Presentation on theme: "Metric Conversions, Roman Numerals, and Fractions"— Presentation transcript:
1 Metric Conversions, Roman Numerals, and Fractions
2 IntroductionPharmacy measurements come from different regions of the worldThe four most common types of calculation systems are:Metric systemHousehold measurementsApothecary systemAvoirdupois systemThe avoirdupois (AH-vair-duh-PWAH) system is actually the name of one type of weights in the English (or British Imperial) system of weights and measures.
3 Metric System Used throughout pharmacy because of its accuracy Metric units include:Milliliters, cubic centimeters, and liters for volumeKilograms, grams, milligrams, and micrograms for weightMillimeters and meters for distanceIn what fields is the metric system commonly used in the United States?The metric system is the standard for use in laboratories and in scientific publications.The formal name for the metric system is SI, which is the abbreviation for Systèm International d’Unités.Is the United States ever going to switch to SI?Federal agencies are now required to use the metric system. Private industries are now voluntarily converting (for example, nuts and bolts in automobiles) to be more competitive internationally.
4 Metric System (Continued) There is a 1000-unit difference between each measurementMost Common Metric Measurementskg______g________mg________mcg1000x x x
5 Metric System (Continued) The use of millimeters is reserved for drug calculations based on body surface areasKnowing the basics for volume and weight conversions is adequateWhat types of drugs might require body surface calculations?Topical preparations such as creams and ointments might require an estimate of body surface area.
6 Writing Units Using Each System (Continued) Metric measurementscc and ml can be used interchangeablyDry weights use mcg, mg, g, and kgLiquid volumes use ml and L
7 Household Measurements The most common measurement system still used in the United States is the household systemMeasurements come in a variety of unitsVolume refers to liquidsWeight refers to dry ingredientsLength refers to distanceMost common measurement is the teaspoonThe U.S. Customary System is the official name for the system of household measurements. It’s also a subset of the English/Imperial system.
8 Common Household Measurements Household Measurements Metric (Volume) (Volume) Household1 teaspoon 5 ml or cc* 1 teaspoon1 tablespoon 15 ml or cc 3 teaspoons1 cup 240 ml or cc 8 ounces1 pint 480 ml or cc 2 cups1 quart 960 ml or cc 4 cups1 gallon 3840 ml or cc 16 cups or 3.84 L*Remember that 1 ml and 1 cc contain the same amount of liquid.
9 Oral cups show equivalent volumes between household to metric and household to apothecary.
10 Conversions Metric system slide When converting metric measurements from one unit to another you need to move the decimal either to the right or to the leftAll changes of the metric system involve either dividing or multiplying by tensEach unit is a multiple of 1000Remember the difference between 1 kg, 1 g, 1 mg, and 1 mcg is 1000What are the base metric units for mass, volume, and length?The base units are the words without any prefixes: grams for mass, liters for liquid, and meters for length.
11 Conversions (Continued) Method for determining metric conversionsLeft RightLargest Smallest1________1_______1_________ kg g ,000,000 mg 1,000,000,000mcg
12 Conversions (Continued) Decimals are not placed at the end of a number unless there is a fraction, such as 1.1 kgDecimals and periods have been the main source of mistakes in pharmacies
13 Determining WeightBecause all manufacturers provide proper dosing regimens based on kilograms, it is necessary to convert pounds into kilogramsThere are 2.2 pounds per kilogram16 ounces = 1 lb 2.2 pounds = 1 kgTo determine how many kg in 1 lb, divideTo determine how many lbs in 1 kg, multiplyA way to remember the pounds to kilogram conversion is that you “lose weight” when going from pounds to kilograms. For example, a 220-pound person weighs 100 kilograms.
