Dimensional Analysis for Meds Chapter 4

Chapter 4 Metric, International (SI) System You do not need to know all of the System! Much easier than English System All units of measure differ from teach other in powers of ten (10). Conversions between units in the system are accomplished by simply moving the decimal point.

English Lengths 12 inches = 1 foot 3 feet = 1 yard 5 ½ yards = 1 rod 40 rods = 1 furlong 8 furlongs = 1 mile

English Weights 27 11/32 grains = 1 dram 16 drams = 1 ounce 16 ounces = 1 pound 200 pounds = 1 ton

English Volumes 2 pints = 1 quart 4 quarts = 1 gallon 31 ½ gallows = 1 barrel 2 barrels = 1 hogshead

English Lengths 500 inches x 1 foot/12 inches = 41.67 feet 12 inches = 1 foot 3 feet = 1 yard 5 ½ yards = 1 rod 40 rods = 1 furlong 8 furlongs = 1 mile If you have a piece of sting that is 500 inches long, how many feet is that? How many yards? 500 inches x 1 foot/12 inches = 41.67 feet 500 in x 1 ft/12 in x 1 yrd/3 ft = 13.89 yards

Metric System 3 Basic words It does not mater what prefix you have. Meter = length Gram = weight Liter = volume It does not mater what prefix you have.

Small Group Quiz! L = Length W = Weight V = Volume Milligram Centimeter Milliliter Kilometer Microgram L = Length W = Weight V = Volume

Small Group Quiz! Milligram = (W) weight Centimeter = (L) length Milliliter = (V) volume Kilometer = (L) length Microgram = (W) weight

Metric prefixes Same prefix for length, volume, weight. Kilogram Kiloliter Kilometer

Kilo Kilo Prefix Larger than basic by 1000 1 kilometer = 1000 meters 1 kilogram = 1000 grams 1 kiloliter = 1000 liters

3 Prefixes (smaller than basic) Centi – ( centimeter) 100x smaller than basic Milli – (Millimeter) 1000x smaller than basic Micro (microgram) 1,000,000x smaller than basic

1 Kilometer = 1 meter = 1 millimeter = 1000 meters 1000 millimeters 1000 micrometer

1 Kilogram = 1 gram = 1 milligram = 1000 gram 1000 milligram 1000 microgram

Kiloliter = 1 Liter = 1 milliliter = 1000 Liter 1000 milliliter 1000 microliter

Symbols Prefix Kilo = k Basic unit Centi = c Milli = m Micro = mc Kiloliter = kL Centi = c Centimeter = cm Milli = m Millimeter = mm Micro = mc Microgram – mcg Basic unit Meter = m Liter = L Gram = g

Rules! mL = cc Do not chart Microgram = mg

Small group Quiz Write the following in abbreviated form Microgram Milliliter Kilometer Kilogram Microliter Centimeter

Small group Quiz Write the following in abbreviated form Microgram = mcg Milliliter = mL Kilometer = km Kilogram = kg Microliter = mcL Centimeter = cm

Metric System & Meds Weight Volume Only use dosages that differ by 1000 units to the next measurement Weight Volume 1 kg = 1000 g 1 L = 1000 mL 1 g = 1000 mg 1 mg = 1000 mcg

Conversions between units Conversion between units are accomplished by moving the decimal point! How far? (How many places)? How many “0” in 1000? 3 Move the decimal point 3 places

Conversions between units Which direction do you move the decimal point? IF large units to small units The quantity (number) must get larger Large  smaller Move the decimal to the right 0.5 g = __?__ mg g to mg is a difference of 1000 units Kg g  mg  mcg 500 mg

Conversions between Units 2.5 L = __?__ mL L to mL is a difference of 1000 units L  mL Large  small 2500 mL 500 mg = __?__ mcg mg to mcg is a difference of 1000 units Kg  g  mg  mcg 500,000 mcg

Small Group Practice 9 mg = ___?___ mcg 2.3 L = ___?___ mL 0.09 kg = ___?___ g 4.7 g = ___?___ mg 0.75 kg = ___?___ g

Small Group Practice 9 mg = 9000 mcg 2.3 L = 2300 mL 0.09 kg = 90 g 4.7 g = 4700 mg 0.75 kg = 750 g

Conversions between Units What if we are converting up the scale, going from smaller  larger units? Move the decimal point 3 places to the Left 200 mL = ___?___ L mL to L is different of 1000 units L  mL Smaller  larger 0.2 L

Conversions between Units 50 mcg = ___?___ mg mcg to mg is different of 1000 units Kg  g  mg  mcg Smaller  larger 0.05 mg

Small group Practice 4200 mL = ___?___ L 520 mg = ___?___ g 30 mcg = ___?___ mg 7420 g = ___?___kg 2.2 L = ___?___ mL

Small group Practice 4200 mL = 4.2 L 520 mg = 0.52 g 30 mcg = 0.03 mg 7420 g = 7.42 kg 2.2 L = 2200 mL