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A physician ordered magnesium sulfate 2 grams per hour for a maintenance dose. There are 40 grams of magnesium sulfate in 1 liter of lactated Ringers solution.
What is the rate per hour to administer the maintenance dose?

A.

10 mL/hr

B.

25 mL/hr

C.

50 mL/hr

D.

100 mL/hr

E.

100 mL/hr

Answer and Explanation

The Correct Answer is C

the correct rate to administer the maintenance dose is 50 mL/hr.

Step 1: Determine the concentration of magnesium sulfate in the solution.

  • There are 40 grams of magnesium sulfate in 1 liter of solution.
  • 1 liter = 1000 mL.

Step 2: Calculate the concentration in grams per mL.

  • 40 grams ÷ 1000 mL = 0.04 grams per mL.
  • Result: 0.04 grams per mL.

Step 3: Determine the required dose per hour.

  • The physician ordered 2 grams per hour.

Step 4: Calculate the volume of solution needed to provide 2 grams of magnesium sulfate.

  • Required dose (2 grams) ÷ concentration (0.04 grams per mL) = volume in mL.
  • 2 grams ÷ 0.04 grams per mL = 50 mL.
  • Result: 50 mL.
  • The calculated rate is 50 mL/hr.

the correct rate to administer the maintenance dose is 50 mL/hr.


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Related Questions

Correct Answer is A

Explanation

To find the rate in mL/hr, you need to calculate the following:

- The concentration of nitroglycerin in the IV solution in mcg/mL
- The infusion rate in mL/hr using the formula: Infusion rate (mL/h) = (Dose (mcg/min) x 60 min/h) / Concentration (mcg/mL)

First, convert the concentration of nitroglycerin from mg to mcg by multiplying by 1000:

125 mg x 1000 = 125,000 mcg

Then, divide the amount of nitroglycerin by the volume of the IV solution to get the concentration in mcg/mL:

125,000 mcg / 500 mL = 250 mcg/mL

Next, plug in the values into the formula for infusion rate:

Infusion rate (mL/h) = (42 mcg/min x 60 min/h) / 250 mcg/mL

Simplify and solve for the infusion rate:

Infusion rate (mL/h) = 10.08 mL/h

Therefore, the nurse should program the IV pump to deliver **10.1 mL/h** to infuse nitroglycerin at 42 mcg/minute.

Correct Answer is B

Explanation

The infusion will be completed at 3:15 p.m.

This answer is correct because it is based on a simple division and addition calculation. The nurse should follow these steps to determine when the infusion will be completed:

1) Convert the volume of the fluid from liters to milliliters by multiplying by 1000, since there are 1000 mL in 1 L. The volume of the fluid is 750 mL.

2) Divide the volume of the fluid by the infusion rate to get the duration of the infusion in hours, as follows:

750 mL / 120 mL/hr = 6.25 hr

Therefore, the infusion will take 6.25 hours to complete.

3) Add the duration of the infusion to the start time of the infusion to get the end time, as follows:

9:00 a.m. + 6:25 = 3:15 p.m.

Therefore, the infusion will be completed at 3:15 p.m.

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