[N395V]

From another thread.

No O2 for the backseater, or did he take off the cannula to look cool in the photo?

I am curious as to:

How and when everyone uses 02, cannula, mask, continuous, intermittent, etc.

What symptoms you experience at what altitude.

The effect on your vision (especially color).

Any differences between day and night.

Anything else.

I use cannulas, no mask no matter the altitude above 13,000 if I am gonna be up there for more than 1 hr.

First symptom is numb lips followed by a noticable decrease in color perception.

At night I put the 02 on at 7000 because of vision.


Long trips above 7000 if I use it I seem to feel less fatigued. Not sure if this is actual or a perception.

Younger passengers seem to routinely tolerate higher altitude before they notice symptoms.

I know what the FARs say but I am curious as to your experiences.

 

[Ironflight]

Milt,

I am fortunate (if that's the word) to have a required altitude chamber ride every three years. My symptoms are very repeatable - a sense of anxiety, a buzzing around the lips, and a flushed feeling - to start. I have a pretty good tolerance for altitude, but it is hard to say if it has gone down with age, because over the years, the chamber rides have gotten more conservative - they have us do "masks off" stuff at lower altitudes than before, so I go longer than I did in earlier years, but can't tell you what my tolerance would be at the higher altitudes.

Your protocals sound very good! I generally carry my O2 system on long cross-countries, and rig it up if I plan to cruise above 12K in the daytime, 10K at night. I don't generally plan cruise altitudes above 14K, unless there is a rip-roaring wind I can take advantage of. I will use O2 to stay on top of weather if I can, and if I'm going that route, I generally use a helmet and mask, becasue I don't personally like the feel of canulas. If I am using O2 as a night supplement, I'll sometimes just go with a canula, because it is easier and quicker to rig the cockpit for that than for the mask and helmet rig.

For me, the most important thing is knowing your symptoms, and the best way to do that is to get a chamber ride with good supervision!

Paul

 

[Stephen Lindberg]

As an anesthesiologist of 25 years experience, taking care of the lame and the halt on a daily basis, I can claim applied respiratory physiology for my stock in trade. Here is my take. Humans are notoriously poor at gauging their degree of mental impairment from whatever cause, be it hypoxia, alcohol, or drugs. So don't rely on self-reported symtoms to gauge your need for supplemental oxygen while flying. You will easily convince yourself that you are doing "pretty good" because hypoxia clouds your higher mental functions and makes you feel a little giddy, just like having a drink of alcohol. If you want to add some science get a pulse oximeter for $400 and use enough oxygen to keep your hemoglobin saturation above, say, 90%. Most of the young and healthy will do fine by following the FARs regarding oxygen use. Increasing age, even if you are otherwise healthy, increases the need for supplemental O2, as does a recent respiratory illness, a history of smoking, and possibly obesity. If you want to see the effects of hypoxia without an altitude chamber ride, go to 12 thousand feet at night without using any supplemental oxygen. Adjust the instrument lights to a comfortable level. Now put on the O2 mask. When I have done this I noticed a rapid brightening of the instrument lights as my retina and brain got the oxygen they needed. To continue the experiment, remove the mask and breath ambient air again. You will probably not notice the lights getting dim. After ten minutes of breathing without extra O2, put on the mask again. The lights will brighten as before, proving that you didn't notice the onset of hypoxia even though you were looking for it. The good news is that a small amount of supplemental oxygen can reverse the effects of hypoxia at the lower altitudes. Steve