A physician ordered IV insulin 3 Unit/Hour. The solution contains 50 units of insulin in 100 ml of dextrose. How many ml of solution should be infused per hour?

1. A

   3 ml

2. B

   6 ml

3. C

   12 ml

4. D

   30 ml

Appeared in: AIIMS Rishikesh NO - 2019

Explanation

• The correct infusion rate is 6 ml/hr, which is calculated to deliver the prescribed 3 Units of insulin per hour.
• The available solution has a concentration of 50 Units of insulin in 100 ml of dextrose.
• This concentration simplifies to 0.5 Units of insulin per 1 ml of solution (50 Units ÷ 100 ml).
• To deliver the desired 3 Units, the required volume is 6 ml (3 Units ÷ 0.5 Units/ml).
• The calculation using the standard formula is: (Desired Dose: 3 U/hr ÷ Available Dose: 50 U) × Volume: 100 ml = 6 ml/hr.

Why Other Options Were Wrong

• Option A: Infusing at 3 ml/hr would only deliver 1.5 Units of insulin per hour, which is half the prescribed therapeutic dose.
• Option C: Infusing at 12 ml/hr would deliver 6 Units of insulin per hour, which is double the prescribed dose and significantly increases the risk of severe hypoglycemia.
• Option D: Infusing at 30 ml/hr would deliver 15 Units of insulin per hour, a dangerous overdose that could lead to life-threatening hypoglycemia.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain IV infusion rate calculation for a high-alert medication (insulin) as background academic context rather than a clinical decision trigger.
• Insulin is a high-alert medication due to the high risk of significant patient harm if administered incorrectly. Dosage calculations must be precise and double-checked.
• All IV insulin infusions must be administered via an infusion pump to ensure accurate and controlled delivery, preventing accidental boluses that can cause severe hypoglycemia.
• Nursing protocol in most facilities requires an independent double-check of all high-alert medication calculations, including insulin, by a second qualified nurse before administration begins.

How to Approach the Question

• First, identify the key pieces of information provided: the desired dose (3 Units/hr), the available dose concentration (50 Units in 100 ml).
• Recognize this as an analytical, rate calculation problem for a continuous IV infusion.
• Select the appropriate dosage calculation formula: (Desired Dose / Available Dose) × Total Volume.
• Substitute the values into the formula: (3 U/hr / 50 U) × 100 ml.
• Perform the calculation: 0.06 × 100 ml = 6 ml/hr.
• Alternatively, first calculate the concentration per ml (50 U / 100 ml = 0.5 U/ml), then divide the desired dose by the concentration (3 U / 0.5 U/ml = 6 ml) to find the required volume per hour.

Concept Tested & Keywords

• Concept Tested: IV infusion rate calculation for a high-alert medication (insulin).
• Stem keywords: IV insulin, 3 Unit/Hour, 50 units, 100 ml, infuse per hour
• Lead-in keywords: How many ml
• Clinical cues: IV insulin: Indicates a high-alert medication requiring precise calculation.
• Clinical cues: Unit/Hour: Specifies a continuous infusion rate, not a one-time bolus.

Question ID

Q3hxV-I9Ox89OK0OTdgKmj

Copy ID

Reference Book

E6 Pharmacology Nurses Shanbhag 3e p. 54-56

E6 Nursing Fundamentals Potter Perry 12e Part 3 p. 170-172