My personal preference is to always hang a bag. If I am starting an IV in the field, it is because the patient needs, or potentially needs, either fluid or IV meds. Most meds should be administered with fluid(slow IV push) or with a flush(rapid IV push), both of which require IV fluids. If the patient condition deteriorates rapidly, I do not want to have to spike a bag prior to giving meds. If the patient does not need this potential therapy, I probably will not start a line. The argument about cost is negligible. If you start a lock, you have to use a catheter, lock device, syringe, and a vial of saline. With a bag you use the same catheter, IV tubing, and a bag. Per my PM coordinator the cost is about the same. Also, I am a dinosaur, so we did not have locks available when I started in this business!
