A nurse is preparing to administer magnesium sulfate 4 g to a client byintermittent IV bolus over 20 min. Available is magnesium sulfate 4 g in 0.9% sodiumchloride 50 mL. 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 how many milliliters per hour (mL/hr) the nurse should set the IV pump to deliver, we need to calculate the infusion rate required to administer 4 grams of magnesium sulfate over 20 minutes using the available solution of 4 grams in 50 mL of 0.9% sodium chloride.
Steps for Calculation:
- Determine the Total Volume to be Infused:
The total volume of the solution to be administered is 50 mL. - Determine the Total Infusion Time in Hours:
The infusion time is 20 minutes. To convert this into hours:
[
\text{Infusion Time (in hours)} = \frac{20 \text{ minutes}}{60 \text{ minutes per hour}} = 0.333 \text{ hours}
] - Calculate the Infusion Rate in mL/hr:
The infusion rate is calculated by dividing the total volume by the total infusion time:
[
\text{Infusion Rate (in mL/hr)} = \frac{\text{Total Volume (mL)}}{\text{Infusion Time (hours)}}
]
[
\text{Infusion Rate (in mL/hr)} = \frac{50 \text{ mL}}{0.333 \text{ hours}} \approx 150 \text{ mL/hr}
]
Thus, the nurse should set the IV pump to deliver 150 mL/hr to administer the magnesium sulfate at the correct rate over the specified time.
Explanation:
The calculation involves finding out how fast the IV pump should infuse the medication to meet the required delivery time. The medication needs to be infused over 20 minutes, which translates to 1/3 of an hour (or 0.333 hours). By dividing the total volume of 50 mL by this time, we obtain the infusion rate in mL/hr.
Setting the IV pump to deliver 150 mL/hr ensures that the 50 mL of solution containing 4 grams of magnesium sulfate is administered within the 20-minute period. This rate ensures that the client receives the full dose of magnesium sulfate in the correct time frame, achieving the therapeutic goal efficiently.