Central line confusion

[Emmers4]

I have a question regarding PICC lines, or just all central lines in general. I understand that these lines are placed for either long-term IV access, such as antibiotics, poor IV access, or medications such as TPN. I have been told that they also are helpful if medications are incompatible with each other as well. However, even if incompatible medications are run into different ports, they all end up in the same line. Unless, do they have separate tubing within the single internal line? And then do they have different exit points into the blood stream? But then they all end up in the blood stream together, so aren't they still incompatible then as well?

I apologize if this is confusing at all! I am a nursing student that is just curious and I just want to make sure I am understanding everything correctly! If you can shed any light on the subject, that would be fantastic, thank you!

[meanmaryjean, DNP, RN]

Multi-lumen central lines did indeed have separate tubes within. The opening of each lumen into the bloodstream is also on a different place along the line. So yes, incompatible fluids/drugs are released into the bloodstream in very close proximity- BUT they are immediately diluted and moved downstream by the circulation.

Does this answer your question?

[Asystole RN]

When you look at multi-lumen PICC or a CVC the catheter portion, despite looking like a single tube, is bifurcated all the way down. If you cut them in half they look like someone put in a plastic septum splitting the tubing down.

Some brands of catheters such as some Arrow central lines will have actually have ports that terminate at different intervals down the catheter with a port at the tip and a port or two a centimeter or two from the end. To contrast this are common catheters like Bard PICCs with have all of the ports terminate together from the tip.

One of the reasons why it is important to verify placement and blood return is to ensure that the tip is still located within the superior (rarely the inferior) vena cava. If you look at some of the the blood vessels in your hand may carry well under 100ml of blood a minute. A medication infused there will not move all that fast and there is little blood to dilute the medication so chemical reactions can occur. The blood flow through the superior vena cava can be measured in the thousands of mls/min so the medications are quickly diluted before they can chemically react with each other.