If an infusion pump is set at 120 mL/h, how long will it take to deliver 1 L of Hartmann's solution?

If an infusion pump is set at 120 mL/h, how long will it take to deliver 1 L of Hartmann's solution?

• A. 8 h 20 minutes
• B. 8 h
• C. 8 h 30 minutes
• D. 9 h

Answer: (A)

The key idea is that time equals volume divided by the infusion rate. You want 1 liter, which is 1000 milliliters, delivered at 120 mL per hour. So the time needed is 1000 / 120 hours = 8.333... hours. Converting 0.333... hours to minutes gives 0.333... × 60 ≈ 20 minutes. Therefore, it takes 8 hours and 20 minutes to deliver 1000 mL. For context: in 8 hours at 120 mL/h you’d deliver 960 mL; in 8 hours 30 minutes (8.5 hours) you’d deliver 1020 mL, which overshoots 1000 mL; in 9 hours you’d deliver 1080 mL.

The key idea is that time equals volume divided by the infusion rate. You want 1 liter, which is 1000 milliliters, delivered at 120 mL per hour. So the time needed is 1000 / 120 hours = 8.333... hours. Converting 0.333... hours to minutes gives 0.333... × 60 ≈ 20 minutes. Therefore, it takes 8 hours and 20 minutes to deliver 1000 mL.

For context: in 8 hours at 120 mL/h you’d deliver 960 mL; in 8 hours 30 minutes (8.5 hours) you’d deliver 1020 mL, which overshoots 1000 mL; in 9 hours you’d deliver 1080 mL.