Dosage Calculations
for
EMS Providers (Part 1)
Ray Taylor
Valencia Community College
Department of Emergency Medical Services
Intravenous Infusion Calculations
• Formula
– Volume to be Infused x Administrative Set (10, 15, 60,
etc) Divided by Time in Minutes
– Practice Example
• Order: 2500ml of Lactated Ringers IV in 24 hours
• Drop Factor: 15gtts/ml
• Formula: 2500ml x 15 = 26gtts/min
1440min
* Complete Practice Problems 1-14 Page 1 of Dosage
Calculations Section
Dosage Calculations
• Units of Measurements
– Apothecary
– Household
– Metric
• Most common method used in clinical medicine
Dosage Calculations
• Metric System Fundamental Units
– Grams = Mass
– Liters = Volume
– Meters = Distance
Dosage Calculations
• Common units of conversion
– Grams to milligrams (x 1000)
– Milligrams to grams (divide 1000)
– Milligrams to micrograms (x 1000)
– Micrograms to milligrams (divide 1000)
• Grains to milligrams (x 60)
• Milligrams to grains (divide 60)
Dosage Calculations
• Common units of conversion
– Liters to milliliters (x 1000)
– Milliliters to liters (divide 1000)
– 1 milliliter = 1 cubic centimeter (consider
equivalent)
• 1ml of water occupies 1cc of space
Dosage Calculations
• Pounds (lb) to Kilograms (kg)
– Formula
• Patient’s weight in pounds divided by 2.2
• Example
– 150lb patient divided by 2.2 = 68kg
*Assignment: Complete practice problems on pages 3-5 in
the dosage calculations workbook
Dosage Calculations
for
EMS Providers (Part 2)
Ray Taylor
Valencia Community College
Department of Emergency Medical Services
Dosage Calculations
• Master Formula
– Desired Dose divided by the concentration on
hand x Vehicle
or
Order divided by the supply x Vehicle
Vehicle is the volume of liquid in which the
supply is contained
Dosage Calculations
• Master Formula
– Example 1 (page 7 in workbook)
• Order: 30mg Demerol IM
• Supply: Demerol 50mg/ml
• Step 1: Evaluate order and supply
Ensure same unit measurement
• 30mg = 0.6ml
50mg/ml
Dosage Calculations
• Master Formula
– Example 2 (page 7 in workbook)
• Order: Streptomycin 250mg IM
• Supply: 0.5gm/2ml
• Step 1: Evaluate order and supply
– Order in mg and supply in gm
– Always convert supply to same unit of measurement as the
order
» 0.5 gm x 1000 = 500mg/2ml
• Calculate
– Order = 250mg x 2ml = 1ml
500mg
Dosage Calculations
• Examples
– Order: Kantrex 150mg IM
– Supply: Kantrex 0.5gm/2ml
– Order: Sodium phenobarbital 100mg IM
– Supply: Sodium phenobarbital 125mg/2ml
Dosage Calculations
• Assignment
– Complete the practice problems on pages 7 –
16 in the dosage calculations worksheets