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A physician orders Garamycin (gentamicin) 4 mg/kg/dose IV piggyback every 12 hours for a newborn weighing 7 lb, 11.2 oz. After reconstitution, the dosage is 20 mg/10 mL.
How many milliliters should the nurse administer to the patient?

A.

1.4 mL

B.

14 mL

C.

7 mL

D.

0.7 mL

E.

0.7 mL

Answer and Explanation

The Correct Answer is C

To answer this question, the nurse needs to perform the following steps:


1) Convert the patient's weight from pounds and ounces to kilograms, using the conversion factor of 1 pound = 0.45359237 kilograms¹². To do this, first convert the ounces to a fraction of a pound by dividing by 16, then add this fraction to the pounds, and then multiply by the conversion factor. For example:


7 lb, 11.2 oz = 7 + (11.2 / 16) lb
= 7.7 lb
= 7.7 × 0.45359237 kg
= 3.492 kg


2) Calculate the dose of Garamycin in milligrams, using the prescribed dose of 4 mg/kg and the patient's weight in kilograms. To do this, simply multiply the dose per kilogram by the weight in kilograms. For example:


4 mg/kg × 3.492 kg = 13.968 mg


3) Calculate the volume of Garamycin in milliliters, using the reconstituted dosage of 20 mg/10 mL and the dose in milligrams. To do this, use a proportion to find the unknown volume that corresponds to the known dose. For example:


20 mg / 10 mL = 13.968 mg / x mL Cross-multiply and solve for x: 20x = 139.68
 
x = 6.984 mL
x =7 mL
 


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Related Questions

Correct Answer is C

Explanation

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.

Correct Answer is C

Explanation

The nurse should add 250 mL of water to the formula to dilute it to half strength.

This answer is correct because it is based on a simple ratio and proportion calculation. The nurse can set up a proportion as follows:

250 mL / 1 = x mL / 0.5

Cross-multiplying and solving for x gives:

x = 500 mL

Therefore, the nurse should add 250 mL of water to the formula to make a total volume of 500 mL, which is half the concentration of the original formula.

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