Dosage Calculation Complete: The Practice Test

dosage Calculationcomplete The Dosage Calculation Practice Test To

Complete the dosage calculation practice test. To best prepare yourself for the dosage calculation test, only allow yourself to use a pencil and calculator. You will have 30 minutes to complete 10 questions for the actual dosage calculation test. You do not need to turn in the dosage calculation test. This is for you to practice.

1. A physician ordered Magnesium Sulfate bolus 4 grams in 100 MLS of LR to be given over 20 minutes. What rate should the nurse set the infusion pump at?

2. Your patient Zachary weighs 6 kg. He has prescribed rifampin 75 mg per nasogastric tube. You have rifampin 20 mg/mL suspension. How many mL will you give via the nasogastric tube? Round to the nearest 10th.

3. A Physician ordered Magnesium Sulfate 40 grams in 1,000mL of LR at a rate of 2g/hour for a woman in preterm labor. What rate should the infusion pump be set at? It should be a whole number.

4. Betony is a 2 ½-year-old who is newly diagnosed with HIV infection. She is to be started on Retroviral 120 mg by mouth every 12 hours. She weighs 13 kg and is 90 cm long. A. Using the formula for BSA calculate her body surface area: BSA (m²) = Ht (cm) X Wt. (kg) / 3600 B. Retroviral is prescribed on an individual basis ranging from 180 to 240 mg/m² per dose every 12 hours. It comes in a concentration of 10 mg/mL. Is her dose of 120 mg within the acceptable range? How many mL will you administer?

5. Your patient Nicole is admitted with sepsis and you have an order for meperidine 29 mg intramuscular. A vial comes up Meperidine 100mg/mL. How many mL will you give? Round to the nearest 100th.

6. Your post-op patient has fentanyl 42 mcg intramuscular ordered. The vial you have is 250 mcg/mL. How much will you give? Round to the nearest 100th.

7. Your patient weighs 21 lbs. She has captopril 3 mg PO QD ordered. The safe range is 0.3 to 0.5 mg /kg/day. You have a Captopril solution 1mg/mL on hand. Is this dose within the safe dose range and if so how many MLS would you administer? Round to a whole number.

8. Your 5-year-old post-op patient is having pain. The doctor wants to order fentanyl and ask for the safe dose range. Your patient weighs 53 lbs. The safe range for fentanyl is 1-2 mcg/kg. What would be a safe dose for this patient? The doctor wants to order 42 mcg, is this within the safe dose? You have an ampule that contains 50mcg/mL. How many MLS would you administer IV? Round to the 100th place.

9. Your patient has metoclopramide 0.68 mg PO. You have metoclopramide syrup in a concentration of 5 mg/5 mL. How many MLS will you administer? Round to the nearest 100th.

10. You have oral Lasix 10 mg/mL. The prescribed dose is 25 mg PO once daily. The patient weighs 9.5 kg. The safe range for this medication is 1 to 6 mg/kg/day. How many MLS will you administer? Round to the nearest 10th.

Paper For Above instruction

Introduction

Dosage calculation is an essential skill for nurses and healthcare professionals to ensure the safe and effective administration of medications. Accurate calculations prevent medication errors and are critical for patient safety. This paper addresses ten practice problems encompassing various concepts such as infusion rates, dosage conversions, body surface area calculations, and safe dosing ranges, providing comprehensive examples to reinforce understanding and proficiency in dosage calculations.

Question 1: Magnesium Sulfate Bolus Rate Calculation

The physician ordered 4 grams of Magnesium Sulfate to be infused in 100 mL of Lactated Ringer's (LR) over a period of 20 minutes. To determine the infusion rate, first consider the total volume to be infused and the time duration. The infusion rate in mL per minute is calculated as:

Rate = Total volume / Time in minutes = 100 mL / 20 minutes = 5 mL/min.

Thus, the nurse should set the infusion pump at 5 mL per minute to deliver the magnesium sulfate as ordered.

Question 2: Rifampin Dose Calculation

Patient Zachary weighs 6 kg and requires 75 mg of rifampin via nasogastric tube. The suspension available is 20 mg/mL. The volume to be administered is calculated as:

Volume = Dose / Concentration = 75 mg / 20 mg/mL = 3.75 mL.

Rounding to the nearest tenth, the nurse should administer 3.8 mL via the nasogastric tube.

