## Bonus free practice exam #2 question #10 setup

by Jonn

(Willoughby, Ohio )

Can you show how to get the answer to this one?

Reply (Keith): Sure, Here it is:

An IV Drip is ordered to run at 4 gtt/min. It contains 875 mg of a drug in a 250 ml solution. How many mg will the patient receive per hour if the infusion set is calibrated to deliver 12 gtt/ml?

a. 0.70mg/hr

b. 16mg/hr

c. 70mg/hr

d. 160mg/hr

So,

**1. How many mL per Min.?**

12 gtt/mL means that it takes 12 drops to equal 1mL.

4 gtt/min is how many drops will fall every min.

12 Divided by 4 = 3

So that's **= 1mL every 3 minutes**

(right?, since also 4 times 3 equals 12)

**2. How much drug per mL?**

875mg drug divided by 250mL **= 3.5mg/mL**

**3. How many mL per Hr.**

and 60 minutes (one hour) divided by 3 = 20

since **one mL will drop 20 times per hour**

(or every 3 minutes)

**4. Add it all up.**

Then **20 X 3.5mg/mL = 70mg/hr**

This infusion device math is kind of confusing at first. Sometimes drawing a circle (representing a minute) and then drawing little drops in it helps to visualize it. I know that sounds a little silly, but it works for lots of people.