----- Original Message -----
Sent: Friday, August 05, 2005 11:35
AM
Subject: [FlyRotary] Re: Back from Osh/
Dave & Buly repair notes
On 8/5/05, Ernest
Christley <echristley@nc.rr.com>
wrote:
John
Slade wrote:
> I will want one suitable for two
users. My back seater won't go over
> 10,500 without it.
>
> Tracy.
> Glad you survived that one. We'd miss you
for all sorts of reasons :)
> Take a look at http://www.aeromedix.com
> I got
their 2 place system for around $400 complete with a full 640 ox
>
bottle. It's gone up a bit since. Haven't had a chance to use it
yet,
> but the quality and service seem good.
>
Regards,
> John
>
I've bookmarked this
page. Very interesting stuff. I'm basically
healthy, and don't plan on much FL flying. But I think one
of their
miniature, $289 systems would be useful for the type of
situation Tracy
found himself in. If I had that and the
Nonin Flightstat, it would
minimize the weight I carry around but still
maximize safety. $600 for
a complete oxygen system isn't all
that bad.
David, this is probably a good question for
you. Would it be necessary
to carry one of the oxygen
monitors all the time, or would it be enough
for someone to wear one
for a few flights to characterize how their body
reacts and then just
use oxygen in those conditions? In other words,
can a person
expect to react the same everytime, or is it unpredictable?
Difficult question. In general over the short term you will react
pretty much the same as long as nothing else changes. Also, it is not
so much your O2 saturation that matters as your ability to tolerate lower
saturations. For example, some mountain climbers can function in
strenuous environments with SpO2 in the low 30's!!! Others will begin
to notice significant effects in the low 90's. Some people live in the
low 80's at sea level.
With age, in general, tolerance declines while the amount your
saturation drops increases. Many things affect your tolerance such as
smoking or other carbon monoxide exposure, lung disease, dehydration,
anemia, cerebral vascular disease, heart disease, change in activity
level or even a hang over.
So really, the SpO2 monitor tells you very little. It will drop
more or less predictably with altitude, but there is no way to say what
number is a safe decline.
As expected, the FAA regulations are set for a reasonable lowest common
denominator. That means that a few people will experience
significant effects even while following the letter of the law, while most
can tolerate significantly higher altitudes.
A few years ago I spent about 10 min at 27,000' in an altitude
chamber. I was somewhat dizzy, but could communicate and do
math. My O2 sat was in the low 70's and dropping. Longer
exposure might change things somewhat. Probably couldn't do that
now. I notice very little effects at 23k (in a chamber) except for
loss of color vision and slight uncoordination - I certainly would have the
where-with-all to fly en-route stuff for short periods.
What is hard for me to remember is that I am getting older, as I am in
denial. Either way, the important thing is to be able to
recognize the subtle effects and say "that's enough," above 14.5k
or not.
If you get the opportunity, a chamber ride is an excellent
experience. A few people, even those young and in great shape, do
react very strangely - and it can vary day to day.
Also, having O2 readily available even if not continuously used would
be an excellent and cost effective safety measure for those fly at
altitudes where there is the possibility of an issue.
--
Dave Leonard