Newrnnow

I am wondering about doing IV piggyback. I have always programmed the pump to match what pharmacy/ the order puts on the label on the bag (antibiotics for example). I also backprime the secondary tubing with normal saline usually. So essentially if I have vancomycin, it will be labeled saying rate:100 ml/hr and vtbi:250ml so I program this into the pump for secondary. I also set the primary to infuse once the secondary is done. I will do something like 50ml/hr for 20ml to flush the line. However i am wondering if when i program the pump I should be making the secondary vtbi more than 250ml to account for the backprime of saline I did. Does this make sense? Thank you for the help!