Dobutamine hydrochloride 2 mcg/kg/min is prescribed for a client weighing 165 pounds. The solution is mixed with 50 mg of dobutamine in 1,000 mL of D5W. The nurse should set the infusion pump to deliver how many mL/hour? (Enter numeric value only.)
The Correct Answer and Explanation is:
To solve this problem, we need to determine how many milliliters (mL) per hour to set on the infusion pump based on the prescribed dosage of dobutamine hydrochloride.
Step-by-Step Calculation:
- Convert the client’s weight from pounds to kilograms:
- 1 kilogram (kg) = 2.2 pounds (lbs).
- The client’s weight is 165 lbs.
- [
\frac{165}{2.2} = 75 \text{ kg}
]
- Determine the dosage in mcg per minute:
- The prescribed dosage is 2 mcg/kg/min.
- Multiply the dosage by the client’s weight in kilograms to get the dosage in mcg/min:
[
2 \, \text{mcg} \times 75 \, \text{kg} = 150 \, \text{mcg/min}
]
- Convert mcg/min to mg/min:
- There are 1,000 mcg in 1 mg.
- [
\frac{150 \, \text{mcg}}{1000} = 0.15 \, \text{mg/min}
]
- Determine the concentration of the dobutamine solution:
- The solution contains 50 mg of dobutamine in 1,000 mL of D5W.
- The concentration of dobutamine is:
[
\frac{50 \, \text{mg}}{1000 \, \text{mL}} = 0.05 \, \text{mg/mL}
]
- Calculate the infusion rate in mL/min:
- To find the infusion rate in mL/min, divide the dosage in mg/min by the concentration in mg/mL:
[
\frac{0.15 \, \text{mg/min}}{0.05 \, \text{mg/mL}} = 3 \, \text{mL/min}
]
- Convert mL/min to mL/hour:
- There are 60 minutes in 1 hour. Multiply the infusion rate in mL/min by 60 to get the rate in mL/hour:
[
3 \, \text{mL/min} \times 60 = 180 \, \text{mL/hour}
]
Final Answer:
The nurse should set the infusion pump to deliver 180 mL/hour.
Explanation:
This calculation involves several conversion steps, starting with converting the client’s weight from pounds to kilograms. Once we know the weight in kilograms, we apply the prescribed dosage of 2 mcg/kg/min to determine the actual dose in micrograms per minute. Converting this to milligrams per minute allows us to work with the drug’s concentration in the solution. The concentration of dobutamine is given as 50 mg in 1,000 mL, so dividing the dose by this concentration gives the required rate in mL per minute. Finally, we convert the rate to mL per hour, as that is the setting used on most infusion pumps.