ati dosage calculation practice questions

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18-03-2025

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ATI Dosage Calculation Practice Questions: A Comprehensive Guide

Dosage calculation is a critical skill for nurses and healthcare professionals. Accuracy is paramount, as even minor errors can have severe consequences for patients. The ATI (Assessment Technologies Institute) provides valuable resources for nursing students, including practice questions to hone dosage calculation skills. This article presents a range of ATI-style dosage calculation practice questions, covering various medication forms and calculation methods. Each question includes a detailed solution, emphasizing the step-by-step process to ensure understanding. Mastering these concepts is essential for safe and effective medication administration.

Before We Begin: Essential Concepts

Before tackling the practice questions, let's review some fundamental concepts:

• Units of Measurement: Familiarize yourself with common units like milligrams (mg), grams (g), kilograms (kg), liters (L), milliliters (mL), micrograms (mcg), and ounces (oz). Understanding conversions between these units is crucial.

• Medication Labels: Learn to interpret medication labels accurately. Pay close attention to the medication name, dosage strength, dosage form, total volume, and any specific instructions.

• Order Interpretation: Physician orders must be interpreted precisely. Identify the medication name, dosage, route, frequency, and any special instructions.

• Calculation Methods: Several methods exist for dosage calculation, including ratio and proportion, dimensional analysis (factor-label method), and formula methods. Choose the method you find most comfortable and consistently apply it.

• Rounding: Follow specific guidelines for rounding dosages. Always check your institution's policy on rounding, as variations exist.

Practice Questions:

Question 1:

A physician orders 250 mg of acetaminophen for a patient. The available medication is acetaminophen 500 mg tablets. How many tablets should be administered?

Solution:

This is a simple ratio problem.

• Desired dose: 250 mg
• Available dose: 500 mg/tablet

(250 mg / 500 mg/tablet) = 0.5 tablets

Answer: Administer ½ tablet of acetaminophen.

Question 2:

The physician orders 10 mg/kg of morphine sulfate intravenously for a 70 kg patient. The available medication is morphine sulfate 2 mg/mL. How many mL should be administered?

Solution:

1. Calculate the total dose: 10 mg/kg * 70 kg = 700 mg

2. Use ratio and proportion:

   • 2 mg : 1 mL = 700 mg : x mL

   • x = (700 mg * 1 mL) / 2 mg = 350 mL

Answer: Administer 350 mL of morphine sulfate.

Question 3:

A patient is to receive 0.5 g of medication. The medication is available as 250 mg tablets. How many tablets should be administered?

Solution:

First, convert grams to milligrams: 0.5 g * 1000 mg/g = 500 mg

Then, calculate the number of tablets:

• Desired dose: 500 mg
• Available dose: 250 mg/tablet

(500 mg / 250 mg/tablet) = 2 tablets

Answer: Administer 2 tablets.

Question 4:

A physician orders 500 mcg of digoxin. The available medication is digoxin 0.25 mg/mL. How many mL should be administered?

Solution:

First, convert mcg to mg: 500 mcg * (1 mg/1000 mcg) = 0.5 mg

Then, use ratio and proportion:

• 0.25 mg : 1 mL = 0.5 mg : x mL

• x = (0.5 mg * 1 mL) / 0.25 mg = 2 mL

Answer: Administer 2 mL of digoxin.

Question 5:

A child weighing 30 lbs needs a medication at a dose of 10 mg/kg. The medication is available as a solution of 25 mg/5 mL. (Note: 1 kg ≈ 2.2 lbs)

Solution:

1. Convert pounds to kilograms: 30 lbs / 2.2 lbs/kg ≈ 13.6 kg

2. Calculate the total dose: 10 mg/kg * 13.6 kg = 136 mg

3. Use ratio and proportion:

   • 25 mg : 5 mL = 136 mg : x mL

   • x = (136 mg * 5 mL) / 25 mg ≈ 27.2 mL

Answer: Administer approximately 27.2 mL of the medication. Always double-check your calculations and refer to institutional rounding guidelines.

Question 6: (IV Infusion Rate)

A physician orders 1000 mL of normal saline to be infused over 8 hours. What is the infusion rate in mL/hour?

Solution:

1000 mL / 8 hours = 125 mL/hour

Answer: The infusion rate is 125 mL/hour.

Question 7: (IV Piggyback)

A physician orders 50 mL of an antibiotic to be infused over 30 minutes. What is the infusion rate in mL/minute?

Solution:

50 mL / 30 minutes ≈ 1.67 mL/minute

Answer: The infusion rate is approximately 1.67 mL/minute.

Question 8: (Medication Reconstitution)

A vial of medication contains a powder that needs to be reconstituted. The instructions state to add 10 mL of diluent to yield a final concentration of 100 mg/mL. What is the total dose in the reconstituted vial?

Solution:

10 mL * 100 mg/mL = 1000 mg

Answer: The reconstituted vial contains a total dose of 1000 mg.

Addressing Common Errors:

• Incorrect Unit Conversions: Carefully convert units before performing calculations. Double-check your work.

• Misinterpretation of Orders: Ensure you understand the physician's order before proceeding with calculations. Clarify any ambiguities.

• Calculation Mistakes: Use a calculator and double-check your calculations. Re-work problems using a different method to verify accuracy.

• Rounding Errors: Adhere to institutional rounding policies.

Conclusion:

Dosage calculations are a critical aspect of safe medication administration. Consistent practice is essential to develop proficiency. These practice questions offer a starting point for honing your skills. Remember to utilize available resources, such as ATI materials and textbooks, to further enhance your understanding. Always verify calculations with a colleague before administering medication to a patient. The safety of your patients depends on your accuracy and attention to detail. Seek additional practice questions and resources if needed to achieve mastery of this essential skill.