Just wondering….

Well Cheryl, you have brought up an interesting “tidbit”. Plastic is petroleum based and we know that petroleum isn’t “good” for any living thing!! There are so many unknown “side effects” from so many things which we use in our daily lives. Anything that involves “foreign to the body” chemicals is suspect. There is always the “flip-side” to every coin 🙁

I’m still sending hugs and prayer thoughts your way.

This is a long reply – and it’s not from me, it’s from my father. I remembered that my Dad was involved in some research on the plastics used to store blood products so I posted your question to him and this is what he said. I have taken out personal names and the name of the company to protect their privacy and it’s rather technical but I’m not sure I could explain it any better than this.

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First some basic chemistry: Reaction of blood with anything is slow at room temperature, let alone cold or frozen blood. Blood bags show appearance of a chemical because contact time is quite long, but the chemical is not from plasma but from a plasticizer.

More Chemistry: Blood bags have been made of a polymer named polyvinylchloride (PVC) and PVC is used in too many consumer and industrial uses to guess at. Pure PVC is too hard to be useful and I doubt there is much “pure” PVC used. Plastic compounders add a plasticizer which, of course, makes PVC easier to use in whatever it is intended for. In blood bags, the plasticizer is DOP. Dioctylphthallate as if it were a reaction of two eight member straight chain alcohols with phthallic acid, which in fact is not the case. The two eight membered alcohols are actually 2-ethylhexyl alcohol, still eight members but the ethyl portion is attached to hexyl alcohol at its 2 position. A more nearly correct name for DOP is: di-2 ethylhexylphthallate and it is an excellent plastizicer for PVC. The reaction of an alcohol and an acid (in organic chemistry) results in an ester and “DOP” is a diester.

During storage DOP leaches from PVC and affects blood favorably in the sense it plasticizes the red cell wall so it is stable for storage, but (of course) everything in the blood bag gets into a human’s blood stream during a transfusion and that includes DOP. In short you can demonstrate red cell breakdown by storing blood in glass jars and it is reasonably soon, but add a bit of DOP and breakdown is retarded. PVC Blood bags with added DOP has been the standard for 50 maybe 60 years.

The problem: Upon long term storage DOP undergoes hydrolysis and loses one of its 2 ethylhexyl alcohols, and the remainder is called the half ester and it has been shown to be carcinogenic.

That was the status of about 20 years ago and probably still is. FDA’s attitude is/was: since there is no viable alternative to PVC bags, we have to accept the risk but expressed more concern over people who have to take many transfusions, usually people quite ill and (perhaps) more vulnerable.

Enter the —–bag or simply “—Bag”.

Polyester plastic for soft drinks etc do not need a plasticizer. It is the built in nature of the plastic, but (as seen in glass bottles) a polyester bag allows red cell breakdown i.e. lysis. Whereas the bag per se needs no plasticizer, the RBCs do.

Enter Vitamin E. It has many of the same characteristics as does DOP, high boiling point, high molecular weight and would no doubt plasticize PVC, expensively. It also has an outstanding property absent from DOP. It already circulates, is used and stored by humans. It would be transfused but with no concern for safety.

We created a new polyester (no plasticizer) that felt and handled exactly the same as the old PVC bags and when Vit E was added to blood in the bag, RBC stability was as good as the old technology. We took the idea to FDA for comment and they said “we are happy someone is trying to solve this problem”. I felt we had been given huge encouragement to proceed.

So what is the solution worth? At the time the blood bag business was worth $250,000,000 per year. Our solution appeared to work but additional work on safety and effectiveness would be required (just standard stuff). At the Spring 1987/1988? R and D meeting of all company managers, I presented our blood bag storage solution and it got unanimous endorsement from all present. A top research project winner. We got patents, we had FDA’s gratitude and given commercial success, FDA might have disallowed PVC bags.

So what happened: (my father was transferred overseas to start up a new division of the company, the person who took over) killed it by: offering the technology to PVC bag producers who had zero interest in cannibalizing their PVC business.

I have felt since then that Company Officers who were well aware of the project just let a project worth a quarter billion dollars just slip away on lack of interest or misdirected interests. That changed my perception of (the company) management, but too long a story.

Relevance to you: Is a very definite MAYBE as I have suggested a couple of times. Sickle anemia causes RBCs to become misshapen and their passage through capillaries is painful. Where Vit E works, it is believed the sickled cell (wall) gets plasticized and allows it to distort its shape such that transport is not so painful.

You may have a Vit E transport problem not reaching the myelin. Or you may have a Vit E deficiency problem if you are a malabsorber, some people are. Your pharmacy might already carry water soluble Vit E and an inexpensive experiment to try WITH YOUR MD’S PERMISSION.

Rereading your message, I wonder if in heart lung machines et al if blood is in contact with any plastic long enough, if dealing with healthy RBCs, where “health” of RBCs is in its ability to resist lysis. Obviously my point gets to cell wall fragility and the ability of added Vit E to improve RBC cell wall resistance.

In summary: By direct observation Vit E added to RBCs works to resist lysis and lysis may be the problem related to transfusions and the immune system kicking in to react to the consequences of lysis.
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I hope you all have some sympathy for me for what it was like growing up now with two chemists for parents. :rolleyes:

Julie

[COLOR=black]To Julie,[/COLOR]
[COLOR=black]I too am a chemist. Why do you think you need sympathy? What your dad said was really easy to understand. By the way, I did come up with a common use for unplasticized PVC: household plumbing.[/COLOR]

[COLOR=black]To Cheryl,[/COLOR]
[COLOR=black]Like Julie’s dad said, the blood is not in contact long enough to leach much material from the tubing. I think his point about the lysis of the RBC’s is the right one. The heart-lung machine is known to lyze some small fraction of the RBC’s. Once lyzed, they are bound to cause inflammation. The cause of the lysis is not completely known, but it is probably partly related to turbulence and partly to the surface chemistry, both in terms of generating static electricity from friction and interaction of the RBC’s with something they normally don’t interact with.[/COLOR]

[COLOR=black]If you have a catheter for your plasmapheresis, it is made of either polyurethane or silicone. Both of these materials have components that can leach out. However, the leaching rate is what is most important, and these materials are designed and tested to have very low leaching rates. I don’t know if the typical tubing used in IV is PVC, polyurethane or silicone, but at least for my PP, the tubing set appears to be silicone.[/COLOR]

[COLOR=black]Since I said silicone, I am sure somebody is thinking why this should be any different than breast implants. The reason is in the nature of the construction of the implant. A silicone implant is made up of two different silicones, a stiffer outer shell and a more compliant inner core. Understanding the causes of why implants cause so much trouble is very complicated. From a chemist’s perspective, though, one reason could be that the more compliant material diffuses through the stiffer material, analogously to helium diffusing through a balloon. The second is that there is a lot of it available. The silicone tubing used in a catheter is all of the same type, and is more like the stiffer shell of an implant. The diffusion cannot occur (leaching still can, however) and there is a lot less tubing (about 2 cubic centimeters (assuming a rather thick wall) versus around 700 cubic centimeters for dual implants).[/COLOR]

[COLOR=black]To Julie,[/COLOR]
[COLOR=black]Oh, now I see why. :D[/COLOR]

[COLOR=black]MarkEns[/COLOR]

MarkEns,
Because having brilliant parents meant dinnertime was always preceeded by a logic puzzle, explanations always required research to understand, and both my parents are still smarter than me. ARGH! Seriously though, I love my parents and I do appreciate the background in logical thinking they gave me – now if I could just remember how to use my brain… 😮

Julie