Welcome to Alma Clinical Education

1
Welcome to Alma Clinical Education

• Our tutorials remain on line for twelve weeks and
  are free of charge
• This quarters subject is Drug Calculations
• Feel free to enjoy this presentation and if you
  wish to see our full portfolio of courses then
  please click here

2
First of all get ready and relax
ACE

• Please have a calculator, pen or pencil and paper
  available and some good coffee to start your ACE
  course.

3
Menu
ACE

• Objectives
• Basic Mathematics
• Units of Measure
• Ratios and Proportions
• Intravenous flow (drip) rate calculations

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ACE Course objectives
ACE

• Review basic mathematics
• Review units of measure
• Review ratios and proportions
• Review concentration and dilution
• Review intravenous flow (drip) rate calculations
• Provide sample problems and solutions

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Basic Mathematics
ACE

• Numerals
• A numeral is a word or a sign, or a group of
  words or signs that expresses a number.
• Arabic (0, 1, 2, 3, 4...)
• Roman (I, X, L, D, C, M )
• Numbers
• A number is a total quantity or amount that is
  made of one or more numerals.

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Basic Mathematics types of numbers
ACE

• Whole Numbers (10, 220, 5, 19)
• Fractions
• Parts of whole numbers (1/4, 2/7, 11/13)
• Decimal Numbers
• Another means of writing fractions
• (1/2 0.5, 13/4 1.75)

Numerator
Denominator
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Basic Mathematics types of numbers
ACE

• WARNING Writing decimals incorrectly can lead to
  medication errors.
• Trailing zeros
• Write 5 not 5.0
• Naked decimal points
• Write 0.5 not .5
• Decimal points ere sometimes unclear and
  difficult to see leading to a 10 fold error.

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Lesson 1
ACE

• Convert the following fractions to decimal
  numbers
• a.1/2 b. 3/4 c.1/3 f. 5/8

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Lesson 1 Answers
ACE

• Answers for lesson 1
• a.0.5 b.0.75 e.0.33 d.0.625
• Well done if you got them all right
  remember you just divide the numerator by the
  denominator.
• So to convert ½ on your calculator simply
  divide 1 by 2 which 0.5 if you want to convert
  5/8 divide 5 by 8 0.625

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Lets do it without a Calculator
ACE

• Ok have a good slug of coffee and lets convert
  5/8 into a decimal without a calculator!
• 5/8 means 5 divided by 8

8 will divide equally into 5.This means the
answer must be less than 1.Therefore the first
thing we do is start with a point. We now add a
zero to the 5. 8 will divide into 50 6
times(6x848) so after the point we write 6. We
have 2 remainder. 8 will not go into 2 so we add
another zero. 8 divides into 20 2 times (2x816)
so we write a 2. We now have 4 remainder 8 will
not go into 4 so we add another 0. 8 ill go into
40 5 times(5x8)40 with no remainder so we put a
final 5, the answer is .625
.
2
5
6
4
2
5
0
8
0
0
Well done have another coffee
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Percentages
ACE

• Percentage means in a hundred. Percents ()
  are just fractions, but fractions with a set
  denominator of 100.
• Example 50 means 50 in a hundred or
  50/100 or 1/2.
• Converting percentages to fractions
• Write the number before the percent sign over 100
  and simplify the resulting fraction
• Example 2525/1001/4 there are 4 25s in 1 100

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Percentages Lesson 2Converting fractions to
percentages
ACE

• What is ¾ as a percentage ?
• Write the fraction in decimal form. (3/40.75)
• Write the decimal over one. (0.75/1)
• Multiply the numerator and denominator by 100.
  (0.75/1 75/100) (go back to slide 5 if you are
  not sure)
• Because you already know the divided by a
  hundred is the same as percent you can write
  75/100 as 75.
• Eureka! Once you get to the decimal
  you are already there

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Percentages
ACE

• Concentration expressed as percentage
• Percent weight-in-weight (w/w) is the grams of
  drug in 100 grams of the product.
• Percent weight-in-volume (w/v) is the grams of
  drug in 100ml of the product.
• Percent volume-in-volume (v/v) is the milliliters
  of drug in 100ml of the product.

