A client receives a prescription for norepinephrine 3 mcg/min intravenously (IV). The IV bag is contains norepinephrine 4 mg in dextrose 5% in water (D,W) 1,000 mL. How many mL/hour should the nurse program the infusion pump? (Enter numerical value only.)
The correct answer and Explanation is :
To calculate the infusion rate in mL/hour, follow these steps:
- Determine the total amount of norepinephrine in the IV bag:
- The IV bag contains norepinephrine 4 mg in 1,000 mL of Dextrose 5% in water (D5W).
- Calculate the concentration of norepinephrine in the IV bag:
- Concentration = Total amount of norepinephrine / Total volume of the IV bag
- Concentration = 4 mg / 1,000 mL
- Concentration = 0.004 mg/mL
- Convert the prescribed dosage from mcg/min to mg/mL:
- The prescription is 3 mcg/min.
- Convert mcg to mg: 3 mcg = 0.003 mg
- Desired concentration = 0.003 mg/min
- Calculate the required flow rate to deliver the prescribed dose:
- Using the concentration of norepinephrine in the IV bag (0.004 mg/mL), determine how many mL per minute is needed to deliver 0.003 mg/min.
- Required volume (mL/min) = Desired dose (mg/min) / Concentration (mg/mL)
- Required volume (mL/min) = 0.003 mg/min / 0.004 mg/mL
- Required volume = 0.75 mL/min
- Convert the infusion rate to mL/hour:
- There are 60 minutes in an hour, so multiply the flow rate by 60.
- Infusion rate (mL/hour) = 0.75 mL/min × 60 min/hour
- Infusion rate = 45 mL/hour
The nurse should program the infusion pump to deliver 45 mL/hour.
Explanation:
The calculation involves determining the concentration of norepinephrine in the IV solution and then using that concentration to find out how much volume is needed per minute to meet the prescribed dosage. By converting this to an hourly rate, you ensure the patient receives the correct dose of norepinephrine continuously over time. This method ensures precise dosing, which is critical for medications like norepinephrine, used to manage blood pressure and other vital functions.