X-Message-Number: 2458
From: Tim Freeman <>
Subject: CRYONICS: Sealed containers
Date: Sun, 14 Nov 93 11:44:28 EST

In cryomsg 2456, "Richard Schroeppel" <> suggests
placing the patients in sealed containers individually which are, in
turn, inside the dewars.  This sounds good to me.  Are there technical
problems?  Do cheap plastic-like bags exist that remain flexible at
that temperature?  Do the bags need to remain flexible?  Is it
feasible to disassemble all of the present patient containers, wrap
the patients, and reassemble them?  Would the troublesome Arizona
regulator approve of this?  Maybe you want to videotape the wrapping
process so you don't have to open everything up to prove to the
regulators that things are adequately sealed.  An experiment where you
wrap something in a plastic bag, freeze the assembly at LN2 temp, then
pull the whole thing back out of the dewar with the bag intact might
be necessary.

For new patients, it might be worthwhile to wrap them in the plastic
bag before being cooled to LN2 temperatures.  This would keep the bag
from rupturing if the patient thaws, which ought to make the
regulators happier.  It would also make the patient more bouyant
(since the body cavities wouldn't be filled with LN2), so you might
have to weight the individual patient containers.  (What would fill
the body cavities in this scenario?  Vacuum?  Would this be better or
worse than having LN2 in the body cavities?  I suppose I'm most
concerned about the sinuses.)  On the other hand, it sounds like the
regulators would be too stupid to understand this point, so maybe it's
not worth the trouble.

Tim

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