CSPT Sterile Compounding Calculations 5

Question 1

A dopamine drip is ordered at 5 mcg/kg/min for a 70 kg patient. The bag contains 400 mg in 250 mL. What is the infusion rate in mL/hr?

Accepted Answer

13.1 mL/hr

Answer

5 mcg/kg/min × 70 kg = 350 mcg/min; 400 mg/250 mL = 1.6 mg/mL = 1600 mcg/mL; 350 mcg/min ÷ 1600 mcg/mL × 60 = 13.1 mL/hr.

Question 2

How many mL of sterile water are needed to reconstitute a 1 g vial of cefazolin to achieve a concentration of 100 mg/mL?

Accepted Answer

10 mL

Answer

1 g = 1000 mg; 1000 mg ÷ 100 mg/mL = 10 mL.

Question 3

A TPN requires 60 mEq of magnesium sulfate. Magnesium sulfate is available as 50% (4 mEq/mL). How many mL are needed?

Accepted Answer

15 mL

Answer

60 mEq ÷ 4 mEq/mL = 15 mL.

Question 4

An IV bag labeled '2 mg/mL' morphine must deliver 0.05 mg/kg/hr to a 60 kg patient. What rate in mL/hr is required?

Accepted Answer

1.5 mL/hr

Answer

0.05 mg/kg/hr × 60 kg = 3 mg/hr; 3 mg/hr ÷ 2 mg/mL = 1.5 mL/hr.

Question 5

A 250 mL NS bag contains 500 mg of ciprofloxacin. After 100 mL has infused, how many mg of drug remain in the bag?

Accepted Answer

300 mg

Answer

500 mg ÷ 250 mL = 2 mg/mL; 150 mL remain × 2 mg/mL = 300 mg.

CSPT - Compounded Sterile Preparation Technician Practice Test