Organization: University of Illinois at Chicago
Date: Tuesday, 5 Jan 1993 22:14:56 CST
From: MATT HUNSAKER <U61474@uicvm.uic.edu>
Newsgroups: rec.scuba
Subject: "liquid Breathing" -long

The following is some information on "Liquid Breathing", I wrote it in
response to a request for info on SCUBA-L. I've been asked to post it to
rec.scuba so that it can be archived.  Whatever.  If you have any
questions/corrections let me know.
-Matt




Date:         Mon, 28 Dec 92 19:35:42 CST



========================================================================
On Mon, 28 Dec 1992 13:27:56 PST Chan, Humphrey said:
>To fellow divers:
>
>   Anyone knows the latest on the development of liquid
>oxygen ??  Is it still under experimentation ??
>Will it ever be available commercially ??

If you are talking about the respiration of Oxygenated Fluorocarbon Emulsion
Respiration Technology, it is alive and well.   The bulk of this technology is
dedicated to the discovery of an adequate  blood substitute, or at least this
is where the technology came from.  In 1966,  Leland C.Clark of Children's
Hospital of Cincinnati discovered the perfluorocarbon's  application for
"Liquid Breathing".  Leland's original focus was to pioneer technology that
would allow the Oxygen/Carbon Dioxide Exchange to occur in the lungs in the
abscence of a surfactant.  This would be useful in the treatment of patients
with compromised lung tissue,(ie:Emphysema, Smoke inhalation, and most recently
premature babies.)


**************Warning  Academic Chemistry to Follow*************************

Some of you no doubt will be interested in the molecular structure of
perfluorocarbon, so I will try and explain it in simple chemical/phsiological
terms.  For those who aren't interested in this, skip down to the end of this
section.

Perfluorocarbon's are extremely stable compuonds, that are generally non-toxic
to humans.  The name denotes an organic molecule structure in which every
possible hydrogen atom has been replaced with a fluorine atom.  The value of
this compound is that it can carry more dissolved oxygen than air. The liquid
can coat the alveoli and provide a surface for gas exchange, acting as an
artificial surfactant of sorts.  In the healthy lung, the moist inner membranes
are coated with a natural detergent that lower's the surface tension of the
water.  This detergent is called a surfactant.  This surfactant allows the
lungs to inflate.  If the surface tension of the membranes in the lung were
equal to that of ordinary water, the tiny little alveoli would collapse.

In premature babies this is what happens in births before about 35 weeks.  The
lung is not yet competent to make an adequate amount of surfactant to allow the
baby to breathe.  Babies  have breating movements before birth in which
amniotic fluid is aspirated.  These prenatal movements are not continuous, but
they do occur.  Oxygen exchange, does not occur in a significant amount, but it
does help strengthen the lung tissue.  In premature babies, high pressure O2
is required to keep many of these babies alive,  BUT high-pressure O2 destroys
lung tissue.

The perfluorocarbon has a very low surface tension, which allows it to
penetrate deep in to the smallest  alveoli and keep them inflated at normal
atmospheric pressures, thus providing adequate oxygen WITHOUT damaging the
lung tissue.  The trick in all this technology is to determine the ideal
rate and the level of exchange at the alveoli.  The bulk of experiments were
done on premature sheep.  Dr. Thomas Shaffer at the Children's Hospital in
Philadelphia had demonstrated that a lamb of gestational age equivalent to
a human baby's 20 weeks could survive on perfluorocarbon.(1989)

*******************************************************************************
End of Chemistry/physiology section

The jump from animals to humans was made on May 10, 1989, under the direction
of Thomas Shaffer at the Saint Christopher's Children's Hospital in
Philadelphia, PA, USA.  An infant of 28 weeks(premature), was not responding to
treatment and was her condition was declining quickly. Her lungs were filled
with oxygenated perfluorocarbon Emulsion and her condition improved.  She
survived for 19 hours after the use of this radical new treatment.

Prior to this 1989, test involving a premature infant, a Houston Heart Surgeon
named Arnold Lande, had invented equipment that would enter a diver's lungs
through a tracheal catheter and would be moved in and out by a fluid respirator
.  The used Fluorocarbon would be shunted to a sea scooter that would scrub the
Fluorocarbon Emulsion and reoxygenate it.  His design also called for the
placement of a groin catheter to carry blood to the scrubber to be
reoxygenated.  I've never heard any thing more about this device.

The movie "THE ABYSS" extensively cited the design Shaffer created while
working under Gordon Moskowitz at Drexel University in the early 1970's.

Although the likelihood of actual "Liquid Breathing Systems" using Oxygenated
Fluorocarbon Emulsion is VERY, VERY, probable, the exposure of these systems
to a civilian market is probably unrealistic in the near future.
*****************************************************************************


Personal Note:  If any of you are currently involved in such a project, I
                will be looking for a job in about two years.  I will have
                an M.D.  and B.S. Biology/Chemistry.



                ************ assigned to this/similar project.


-Matt


MATT HUNSAKER   ~~~~~~~~~___100       ..            __  |__
DIVING RESEARCH GROUP        ___200  >->O      . .__L L_|L L__
HOME OF THE SPORTSMAN 300 MINISUB___300FT   . .[+(____________)
E-MAIL:U61474@UICVM   (815)399-1615                _________/
STUDENT, U OF IL COLLEGE OF MEDICINE