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Clinical Calculation 5 th Edition. Chapter 1 Dimensional Analysis Pages 1-18. Introduction. Clinical calculations: refers to the solving of computational problems associated with administration of medications. Determining correct dosage needed
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Clinical Calculation5th Edition Chapter 1 Dimensional Analysis Pages 1-18
Introduction • Clinical calculations: refers to the solving of computational problems associated with administration of medications. • Determining correct dosage needed • There are different approach to clinical calculations • Ratio and Proportion ( this methods may becomes cumbersome and confusing if 2 or more conversion may be required) • DIMENSIONAL ANALYSIS
Dimensional Analysis • Is a computation method whereby one particular unit of measure is converted to another unit of measure by use of a conversion factor or factors • It focus on quantity of unit in a problem that needs to be converted in the same or in the another system of measurement.
continued • Starting factor: the known quantity and unit. • Answer: Desired Unit. • Conversion factors: Utilized to convert one system of measurement to another. • Known factors (learned) • Obtained from Table
Steps in Dimensional Analysis • Determining the starting factor and answer UNIT. • Formulating a conversion equations • LABEL FACTORS • Conversion factors • Solving the conversion equation by use of cancellation and simple arithmetic.
Example 1: How many feet are there in 5 yards? • We are converting from yard to feet • Starting factor in this problem is: • 5 yards • Final or ending unit in this problem is • Feet (ft) • Conversion factor in this problem is • 3 feet = 1 yard
Example 2How many minutes are in 480 seconds • We are converting from seconds to minutes • Starting factor in this problem is: • 480 seconds • Final or ending unit in this problem is • minutes • Conversion factor in this problem is • 60 seconds = 1 minutes
Example 3How many ounces are there in 4 cups? • We are converting from cups to ounces • Starting factor in this problem is: • 4 cups • Final or ending unit in this problem is • ounces • Conversion factor in this problem is • 8 ounce = 1 cup
Step II – Formulating the conversion equation • The second step in dimensional analysis is to setup a sequential series of equivalent values called conversion factors • For example: • 60 sec = 1 min • The conversion factor OR Note that all the conversions are 1:1 relationships and when written as conversion factors, the denominator and numerators can be interchangeable.
More on conversion factors • Approximate Equivalents • You must know • Table • There are some approximate equivalent sometimes fall within a range for example 60-65 mg = 1 grain (gr) or 4-5 ml = dram (dr) 1 • For our purpose here we will use table 5-1 in chapter 5 (page 35 in the book) or the handout in class. • During the test, we will use the handout.
Identifying the Equivalents • How many quarters are there in $25.00? Page 8, #3 • Equivalent value: 4 quarters = $1.00 • How many milliliters would be administered if the order was for 2 teaspoons? Page 8, #10 • Equivalent value: 30 mL = 6 tsp (t)
How many quarters are there in $25.00? Page 8, #3 • Starting factor: $25.00 • Ending unit: quarters • Equivalent value: 4 quarters = $1.00
How many milliliters would be administered if the order was for 2 teaspoons? Page 8, #10 • Starting factor: 2 teaspoon (t) • Ending unit: mL • Equivalent value: 30 mL = 6 teaspoon (table 1-1)
Clinical Calculation5th Edition Chapter 2 The metric System of Measurement Pages 19-24
Basic Unit of Measurement in Metric System • Weight • gram (g) • Volume • Liter (L) • Length • Meter (m)
Metric Prefixes Factors of 10 mega (M) micro (mc) kilo (k) hecto (h) deca (da) deci (d) milli (m) centi ( c ) Base unit deka = 10 hecto = 100 kilo = 1,000 Mega = 1,000,000 deci = 0.1 centi = 0.01 milli = 0.001 micro = 0.000001
Metric Prefixes - gram microgram (mcg) hectogram (hg) dekagram (dag) centigram ( cg ) Mega gram (Mg) (ton) milligram (mg) kilogram (kg) decigram (dg) gram (g) 1 dekagram = 10 g 1 hectogram = 100 g 1 kilogram = 1,000 g 1 Mega gram = 1,000,000 g 1 decigram = 0.1 g 1 centigram = 0.01 g 1 milligram = 0.001 g 1 microgram = 0.000001 g
Convert 375 mg to g (page 24, #3) • Starting factor: 375 mg • Ending unit: g • Conversion factor: 1000mg = 1 g
Metric Prefixes - meter micrometer (mcm) millimeter (mm) megameter (Mm) decameter (Dm) hectometer (Hm) centimeter ( cm ) decimeter (dm) kilometer (Km) Meter (m) 1 dekameter = 10 m 1 hectometer = 100 m 1 kilometer = 1,000 m 1 Mega meter = 1,000,000 m 1 decimeter = 0.1 m 1 centimeter = 0.01 m 1 millimeter = 0.001 m 1 micrometer = 0.000001 m
Convert 29 cm to m (page 24, #5) • Starting factor: 29 cm • Ending unit: m • Conversion factor: 100 cm = 1 m
Convert 25 mm to cm (page 24, #9) • Starting factor: 25 mm • Ending unit: cm • Conversion factor: 10 mm = 1 cm
Metric Prefixes - Liter kiloliter (kL) deciliter (dL) microliter (mcL) megaliter (ML) hectoliter (hL) decaliter (daL) milliliter (mL) centiliter ( cL ) Liter (L) 1 dekaliter = 10 L 1 hectoliter = 100 L 1 kiloliter = 1,000 L 1 Megaliter = 1,000,000 L 1 deciliter = 0.1 L 1 centiliter = 0.01 L 1 milliliter = 0.001 L A microliter = 0.000001 L
Convert 0.75 L to mL (page 24, #6) • Starting factor: 0.75 mL • Ending unit: L • Conversion factor: 1000mL = 1 L
Clinical Calculation5th Edition Chapter 3 The Apothecaries System of Measurement Pages 25 - 29
Apothecaries Basic units and Abbreviations • Weight • grain (gr) • Volume • Minim • Fluid dram = drams • Fluid ounce = ounces For dry weight they also use drams and ounces, but it is rarely used. In traditional apothecaries system one pound consists of 12 (dry weight) ounces. What is conversion that is used today 1 pound = ?? ounces?
