A client in cardiogenic shock is prescribed a continuous intravenous (IV) infusion of dobu… — NCLEX-RN

A client in cardiogenic shock is prescribed a continuous intravenous (IV) infusion of dobutamine at a rate of $5 \text{ mcg/kg/min}$ . The client weighs $80 \text{ kg}$ . The pharmacy provides a premixed IV bag containing $500 \text{ mg}$ of dobutamine in $250 \text{ mL}$ of $5\%$ dextrose in water (D5W). At what rate, in $\text{mL/hr}$ , should the nurse program the electronic infusion pump?

12Answer
B
24
C
48
D
5.5

Answer

The electronic infusion pump should be programmed to

12 \text{ mL/hr}

To determine the correct pump rate, the nurse must first calculate the client's specific dose per minute (

5 \text{ mcg} \times 80 \text{ kg} = 400 \text{ mcg/min}

), convert this to an hourly dose (

400 \text{ mcg/min} \times 60 \text{ minutes} = 24,000 \text{ mcg/hr}

), and then convert micrograms to milligrams (

24 \text{ mg/hr}

). Next, the concentration of the IV bag is determined (

500 \text{ mg} \div 250 \text{ mL} = 2 \text{ mg/mL}

). Finally, dividing the hourly dose by the concentration yields the correct pump rate (

24 \text{ mg/hr} \div 2 \text{ mg/mL} = 12 \text{ mL/hr}

Step-by-Step Solution

Calculate the total required dose per minute based on the client's weight.

5 \text{ mcg/kg/min} \times 80 \text{ kg} = 400 \text{ mcg/min}

Critical care vasoactive drips are often weight-based and must be individualized to the client's mass.

Convert the per-minute dose to an hourly dose.

400 \text{ mcg/min} \times 60 \text{ min/hr} = 24,000 \text{ mcg/hr}

Electronic infusion pumps are programmed in

\text{mL/hr}

, so the time unit must match the pump's hourly setting.

Convert the required dose from micrograms (mcg) to milligrams (mg).

24,000 \text{ mcg/hr} \div 1,000 \text{ mcg/mg} = 24 \text{ mg/hr}

The supplied medication is measured in milligrams (

500 \text{ mg}

). Units must align before calculating the final fluid volume.

Calculate the concentration of the supplied IV bag.

500 \text{ mg} \div 250 \text{ mL} = 2 \text{ mg/mL}

This determines the exact amount of active drug contained in each milliliter of the IV fluid.

Determine the final infusion pump rate.

24 \text{ mg/hr} \div 2 \text{ mg/mL} = 12 \text{ mL/hr}

Dividing the required hourly dose by the concentration provides the exact volume of fluid the pump must deliver each hour.

Key Concept

Weight-based intravenous continuous infusion calculations and unit conversions.

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