Question 3: Magnesium Sulfate Infusion Rate

The order is for 40 grams of Magnesium Sulfate in 1,000 mL of LR to be infused at 2 g/hour. The infusion rate in mL per hour is calculated as:

Rate = (Dose in grams per hour) / Concentration per mL = 2 g / (40 g / 1000 mL) = 2 g / (0.04 g/mL) = 50 mL/hour.

Hence, set the infusion pump at 50 mL/hour to deliver the magnesium sulfate appropriately.

Question 4: BSA and Dose Range for Retroviral

Betony's height is 90 cm, and her weight is 13 kg. Calculate her body surface area (BSA):

BSA = (Ht in cm x Wt in kg) / 3600 = (90 x 13) / 3600 = 1170 / 3600 ≈ 0.325 m².

The prescribed dose is 120 mg every 12 hours. The maximum and minimum doses based on BSA are:

Minimum: 180 mg/m² x 0.325 m² ≈ 58.5 mg

Maximum: 240 mg/m² x 0.325 m² ≈ 78 mg

Since 120 mg exceeds the maximum calculated dose, it is above the recommended range. Therefore, administering 120 mg would be considered unsafe based on the BSA calculation.

Question 5: Meperidine Dose Calculation

The order is for 29 mg IM, and the vial contains 100 mg/mL. The volume to administer is:

Volume = Dose / Concentration = 29 mg / 100 mg/mL = 0.29 mL.

Rounded to the nearest hundredth, the nurse should administer 0.29 mL.

Question 6: Fentanyl Dose Calculation

The ordered dose is 42 mcg IM, with a vial concentration of 250 mcg/mL. The volume to give is:

Volume = Dose / Concentration = 42 mcg / 250 mcg/mL = 0.168 mL.

Rounding to the nearest hundredth, administer 0.17 mL.

Question 7: Captopril Dose Calculation and Safety Range

Patient weighs 21 lbs, which equals approximately 9.5 kg (since 1 lb = 0.453592 kg). The prescribed dose is 3 mg PO daily. The safe dose range is 0.3 to 0.5 mg/kg/day, so:

Minimum safe dose: 0.3 mg/kg x 9.5 kg = 2.85 mg

Maximum safe dose: 0.5 mg/kg x 9.5 kg = 4.75 mg

The ordered dose of 3 mg falls within this safe range. The required volume of the solution is:

Volume = Dose / Concentration = 3 mg / 1 mg/mL = 3 mL.

Next, verify if the dose is within the safe range, which it is. Hence, 3 mL is administered.

Question 8: Fentanyl Safe Dose Range and Administration

The patient weighs 53 lbs (~24.05 kg). The safe dose for fentanyl is 1-2 mcg/kg:

Minimum: 1 mcg/kg x 24.05 kg ≈ 24.05 mcg

Maximum: 2 mcg/kg x 24.05 kg ≈ 48.1 mcg

The ordered dose is 42 mcg, which is within this range. The volume to administer from a 50 mcg/mL ampule:

Volume = Dose / Concentration = 42 mcg / 50 mcg/mL = 0.84 mL.

Rounded to the hundredth, the nurse administers 0.84 mL IV.

Question 9: Metoclopramide Dose Calculation

The prescribed dose is 0.68 mg PO, and the syrup concentration is 5 mg/5 mL, which simplifies to 1 mg/mL. The volume to give:

Volume = Dose / Concentration = 0.68 mg / 1 mg/mL = 0.68 mL.

Rounded to the hundredth, administer 0.68 mL.

Question 10: Lasix Dose Calculation

The ordered dose is 25 mg PO. The concentration is 10 mg/mL, and the patient's weight is 9.5 kg. The safe dose range is 1-6 mg/kg/day, so:

Minimum dose: 1 mg/kg x 9.5 kg = 9.5 mg

Maximum dose: 6 mg/kg x 9.5 kg = 57 mg

The prescribed dose of 25 mg falls within the safe range. The volume to administer:

Volume = 25 mg / 10 mg/mL = 2.5 mL.

Rounded to the nearest tenth, administer 2.5 mL.

Conclusion

Accurate dosage calculation remains vital for patient safety, preventing medication errors, and ensuring therapeutic effectiveness. This practice set provides comprehensive exercises to develop and reinforce the necessary skills for healthcare practitioners. Mastery of these calculations fosters confidence and competence in administering medications responsibly and accurately.

References

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