From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: High Altitude Oxygen Failure
To: lml
Date: Tue, 12 Sep 2006 12:35:40 -0400
Message-ID: <web-1377335@logan.com>
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Posted for "Bryan Burr" <bjburr@mwheli.com>:

  Mark,
  Thank you for that post and explanation.  I have been using a cannula
  over 18,000 feet.  Now I will change my ways.  I have the mask but it is
  so inconvenient.  But not that inconvenient.
  
  Bryan
  N132BB
  LNCE
  
  -----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
  Marvin Kaye
  Sent: Tuesday, September 12, 2006 8:06 AM
  To: Lancair Mailing List
  Subject: [LML] Re: High Altitude Oxygen Failure
  
  Posted for "Mark Sletten" <marknlisa@hometel.com>:
  
   Listers,
   
   Please be careful here... There is an altitude at which the ambient
  pressure
   is low enough that oxygen exchange in the blood does not occur. I
  don't
   believe Lorn is advocating the use of a cannula above 18,000 feet, but
  just
   in case someone else gets the impression he, or, here's why you
  shouldn't...
   
   
   As you climb, the percentage of oxygen in the air remains constant,
  but as
   ambient pressure is drops, there is less oxygen overall. That problem
  can be
   overcome by adding oxygen to the ambient air -- most supplemental
  oxygen
   system manufacturers do this by squirting oxygen up your nose via a
  cannula.
   
   But, that solution doesn't address the *OTHER* problem with altitude,
  lower
   pressure. Let me give an example: Gas pressure is what holds the
  carbon
   dioxide in the liquid of a soda -- the can is pressurized (try to
  squeeze
   one before opening it). When you pop the top, you reduce the pressure
  on the
   liquid such that the gas escapes -- you get bubbles.