Dosage Calculation of Critical Care Medications: mcg/kg/min Dimensional Analysis Method

mL/h to mcg/kg/min Scenario: A patient is receiving Dobutamine at 20 mL/h. The concentration of Dobutamine is 500 mg in 250 mL of D5W. The patient’s weight is 120 lb. The nurse needs to calculate the micrograms per kilogram per minute (mcg/kg/min) the patient is receiving. Question: How does the nurse convert the infusion rate of 20 mL/h to the dose the patient is receiving?

mL/h to mcg/kg/min x mcg = kg/min

mL/h to mcg/kg/min x mcg = 1000 mcg kg/min 1 mg

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg kg/min 1 mg 250 mL

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg x 20 mL kg/min 1 mg 250 mL 1 h

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg x 20 mL x 1 h kg/min 1 mg 250 mL 1 h 60 min

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg x 20 mL x 1 h x 2.2 lb kg/min 1 mg 250 mL 1 h 60 min 1 kg

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg x 20 mL x 1 h x 2.2 lb x ____ kg/min 1 mg 250 mL 1 h 60 min 1 kg 120 lb

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 mg x 20 mL x 1 h x 2.2 lb x ____ kg/min 1 mg 250 mL 1 h 60 min 1 kg 120 lb

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 x 20 x 1 x 2.2 x ____ kg/min 1 250 1 60 min 1 kg 120

mL/h to mcg/kg/min x mcg = 1000 mcg x 500 x 20 x 1 x 2.2 x ____ kg/min 1 250 1 60 min 1 kg 120 = 22,000,000 = 12.222 = 12.2 mcg/kg/min 1,800,000

mL/h to mcg/kg/min So, 20 mL/h will deliver Dobutamine at 12.2 mcg/kg/min to a 120 lb person with a concentration of 500 mg in 250 mL.

mcg/kg/min Feel free to contact your instructor for any questions or concern you may have.