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Medical Dosage Calculation
A Dimensional Analysis Approach
Tenth Edition
CHAPTER
12
Calculating Pediatric
Dosages
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
A 10 year old child has a fever of 101
degrees F, and 400 mg po of the antipyretic
acetaminophen (Tylenol) has been ordered.
If the elixir is labeled 160 milligrams per 5
milliliters, how many teaspoons will you give
to the child?
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.
0.25 t
5 tsp
2 ½ tsp
0.4 t
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.
0.25 t
5 tsp
2 ½ tsp
0.4 t
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
The prescriber ordered: amoxicillin 20 mg/kg
q8h. Calculate the dose of this antibiotic for
a child who weighs 42 kilograms.
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.
240 mg
270 mg
820 mg
840 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 #2 Response
1.
2.
3.
4.
240 mg
270 mg
820 mg
840 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 #3
A child is to receive an IV bolus of 1%
lidocaine, 0.1 milligram per kilogram. How
many milliliters will you prepare for a child
who weighs 40 kilograms?
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.
0.4 mL
0.004 mL
000.3 mL
000.04 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.
Question #3 Resopnse
1.
2.
3.
4.
0.4 mL
0.004 mL
000.3 mL
000.04 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.
Question #4
Prescriber’s order: Lanoxin (digoxin) 0.1 mg
IM daily. The label reads 0.1 mg/mL
injection. What is the dose in micrograms?
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.
0.1 mcg
0.01 mcg
0.001 mcg
0.0001 mcg
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.
0.1 mcg
0.01 mcg
0.001 mcg
0.0001 mcg
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
A child who weighs 18 kg is to receive
Motrin (ibuprofen) 8 mg/kg po q4h prn for
pain. The label reads 100 mg/5 mL. How
many milliliters will you administer?
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.
0.7 mL
0.9 mL
7.3 mL
7.2 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.
Question #5 Response
1.
2.
3.
4.
0.7 mL
0.9 mL
7.3 mL
7.2 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.
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 Objectives
1. Determine if a pediatric dose is within the safe
dose range.
2. Calculate pediatric oral and parenteral
dosages based on body weight.
3. Calculate pediatric oral and parenteral
dosages based on body surface area.
4. Perform calculations necessary for
administering medications using a volume
control chamber.
5. Calculate daily fluid maintenance.
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.
Figure 12.1 A bottle of oral medication and a measuring spoon.
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.
Figure 12.2 Liquid medication administration devices:Two droppers, an oral syringe, and a measuring spoon.
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.
Example 12.1
• Order: erythromycin 30 mg/kg po q6h. Read the label
below. The child weighs 38 kilograms. How many
milliliters of the drug will you administer to this child?
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.
Example 12.1
• Start with the size of the patient.
1
38 kg 30 mg
5 mL


 28.5 mL
1
kg
200 mg
4
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.
Example 12.2
• A drug is ordered: 0.045 mg IM stat. The
child weighs 40 kilograms, and the
recommended dose is (0.001-0.002)
milligram per kilogram.
• Is this ordered dose safe for this child?
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.
Example 12.2
• Using the minimum recommended dose of
0.001 mg/kg, find the minimum
recommended dose in mg for this child.
40 kg 0.001 mg
 0.04 mg

1
1 kg
• Using the maximum recommended dose
of 0.002 mg/kg, find the maximum
recommended dose in mg for this child.
40 kg 0.002 mg
 0.08 mg

1
1 kg
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.
Example 12.2
• So, the safe dose range for this child is
(0.04–0.08) mg. Because the prescribed
dose of 0.045 mg is in this range, it is a
safe dose for this child.
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.
Figure 12.5 Volume control chamber.
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.
Pediatric Daily Fluid Maintenance
Formula
• For the first 10 kg of body weight: 100 mL /kg
• For the next 10 kg of body weight: 50 mL / kg
• For each kg above 20 kg of body weight: 20 mL /
kg
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.
Example 12.3
• The order is maintenance for a child who
weighs 35 kg. At what rate should the
pump be set in mL/h?
Divide the child’s weight (35 kg) into
three portions as follows:
35 kg = 10 kg + 10 kg + 15 kg
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.
Example 12.3
1st
Portion
2nd
Portion
10 kg
10 kg
3rd
Portion
15 kg
Total
35 kg
x
100 mL
kg
=
1,000 mL
x
50 mL
kg
=
500 mL
x
20 mL
kg
=
300 mL
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
1,800 mL
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 12.3
• The daily “maintenance” was determined
to be 1,800 mL per day.
1,800 mL
mL
?
day
h
1,800 mL 1 day
mL

 75
day
24 h
h
So, the pump would be set at 75 mL/h.
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
• Taking shortcuts in pediatric medication
administration can be fatal to the child.
• Check to see if the order is in the safe
dose range.
• Consult a reliable source when in doubt
about a pediatric medical order.
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
• Question the order or check your
calculations if the ordered dose differs
from the recommended dose.
• Pediatric dosages are sometimes rounded
down (truncated) to avoid the danger of an
overdose.
• IV bags of no more than 500 mL should be
hung for pediatric patients.
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
• No more that 2 mL should be given IM to a
pediatric patient.
• Because accuracy is crucial in pediatric
infusions, electronic control devices or
volume control chambers should always
be used.
• For a volume control chamber, a flush is
always used to clear the tubing after a
medication is infused.
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
• Know the facility policy regarding the
inclusion of medication volume as part of
the total infusion volume.
• Minimal and maximal dilution volumes for
some IV drugs are recommended in order
to prevent fluid overload, minimize
irritation to veins, and reduce toxic effects.
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
• When preparing IV drug solutions, the
smallest added volume (minimal dilution)
results in the strongest concentration; the
largest added volume (maximal dilution),
results in the weakest concentration.
• Daily fluid maintenance depends on the
weight of the child and includes both oral
and parenteral fluids.
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.