A physician orders 250 mL of solution to infuse over 75 minutes. What is the required infusion rate in mL/hour?

A physician orders 250 mL of solution to infuse over 75 minutes. What is the required infusion rate in mL/hour?

• A. 167 mL/hour
• B. 200 mL/hour
• C. 187 mL/hour
• D. 250 mL/hour

Answer: (B)

Infusion rate is found by dividing the total volume by the infusion time, with time converted to hours. Convert 75 minutes to hours: 75 ÷ 60 = 1.25 hours. Then 250 mL ÷ 1.25 h = 200 mL/hour. So the required infusion rate is 200 mL/hour. Rates like 167 mL/hour would deliver the total volume in about 89–90 minutes, not 75; 250 mL/hour would finish in 60 minutes; 187 mL/hour would take about 80 minutes.

Infusion rate is found by dividing the total volume by the infusion time, with time converted to hours. Convert 75 minutes to hours: 75 ÷ 60 = 1.25 hours. Then 250 mL ÷ 1.25 h = 200 mL/hour. So the required infusion rate is 200 mL/hour. Rates like 167 mL/hour would deliver the total volume in about 89–90 minutes, not 75; 250 mL/hour would finish in 60 minutes; 187 mL/hour would take about 80 minutes.