Physiology of blood transfusions and meds

[elizabells, BSN, RN]

Hey all

I've been thinking a lot lately about WHY we can't give meds into a line that's running blood, I guess because I've had a patient in DIC (thus needing lots of products) who is also an access nightmare, so the timing of meds has been tricky. The only reference I've been able to find says that glucose (as in IVF) causes clumping, and calcium reverses the anticoagulant added to the blood in the blood bank.

But... and I realize that this is so simplistic... IV meds go into the patient's circulation. Which is full of blood. And their blood doesn't clump or clot. So where's the problem? Is it that PRBCs, platelets, FFP, etc are different than the actual circulating blood because they're just components? If that's the case, could you give meds with a whole blood transfusion? Does the blood change in some way when it's separated into components and stored? I know the K goes up, but other than that, what? If there *is* something different about blood bank blood, what about double volume exchange transfusions? Does that blood react badly with medications once it's in the patient? We push meds directly into ECMO pumps all the time, which if you think about it is kind of like an enormous blood transfusion.

I'd love it if someone could explain the actual physiology of this to me. Obviously there's a good reason, or we wouldn't be so fanatical about it, but the logic doesn't track for me.

[GilaRRT]

We are actually talking about different concepts. Banked blood products are not like the circulating blood within our bodies.

First, many types of blood products are treated with citrate to prevent clotting. It is possible that anything containing calcium can initiate clotting and hemolysis.

Next, stored blood can loose it's ability to buffer significant PH changes. Many medications have a base PH that is well outside the physiological norm. It may be possible to damage the bood product due to a sudden PH change that cannot be buffered.

Next, any solution that is hypotonic could cause the cells to take on water and possibly rupture. This could produce a suboptimal situation at best.

I understand case reports do exist where patients have been given meds with blood products without any known ill effect; however, following your facility policy would be the best thing to do.

[classicdame, MSN, EdD]

when you add to blood the clotting my occur in the line. When meds are in the blood stream they are diluted and in a turbulent flow.