Why is the central line preferred over a peripheral IV for TPN?

caroladybelle, BSN, RN · Sep 9, 2009

TPN contains very irritating components, thus it is preferred that it go via a central line. Just like it is preferable for chemos and other continous infusion irritant drugs to go via central line.

TPN (usually referred to as PPN when peripheral) has to be formulated differently if to be given peripherally. Generally the overall dextrose percentage has to be lower, and it is harder to infuse high doses of electrolytes if needed. Often this means the pt getting a lot more fluid to dilute things done. As many pts that are getting nutrition IV, are already dealing w/malnutrition, most have low serum protein/albumin. If your patient has low serum protein/albumin, they are going to fluid shift, resulting in edema. Thus peripheral TPN/PPN would have you pouring more fluid into a pt that is more likely to shift the extra fluid into the tissues resulting in edema. With central TPN, one can limit fluid better.

The other issue is that most pts receiving TPN are seriously ill. Because of the illness, and the fact that there are multiple required labs for titrating the chemicals/lytes/dextrose in the TPN, these patients will have extra blood draws. They will also probably be on multiple other IV infusions. Sticking this pt multiple times for IV meds, blood draws, and fresh rotations of the PPN site as it is very irritating, would not be kind especially since most will have poor veins to start with, and added edema from putting in lots of fluids. Most central lines have multiple lumens, thus quite useful in this situation.

pharho · Sep 9, 2009

Thank you very much!!

I'mANurse! · Sep 12, 2009

Caroladybelle gave an excellent answer to your question, but I just wanted to point out that in your original post you were thinking that it may be because of a "less chance of systemic infection".

Central lines actually have a GREATER chance for systemic infection than a PIV because your catheter is located centrally within the body and bacteria can migrate up the catheter and then be released into the bloodstream near the heart. Just something to remember :)