A nurse is to administer Dobutamine (Dobutrex) 2.5 mcg/kg/min IV to a patient with severe heart failure who weighs 130 pounds. The pharmacy prepares a solution of 250 mg of Dobutrex in 500 mL D5W. How many mL of the medication should be administered to the patient per hour? Round your answer to the nearest whole number.
_mL/hr
The Correct answer and Explanation is:
To calculate the appropriate dosage of Dobutamine (Dobutrex) to be administered to a patient with severe heart failure, we first need to convert the patient’s weight from pounds to kilograms. The conversion factor is:
1 kilogram = 2.2 pounds.
Step 1: Convert the patient’s weight
The patient weighs 130 pounds. To convert this to kilograms:
[
\text{Weight in kg} = \frac{130 \text{ pounds}}{2.2 \text{ pounds/kg}} \approx 59.09 \text{ kg}
]
Step 2: Calculate the required dosage in mcg/min
The order specifies to administer Dobutamine at a rate of 2.5 mcg/kg/min. Now we can calculate the total required dosage per minute for this patient:
[
\text{Dosage (mcg/min)} = 2.5 \text{ mcg/kg/min} \times 59.09 \text{ kg} \approx 147.73 \text{ mcg/min}
]
Step 3: Convert mcg/min to mg/hr
Since there are 1,000 mcg in a mg, we first convert the dosage to mg/min:
[
\text{Dosage (mg/min)} = \frac{147.73 \text{ mcg/min}}{1000} \approx 0.148 \text{ mg/min}
]
Now, to convert this to mg/hr (since there are 60 minutes in an hour):
[
\text{Dosage (mg/hr)} = 0.148 \text{ mg/min} \times 60 \text{ min/hr} \approx 8.88 \text{ mg/hr}
]
Step 4: Determine the concentration of the Dobutamine solution
The pharmacy provides a solution of 250 mg in 500 mL. To find the concentration:
[
\text{Concentration} = \frac{250 \text{ mg}}{500 \text{ mL}} = 0.5 \text{ mg/mL}
]
Step 5: Calculate the volume to be administered
To find out how many mL of the medication should be administered per hour, we can use the dosage in mg/hr and the concentration:
[
\text{Volume (mL/hr)} = \frac{8.88 \text{ mg/hr}}{0.5 \text{ mg/mL}} = 17.76 \text{ mL/hr}
]
Step 6: Round the answer
Finally, rounding to the nearest whole number gives us:
[
\text{Volume to administer} \approx 18 \text{ mL/hr}
]
Final Answer
The nurse should administer 18 mL/hr of Dobutamine to the patient.