Question about IVPB?

Hello all,

I am in my third year and I am still uncomfortable with IVs. bleh

anywho, I was just wondering, with a IVPB, lets say 50 ml of Ancef, if you have an order for it at 1200, and then at 1800, you would run it at 1200, and leave it because your primary line will automatically start when the ancef IVPB is done right?

then when you come back at 1800 to hang up another ancef, you can use the same secondary line. but since that line is already primed, it is primed with the last bit of ancef from 1200 right? so are we not technically giving 50 ml of ancef to the patient?

I was talking to my friend about this and she said her instructor told that you minus some mls (dont know how much exactly) from the actual dose given,

but this is the first time I have ever heard of this and they have not taught us this during lab.

I always thought you would only add 25ml when you are setting your rate? never subtracting. so when you mark off that med in ins/outs it would be 75ml (50ml ancef + 25ml flush from the primary line that is going into that patient)??

thank you for your help =)