An intensive care nurse is managing a male patient diagnosed with cardiogenic shock. The p… — NCLEX-RN

An intensive care nurse is managing a male patient diagnosed with cardiogenic shock. The patient's body weight is recorded as $198 \text{ lb}$ . The medical team orders an intravenous infusion of dopamine at a rate of $5 \text{ mcg/kg/min}$ to support cardiac output. The available medication from the pharmacy is a premixed bag containing $400 \text{ mg}$ of dopamine dissolved in $250 \text{ mL}$ of $5\%$ dextrose in water (D5W).

Determine the appropriate infusion pump setting in $\text{mL/hr}$ to deliver the prescribed dose. Round the final answer to the nearest tenth.

Answer: 16.9 mL/hr

Answer

16.9

To safely program the infusion pump, the nurse must systematically convert the patient's weight to kilograms, find the total dose required per minute, convert that value to milligrams per hour, and finally divide it by the concentration of the dopamine bag (mg/mL). This mathematically yields the exact fluid volume required per hour.

Step-by-Step Solution

Convert the patient's weight from pounds to kilograms.

198 \text{ lb} \div 2.2 \text{ lb/kg} = 90 \text{ kg}

Weight-based critical care drug dosing requires the patient's weight to be expressed in metric units (kilograms).

Calculate the total required dose per minute.

5 \text{ mcg/kg/min} \times 90 \text{ kg} = 450 \text{ mcg/min}

This establishes the exact amount of medication the patient must receive every minute based on their specific body mass.

Convert the per-minute dose in micrograms to an hourly dose in milligrams.

450 \text{ mcg/min} \times 60 \text{ min/hr} = 27,000 \text{ mcg/hr}

. Then,

27,000 \text{ mcg} \div 1,000 \text{ mcg/mg} = 27 \text{ mg/hr}

Since the infusion pump is programmed in mL/hr and the drug concentration is usually calculated in mg/mL, unifying these units simplifies the final calculation step.

Determine the concentration of the available medication bag.

400 \text{ mg} \div 250 \text{ mL} = 1.6 \text{ mg/mL}

This identifies how many milligrams of dopamine are present in a single milliliter of the IV fluid.

Calculate the final infusion rate and round to the nearest tenth.

27 \text{ mg/hr} \div 1.6 \text{ mg/mL} = 16.875 \text{ mL/hr}

. Rounded to the nearest tenth, this yields

16.9 \text{ mL/hr}

Dividing the total required hourly dose by the fluid concentration provides the volume that the infusion pump must deliver per hour.

Key Concept

Weight-Based Continuous IV Medication Calculations

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