to 2-3hrs. of 70% SpO2 every night, it is much easier to cope with 70% SpO2 due to low pressure environment in high altitudes…
I have regularly flown at FL100 without oxygen before getting an oximeter. When I did, I noted to some surprise that I got values below 90%. Of course, I know that you don’t realise when you’re (slightly) hypoxic, but in retrospect, I can’t see that I made any bad decisions on such flights. (At least not worse than when I fly at low levels. 
)
On the other hand, when I once flew as pax at FL130 for several hours I did note a marked tiredness and lack of concentration that disappeared when I used oxygen.
I’ve got an oxygen concentrator, Innogen One G5, and it seems to be a good device. I use it any time I plan to go outside the flatlands. My initial testing at about 14.5 took me from about 85% to 99%. After a few seconds, you don’t even notice it. Battery for about 3-6 hours, and I plug it into the aircraft 12v for “unlimited” O2. New it’s about 2.5k USD, I found a “used” one for 1.5k Euro in France on leboncoin.fr. It was new, but the box had been opened. Happy to provide more details if anyone is interested.
A very interesting solution.
This is a topic where it is easier to describe the solution than to define the problem. This may be in part due to the solution being amenable to an engineering approach, but the problem being a complex physiological/molecular biology interaction not readily amenable to a mechanistic engineering approach. There may be AI/machine learning approaches with potential to describe/predict, but not explain (yet) some of these phenomena.
