Hi everyone, just some background information--I work in an emergency department as a trauma tech. My co-workers and I got into discussion at work about the fastest method of giving a patient fluid via an IV. We had this really sick patient who needed multiple liters of fluid and I was wondering if you could answer the following question for us. If you are not familiar with how an IV works, the IV bag is "spiked" with the IV tubing (tubing plugged into the bag), then the distal part of the IV tubing is plugged into the IV catheter (into the patient). The IV tubing also has a needless port/connection maybe about one foot from where it connects into the patient so you can hook another set of IV tubing to run in medications, or give medicine via syringe, etc. So, one of the nurses thought that in order to get the most amount of fluid into the patient the fastest, she would connect the IV tubing into the patient like normal, then also prime another set of IV tubing connected to a second bag of fluid and plug that into the needless port of the first line of IV tubing. She thought that this would be a quicker way to get more fluid into the patient than if you were to run the first bag in (on one set of IV tubing) and then just change the bag immediately after it ran dry. I didn't believe her and so we did a little experiment. We replicated the same scenario and found that the time to infuse two bags of fluid was definitely faster using a single line of IV tubing and changing the bag once it became dry instead of connecting two lines together and running both bags in together. However I could not come up with an explanation for this. I was thinking that it had something to do with the pressure and Bernoulli's equation. Both bags experience the same potential energy because they are at the same height (but this is doubled when hanging both at the same time?), I am assuming that the pressure is greater when the two lines are connected together (where the two sets of IV tubing meet). Increasing the pressure should decrease the velocity of the fluid right? When running the single bag in with just one line, the potential energy is just 1, because 1 bag instead of two at a time, so lower pressure, higher velocity? Also, maybe fluid turbulence where the two connections meet slows down the rate? Thanks, this has been bugging me and the ED staff would sure like to know too!