Table of Contents - Red Creek Wildlife Center

Introduction
In wildlife rehabilitation, basic math calculations are needed when determining drug dosages, fluid therapy, feeding
amounts, caloric intake and when evaluating diets. In addition to being able to formulate and solve mathematical problems,
the wildlife rehabilitator needs to be proficient in the use of several instruments of measure such as the weight scale and
syringes. Also, an understanding of the metric system and the ability to covert to and from the US customary units is
essential to proficiency in medical math.
In part 1, we will cover all of the necessary skills to calculate accurate drug dosing and fluid therapy for animals. The
course is broken down into 5 sections:
Comparative (Ratio) Math – the basis of proficient calculations
Drug dosage calculations
Understanding the metric system
Tools of the trade
Fluid Therapy
Table of Contents
Introduction........................................................................................................................................................... 1
Ratio Mathematics ................................................................................................................................................ 2
Solving Ratio Equations..................................................................................................................... 2
Mastering Drug Dosing .......................................................................................................................................... 3
The One-Step Calculation ................................................................................................. 3
The Two-Step Calculation ................................................................................................. 3
The Three-Step Calculation ............................................................................................... 4
Easy System Conversions (Standard vs. Metric Systems) ................................................................... 4
Easy Chart Method ........................................................................................................... 5
Metrics Made Easy for the Wildlife Rehabilitator .................................................................................................. 7
The Metric Scale ............................................................................................................................... 7
Temperature conversion................................................................................................................... 9
Mathematical Tools for Accurate Measure .......................................................................................................... 10
Syringes.......................................................................................................................................... 10
Needle Gauges ............................................................................................................................... 11
Drug Labeling ................................................................................................................................. 12
Drug Strength Listed as a Percentage ............................................................................. 12
Combination Drugs......................................................................................................... 12
Diluting Medications....................................................................................................................... 13
Cutting Tablets and Pills ................................................................................................. 13
Diluting Liquid Drugs ...................................................................................................... 13
Label Your New Drug ...................................................................................................... 13
Prescription Abbreviations .............................................................................................. 14
Scales ............................................................................................................................................. 14
Formulary....................................................................................................................................... 14
The Power of Percentages ................................................................................................................................... 16
Calculating Straight Percentages ..................................................................................................... 16
Stomach Capacity........................................................................................................... 16
Daily Fluid Requirements ................................................................................................ 16
Fluid Replacement Calculations ...................................................................................................... 16
Step by Step Rehydration................................................................................................................ 17
Finding the Whole of a Percentage (Normal Body Weight) .............................................. 17
Three Day Rehydration Protocol ..................................................................................... 17
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 1 of 18
Ratio Mathematics
A math problem is simply a story in steps
and can be broken down into several
small, easily solved problems. This
equation is the simplest:
This is not a fraction but a way to
write a RATIO. Ratios can also
be written in other formats:
Let’s make it easier by using something very common. We know that 1 quarter equals 5 nickels. They both equal 25
cents. If we replace the equation’s numbers with coins it would now look like the following:
is the same as
Because coins are something we work with every day and we are instinctively familiar with how the ratios of coins
work, most people will now automatically say the answer is “10” - which is correct. Labeling the numbers immediately gives
clarity to the problem. It now makes sense.
Labeling is important to keep you from making errors. Get in the habit of labeling from the start. This will be important
later for drug dosing when we start working with milligram and cc measurements. Like items always go on the same level
such as we have the quarters on the top and nickels on the bottom.
Now we know the answer to this is the number 10, but how do we get there? I want to introduce you to one
mathematical concept, and if you learn it well, you will be able to solve all your drug dosing problems accurately. It’s called
comparative or ratio math.
Solving Ratio Equations
The magic of this is that diagonal numbers, multiplied together, will get the
same answer.
But how do you mathematically discover the missing number?
You multiply the diagonal that has 2 numbers
and divide the answer by the odd number.
5 X 2 = 10
10
1 = 10
And it works with all numbers. Try this same equation with different numbers missing:
Remember: multiply the 2 diagonals that you have and divide by the odd one.
