A nurse is preparing to administer dobutamine 10 mcg/kg/min by continuous IV infusion to a client who weighs 110 lb. Available is dobutamine 250 mg in 250 mL dextrose 5% in water. The nurse should set the IV pump to deliver how many mL/hr? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)
The Correct Answer and Explanation is:
To determine the appropriate IV pump setting for administering dobutamine, we first need to calculate the dosage based on the client’s weight and the prescribed rate of infusion. Here’s how to approach this problem step-by-step:
Step 1: Convert Weight from Pounds to Kilograms
The client weighs 110 pounds. To convert pounds to kilograms, use the conversion factor 1 kg=2.2 lb1 \, \text{kg} = 2.2 \, \text{lb}1kg=2.2lb.Weight in kg=110 lb2.2 lb/kg=50 kg\text{Weight in kg} = \frac{110 \, \text{lb}}{2.2 \, \text{lb/kg}} = 50 \, \text{kg}Weight in kg=2.2lb/kg110lb=50kg
Step 2: Calculate the Total Dosage of Dobutamine in mcg/min
The prescribed rate is 10 mcg/kg/min. Multiply the weight in kilograms by the infusion rate:Total dosage=50 kg×10 mcg/kg/min=500 mcg/min\text{Total dosage} = 50 \, \text{kg} \times 10 \, \text{mcg/kg/min} = 500 \, \text{mcg/min}Total dosage=50kg×10mcg/kg/min=500mcg/min
Step 3: Convert mcg/min to mg/min
Since the available solution is in mg, convert micrograms to milligrams:500 mcg/min=5001000 mg/min=0.5 mg/min500 \, \text{mcg/min} = \frac{500}{1000} \, \text{mg/min} = 0.5 \, \text{mg/min}500mcg/min=1000500mg/min=0.5mg/min
Step 4: Calculate the Total Volume to Infuse per Hour
To find out how many milliliters per hour are required, we first need to determine the concentration of dobutamine in the available solution. The available solution is 250 mg in 250 mL, giving a concentration of:Concentration=250 mg250 mL=1 mg/mL\text{Concentration} = \frac{250 \, \text{mg}}{250 \, \text{mL}} = 1 \, \text{mg/mL}Concentration=250mL250mg=1mg/mL
Step 5: Calculate mL/min Required for the Infusion
Now, using the concentration to find out how many mL correspond to the required 0.5 mg/min:mL/min=0.5 mg/min1 mg/mL=0.5 mL/min\text{mL/min} = \frac{0.5 \, \text{mg/min}}{1 \, \text{mg/mL}} = 0.5 \, \text{mL/min}mL/min=1mg/mL0.5mg/min=0.5mL/min
Step 6: Convert mL/min to mL/hr
To convert from mL/min to mL/hr, multiply by 60 minutes:mL/hr=0.5 mL/min×60 min/hr=30 mL/hr\text{mL/hr} = 0.5 \, \text{mL/min} \times 60 \, \text{min/hr} = 30 \, \text{mL/hr}mL/hr=0.5mL/min×60min/hr=30mL/hr
Conclusion
Thus, the nurse should set the IV pump to deliver 30 mL/hr. This dosage ensures that the client receives the correct amount of dobutamine for their weight and prescribed infusion rate.