What is the infusion rate for 500 mL of normal saline to be given over 4 hours?

What is the infusion rate for 500 mL of normal saline to be given over 4 hours?

• A. 60 mL/hr
• B. 100 mL/hr
• C. 125 mL/hr
• D. 200 mL/hr

Answer: (C)

Infusion rate is calculated by dividing the total volume by the time over which it should be delivered. For 500 mL to be given over 4 hours, you divide 500 by 4, which equals 125 mL per hour. This means the IV should deliver 125 mL each hour for 4 hours to total 500 mL. To see why the other rates don’t fit: 60 mL/hr would take about 8 hours and 20 minutes to reach 500 mL, not 4 hours. 100 mL/hr would take 5 hours. 200 mL/hr would finish in 2 hours and 30 minutes. So 125 mL/hr is the rate that matches the 4-hour timeframe.

Infusion rate is calculated by dividing the total volume by the time over which it should be delivered. For 500 mL to be given over 4 hours, you divide 500 by 4, which equals 125 mL per hour. This means the IV should deliver 125 mL each hour for 4 hours to total 500 mL.

To see why the other rates don’t fit: 60 mL/hr would take about 8 hours and 20 minutes to reach 500 mL, not 4 hours. 100 mL/hr would take 5 hours. 200 mL/hr would finish in 2 hours and 30 minutes. So 125 mL/hr is the rate that matches the 4-hour timeframe.