X-Message-Number: 33376
From: 
Date: Mon, 28 Feb 2011 01:58:22 EST
Subject: Melody Maxim's Distorted Reality 11

By the application of both reason and experience we identified  which drugs 
and devices could be used beyond expiry, and for how long. Ultimate  
validation was in the animal lab and often we had help on this from other  
investigators who were using outdated supplies: this was once the way most  
research got done. This practice is now illegal, so a vast reservoir of data  
shared between labs and by manufacturers is now no longer available.   
Most hollow fiber oxygenators and dilyzers are good indefinitely if  they 
are stored under reasonable conditions. This is amazing. However, this is  
most emphatically not the case for bubblers or for cardiotomy reservoirs, and  
storage conditions are critical.  
The urethane column in hardshell reservoirs is subject to oxidation  and 
disintegration over time. Some of you may have observed this effect with old  
urethane bed pillows which have become crumbly and non-elastic. The urethane 
 foam column inside a reservoir stored under uncontrolled conditions or 
past its  expiry becomes a crumbly, embolizing mess. It begins to shed large 
numbers of  particles in 1 to 10 micron range long before this deterioration 
is visible to  the naked eye. High ambient temperature and humidity can 
greatly accelerate this  process (as does UV light, which not a consideration 

here). It is important to  remember that these reservoirs (ATPs) will be stored
under uncontrolled  conditions; no guaranteed, monitored, ISO 900X 
environments.  
I have seen relatively stable in-field PVC items become sticky from  
plasticizer elution due to long storage times, and especially due to storage  
under uncontrolled conditions. Not surprisingly, Florida is where I have  

observed this the most (there used to be a permanent Alcor perfusion facility in
FL which was established in the early 1980s and decommissioned in the late  
1990s. I both implemented and decommissioned it). I am thus very wary of  
components that fail catastrophically with extended storage.  
I agree that the waste dump line should come before the venous  return line 
enters the cardiotomy reservoir. This not only guards against clots,  but 
also reduces contamination with red cells and with agglutinated RBCs.***   
Boon: Disadvantages of hardshell reservoirs include the use of  silicon 
antifoam compounds, which may produce microemboli, risk of  microembolism, and 
increased activation of blood elements. Soft bag reservoirs  eliminate the 
blood-gas interface and by collapsing reduce the risk of pumping  massive air 
emboli. Because of the concerns on microemboli and increased  activation of 
blood elements, some perfusionists have switched back to using  softshell 
bags again.  
Mike Darwin: ***See my commens above. I would also add that the  current 
(Alcor) ATP components retain their utility and safety even when stored  under 
extreme ambient conditions. I am reluctant to give this up. It has been  
hard-won experience. I actually made a complete tubing pack of tubing and  
connectors out of polymer that does not have plasticizers and should have had 
an  indefinite shelf life. This was packed for shipment to SA. I have no idea 
 whether it ever got there. It used polypropylene connectors and the tubing 
was  resistant to the solvents in the vitrification solutions.  
[As an aside, I am very concerned about plasticizer leaching from  PVC 

tubing during CPA perfusion, especially with the addition of  dimethylformamide.
Both DMSO and DMF raidly degrade PVC components at room  temperature. 
Contamination of perfusate with dissolved plastics and housing  failure on 
oxygenators under pressure seems quite possible; for example, the  Sarns 
oxygenator housings are a clamshell with a glue joint holding the two  halves 
together.]***  
Melody Maxim: The reservoir currently available at SA is a  cardiotomy 
reservoir, rather than a venous reservoir, which would be more  desirable. The 
cardiotomy reservoir is designed for blood collection, such as  that from 
general suction lines that are used in the field. Hence, the  cardiotomy r

eservoir has a very effective filter designed to remove debris. One  undesirable
effect of this feature is reduced flow rate, due to the time it  takes the 
perfusate to traverse across the filter. (SAs existing cardiotomy  reservoir 
is rated at a maximum flow of 5LPM.) Another disadvantage of the  cardiotomy 
reservoir is that it does not have a 1/2" port for the venous return  line, 
therefore requiring a 1/2-3/8 reducer in the venous return line. Nor does  
it provide for a venous luer lock for the sampling manifold, thus requiring 
an  additional luer lock connector to be placed in the venous line for this  
purpose.***  
Mathew Sullivan: I agree that we dont want to use a cardiotomy  reservoir 
because of the high flow rates, but the bottom connection is tapered  and 
will hold both a 3/8 and   tubing. At Alcor we used to reduce the tubing  down 
to a  , and ran the tubing coming from and going to the reservoir through a  
pumphead, but changed this to a gravity drain with larger tubing to reduce 
the  amount of air being pumped into the mixing reservoir during 
cryoprotection in  hopes of avoiding pumping micro bubbles into the patient.   
Boon: For your portable circuit (have never seen the actual  circuit, just 
some photos that Charles sent a while back) I dont know whether a  hardshell 
cardiotomy-venous reservoir will fit in the carrying-case or not.  
Obviously the soft bag will have no issues.  
Melody Maxim: Modifications will have to be made to accommodate SAs  level 
detection system, as discussed. 
Mike Darwin: ***ANY decrease or restriction in diameter largely  defeats 
the advantage of using a larger line. In other words, if you are using a    
line (as you should) to facilitate venous return and you put a 3/8 connector  
in that line you have dramatically reduced your flow and increased your  
resistance (and thus your CVP under high flow conditions).***   
2. Melody Maxim: Moved oxygenator recirc line to top of reservoir.   
Should air need to be evacuated from the oxygenator, (this should  be 

unlikely, provided a watchful eye is kept on the reservoir), the air is  handled
without effort, unlike in the previous SA circuit where the removal of  air 
from the oxygenator would have led to filling the bag reservoir with air  
that was somewhat difficult to expel.  
Mathew Sullivan: I agree.  
Boon: Thats the beauty of hardshell reservoirs, they handle air  better 
than the soft bags.  
Mike Darwin: ***I cant comment on this change without seeing the  circuit. 
I will make comments via the pictures and Boons comments below.***   
3. Melody Maxim: Deleted reservoir vent line to waste bag line.   
No longer necessary. If volume is excessive, it can easily be  diverted to 
the waste bags via the Y-connector in the venous return line.  Parallel 
clamps have been placed on the branches of the venous line, past the  

Y-connector, so they are easy to see and manipulate, while continuing to monitor
the 
reservoir.  
Mathew Sullivan: I agree the vent line is no longer necessary, but  I may 
need some clarification on the volume you speak of are we still talking  

about air? Until I see the proposed reservoir, Im not sure to what extent this
might be an issue. With the cardiotomy reservoir as it stands now there is 
more  than enough capability to vent any amount of air we will likely see.   
Boon: I dont think Melody is referring to air when she talks about  

excessive volume. The volume shes talking about is fluids. I do agree with her  
in 
putting a Y-connector in the venous return line instead of having a vent 
line  from the cardiotomy reservoir connected to a waste bag.  


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