Blood Oxygen level question.

Subtle hypoxic effects begin at 5,000 ft., particularly noticeable at
night. In the average individual, night vision will be blurred and
narrowed. Also, dark adaptation will be compromised. At 8,000 ft.,
night vision is reduced as much as 24% without supplemental oxygen.
Some of the effects of hypoxia will be noticed during the daylight at
these altitudes without supplemental oxygen during long flights, i.e. 3
to 5 hours.

At 10,000 ft. the oxygen pressure in the atmosphere is about 10 psia.
Accounting for the dilution effect of water vapor and carbon dioxide in
the alveoli, this is not enough to deliver a normal (or less than
needed) supply of oxygen into the lungs. This mild deficiency is
ordinarily of no great consequence. However, flying at an altitude of
about 10,000 ft. (not taking density altitude into account) for 3 to 5
hours will more likely than not cause fatigue in which the pilot may
have compromised performance once he enters his destination. Since the
beginning of powered flight, pilots have reported experiencing
difficulty in concentrating, reasoning, judging, solving problems and
making precise adjustments of aircraft controls under prolonged flight
conditions at altitudes as low as 8,000 ft. MSL.

Please see my website for the entire article

http://www.craggyaero.com/o2_systems.htm

I turn on my Mountain High EDS system to the D5 setting which starts
delivering O2 at 5000 and continues the correct protocol as you climb.

I like to keep my O2 level above 92%. Things like breathing through
you mouth and holding you breath are common and show immediately on a
pulse oximeter.

Richard
www.craggyaero.com

On Jan 26, 9:09 am, "Udo" wrote:
How long does it take for the blood oxygen level to normalize at 15000
ft, after one discovers the flow meter was not adjusted correctly?
Also at what altitude does Oxygen become beneficial, assuming an
average person? Are there any factors, other then altitude it self,
that can lower Blood oxygen level during flight assuming supplemental
oxygen is not used between 5000 and 10000 ft and the pilot has a normal
cardio vascular health? What oxygen level is considered optimum at sea
level and 10000ft to 15000ft?
Udo

nimbus wrote:
I am also looking for the following information:

Oxygen consumption in function of altitude, age of pilot.


Udo, Bruno: Averages are no good - you are an individual and can vary
greatly from the averages. A finger oximeter like the SPO unit is ~$200.
Get one, use it, and you will know how well you and your oxygen system
are functioning - no guessing.

The objective is to determine when I have to go down when I see a
specific oxygen pressure in my bottle.

My EDS system uses about 100 psi per hour at 18,000', so the real
problem is accurately reading the little gage on the bottle. It's not
very precise and it's hard to read anyway, because it's small. So, when
it's a couple hundred psi from the empty point, I descend. Normally, I
change the bottle out before there is a chance it will get within 500
psi of empty.

Also, I marked the actual zero point on the gage when the bottles were
empty. The zero is off on both of them.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On 26 Jan 2007 09:09:22 -0800, "Udo" wrote:

Are there any factors, other then altitude it self,
that can lower Blood oxygen level during flight assuming supplemental
oxygen is not used between 5000 and 10000 ft and the pilot has a normal
cardio vascular health? What oxygen level is considered optimum at sea
level and 10000ft to 15000ft?
Udo

other factors.....

obesity has an adverse effect. you will see the effects of hypoxia
appearing at a lower level. cabin altitude of around 8,000ft in
commercial airliners is at the level above which obese people will
start showing effects. a lean lerson will probably have the onset of
effects around 12,000ft.

cigarette smoking loads up the system with carbon monoxide which
reacts out some of the haemoglobin and reduces the oxygen transport
capacity of the blood. this can give a smoker an apparent 5000ft
increase in altitude over a non smoker. carbon monoxide in a glider
shouldnt be a risk.

optimum blood oxygenation would be above 98% at any altitude.

it is a complex issue. the oxygen transport ability of the blood is
not a straight line graph and it varies with blood pH. (Co2 levels)

what is important is that your oxygen system maintains oxygen at an
adequate partial pressure. simply supplying oxygen is only part of the
picture. you must supply it at sufficient partial pressure to overcome
the resistence to permeation in the lung tissue.
I havent the figures to hand but over a ceratin altitude a nasal
canula wont work and you need a full pressure mask. I think it is
nominally about 18,000ft

the simplest path out of the mess is to use a functioning finger clip
laser pulse/oxymeter. consider a blood oxygen level below 92 as
something warranting action and make sure you have working batteries.

dont hold your breath....
Stealth Pilot