X-Message-Number: 33380
From: 
Date: Mon, 28 Feb 2011 02:46:08 EST
Subject: Melody Maxim's Distorted Reality 15

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Mke Darwin Mike Darwin  
(Login mgdarwin) 
Veteran Member 
Judge for Yourselves - Part 3       February 3  2009, 11:40 PM  
Darwin-Maxcim Correspondence on the CI_Sci_ Forum:   
In a message dated 11/20/2008 9:18:31 A.M. Pacific Standard Time,  
 writes:  
I originally wasn't going to respond to Mike's post, because I'm  really 
just sick and tired of butting heads with non-professionals, in regard to  

perfusion, in cryonics. However, I don't think it's productive for the cryonics
 community to have Mike Darwin come here making certain (perhaps misguided) 
 assumptions, and criticizing CI for consulting with a medical 

professional, as  it is only likely to reinforce the negative attitude that 
prevails in  
conventional medicine in regard to cryonics, and vice versa.   
MIKE DARWINS RESPONSE:  
Melody,  
I have never criticized any cryonics organization for consulting  with 

medical or other professionals. In fact, on this list-serve I recommended  (some
months ago) that CI contact the AMSECT (American Society of Extracorporeal  
Perfusionists) chapter in the Detroit metro area to see if there were  

perfusionists interested in working with CI and learning what was required to be
 of material assistance in cryonics. I have also offered to put CI in touch 
with  intensivists and others in medicine that might provide advice and 
assistance.   
The only negative attitude I know of in cryonics towards medicine  is that 
of Charles Platt and, in a different way, Bob Ettinger. As I understand  it 
Bob sees much of medicine as it has been applied to cryonics as gilding the  
lily, superfluous, or not worth the cost, or not affordable. If I have any 
of  this wrong (vis a vis Bobs position) Im sure hell correct me.   
You write:  
I find it somewhat confusing that Mike recognizes the need for  someone 
with a "working knowledge of perfusion at Board Certification level - at  a 

bare minimum," and then acts like such a person is too ignorant to participate
in developing perfusion protocols for cryonics. With all due respect, (and  
recognizing that Mike Darwin may know a lot more about medicine, in 
general,  than I do), I think his knowledge regarding clinical perfusion, and 

perfusion  equipment, (especially recent developments in perfusion equipment), 
is 
somewhat  limited.  
Now, I am puzzled! I have, at least to my knowledge, never had any  

exchanges or communications with you beyond a very brief (3-5 min) chat on the

phone when you were employed at SA; Charles put you on the phone with me and we
 exchanged some pleasantries. Beyond that, I don't believe you have 
communicated  with me.  
As to my current state of knowledge in terms of hardware and  consumables; 
I would hazard I'm fairly current. I have e-subscriptions to just  about 

every perfusion/extracorporeal medicine journal, and I read them including  the
adverts. I also count a number of working clinical perfusionists as friends 
 and colleagues, and I visit centers of cardiovascular surgical and 
perfusion  excellence all over the world; I just spent time at the premier 

institute for  cardiovascular surgery in Russia in Moscow. I also read a great 
deal 
of the  primary literature on cutting edge developments in extracorporeal 
medicine; I  have a longstanding interest in LVAD (left Ventricular assist 

Device), TAH  (Total Artificial Heart) and bioartificial organ technology. I am
a device nut  and have a reputation as a medical technophile. I introduced 
the Novametrix  CO2SMO into cryonics (sadly no one knew how to use it 

properly) and have tried  to introduce cerebral function monitoring (onto 15 
years 
now; since Aspect first  started its clinical development of the BIS 
monitor) into Transport operations,  to no avail.  
I pumped some of the first centrifugals and I pumped the very first  
pseudo-membrane oxygenators (the horrible Travenols) as well as the first  
successful hollow fiber membrane (Bentley). I started research perfusion when  
Pemco discs were still in use a (I own both a pediatric and adult disc  

oxygenator and I still know how to disassemble, clean and Siliclad them ). Other
than Charles Platt, you are the only person I know who has ever accused me of  
not being enthralled with, and knowledgeable about the very latest in 

perfusion  or medical hardware (or related technology). I'm not sure my passion
in this  area is a good thing, but nevertheless, it is very real.   
So, again, I'm puzzled by your remarks. I hope you are not  mistaking the 
madness you saw at SA during your tenure there in any way for my  

work-product or advice. In fact, my advice to SA, in almost every respect, was  
not 

followed. To name just a few areas/items related to CPB: use of the wrong  size
arterial pumps, a jury-rigged high-low level sensor for the venous  

reservoir which was made of corrodible metals rather than using highly reliable
and physiologically compatible off-the-shelf integrated level detection and  
marco/micro-bubble detection system equipped with pump shut off and line 

clamp  features, failure to use Biomedicus flat wire cannula for femoral venous
return,  failure to use gravity assisted drainage... I could go on for 

