One issue that I haven't seen mentioned in these posts is the fact
that demand end-tidal pulse devices like the Mountain High assume that
you are breathing through your nose. They also assume that you clear
the physiogical dead-space sufficiently with each tidal breath to
deliver a reasonable concentration of O2 to the alveoli.

The only mammals I'm aware of that are obligate nose-breathers are
rodents, so, unless you're a rat, you've got one more reason to use
that oxymeter.

The Nonin Company showed some neat recording oxymeters with alarms at
a meeting I'm attending and at least one company showed a combination
ECG monitor and oxymeter on a single PCMCIA card which fits in the
accessory backpack of an IPAQ. These devices cost less than a grand.
A bit of programing should be capable of integrating this information
and alarm ranges based on it with existing flight software like
Winpilot which more and more folks are using as primary flight
displays. If you store the information, you've got a cheap, quick and
dirty research project.

There's no doubt that pressure-demand systems using fitted masks are
the way to go for flights to high altitude(18,000 feet). My concern
is with what happens down low (between 5,000 and 18,000 feet). My
suspicion and concern is that more than a few pilots are, at
relatively low altitudes, desaturated sufficient to experience
measurable performance decrements.

Raphael Warshaw
Claremont, CA

PS: According to my oxymeter, my Mountain High device maintains my O2
sat at 94-96 % at altitudes up to 16,400 ft which is as high as I've
gotten with it. This is, however, limited data on a single
individual; your results may vary.







"Bill Daniels" wrote in message news:hMusc.111328$xw3.6407916@attbi_s04...
Blank
Dave, keep your eye open for a surplus source of 0 - 2000 PSI panel
mounted regulators like the MD-2, CRU-72/A, 29255-6B1 or 29255-6B-A1.
These regulators are proving very hard to find. The masks that work
with them are very easy to find though.

Bill Daniels
"Neptune" wrote in message
...
Thanks, Bill - actually I was recently involved in a study at USAFA (I
am a 1960 graduate) in which it was shown that jumpers could wear
cannulae up to their highest jump altitude of 18,000 using "regular"
nasal cannulae at flow reates of around 2.5. and not saturate at under
90%. Prior to this they had to wear a mask, and you can imagine the
hassle of getting out of a mask with all the jump gear all over the
place. They are awaiting approval from HQ but it seems like this will be
approved. Just how low the flow could get and stil saturate at over 90%
unfortunately was not part of the protocol.

I did try to contact the Army Flight Surgeons at Fort Carson but
didn't get any replies to my phone messages. Shortly after this I
departed for six months in New Zealand so didn't follow it up.

This summer there is going to be a series of studies starting at AFA
level and going up to Pikes Peak where the Army has a facility.
Unfortunately this will not involve oxygen delivery systems asit has to
do moreso with exercise physiology, but I will get a chance to meet the
Army docs out of their facility at Natick, Mass who will be coming to
Colorado. So thanks for the thought - I'm onto this one, thought.

Any other thoughts for getting data? Have any ides as to whether
anyone has done objective medical research on nasal cannulae and pulsed
systems, or even masks and pulsed systems over 18,000?

Dave Reed M.D., Boulder CO.

"Bill Daniels" wrote in message
news:MsAqc.4202$zw.1832@attbi s01...
You didn't mention if you had contacted the US military. They have
an interest in seeing to it that their expensively trained personnel
operating even more expensive equipment are performing at an optimum
level. They also spend a lot of money on aeromedicine. I would expect
that the Pentagon has public access records on their research. Start
with the Virtual Naval Hospital. ( www.vnh.org search keyword "oxygen")

It's possibly worth noting that no military oxygen system uses a
cannula. Constant flow oxygen systems were discarded early in WWII when
they were found inadequate above 18,000 feet. If you need oxygen as a
military pilot today you will use a well fitted and sealed full-face
mask connected to a pressure demand regulator. Anything less is
inadequate. My reading of the literature indicates that pressure demand
systems have been extensively tested at cabin altitudes up to 45,000 and
found safe for healthy personnel.

I have used both a cannula and a pressure demand system with a pulse
oxymeter on wave flights. I found that the constant flow cannula system
could not maintain a steady SpO2 with fluctuations above and below 90%
but the pressure demand system delivered a rock solid 98% - 99% SpO2
readings at all altitudes. I'd like to see all wave flights use
pressure demand O2 systems.