On Your Calculator
7 X 12 ÷ 3 =
7 X 12 ÷ 28 =
3 X 28 ÷ 12 =
3 X 28 ÷ 7 =
Practice problems
1
12
4
108
?
Answer ____________
4
22.7
1
15
?
Answer _____________
2
625
25
100
?
Answer __________
5
5
454
?
600
Answer ___________
3
21
28
?
7
Answer __________
6
15.8
1000
?
820
Answer ___________
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 2 of 18
Mastering Drug Dosing
The One-Step Calculation
Your animal weights 35 lb
Worm medicine
directions:
2 tablets for every 10 lbs
Now let’s see how this can be put into practice.
A prescription is actually a story that can be set up as a calculation.
You have a worm medicine that the labeling says to give 2 tablets per 10 pounds.
Your animal weighs 35 pounds.
Now let’s lay out the calculation. The line in the fraction can be considered the same as
the word “per.” You have 2 tablets per 10 pounds.
Remember to keep “like” comparisons on the same level – SO LABEL!
This is a 1 calculation problem. You only need to find the quantity to give.
2 X 35 ÷ 10 =
The Two-Step Calculation
What if the dosing instructions said 20 mg for every 10 lb and each tablet is 10 mg? You now have a 2 step problem.
You must now figure out the dosage and then the quantity.
Dosage - How many mg do I need?
Quantity - How many tabs does that equal?
We figure out the dosage the same way we did in the last calculation.
First we set up the problem with labels.
Then we fill in what we know.
We know we need 20mgs per 10 pounds.
Your animal weights 35 lb
Worm medicine directions:
20 mg for every 10 lb
Each tablet is 10 mg
We also know our animal weighs 35 pounds.
Multiply the 2 diagonal numbers … and divide by the odd one.
Your answer is the number you carry through to the next step.
lay out your calculation here
Now we need to figure out the quantity.
Set up the problem and label it!
We know there are 10 mg per tablet and we know we need 70 mg. We
need to discover how many tablets that is.
lay out your calculation here
2 Step Practice problems
Remember: LABEL all of your equations
Problem
7
Animal weight = 5 pounds
Dosage is 15 mg per pound
You have 25 mg tablets
8
Animal weight = 2.5 pounds
Dosage is 15 mg per pound
You have 5 mg tablets
9
Animal weight = 5 pounds
Dosage is 15 mg per 10 pounds
You have a liquid with 30 mg per mL
Dosage
Quantity
Answer
______
______
______
______
_____
______
______
______
______
_____
______
______
______
______
_____
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 3 of 18
The Three-Step Calculation
What if the dosing instructions give you a dose per kilogram? Now you have a problem.
You must always make sure you are working in the same system. Whether it is pounds, ounces, kilograms or grams, the
weight you have must be the same as the weight mentioned in the directions.
These are the three steps you need for any drug dosing question:
The Three Steps To Accurate Drug Dosing
If you start from the top and work your way down, skipping steps you don’t need,
you won’t make mistakes.
System
This mnemonics device will
help you remember the steps:
Safe
Am I using the same system?
Dosage
Quantity
Drug
Questions
What is the dose? How many mg do I need?
What quantity do I measure?
How many tabs does that equal?
Easy System Conversions (Standard vs. Metric Systems)
There are several ways to convert back and forth between standard measures (pounds and ounces) and metrics
(grams and kilograms). You can use these to do the first step of a 3 step drug dosage calculation, and it is quite easy.