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Metric System
ACE

• The metric system is a decimal system.
• Standard measures
• Metres Length
• Gram Weight
• Litre Volume
• Prefixes
• kilo- 1000
• milli- 1/1000 0.001
• micro- 1/1000000 0.000001

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Volume
ACE

• Volume is the amount of space occupied by a
  three-dimensional object as measured in cubic
  units (as milliliters or liters)
• L Litre
• ml milliliters
• 1 Litre 1000ml milliliters
• 3.5L 3500ml

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Mass
ACE

• Mass is a property of physical objects which
  measures the amount of matter in an object.
• kg kilograms
• g gram
• mg milligram
• mcg microgram
• ng nanogram
• 1 kilogram 1000 grams
• 1 gram 1000 milligrams
• 1 milligram 1000 micrograms
• 1 microgram 1000 nanograms

Example 0.004kg 4g 4000mg 4,000,000mcg
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Lesson 2
ACE

• Try to convert these.
• 1000g kg
• 1g mg
• 1000mcg mg

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Answers to lesson 2
ACE

• 1000 g 1 kg
• 1 g 1000 mg
• 1000 mcg 1 mg

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Ratios
ACE

• A ratio states a relationship between two
  quantities.
• Example 5 g of dextrose in 100 ml of water
  (Dextrose 5 in Water often abbreviated as D5W)
• A proportion is two equal rations.
• Example 5 g of dextrose in 100 ml of water
  equals 50 g of dextrose in 1000 ml of water
• 5 g 50 g
• 100ml 1000ml
• If you know three of the four terms you can
  calculate the fourth.

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Ratios and Proportions
ACE

• A vial of drug a contains 40mg/2ml. How many
  milliliters (ml) are required to obtain 300mg of
  drug a?
• 1. 40mg/2ml
• 2. You have 40mg in 2ml you want 300mg
• 3. simply divide 300 by 40 7.5ml x 2 (2ml)
  15ml

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Concentration and Dilution
ACE

• Terminology
• 5 dextrose in water is the same as Dextrose 5
  Water.
• 0.9 sodium chloride (NaCl) is the same as normal
  saline (Normal Saline).
• Half-normal saline is half the strength of normal
  saline (0.9 NaCl), or 0.45 NaCl. This may also
  be referred to as ½ NS

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Concentration and Dilution
ACE

• Reminder
• Percent weight-in-weight (w/w) is the grams of
  drug in 100 grams of the product.
• Percent weight-in-volume (w/v) is the grams of
  drug in 100ml of the product.
• Percent volume-in-volume (v/v) is the milliliters
  of drug in 100ml of the product.

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Concentration and Dilution
ACE

• Example 1
• 0.9 sodium chloride (w/v) 0.9 g of sodium
  chloride in 100 ml of solution.
• Example 2
• 5 dextrose in water (w/v) 5 g of dextrose in
  100 ml of solution.
• Example 3
• 23.4 sodium chloride (w/v) 23.4 g of sodium
  chloride in 100 ml of solution.

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Concentration and Dilution
ACE

• Example 4
• How many grams of dextrose are in 1l of D5W?
• Known ratio D5W means 5g
• 100ml
• Unknown ratio X
• 1000ml
• Write the proportion and solve for X
• X 5g X 50 g
• 1000ml 100ml

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Concentration and Dilution
ACE

• Solving concentration and dilution problems
• Calculate the number of grams in 100 ml of
  solution. That is your known ratio.
• Then calculate the number of grams in the
  volume requested in the problem by setting up a
  proportion.
• Check to make sure your units are in the same
  order.
• Make sure that the units that are across from
  each other are the same.
• Convert your answer to the requested units.

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Concentration and DilutionLesson 3
ACE

• In 100 ml of D5W/0.45 NaCl solution
• How many grams of NaCl are there?
• How many grams of dextrose are there?
• How many grams of dextrose are in 1l of a 10
  dextrose solution?
• How many grams of NaCl are in 1 L of ½ NS?
• How many mg of neomycin are in 50 ml of a 1
  neomycin solution?
• How many grams of amino acids are in 250 ml of
  a 10 amino acid solution?

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Concentration and Dilution Lesson 3 Answers
ACE

• 1. a. 0.45g
  
• b. 5g
• 2. 100g
• 3. 4.5 g
• 4. 500 mg
• 5. 25 g

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Intravenous (IV) flow (drip) rate calculations

• Using flow rates you can calculate the volume
  of fluid or amount of drug a patient will be
  receiving over a certain period of time.
• Calculation of IV flow (drip) rates is
  necessary to ensure that patients are receiving
  the amount of medication the clinician ordered.

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Intravenous (IV) flow (drip) rate calculations
cont.
ACE

• A prescription is written for 25,000 units of
  heparin in 250 ml of D5W to infuse at
  1000units/hr, what is the correct rate of the
  infusion (in ml/hr)?
• 1. Concentration of IV 4. IV rate
• 2. Concentration of IV 5. IV rate
• Concentration of IV 100units/ml of heparin
  6. IV rate 10 ml/hr

(1000 units/hr) (100 units/ml)
Total amount of drug Total volume
25,000 units of heparin 250ml of D5W
Dose desired Concentration of IV
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The end of your tutorial
ACE

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