Bill Daniels


"Neptune" wrote in message
...
Thanks to all who have replied to my previous messages. I admit I
may not have
been clear in why I am asking for feedback/information on flight
testing of oxygen
delivery systems. Apologies. Let me explain and ask for HELPFUL
feedback.

My concern is with the lack of scientifically-valid information
available on
the performance of light aircraft/glider oxygen systems. As an
anesthesia doc (and former USAF
fighter jock) I feel have some background in this area. In addition
I have done significant medical literature research, been to CAMI to
speak with the honchos there, had contact with the Brits, in-person
chats with several New Zealanders at Omarama, etc.

When I started to fly gliders out of Boulder several years ago I was
surprised at the masks that pilots were taking up into the wave.
Having had
a cardiac bypass operation myself perhaps I was unusually concerned.
I began
to do National Library of Medicine research and found no published
studies
that dealt with the use of nasal cannulae or masks performance at
altitude.

I then got access (with permission from the CEO as long as I didn't
mention the
name) to company data that had to do with a flight to 18,000 during
which 6
subjects using an A4 had pulse-ox readings taken at FAA-mandated
flow rates.
In the process the Oxymizer was compared with the "regular" cannula.
At each
altitude from 13,000 to 18,000 at least one subject was hypoxic with
one subject,
at 18,000, saturating at 78% on an Oxymizer at the FAA rate of 1.46.
All six were
supposedly all fit and healthy people. One had a bypass operation,
but he was never
one of the hypoxic ones. No physician had been involved.

I then discovered that FAA mandates oxygen flow rates only - not
oxygen
saturations. The mandates, so I discovered, are at least 40 years
out of
date and relate to tracheal oxygen measurements - two levels of
medical
monitoring sophistication out of date (arterial blood gases, pulse
oximetry). Of course the modern "pulse" systems are not mentioned.

I then discovered that there are no FAA mandates requiring an oxygen
delivery system to meet any specific performance requirements as
long as it
is "portable".

I noticed that manufacturers were making remarkable claims for the
oxygen-saving abilities of their systems but - as I discussed above
- not
based on any form of objective peer-reviewed published study. It
seemed to
me that I could show that the A4 at FAA rates probably produced some
hypoxia, and the Oxymizer probably did not have the characteristics
claimed
for it, but how about "pulsed" systems and mask performance over
18,000?

Please note - I am not saying they are wrong - but before trusting
my pink body
and those of my passengers to a strange-looking system I'd like some
objective
and verifiable proof.

I use a D1 and I think the modern pulse systems are magnificent -
probably -
at least as far as their use up to 18,000 with cannulae are
concerned (but I
cannot prove this - no releasable data). They have been in use for
many years with no
apparent untoward events. I am more concerned, however, at how the
pulsed
systems perform with mask systems above 18,000. Several of the mask
systems
I have seen in use appear to me to be dangerous regardless of the
system
used to deliver the oxygen. Again - no data.

It doesn't make sense to me that a pulsed system should work with
the sorts of
reservoir-style masks that should be used at altitude. But I may be
wrong, that is
why I am asking if anyone out there has any information/data
(preferable data)
that could answer these questions. I have asked several other
companies but they
(rightly) regard what they have done (or possibly not done)as
proprietary information.
So - no objective information.

I agree - pulse oximetry should solve the problem, IF one doesn't
consider
the realities of what pilots are ACTUALLY liable to do as far as
non-use. Will every
pilot who might go over 14,000 buy a pulse ox just in case? Probably
not. Is it
realistic for an FBO to rent out a pulse ox? Probably not. It seems
more sensible
to me to make sure the claims manufacturers make are objectively
valid, then use
the pulse-ox (if you have one, didn't leave it at home, didn't
realize how good the
thermals/wave were so didn't bring it along, its battery is OK, the
ambient temp
isn't frigid, you have a glove over your finger, etc., etc.) to make
sure.

In summary - In my opinion FAA mandates are way, way out of date and
should
be brought up to modern standards reflecting pulse oximetry. Studies
need to
be done in an open published manner documenting that manufactured
equipment
will produce non-hypoxic saturation levels in every day use for
"most"
pilots. In my opinion it isn't enough for a manufacturer to say
"yep, we
haven't flight-tested the gadget because we don't have to, but trust
me - it is OK".

Please let me know what you think in a helpful manner - after all I
am only trying
to make flying safer for all of us and I have no hidden agendas.

David Reed M.D, Boulder CO
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