Dosage Calculations for EMS Providers Part 1 Ray

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: 2500 ml of Lactated Ringers IV in 24 hours • Drop Factor: 15 gtts/ml • Formula: 2500 ml x 15 = 26 gtts/min 1440 min * 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) • 1 ml of water occupies 1 cc of space

Dosage Calculations • Pounds (lb) to Kilograms (kg) – Formula • Patient’s weight in pounds divided by 2. 2 • Example – 150 lb patient divided by 2. 2 = 68 kg *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 is the volume of liquid in which the supply is contained

Dosage Calculations • Master Formula – Example 1 (page 7 in workbook) • Order: 30 mg Demerol IM • Supply: Demerol 50 mg/ml • Step 1: Evaluate order and supply Ensure same unit measurement • 30 mg = 0. 6 ml 50 mg/ml

Dosage Calculations • Master Formula – Example 2 (page 7 in workbook) • Order: Streptomycin 250 mg IM • Supply: 0. 5 gm/2 ml • 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 = 500 mg/2 ml • Calculate – Order = 250 mg x 2 ml = 1 ml 500 mg

Dosage Calculations • Examples – Order: Kantrex 150 mg IM – Supply: Kantrex 0. 5 gm/2 ml – Order: Sodium phenobarbital 100 mg IM – Supply: Sodium phenobarbital 125 mg/2 ml

Dosage Calculations • Assignment – Complete the practice problems on pages 7 – 16 in the dosage calculations worksheets