Table 3-2 – Apothecaries Notations • 1/10 grain = gr 1/10 • 1 grain = gr I • 1 ½ grain = gr 1 ½ • 7 grain = gr vii • 10 grain = gr x • 15 minims = minims 15 • 150 minims = minims 150 • 2 ½ ounces = oz 2 ½
Table 3-3 Apothecaries Fluid units • 60 minims = 1 dr • 8 dr = 1 oz • 16 oz = 1 pt • 2pt = 1 qt pt = pint qt = quarts
Starting factor: 2 pts Ending unit: dr Conversion factors: 16 oz = 1pt; 8 dr = 1 oz Convert within the apothecaries system2 pts to dr (page 29, #8) Please note that I had to use more than one conversion factors in order to reach my ending units
Clinical Calculation5th Edition Chapter 4 The Household System of Measurement Pages 30 - 33
Weight Pounds (lbs) Ounces (oz) Length Inch (in) Feet (ft) Yard (yard) Mile (mile) Volume Gallon (gal) Ounce (oz) Teacup (teacup) Cup/Glass (c/gl) Quart (qt) Pint (pt) Teaspoon (tsp) (t) Tablespoon (tbs) (T) Drop (gtt) Basic Unit of Measurement in Household System
60 gtt = 1 tsp 3 tsp = 1 tbs 2 tbs = 1 oz 6 oz = 1 teacup 8 oz = 1 cup/glass 16 oz = 1 pt 2 pt = 1 qt 4 qt = 1 gal 16 oz = 1 lb 12 in = 1 ft 3 ft = 1 yard 5280 ft = 1 mile Table 4-2 Household Equivalents and more
Starting factor: 1 glass Ending unit: teaspoon Conversion factors: 8oz = 1 cup; 2 tbs = 1 oz; 3 tsp = 1 tbs Convert within the household system1 glass to tsp (page 33, #1) Please note that I had to use more than one conversion factors in order to reach my ending units
Starting factor: ½ gallon (gal) Ending unit: ounces (oz) Conversion factors: 16 oz = 1 pt; 2 pt = 1 qt; 4 qt = 1 gal Convert within the household system½ gal to oz Please note that I had to use more than one conversion factors in order to reach my ending units
Clinical Calculation5th Edition Chapter 5 Conversion of Metric, Apothecaries, and Household Units Pages 34 - 39
Table 5-1 Approximate Equivalent among Metric, Apothecaries and Household Units – Dry Weight = dram or fluid dram = ounce or fluid ounce
Table 5-1 Approximate Equivalent among Metric, Apothecaries and Household Units - Liquid
Table 5-1 Approximate Equivalent among Metric, Apothecaries and Household Units - Length
Starting factor: oz iv = 4 oz Ending unit: tbs Conversion factors: 1 oz = 8 tbs Convert and round to nearest tenthoz iv to tbs (page 38, #8) If problem asks to round to nearest tenth, then the final answer has to be written that way and with correct unit, 32.0tbs otherwise it is counted incorrect.
Starting factor: minims XX = 20 minims Ending unit: mL Conversion factors: 75 minims = 5 mL Convert and round to nearest tenthminims XX to mL (page 38, #7) If problem asks to round to nearest tenth, then the final answer has to be written that way and with correct unit, 1.3mL otherwise it is counted incorrect.
Starting factor: 157lb Ending unit: kg Conversion factors: 2.2 lbs = 1 kg Convert and round to nearest tenth157lb to kg (page 39, #20) If problem asks to round to nearest tenth, then the final answer has to be written that way and with correct unit, 71.4kg otherwise it is counted incorrect.
Starting factor: 5.5g Ending unit: gr Conversion factors: 60mg=15gr; 1000mg= 1g OR 1 g = 15 gr You may use either of the two equivalent, they both consider correct, one is more direct conversion Convert and round to nearest tenth5.5 g to gr (page 39, #28) ss = ½ your test book may not use this, but your handout may refer to it. If problem asks to round to nearest tenth, then the final answer has to be written that way and with correct unit, 82.5gr otherwise it is counted incorrect.
Starting factor: 6 tsp Ending unit: dr Conversion factors: 4 dr = 3 tsp Convert and round to nearest tenth6 tsp to dr (page 39, #18) If problem asks to round to nearest tenth, then the final answer has to be written that way and with correct unit, 8.0dr otherwise it is counted incorrect.