A client who weighs 176 pounds receives a prescription for dobutamine 2 mcg/kg/min intravenously (IV). The IV bag contains dobutamine 500 mg in dextrose 5% in water (D5W) 500 mL. How many mL/hour should the nurse program the IV infusion pump? (Enter numerical value only. If rounding is required, round to the nearest whole number.)
The correct answer and Explanation is :
To determine the mL/hour rate for administering dobutamine, we first need to calculate the client’s weight in kilograms, the required dose in mcg/min, and the concentration of the dobutamine solution.
- Convert the weight from pounds to kilograms:
[
\text{Weight (kg)} = \frac{\text{Weight (lbs)}}{2.2} = \frac{176}{2.2} \approx 80 \text{ kg}
] - Calculate the required dose in mcg/min:
[
\text{Dose (mcg/min)} = \text{Dose (mcg/kg/min)} \times \text{Weight (kg)} = 2 \text{ mcg/kg/min} \times 80 \text{ kg} = 160 \text{ mcg/min}
] - Convert mcg/min to mg/min (since 1 mg = 1000 mcg):
[
\text{Dose (mg/min)} = \frac{160 \text{ mcg/min}}{1000} = 0.16 \text{ mg/min}
] - Calculate the concentration of dobutamine in the IV bag:
The IV bag contains 500 mg of dobutamine in 500 mL of D5W. Therefore, the concentration is:
[
\text{Concentration (mg/mL)} = \frac{500 \text{ mg}}{500 \text{ mL}} = 1 \text{ mg/mL}
] - Determine how many mL/min are needed:
[
\text{mL/min} = \frac{\text{Dose (mg/min)}}{\text{Concentration (mg/mL)}} = \frac{0.16 \text{ mg/min}}{1 \text{ mg/mL}} = 0.16 \text{ mL/min}
] - Convert mL/min to mL/hour:
[
\text{mL/hour} = 0.16 \text{ mL/min} \times 60 \text{ min/hour} = 9.6 \text{ mL/hour}
] - Round to the nearest whole number:
[
\text{Final rate} = 10 \text{ mL/hour}
]
Answer: 10
Explanation
In this calculation, we first converted the client’s weight from pounds to kilograms, which is essential because medication dosages are often given in mcg/kg/min. We then calculated the total required dose of dobutamine based on the client’s weight and the prescribed rate, converting mcg/min to mg/min for consistency with the medication’s concentration.
Next, we found the concentration of the dobutamine in the IV solution, allowing us to determine how many mL are needed to achieve the required dosage. Finally, we converted the rate from mL/min to mL/hour for practical administration on an IV pump, rounding to the nearest whole number as needed. Proper calculations like these ensure that clients receive the correct medication dosage safely and effectively.