TPN and Ceftriaxone

if two medications are not "Y compatible" then you cannot run them at the same time into two different ports in the same central line access site. All the lumens go to the same central line so they would be mixing and if they are not compatible you just destroyed a perfectly good central line and your patient may be forced to endure another central line placement at a different site. You only have two possible femoral sites the it can go to the subclavian which usually freaks out patients. Something about a "huge catheter" in their neck is intimidating to some patients.

That is not true. Multi lumen central venous lines have completely separate lumens that exit the line at different spots along the side of the line with the largest lumen usually opening at the proximal tip. They infuse into large vessels with rapid, high-volume blood flow that does not allow physical mixing of incompatible meds. Catheters used for hemodialysis and continuous renal replacement therapy have two large lumens that allow the aspiration of blood from one lumen and the infusion of blood into the other. It would seem somewhat counterproductive if the contents of the two lumens mixed inside the catheter in those circumstances now wouldn't it?

Those pictures are cross-sections of two different types of multi lumen CVCs. The idea was to show how the lines are designed with the lumens completely separate from each other. That essentially means that the line isn't a single line, it's three lines. I've worked in PICU for more than 12 years and we run incompatible solutions into our lines all the time, as long as they're in different lumens. The only access we may have in a child is a triple lumen CVC through which we could be running TPN and lipids in one lumen, epinephrine, norepinephrine, milrinone, morphine, and midazolam in another and furosemide in the third. The furosemide would be stopped and flushed for antibiotic or other incompatible med infusions. I'm not sure why your HIV patients would need a second site for antibiotics unless they had something else running into one of the lumens that couldn't be interrupted. Our transplant patients often have tacrolimus (which doesn't play well with others) in one lumen and ATGAM (which MUST run alone) in another. If we need to give meds and have no other access it will be into the lumen with the TPN... which jacks up their infection risk hugely. Some meds are compatible with TPN and lids and we have a list of them so they can be run together. Not ideal but then a lot of what we do is under less-than-ideal conditions.

Here's a link to a critical care forum study into the infusion of incompatible solutions (TPN and phenytoin - the great killer of IV access!) via multi lumen central line. It revealed no particulate matter of clinical significance. http://ccforum.com/content/3/1/51

Another report on the simultaneous infusion of pH-incompatble solutions via double lumen catheter:

http://www.theannals.com/cgi/content/abstract/32/9/875

This product utilization guide includes a description of a double lumen peripheral catheter that allows simultaneous infusion of two or more incompatible infusions on page 8:

http://www.mayohealthcare.com.au/products/pdf/cardioVas/trm-c1200.pdf

There's some limited information in this CEU package:

http://www.nurseceusonline.com/viewcourse/20-53217.htm

This is a fairly comprehensive educational package from a major line manufacturer. The infusions section starts on page 31:

http://www.arrowintl.com/documents/pdf/education/ml-ng1201.pdf