14 Determining Length Metric Household/English 1 meter in / ft0.914 meter3 feet / 1 yardmeters12 inches / foot2.54 cm1 inch
15 Roman NumeralsThe number system commonly used in the United States is the Arabic system, consisting of numbers 1, 2, 3, and so forthMany physicians use Roman numerals to indicate the quantity of tablets or capsules to be filled or to order the strength of medicationWhat is the current year in Roman numerals?2006 = MMVI2007 = MMVII2008 = MMVIII
16 Roman Numerals (Continued) When working with Roman numerals, remember that if a larger number is placed in front of a smaller one, you must add both to determine the valueHowever, if a smaller number is placed before a larger number, then you must subtractRemember that you can only place a letter for the next power of 10 “size down” to the left of a letter.For example, you can’t take the shortcuts IC for 99 or VC for 95 because I (1) and V (5) are more than one power of 10 smaller than C (100).
18 Roman Numeral Practice XIV =XC =CIV =XL =VIII =C =IV =
19 Military TimeIn hospital settings, international time, also known as military time, is used exclusivelyOrders are written 24 hours a day and all medical-related caretakers must understand exactly when the order was written and when the medication or treatment is to take place
20 Military Time (Cont’d) The system is based on 100Starting with the first hour of the day, the clock begins at 0100 (1 AM) through 2400 or 12 midnightBy using this system there is never any question as to when an order was written or which order came firstNever use a colonDo not use a colon to separate hours and minutes.It might seem redundant and confusing, but a slight distinction can be made between 2400 and The end of a day is 2400, and the beginning of the next day is considered 0000.
22 Question #1A mother was told to give her 3 year old a ¼ cup of water every 4 hours. In 24 hours she will give the child ___ A. 6 fluid ounces B. 8 fluid ounces C. 10 fluid ounces D. 12 fluid ounces
23 Answer #1D – 12 fluid ounces 24 hours / every 4 hours = 6 doses 6 doses x ¼ c = 1 ½ cups total 1 c = 8 oz 1.5c x 8 oz = 12 fluid ounces
24 Question #2You assist a patient in wrapping an ace bandage around the leg. You use 30 cm. of ace bandage. How many inches did you use? A. 12 inches B. 75 inches C inches D inches
25 Answer #2A = 12 inches 1 inch = 2.54 cm 30 cm / 2.54 = inches
26 Question #3How many days will an 8-ounce bottle of medication last, if an adult takes the maximum dose of 2 tsp. every 8 hours?A. 8 daysB. 10 daysC. 15 daysD. 30 days
27 Answer #3 A – 8 days 1 oz = 30 ml, 5 ml = 1 tsp 8 oz x 30ml = 240 ml 240 ml / 5 ml = 48 tsp in the bottle48 tsp in bottle / 2 tsp dose = 24 dosesDose every 8 hours / 24 hrs in a day = 3 doses per day24 doses / 3 doses per day = 8 days
28 Question #4The doctor ordered 0.25 g. of a medication for the patient. The medication comes in 125 mg per 5 cc's. You should give _____. A. 2½ cc B. 5 cc C. 7½ cc D. 10 cc
29 Answer #4D = 10cc 1g = 1000mg 0.25g x 1000mg = 250mg 250mg / 125mg = 2mg 5cc’s per every 125mg 2mg x 5cc’s = 10cc
30 Question #5A medical records clerk is asked to collect records regarding cancer patients. It is found that a ¼ of the records relate to breast cancer. There are a total of 20,920 records. How many are related to breast cancer? A. 83,680 B. 10,460 C. 5,230 D. 2,660
36 Question #8You are to use a needle, 3 inches long, to give an injection. How many mm. is this? A. 7.5 mm. B mm. C mm. D mm.
37 Answer #8C = 75.0 mm 1 cm = 10 mm 3in x 2.54 cm = 7.62 cm 7.62 cm x 10mm = 76.2mm * A 75mm needle is a standard size*
38 Question #9Marjorie has joined Weight Watchers. She would like to lose 12 kg in 30 days. On the average, how many pounds per day will Marjorie lose to meet her goal? A lbs. B lbs. C. 1.1 lbs. D. 2.5 lbs.