The physician ordered 15 units of Pitocin in 500 mL of D5W. It is to infuse at 2 milliunits/minute per infusion pump. What is the correct IV rate in milliliters per hour? Round to the nearest whole number.
A) 1
B) 2
C) 3
D) 4

Question

Quizplus · Accepted Answer

When solving any problem, first check that the order and the supply are in the same weight measure. For this problem, an equivalent is necessary. This is a multi-step problem. First, reduce the numbers in the standard solution to units per milliliter: 15 units/500 mL = 0.03 units/1 mL. Then, change units to milliunits: 0.03 units/mL *1000 = 30 milliunits/mL (1 unit = 1000 milliunits). Next, divide by 60 to get milliunits per minute: 30 milliunits/mL ÷ 60 minutes = 0.5 milliunits/minute. Round to the nearest whole number. Solve for milliliters per hour. Estimate the amount to give. Formula Method: 2 milliunits/minute ÷ 0.5 milliunits/minute *1 mL = 2/0.5 = 20/5 = 4 mL/hour. Proportion (Ratios): 1 mL : 0.5 milliunits :: x mL : 2 milliunits; 0.5x = 2/0.5 = 20/5 = 4 mL/hour. Proportion (Fractions): 1 mL/0.5 milliunits = x mL/2 milliunits; 0.5x = 2/0.5 = 20/5 = 4 mL/hour. Use two conversion factors for dimensional analysis. Dimensional Analysis: 500 mL/15 units * 2 milliunits/minute * 60 minutes/1 hour * 1 unit/1000 milliunits = 500 mL * 2 * 60 * 1/15 *1 hour * 1000 = 60,000/15,000 = 4 mL/hour.

The Physician Ordered 15 Units of Pitocin in 500 ML