Question

You want to start an infusion of noradrenaline at 0.05 micrograms/kg/min. You have an infusion containing 8 mg in 50 mL. Your patient weighs 80 kg. What rate will you set the infusion pump in mL/hr?

A) 1.5 mL/hr
B) 0.5 mL/hr
C) 3 mL/hr
D) 0.025 mL/hr

Answer 1

To set the infusion pump for noradrenaline at 0.05 micrograms/kg/min for an 80 kg patient, with a concentration of 8 mg in 50 mL, the correct infusion rate is calculated to be 0.025 mL/hr, which is option D.

Step-by-step explanation:

To calculate the infusion rate for noradrenaline, we need to use the dosage formula:

Dosage (mcg/min) = rate (mL/hr) × concentration (mcg/mL) × 60 (min/hr).

First, we'll convert the concentration of the noradrenaline solution from milligrams to micrograms:

8 mg = 8000 mcg.

Now, the concentration in micrograms per milliliter (mcg/mL):

Concentration = Total mcg / Total mL = 8000 mcg / 50 mL = 160 mcg/mL.

Next, we calculate the required dosage for the patient:

Dosage = 0.05 mcg/kg/min × 80 kg = 4 mcg/min.

Then we rearrange the dosage formula to solve for the rate:

rate (mL/hr) = Dosage (mcg/min) / (Concentration (mcg/mL) × 60 (min/hr)).

rate = 4 mcg/min / (160 mcg/mL × 60 min/hr) = 0.00041666667 mL/min.

Converting the rate to mL/hr:

rate = 0.00041666667 mL/min × 60 min/hr = 0.025 mL/hr.

Therefore, the correct infusion rate to set on the pump is 0.025 mL/hr, which corresponds to option D.