A nurse is preparing to administer intravenous fluids. The order is 2500 mL NS to infuse at 150 mL/hour with a drop factor of 15 gtt/mL. How many drops per minute should be set (rounded to the nearest whole drop)?

A nurse is preparing to administer intravenous fluids. The order is 2500 mL NS to infuse at 150 mL/hour with a drop factor of 15 gtt/mL. How many drops per minute should be set (rounded to the nearest whole drop)?

• A. 31 gtt/min
• B. 37 gtt/min
• C. 38 gtt/min
• D. 39 gtt/min

Answer: (C)

The key idea is converting the IV rate into drops per minute using the drop factor. The drop factor tells you how many drops make 1 mL, so you multiply the hourly mL rate by the drop factor to get drops per hour, then convert to drops per minute. Calculate: 150 mL/hour × 15 gtt/mL = 2250 gtt/hour. Then 2250 gtt/hour ÷ 60 minutes/hour = 37.5 gtt/min. Rounded to the nearest whole drop, that’s 38 gtt/min. Note: the total volume (2500 mL) isn’t needed for the rate, but if you want the time to finish, it would be 2500 mL ÷ 150 mL/hour ≈ 16.7 hours.

The key idea is converting the IV rate into drops per minute using the drop factor. The drop factor tells you how many drops make 1 mL, so you multiply the hourly mL rate by the drop factor to get drops per hour, then convert to drops per minute.

Calculate: 150 mL/hour × 15 gtt/mL = 2250 gtt/hour. Then 2250 gtt/hour ÷ 60 minutes/hour = 37.5 gtt/min. Rounded to the nearest whole drop, that’s 38 gtt/min.

Note: the total volume (2500 mL) isn’t needed for the rate, but if you want the time to finish, it would be 2500 mL ÷ 150 mL/hour ≈ 16.7 hours.