Conversion Ratio Chart
Mass (Weight)
Volume
1 lb = 16 oz = 454 gm = .454kg
1 oz = 28 gm = 0.028 kg = 0.0625 lb
1 kg = 1000 g = 2.2 lb = 35.2 oz
1 g = 0.035 oz = 0.001 kg = 1000mg
1 tsp = 0.33 Tbsp = 0.034 fl oz = 0.5 mL
1 Tbsp = 3 tsp = 0.5 fl oz = 15mL
1 fl oz = 2 Tbsp = 6 tsp = 30 mL
1 mL = 0.2 tsp = 0.0666 Tbsp = 0.0333 fl oz
Conversion Calculation Chart
Mass (Weight)
Convert From:
pounds (lb)
pounds (lb)
pounds (lb)
ounces (oz)
ounces (oz)
ounces (oz)
grams (g)
grams (g)
grams (g)
kilograms (kg)
kilograms (kg)
kilograms (kg)
Convert To:
grams (g)
kilograms (kg)
ounces (oz)
grams (g)
kilograms (kg)
pounds (lb)
kilograms (kg)
pounds (lb)
ounces (oz)
grams (g)
pounds (lb)
ounces (oz)
Do This:
multiply by 454
divide by 2.2
multiply by 16
multiply by 28
divide by 35.2
divide by 16
divide by 1000
divide by 454
divide by 28
multiply by 1000
multiply by 2.2
multiply by 35.2
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Volume
Convert From:
fluid ounces (fl oz)
fluid ounces (fl oz)
fluid ounces (fl oz)
teaspoons (tsp)
teaspoons (tsp)
teaspoons (tsp)
tablespoons (Tbsp)
tablespoons (Tbsp)
tablespoons (Tbsp)
milliliters (mL)
milliliters (mL)
milliliters (mL)
Convert To:
milliliters (mL)
teaspoons (tsp)
tablespoons (Tbsp)
milliliters (mL)
tablespoons (Tbsp)
fluid ounces (fl oz)
milliliters (mL)
teaspoons (tsp)
fluid ounces (fl oz)
teaspoons (tsp)
tablespoons (Tbsp)
fluid ounces (fl oz)
Do This:
multiply by 30
multiply by 6
multiply by 2
multiply by 5
divide by 3
divide by 6
multiply by 15
multiply by 3
divide by 2
divide by 5
divide by 15
divide by 30
Page 4 of 18
Let’s return to our problem. Since we know the pounds but the prescription is in kilograms, we need to convert to
kilograms.
Your animal weights 35 lb
Worm medicine directions:
4.4 mg per kg
Each tablet is 10 mg
Easy Chart Method
We have the animal’s weight in pounds but we need kilograms.
Following the chart instructions we take the animal’s weight in pounds (35) and divide by 2.2. Round the answer off
and you get what?
Convert From:
Convert To:
Do This:
pounds (lb)
grams (g)
multiply by 454
pounds (lb)
kilograms (kg)
divide by 2.2
pounds (lb)
ounces (oz)
multiply by 16
ounces (oz)
grams (g)
multiply by 28
35 lb ÷ 2.2 = __________kg
Let’s do the same thing but this time with the Conversion Ratio Chart.
We have pounds but we need kilograms, so we look for the comparison between the two.
We find that on the first line where both are present
This is a ratio problem just like we’ve been doing.
Mass (Weight)
1 lb = 16 oz = 454 gm = .454kg
1 oz = 28 gm = 0.028 kg = 0.0625 lb
1 kg = 1000 g = 2.2 lb = 35.2 oz
1 g = 0.035 oz = 0.001 kg = 1000mg
Volume
1 tsp = 0.33 Tbsp = 0.034 fl oz = 0.5 mL
1 Tbsp = 3 tsp = 0.5 fl oz = 15mL
1 fl oz = 2 Tbsp = 6 tsp = 30 mL
1 mL = 0.2 tsp = 0.0666 Tbsp = 0.0333 fl oz
Class Example
Real Life Problem
System =
System 1.36 kg
Dosage
13.6 mg
Dosage
=
Quantity 0.59mL
Quantity =
lay out your calculation here
So we set up the problem
and we label the components.
We put in the ratio from the chart on one side
and we add what we know to the other.
Dosage
System
lay out your calculation here
Quantity
lay out your calculation here
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
lay out your calculation here
Page 5 of 18
Practice Problems
10. You have a 3 pound animal recovering from a car accident. You are to give it 10mg/kg of Amikacin. The bottle
of Amikacin reads “Amikacin 50mg/mL.” How many mL does it receive?
11. You have a 80 gram bunny that was attacked by a cat. You are to give it Bactrim at a rate of 30mg/kg. The
bottle says there is 240mg of medication in 5mL. How many mL do you give?
