Hello,

I am working on my medical directive and I'm considering including a phrase to say that I will not accept fractions that don't naturally cross the placental barrier. This principle is not the only statement on my directive concerning blood fractions, but it is among the choices that I think my doctor should know about.

My questions are:

1. Is this a choice that would be useful for my doctor in deciding what alternatives to use? I mean, my directive could also say that I refuse prosthetic limbs, but that choice is practically irrelevant in the world of bloodless surgery. Is this choice concerning the placental barrier similarly irrelevant?
2. Would this type of "principled" statement cause problems in an emergency? Do doctors generally know whether a particular fraction crosses the placental barrier, or are such things pretty obscure, requiring research and delaying treatment?
3. Is there a list anywhere that could help me spell out specifics in this part of my directive? I have found a few descriptions of the placental barrier that that have lists like "some immunoglobulins," or "most large proteins" and the like. How can I find out which immunoglobulins? Which proteins? etc.
4. Is this as a lawyer-question instead of a doctor-question? Can you recommend any doctors who have become lawyers? (just kidding)

I have enjoyed reading the other posts you've offered in this good forum - I am eager to see what you think on this question. I've been thinking about it for a while.

Thanks,
~Jen

PS - I'm a little reluctant to post this question in view of the results the last time it was asked, but I worded it carefully to remove the religious elements and ask only the healthcare parts of the question. Do correct me if I'm still too far off topic.