Which of the following is a factor that can affect IV flow rate?

• A. The amount to be infused
• B. The time over which it is infused
• C. The size of the tubing
• D. All of the above

Answer: (D)

IV flow rate is determined by how much volume you plan to deliver, over what period you want to deliver it, and the resistance in the delivery system. The rate is basically volume divided by time, so increasing the volume or shortening the time raises the rate. The tubing size influences the rate because a larger inner diameter lowers resistance and allows more fluid to flow for the same pressure, while a smaller diameter increases resistance and slows the flow. Taken together, these three factors can all affect how fast fluid moves from the IV bag to the patient, so all of the above are relevant.