An order is for 500 mL of saline to infuse over 4 hours. What is the infusion rate in mL/hour?

To determine the infusion rate in mL/hour for an order of 500 mL of saline to be infused over 4 hours, divide the total volume of saline by the total time in hours.

The calculation is as follows:

1. Total volume to infuse: 500 mL

2. Total time for the infusion: 4 hours

Infusion rate (mL/hour) = Total volume (mL) / Total time (hours)

Infusion rate (mL/hour) = 500 mL / 4 hours

Infusion rate (mL/hour) = 125 mL/hour

This indicates that the infusion should occur at a rate of 125 mL each hour to complete the total volume of 500 mL within the designated time of 4 hours. This calculation is critical in clinical settings to ensure that fluid administration is done at a safe and effective rate, preventing complications associated with too rapid or too slow of an infusion.