12. You are treating a 28 pound coyote for mange. You are to give 0.3mg/Kg of ivermectin. Your ivermectin is 10
mg/ mL. How much do you give?
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 6 of 18
Metrics Made Easy for the Wildlife Rehabilitator
Welcome to the Metric System: an easy, understandable measure of volume, weight and distance.
The metric system is set up on a scale of ten. The simplicity of the system is the lack of confusion between units with
different conversion factors.
Each type of measurement
(length, volume and
weight) has a base unit:
distance (length) = “meter”
volume = “liter”
weight = “gram”
The prefix before the unit is uniform throughout each type of measurement and tells you the number of units you are
working with. For example: a “kilogram” equals 1000 grams.
The Metric Scale (BOLDED is most commonly used by wildlife rehabilitators)
Prefix
Scale range
used in
wildlife
rehabilitation
exa
giga
mega
kilo
hecto
deka
Symbol
E
G
M
k
h
da
Multiplier
1,000,000,000,000
1,000,000,000
1,000,000
1000
100
10
BASIC UNIT ( meter, liter, gram )
deci
centi
milli
micro
nano
pico
d
c
m

n
p
0.1
0.01
0.001
0.000001
0.000000001
0.000000000001
Try this mnemonic device:
kilo
hecto
deka
(unit)
deci
centi
milli
Kangaroos
Hop
Down
Under
Dodging
Crocodile
Mouths
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 7 of 18
The Ladder Methodi
To easily convert numbers within the system, you need only count the number of “jumps” towards the level you wish
to convert to, and move a number’s decimal point the same jumps in the direction as our scale.
KILO
1000
Units
HECTO
100
Units
To convert to a smaller unit move the
decimal point to the right
DEKA
10
Units
BASIC UNIT
gram
liter
meter
To convert to a larger unit move the
decimal point to the left
DECI
0.01
Units
CENTI
0.001
Units
MILLI
0.0001
Units
You have 1.5 liters of liquid and you need to know how many milliliters that equals.
1.
2.
3.
4.
1.5
Determine your starting point. (What you know)
Count the “jumps” to your ending point. (What you want to know)
Move the decimal the same number of jumps in the same direction.
If you run out of room, add “0s” to fill the space.
KILO
1000
Units
HECTO
100
Units
kg
1 5 0 0. g
To convert to a smaller unit move the
decimal point to the right
DEKA
10
Units
BASIC UNIT
gram
liter
meter
To convert to a larger unit move the
decimal point to the left
DECI
0.01
Units
CENTI
0.001
Units
MILLI
0.0001
Units
According to your scale, a baby bunny weighs 30 grams. Your medication’s dosage specifies kilograms.
1.
2.
3.
4.
Determine your starting point. (What you know)
Count the “jumps” to your ending point. (What you want to know)
Move the decimal the same number of jumps in the same direction.
If you run out of room, add “0s” to fill the space.
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
3 0. g
.0 3
kg
Page 8 of 18
KILO
1000
Units
To convert to a smaller unit move the
decimal point to the right
HECTO
100
Units
DEKA
10
Units
BASIC UNIT
gram
liter
meter
DECI
0.1
Units
To convert to a larger unit move the
decimal point to the left
CENTI
0.001
Units
MILLI
0.0001
Units
Using the ladder method, convert the following:
13.
1000 mg = _____ g
15.
0.5 L = _______ mL
17.
170 cm = _______ mm
14.
385 g = _____ kg
16.
1.45 kg = _______ g
18.
128 daL = _______ L
Temperature conversion
Celsius
Fahrenheit
27
80.6
28
82.4
29
84.2
30
86
Celsius
Fahrenheit
36
96.8
37
38
39
98.6 100.4 102.2
31
87.8
32
89.6
33
91.4
34
93.2
35
95
40
41
42
43
44
104 105.8 107.6 109.4 111.2
To convert exactly – use these calculations:
Celsius x 1.8 + 32 = Fahrenheit
(Fahrenheit - 32) ÷ 1.8 = Celsius
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 9 of 18
Mathematical Tools for Accurate Measure
Reading dosing directions and converting those directions into usable numbers is essential for administering
medication to wildlife. Accurately measuring the result requires complete understanding of the basic devices of measure,
such as syringes and scales, as well as the ability to accurately read drug labels.
