You prepare dopamine by mixing 200 mg in 250 mL of solution. What is the infusion rate in mL/hr needed to achieve 5 µg/kg/min for a 70-kg patient?

You prepare dopamine by mixing 200 mg in 250 mL of solution. What is the infusion rate in mL/hr needed to achieve 5 µg/kg/min for a 70-kg patient?

• A. 6 mL/hr
• B. 10 mL/hr
• C. 16 mL/hr
• D. 26 mL/hr

Answer: (D)

The main idea is to convert a weight-based dose into an infusion rate using the solution’s concentration. Target dose: 5 µg/kg/min for a 70-kg patient equals 350 µg/min, which is 0.350 mg/min. The dopamine mix provides 200 mg in 250 mL, giving a concentration of 0.8 mg/mL. To deliver 0.350 mg each minute from this solution, you need 0.350 ÷ 0.8 = 0.4375 mL/min. Convert to mL/hour: 0.4375 × 60 ≈ 26.25 mL/hr, about 26 mL/hr.

The main idea is to convert a weight-based dose into an infusion rate using the solution’s concentration. Target dose: 5 µg/kg/min for a 70-kg patient equals 350 µg/min, which is 0.350 mg/min. The dopamine mix provides 200 mg in 250 mL, giving a concentration of 0.8 mg/mL. To deliver 0.350 mg each minute from this solution, you need 0.350 ÷ 0.8 = 0.4375 mL/min. Convert to mL/hour: 0.4375 × 60 ≈ 26.25 mL/hr, about 26 mL/hr.