Transcript olsen_ch08_lecture

Medical Dosage Calculation
A Dimensional Analysis Approach
Tenth Edition
CHAPTER
8
Preparation of
Solutions
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Directory
• Classroom Response System Questions
• Lecture Note Presentation
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Classroom Response
System Questions
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1
If a 25% solution is diluted, what might be
the strength of the resulting solution?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1 Choices
1.
2.
3.
4.
50%
25%
10%
75%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1 Response
1.
2.
3.
4.
50%
25%
10%
75%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2
If a 1:69 solution is diluted, what might be
the strength of the resulting solution?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2 Choices
1.
2.
3.
4.
1:30
1:90
2:120
3:12
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2 Response
1.
2.
3.
4.
1:30
1:90
2:120
3:12
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3
If 1 liter of a solution contains 100 grams of
pure drug, what is the strength of this
solution as a fraction, ratio, and as a
percentage?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3 Choices
1.
2.
3.
4.
1/100 strength, 1:100, 1%
1/1000 strength, 1:1000, 0.1%
½ strength, 1:2, 50%
1/10 strength, 1:10, 10%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3 Response
1.
2.
3.
4.
1/100 strength, 1:100, 1%
1/1000 strength, 1:1000, 0.1%
½ strength, 1:2, 50%
1/10 strength, 1:10, 10%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4
The strength stated on a drug label is 100
mg/mL. Write this strength in the form of a
percentage.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4 Choices
1.
2.
3.
4.
500%
50%
5%
10%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4 Response
1.
2.
3.
4.
500%
50%
5%
10%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5
The physician orders minoxidil (Rogaine)
2%; apply 2 mL to scalp b.i.d. How many
milligrams of minoxidil will be applied to the
scalp with each dose?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5 Choices
1.
2.
3.
4.
40 mg
4 mg
5 mg
2 mg
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5 Response
1.
2.
3.
4.
40 mg
4 mg
5 mg
2 mg
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Lecture Note Presentation
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Learning Outcomes
1. Describe the strength of a solution as a ratio,
fraction and as a percent.
2. Determine the amount of solute (drug) in a
given amount of solution.
3. Determine the amount of solution that would
contain a given amount of solute (drug).
4. Do the calculations necessary to prepare a
solution from a solute.
5. Do the calculations necessary to prepare
solutions for irrigations, soaks, and nutritional
feedings.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Strength of a Solution
Amount of Drug (Solute)
Strength =
Amount of Solution
Examples of strength using stated units of measurement:
5 mg 25 mcg
8g
,
, and
mL
5 mL
L
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Strength of a Solution
• Solution strength can also be stated
without explicit units of measurement. For
example, a solution which is 1 part iodine
in 2 parts of solution has strength of:
1:2
Ratio
1
strength
2
Fraction
50%
Percent
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Strength of a Solution
• Measure the Amount of Drug (Solute) in
either g or mL
• Measure the Amount of the Solution in mL
1:100 NaCl solution has
1 g NaCl in 100 mL of the solution
1/3 strength solution of Iodine has
1 mL of Iodine in 3 mL of solution.
7% magnesium sulfate solution has
7 g magnesium sulfate in 100 mL of solution
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Find the Strength
• What is the strength of a 500 milliliter
solution that contains 50 mL of iodine?
a
m
o
u
n
t
o
f
d
r
u
g
s
t
r
e
n
g
t
h

a
m
o
u
n
t
o
f
s
o
l
u
t
i
o
n
1
=
50 mL
500 mL
10
The strength is 1:10, 1/10 strength, or 10%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Find the Strength
• What is the strength of a 200 milliliter
solution that contains 50 g of NaCl?
a
m
o
u
n
t
o
f
d
r
u
g
s
t
r
e
n
g
t
h

a
m
o
u
n
t
o
f
s
o
l
u
t
i
o
n
1
=
50 g
------------200 mL
4
5
0
g1
s
t
r
e
n
g
t
h



2
5
%
2
0
0
m
L
4
The strength is 1:4, ¼ strength, or 25%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Find the amount of solute in a given
amount of solution of known strength
• How many grams of dextrose would you
need to prepare 1000 milliliters of a 5%
solution?
Amount of solution is 1,000 milliliters.
 5 
Strength is 5% 
 100 
5g
This means
100 mL
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Convert 1,000 mL of solution to g of dextrose
5g
1,000 mL 
 ?g
100 mL
5g
1,000 mL 
 50 g
100 mL
So, you need 50 grams of dextrose to prepare
1,000 milliliters of a 5% solution.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Finding the Amount of Solute
• How would you prepare
250 milliliters of a 1/2%
creosol solution? Creosol
comes in liquid form.
Amount of solution is 250 milliliters.
Strength is ½% or 0.5%
0.5 g Creosol
This means
100 mL Solution
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Convert 250 mL solution to ? mL of Creosol
0.5 g Creosol
250 mL Solution

100 mL Solution
1
=? mL of Creosol
0.5 g Creosol
250 mL Solution

100 mL Solution
1
=1.25 mL Creosol
So, 1.25 milliliters of creosol is diluted with water to
250 milliliters of solution.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Find the amount of solution of known
strength containing a given amount of solute
• How many milliliters of a
20% magnesium sulfate
solution will contain 40
grams of the solute
magnesium sulfate?
You want to convert the 40 grams of pure drug to
milliliters of solution.
40 g = ? mL
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
In a 20% solution, there are 20 grams of solute per
100 mL of solution. So, the strength is
20 g
100 mL
40 g 100 mL

 ?g
1
20 g
2
40 g 100 mL

 200 mL
1
20 g
1
So, 200 mL of a 20% magnesium sulfate solution
contains 40 g of magnesium sulfate.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Finding the Amount of Solute
• How many ounces of full-strength Sustacal
are needed to make 16 ounces of ¼
strength Sustacal?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
1
1 oz (Sustical)
strength means
4
4 oz (Solution)
16 oz Solution = ? oz Sustical
16 oz Solution 1 oz (Sustical)

= ? oz Sustical
1
4 oz (Solution)
4
16 oz Solution 1 oz (Sustical)

= 4 oz
1
4 oz (Solution)
1
So, 4 oz of full-strength Sustical are needed to make 16
ounces of ¼ strength Sustical.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• The strength of a solution is the ratio of the
amount of solute dissolved in the solution
to the total volume of the solution.
• The strength of a solution may be
expressed in the form of a ratio,fraction,or
percentage.
• A 1/2 strength solution is a 1:2 or a 50%
solution, and should not be confused with
a 1/2 % solution.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• The amount of solute dissolved in the
solution should be expressed in milliliters if
the solute is a liquid.
• The amount of solute dissolved in the
solution should be expressed in grams if
the solute is a solid or powder.
• The volume of a solution should be
expressed in milliliters.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• To determine the amount of solute
contained in a given amount of a solution
of known strength, use the strength as the
known equivalence.
• To determine amount of a solution of
known strength containing a given amount
of solute, use the strength as the known
equivalence.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• The strength of a particular solution may be
written in many different forms. The following
strengths are all equivalent:
• With stated Units of Measurement
Rates
{
Equivalence
500 mg/mL
500 mg per mL
500 mg
1 mL
500 mg = 1 mL
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• Without stated Units of Measurement
Fraction
Ratio
Percentage
1/2 strength
1:2
50%
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.