Syringes
A variety of hypodermic syringes are in common clinical use. We use all different sizes of syringes in wildlife
rehabilitation, from drug and fluid administration to feeding; we use more sizes than most medical professionals.
Recognizing the types of syringes and how they measure is a chief safety concern. You can do all the calculations accurately,
but if you measure incorrectly, it means nothing.
Most syringes are calibrated in mL. However, these various capacity syringes contain calibrations that differ from each
other requiring particular care in dosage measurement.
When very small dosages are required they are measured with a 1 mL syringe calibrated in hundredths. The long
numbered lines are 1/10th of an mL. The shorter lines centered between these are 1/20th of an mL. And the tiny lines are
each 1/100th of an mL.
The amount used in a 1 mL syringe will always be a fraction of a milliliter written as a decimal. It must always have a
leading zero to assure that the decimal point is not overlooked.
If your amount is larger than 1 mL, then use a 3cc syringe to avoid multiple injections.
On the 3 mL Syringe, The longer calibrations identify zero (0), and each ½ and full mL. These longer calibrations are
numbered: ½, 1, 1½, 2, 2½, and 3.
Next, notice the number of calibrations in each mL, which is 10, indicating that on this syringe each mL is calibrated in
tenths. There are no 1/100th markings like on the 1 mL syringe above, so although you can give larger volumes with one
injection, your dosing cannot be as exact.
Larger syringes are reserved for bolus fluids and feeding. Here the longer lines are single milliliters, and in between we
can only measure down to 1/5th of an mL.
Look closely at the syringe you are using and double check the measure.
Some do not measure mL or will have multiple measures. Look for the mL or cc
marking below the scale to avoid errors. This syringe also measures teaspoons.
Minim markings can still be found on some 3 and 1 mL syringes. This is
an old apothecary measurement. Because of the “M,” these are sometimes
ii
confused with milliliters but it actually stands for “Minim.”
U-100 and U-40 insulin syringes are not calibrated the same as metric syringes. Great care must be taken when using
these syringes. These are labeled in units rather than cc
or mL.
U-100 syringes can be easily converted by
imagining a decimal point before the number. U-40
syringes are not easily converted and should be
discarded.
Insulin syringes usually come with colored tops
(orange for U-100, and red for U-40). The calibration
scale should be clearly labeled on the back of the syringe.
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 10 of 18
Practice problems
19
20
= ____ mL
23
21
= ____ mL
24
= ____ mL
22
= ____ mL
25
= ____ mL
= ____ mL
26
= ____ mL
= ____ mL
Needle Gauges
Needle thickness is categorized by gauge. Any gauge needle can come in various lengths but the gauge indicates its
thickness. The larger the number, the finer the needle. Although these can vary depending on the viscosity of the
medication, the following is a guide of recommended needle gauge according to an animal’s body weight.
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Body Weight
Needle Gauge
10-25 grams
26 gauge
25-50 grams
25 gauge
50-100 grams
23 gauge
100-500 grams
22 gauge
500+ grams
18-20 gauge
Page 11 of 18
Drug Labeling
Drugs are also tools and understanding how to interpret labels is essential to accurate dosing.
Determining how much of a drug is available in what amount of volume
is a “drug per volume” ratio and it indicates the drug’s “strength.”
With the “per” written as the fraction line in our ratio equation:
Amount of Drug
Amikacin has 50 mg per 1 mL.
Atropine contains 15 mg per 1 mL.
Benedryl has 12.5 mg per 5ml
Volume
Drug Strength Listed as a Percentage
Drug percentage strength ALWAYS refers to mg per centiliter!
That’s the rule! Drug percentage strength ALWAYS refer to mg per centiliter. Since our syringes measure in milliliters,
that’s what we want so it must be converted.
