Dimensional Analysis for Meds

Chapter 4

Chapter 4

Metric, International (SI) SystemYou do not need to know all of the System!Much easier than English SystemAll 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

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

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

If you have a piece of sting that is 500 inches long, how many feet is that? How many yards?

Metric System

3 Basic wordsMeter = lengthGram = weightLiter = volume

It does not mater what prefix you have.

Small Group Quiz!

1. Milligram

2. Centimeter

3. Milliliter

4. Kilometer

5. Microgram

L = Length

W = Weight

V = Volume

Small Group Quiz!

1. Milligram = (W) weight

2. Centimeter = (L) length

3. Milliliter = (V) volume

4. Kilometer = (L) length

5. Microgram = (W) weight

Metric prefixes

Same prefix for length, volume, weight.KilogramKiloliterKilometer

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 = 1000 meters

1 meter = 1000 millimeters

1 millimeter = 1000 micrometer

1 Kilogram = 1000 gram

1 gram = 1000 milligram

1 milligram = 1000 microgram

Kiloliter = 1000 Liter

1 Liter = 1000 milliliter

1 milliliter = 1000 microliter

Symbols

Basic unitMeter = mLiter = LGram = g

PrefixKilo = k

Kiloliter = kL

Centi = c Centimeter = cm

Milli = m Millimeter = mm

Micro = mc Microgram – mcg

Rules!

mL = ccDo not chart

Microgram = gDo not chart

Small group Quiz

Write the following in abbreviated form1. Microgram2. Milliliter3. Kilometer4. Kilogram5. Microliter6. Centimeter

Small group Quiz

Write the following in abbreviated form1. Microgram = mcg2. Milliliter = mL3. Kilometer = km4. Kilogram = kg5. Microliter = mcL6. Centimeter = cm

Metric System & Meds

Only use dosages that differ by 1000 units to the next measurement

Weight Volume1 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 Large smaller 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 Large small 500,000 mcg

Small Group Practice

1. 9 mg = ___?___ mcg

2. 2.3 L = ___?___ mL

3. 0.09 kg = ___?___ g

4. 4.7 g = ___?___ mg

5. 0.75 kg = ___?___ g

Small Group Practice

1. 9 mg = 9000 mcg

2. 2.3 L = 2300 mL

3. 0.09 kg = 90 g

4. 4.7 g = 4700 mg

5. 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

1. 4200 mL = ___?___ L

2. 520 mg = ___?___ g

3. 30 mcg = ___?___ mg

4. 7420 g = ___?___kg

5. 2.2 L = ___?___ mL

Small group Practice

1. 4200 mL = 4.2 L

2. 520 mg = 0.52 g

3. 30 mcg = 0.03 mg

4. 7420 g = 7.42 kg

5. 2.2 L = 2200 mL