pages...and did. I  recently totted up the raw pages of correspondence from me 
to 
SA and it was over  900 pages long.  
You continue:  
I came to this conclusion a long time ago, after reviewing many of  Mike's 
documents about perfusion, and having had a series of exhanges with him,  
regarding perfusion equipment, when I first began working with SA.   
Again, I have no record of any exchanges with you and I have  published 
nothing related to perfusion vis a vis cryonics in at least a decade.  About 
the only things I can think of you that you may have seen from me were my  
advice to SA against Charles ideas of:  
* using centrifugal pumps (in the field or for CPA perfusion),   
*vacuum assisted drainage in the field (in unskilled hands)   
*and a moderately strong recommendation against hard-shell  reservoirs; 
again for in-field use in unskilled hands.   
SA may have followed my advice about centrifugal pumps, but  certainly didn'
t with respect to hard-shell reservoirs or level/pressure/bubble  alarms; 
at least not until long after I had no further input, if then.   
Interestingly, SA became fixated on vacuum assisted drainage for a  truly 
amazing reason which had nothing to do with prior (competent) experience  
with either in-field TBW or extended duration extracorporeal support of 

cryonics  patients at ~4-6 deg C. This is the story, written for another person
(non-perfusionist; an engineer) at another time:  
I was in Peacehaven (UK) staying with Alan & Sylvia Sinclair  circa 2003. I 
picked up a copy of The Immortalist from their coffee table and on  the 
cover was the Mobile Advanced life Support System (MALSS: the MALSS was the  
forerunner of the MARC a la Alcor) that Saul Kent had purchased from me when  
Kryos folded. It had been modified for operator convenience such that the 
venous  reservoir was at eye level! This will probably mean nothing to you for 
the  moment (long explanation to follow), but the practical effect is 

devastating.  The blood returning to the heart from the body is conducted 
through 
two very  large diameter tubes called the superior and inferior vena cava 
(SVC & IVC).  The SVC drains the head and upper trunk and the IVC the lower 
body. Each is  about 25 mm in diameter under resting conditions and they 

easily distend under  pressure. Normal central venous pressure (CVP) is about 5
torr, and anything  above 15 torr causes rapid development of (interstitial) 
edema. Above 20-30 torr  and you blow the pulmonary alveolar capillary 
tight junctions and the lungs not  only flood with fluid; fluid will start 

pouring out the ET tube inexorably!  Nothing you can do will fix this; it is an
irreversible injury which, at very  least, is going to make CPA perfusion 

(whole body) very difficult because  perfusate will escape the circuit from the
lungs at an enormous rate, even under  low flow and low pressure conditions 
and this perfusate cannot be returned to  the blood circuit via cardiotomy 
suction as would the case with capillary ooze  from transacted small caliber 
vessels in the chest.   
This issue of tolerable CVP is relevant because flow through the  cavae 
obey Poiseuilles Law. In laminar fluid flow through a tube or pipe  frictional 
(viscosity) energy losses occur and these cause a pressure drop along  the 
length of the pipe as a function of the pipe size, the type of fluid, and  
the mean flow velocity or flow rate.  
The central formula in the laminar flow model is the Poiseuille  equation:  
R = (8hL)/pr4.  
or Poiseuille law:  
Q = (pDPr4)/(8hL),  
where P = pressure, n = mean flow velocity, Q = volumetric flow  rate, L = 
tube length, h = fluid viscosity, and r = tube radius.   
The underlying assumption of laminar flow is the condition of  uniform 

viscosity across the diameter of the tube; each fluid molecule within  the tube
is exerting a similar force against each adjacent molecule towards the  

periphery. This means that fluid adjacent to the conduit wall is motionless (no
= 0), maximum fluid velocity (nmax) is in the center of the conduit, and 
fluid  velocity is related to distance from the center (ni) by a parabolic 
function.  Resistive losses (pressure drops) linearly are related to flow rate 
and flow  resistance. While flow resistance linearly relates to conduit 

length, it is  inversely related to the fourth power of the radius (or diameter
of the tube or  pipe). For example, a 1-cmdiameter tube has 16 times the 
flow resistance of a  2-cmdiameter tube of the same length and carrying the 

same fluid. Stated another  way, 16 tubes of 1-cm diameter are needed to handle
the same fluid flow at the  same pressure as a single 2-cmdiameter tube. 
So, when you put someone on  femoral-femoral bypass (CPB) in the field you are 
forcing ALL the flow that  would normally go through TWO tubes each of 
which has a nominal diameter of 25  mm (=50 mm combined) through one tube with 
an absolute diameter of 12.5 mm! If  you do the math you will see that this 
will result in a large and  physiologically unacceptable increase in 

pressure. This difficulty is overcome  only by the expedient of gravity-assisted
drainage. You have to put the patient  at least 30 cm above the venous 

reservoir and be certain to never allow the  blood/perfusate in the venous line 
to 
become air-locked.  


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