DRUG CALCULATIONS

Question 0

What is the drop factor for:
•blood tubing

• adult tubing
• pediatric tubing

Answer 0

• blood “macro” tubing = 10 drops per mL
• adult “regular” tubing = varies(10,15,20 drops per mL)
• pediatric “micro” tubing = 60 drops per mL

Question 1

How many mcg per mg?

How many mg per gram?

How many pounds per kg?

How many mL per liter?

Answer 1

• 1,000mcg per mg
• 1,000mg per gram
• 2.2lbs per kg
• 1,000mL per liter

Question 2

What is the formula for calculating a bolus medication?

Answer 2

Volume x Dose/concentration = mL needed

Ex. give 3mg of Valium
Packing is 10mg/2mL

(2 x 3)/10 = 0.6mL

Question 3

What is the formula for calculating a plain IV infusion rate?

Answer 3

Ordered Volume x Drop Factor/Minutes = drops per minute

Ex. 100mL per hour with 10 drop tubing

(100 x 10)/60 = 17 drops per minute

Question 4

What is the formula for calculating an IV medication infusion?

Answer 4

Volume x Dose x Drop Factor/Concentration x Minutes = drops per minute

Ex. give 5mcg/kg/min of dopamine(90kg patient)
Pkg: 400mg in 250mL

(250 x .450 x 60)/(400 x 1) = 17 drops per minute

Volume= 250mL
Dose= 450mcg(5 x 90)
Tubing= 60(peds)
Concentration= 400mg
Minutes= 1

Question 5

What are the shortcuts for plain IV flow rate calculations?

Answer 5

-As long as the order is over an hour, divide it by:
•6 for blood tubing
•4 for adult(15gtts) tubing
•1 for Peds tubing

Ex.
•Blood tubing
100mL per hour = 100 / 6 = 17 drops/min
•Adult tubing 
100mL per hour = 100 / 4 = 25 drops/min
•Peds tubing
100mL per hour = 100 / 1 = 100 drops/min