correct me if i'm wrong but concurrent piggyback ivs are for when your secondary iv run for a lesser amt than the primary? today in my clinical my pt. had a piggyback of piperacillin 50 ml so VTBI/hr is 100ml/hr primary i believe, sorry for my faulty memory is NaCl 9% w/Kcl 20meq/ 1000ml @ 20ml/hr my pt's other iv piggyback was a Mag Rider @100ml/hr my other question is when do you do or when is it advisable to do a piggyback or a concurrent iv