A nurse is caring for a client with acute decompensated heart failure who is prescribed a … — NCLEX-RN

A nurse is caring for a client with acute decompensated heart failure who is prescribed a continuous intravenous infusion of dobutamine at $5\text{ mcg/kg/min}$ . The client weighs $187\text{ lbs}$ . The pharmacy provides dobutamine as $500\text{ mg}$ mixed in $250\text{ mL}$ of $5\%\text{ dextrose in water}$ (D5W). How many $\text{mL/hr}$ should the nurse set the infusion pump to deliver? (Record your answer to the nearest tenth.)

Answer: 12.8 mL/hr

Answer

12.8

To determine the correct infusion pump setting in

\text{mL/hr}

, the nurse must perform a multi-step calculation involving unit conversions for both weight (pounds to kilograms) and time (minutes to hours). After establishing that the client needs

25.5\text{ mg}

of dobutamine every hour, dividing by the concentration of the IV bag (

2\text{ mg/mL}

) provides the accurate volume of

12.75\text{ mL/hr}

, which rounds to

12.8\text{ mL/hr}

Step-by-Step Solution

Convert the client's weight from pounds to kilograms.

187 \div 2.2 = 85\text{ kg}

The medication dosage is prescribed based on kilograms of body weight.

Calculate the per-minute dobutamine dose for this specific client.

85\text{ kg} \times 5\text{ mcg/kg/min} = 425\text{ mcg/min}

This establishes the exact amount of medication the client needs to receive every minute.

Convert the minute dose to an hourly dose.

425\text{ mcg/min} \times 60\text{ min/hr} = 25,500\text{ mcg/hr}

Intravenous infusion pumps are programmed in milliliters per hour, so the dose must reflect an hourly rate.

Convert the hourly dose from micrograms to milligrams.

25,500\text{ mcg/hr} \div 1000\text{ mcg/mg} = 25.5\text{ mg/hr}

The supplied medication from the pharmacy is measured in milligrams, so the units must match.

Calculate the concentration of the provided IV bag.

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

This determines how many milligrams of dobutamine are in each milliliter of the IV fluid.

Determine the final infusion rate in mL/hr.

25.5\text{ mg/hr} \div 2\text{ mg/mL} = 12.75\text{ mL/hr}

Dividing the required hourly medication dose by the medication concentration yields the fluid volume needed per hour.

Round the final value to the nearest tenth as instructed.

12.8\text{ mL/hr}

Standard rounding rules dictate that a 5 in the hundredths place rounds the tenths place up.

Key Concept

Weight-based continuous intravenous infusion dosage calculation requiring conversion between units of mass and time.

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