MEDICAL MATH

SR DHO 19:8J.J. Nelson RN

•Objectives

Interpret roman numerals

Calculate Dosage/kg

Convert Household measurements

OBJ. 1

Calculate military time (24 hour clock)OBJ. 2

OBJ 5

OBJ. 3

OBJ. 4

Convert Metric measurements

•ROMAN NUMERALS

Used when writing prescriptions and used on drug orders

ASSIGNMENT: WB Page 401

•MILITARY TIME

Uses a 24 hour clock. Remember to record without colons.

EXAMPLE: 2:15 in the afternoon is recorded as 1415

Play the game: http://www.oswego.org/ocsd-web/games/StopTheClock/sthecR.html

•Military Clock

•METRIC SYSTEM

The Basics:The Metric System Basic units of measure:

• meter = Linear• liter = volume • gram = weight (mass)

Each unit is subdivided in units of 10 by moving the decimal point.

• Metric system is based on the power of ten

KILO – 1,000 times greater than base unitHecto – is 100 times greater than base unitDeka – is 10 times greater than base unitBASE UNIT - is the gram, liter or meterDeci – a 10th of the base unitCenti – is a hundredth of base unitMILLI – 1,000 thsof thebase unitMICRO – 1,000,000th of base unit

SO…………… 1 kg = 1000 mg, 1 mg = 1000 mcg,1 kg = 1,000,000 mcg

SO…..If the base unitis a meter…..use thisMnemonic device.

ASSIGNMENT: WB Page 402-403

•Pounds to Kilograms

All weights will be in kg. To convert a patients weight from pounds to kilograms divide the pounds by 2.2 = kg

Example: Pt wt is 220 pounds ÷ 2.2 =100 kg

16 oz = 1 lb1 kg = 2.2 lbs

•Here is why you need to know:

1. Infant is 26 weeks

3. How much gentamicin will you give?

2. Infant weight is 2 lbs 8 oz

CALCUATION:2.2mg/kg Q24H2.5 pounds ÷ 2.2 =1.14 kg1.14 kg x 2.5 mg = 2.85 mg Q24H

Another reason you need to know:

Dr. Smith orders you to give your 198 pound patient dopamine at a dose of 5 mcg/kg. Since we know that it is a “weight based” drug, we first need to figure out the weight in kg.

CALCUATE: 198 pounds ÷ 2.2 = 90 kg.The drug dosage is 5 mcg/kg.This means that for every one kg of patient body weight, we will give 5 mcg of drug.Therefore 90 x 5 mcg = 450 mcg. The desired dose then is finalized at 450 mcg.

•Remember these equivalents.

Weight:60 mg = 1 gr60 gr = 1 dram8 drams = 1 ounce

Volume15 gtts = 1 mL 5 mL = 1 tsp4 mL = 1 dram30 mL = 1 ounce500 mL = 1 pint1000 mL = 1 quart

ASSIGNMENT: WB Page 404-405