Whey do you see blood tinged saline in the extension of a peripheral IV even when clamped.
Patient activity, patient might be up walking around, gravity pulls the blood into the line even tho it is clamped.
Then there is the good ol "vampire" effect. Denise Macklin is better at describing that one, it has to do with the 'physics of flow' (I never took physics, but it makes sense how it was explained to me.
oh wait....that WAS Denise!.....
I have seen this mostly in ambulatory and home care patients when they are not receiving anything thru the IV. Sometimes even if they ARE getting IV fluids and they are up and about, it will back up in the line.
Susan Schuetrumpf, RN, CRNI, VA-BC