PharmPrac7e-Chapter6-WLpresentation

[Audio] Welcome to the Pharmacy Practice for Technicians Seventh Edition presentation..

[Audio] Chapter Six: Pharmacy Measurements and Calculations.

[Audio] At the end of this chapter, you will be able to: Convert percentages to and from fractions and to and from decimals. Convert standard time to 24-hour time and temperatures to and from Fahrenheit and Celsius. Describe the different systems of measurement (avoirdupois, imperial, apothecary, household, and metric) that have been used in pharmacy. Convert from one metric unit to another..

[Audio] Section six point one: numerical systems.

[Audio] Two familiar numerical systems are used in pharmaceutical calculations: Arabic and Roman. Each serves as a kind of numerical abbreviation system for amounts. The Arabic numeral system includes numbers, fractions, and decimals that we use every day . In the Roman numeral system, numerical values are expressed in capital letters or lowercase letters. For example, a capital I or lowercase I equals one; a capital V or lowercase v equals five..

[Audio] Section six point two: Basic Mathematical Principles Used in Pharmacy Practice.

[Audio] When something is divided into parts, each part is considered a fraction of the whole. For example, a pie might be divided into eight slices—each one is a fraction or 1/8 of the whole pie. A simple fraction consists of two numbers: a numerator—the number on the top or the left of the fraction—and a denominator—the number on the bottom or the right of the fraction. The denominator represents the number of equal pieces the whole pie is broken into (eight, in the case of the pie) and the numerator represents the number of those pieces which are selected (one of the pieces)..

[Audio] A decimal is a number written out in proportion to fractions of "tenths" or multiples of ten. In a decimal, everything to the left of the decimal point is a whole number, and everything to the right is a portion of a whole number in powers of ten, such as three one-hundredths, which is zero point zero three. If a decimal number is less than one, place a zero before the decimal point, as in zero point three six. This zero is called a leading zero and is used to prevent confusion and potential medication errors when reading decimals. Any decimal number can be expressed as a fraction by using the appropriate power of ten as the denominator. To do this, remove the decimal point and use the resulting number as the numerator. Then count the number of places to the right of the decimal point in the original decimal number to designate the correct power of ten, with ten for one place, on hundred for two places, and so on..

[Audio] Section six point three: Figuring Ratio and Proportions.

[Audio] Ratios, proportions, and equations are perhaps the most frequently used mathematical equations in pharmacy practice. They are used in determining dosages and in compounding formulas. A ration is a way to demonstrate how two amounts of similar elements compare to each other in a whole. Two ratios that have the same value when simplified are different ways of saying the same. They are called equivalent ratios. A pair of equivalent ratios together is called a proportion..

[Audio] Section six point four: Systems for Measuring Time and Temperature.

[Audio] In the hospital setting, medication orders are commonly written with a 24-hour clock rather than the common 12-hour clock based on Greenwich mean time. Because medical care is around the clock, dosage administration schedules consider that 0000 is midnight and noon is the 1200 hour. The first two digits are the time in hours, and the second two digits are the time in minutes. The 24-hour clock, which is also known as military time, creates less confusion in pharmacies, hospitals, and other healthcare facilities because there is no need for a.m. or p.m..

[Audio] To switch from the 12-hour to the 24-hour clock, cut the 12 in 12:00 a.m. to 00 and start counting minutes and hours from there, dropping the colon and the a.m. or p.m. After 12:59 p.m., just add 1200 to the 12-hour time until you get to 2359 and then start over. To convert military time to regular time, simply take the time after midnight (or 0000) and substitute the first 00s with 12, adding a colon and a.m. up until 0059 military. From 0100 to 1259, simply add the colon and a.m. after the first two numbers and the p.m. from 1201 to 1259. From 1300 on, subtract 1200, adding the colon and the p.m. at the end..

[Audio] To convert military time to regular time, simply take the time after midnight (or 0000) and substitute the first 00s with 12, adding a colon and a.m. up until 0059 military. From 0100 to 1259, simply add the colon and a.m. after the first two numbers and the p.m. from 1201 to 1259. From 1300 on, subtract 1200, adding the colon and the p.m. at the end..

[Audio] The Fahrenheit temperature scale assigns 32°F as the temperature at which water freezes to ice and 212°F as the temperature at which water boils, with the difference between these two extremes of 180°F. In contrast, the Celsius temperature scale designates the freezing point of pure water at sea level to be zero degrees (0°C), the boiling point to be 100°C, and all things to be measured in 100 equal increments within that temperature span, and in equal increments above and below it. Celsius is the scale generally used in pharmacy and medicine. Many thermometers show both Celsius and Fahrenheit..

[Audio] As a pharmacy technician, you must be able to perform conversions between the Celsius and the Fahrenheit scales. To convert from Fahrenheit to Celsius, use this equation: The temperature in Fahrenheit minus thirty-two, divided by one point eight equals the temperature in Celsius. To convert from Celsius to Fahrenheit, use this equation: The temperature in Celsius times one point eight, plus thirty-two equals the temperature in Fahrenheit.

[Audio] Section six point five: Traditional Systems for Measuring Distance, Weight, and Volume.

[Audio] Three common measurement systems used to be applied in pharmacy: the avoirdupois system, which originated in France, is used widely in the U-S, and includes measurements like twelve inches equals one foot and three feet equals one yard, the apothecary system, based on the Roman systems of weight and includes measurements like grains, pounds, ounces, and fluid drams. and the household system, which was based on the apothecary system and includes measurements like drop, teaspoon, tablespoon, and cup. Sometimes, these systems have overlapping measurements. For example, both the avoirdupois and apothecary systems include a grain as a unit of measure. However, because of safety issues, these systems have all been replaced in the modern era of pharmacy by the more scientific and universal metric system..

[Audio] Section six point six: Pharmaceutical Measuring: The Metric System.

[Audio] The metric system is based on multiples of ten, one hundred, and one thousand. Three basic units in the metric system are the meter, measuring length and cubic volume; liter, measuring fluid volume; and gram, measuring mass and weight..

[Audio] The metric system has several distinct advantages over other measurement systems. It contains clear proportional correlations among the differing units of measurement of length, volume, and weight, which simplifies calculations. It is based on decimal notation in which units are described as multiples of 10, making calculations easier. And, with slight variations in notation, the metric system is used worldwide, especially in scientific measurement, and therefore, can be considered a "universal language.".

[Audio] Section six point seven: Converting Other Systems to Metrics.

[Audio] Due to safety reasons, the avoirdupois and apothecary systems have been almost completely phased out. However, occasionally home dosage or medication orders are written in the household system. To convert any other system to metrics, first convert the units into decimals, and then apply the conversion amounts as noted..

[Audio] This concludes the Pharmacy Practice for Technicians Seventh Edition presentation for Chapter Six..