KILO
1000
Units
Drug
HECTO
100
Units
DEKA
10
Units
To convert to a larger unit
move the decimal point to the left
To convert to a smaller unit
move the decimal point to the right
Percentages
BASIC
UNIT
We start with centiliters - And we go toward what we want to know, which
is milliliters.
Count the steps. This is only 1 step.
DECI
0.1
Unit
CENTI
0.01
Unit
MILLI
0.001
Unit
1.0 .
percentages
ALWAYS refer to
mg per centiliter
our syringes
measure in
milliliters
The decimal point given in the percentage is moved accordingly (review
page 8 for reference).
Don’t forget to add a zero because we have no room.
A 1% label means there is 10 mg per 1 mL.
When faced with a drug listed as a percentage, just move the decimal
point one place to the right.
Combination Drugs
Calculating combination drugs (containing more than one active medication) is guided by your prescription orders
(the directions you receive from the vet or from your pharmacology book).
There are 3 common instructions for dosing combination drugs:

Prescription knows the strength and states the measured amount to give

Prescription states to use only one ingredient to calculate dosage

Prescription states to combine the ingredients to calculate (In this case you would
add the milligrams of drugs and make the total the strength in your equation)
Read - Re-Read - And Follow the Instructions!
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 12 of 18
Diluting Medications
Because we so often need to treat tiny animals, drugs may need to be diluted. Capsules can be opened and tablets can
be crushed so that you are working with a powder. The powder can then be added to liquids such as saline, dextrose, water
or syrup for oral administration of tiny amounts.
The math of this is quite easy because it’s based, again, on our ratio calculation.
Cutting Tablets and Pills
Determine how many milligrams of medication are in one capsule or tablet.
Next: Determine how many milligrams of drug you need PER DOSE.
Then estimate what volume you can comfortably get that animal to drink.
Milligrams you
need for 1 dose
_____________
Cross multiply and your answer gives you exactly how many milliliters of fluid
to put the powder in.
Volume you can
comfortably give
the animal
?
Milligrams you
need for 1 dose
_____________
Drug
Strength
__________
Pill Strength
=
__________
Diluting Liquid Drugs
Put in the drug strength listed (per volume)
Determine how many milligrams of drug you need PER DOSE
Then estimate what volume you can comfortably get that animal to drink.
Cross multiply and use your answer for the next step (your answer gives you
the total how medication you will make).
Choose a syringe large enough for the full amount you will make
Pull 1 measure of the medication (the per volume amount of the strength)
Fill syringe with liquid until it reaches the total of how much solution you will
make.
=
Volume you can
comfortably give
the animal
?
When diluting injectables, much care must be taken choosing what to use as the additional liquid. It must be sterile
and must mix with the drug properly. Common choices are:
Sterile water
Sterile saline
Propylene glycol
If you don’t know which to use, ask your veterinarian, pharmacist or consult written material that accompanies the
drug. You can’t just mix in anything. For example: diazepam is insoluble in water; propylene glycol which is a solvent in
its clinical, injectable form is appropriate. iii
Label Your New Drug
You want to label your new dilution as number of milligrams per 1 milliliter.
You do this by doing a second calculation:
Keep one side of your original equation
On the opposite side put the number 1 on the bottom
Cross multiply again. This gives the milligrams per 1 milliliter.
On the label, write the name of the drug, the new strength and the date.
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Milligrams you
need for 1 dose
_____________
Volume you can
comfortably give
the animal
?
=
__________
1
Page 13 of 18
Prescription Abbreviations
Carefully following the directions in a prescription is imperative, and you need to understand the language.
Prescription abbreviations are broken down into 3 categories: Amounts, Frequency and Administration.
(Note – Amounts were previously covered in the metric section – Refer to page 7)
Frequency
b.i.d.
q.i.d.
s.i.d.
t.i.d.
twice a day
four times a day
once a day
three times a day
q4h
q6h
q1d
q1w
q2w
every 4 hours
every 6 hours
every day
every week
every 2 weeks
ad.lib.
freely as wanted
p.r.n.
as needed
to effect until you reach an effective result
Route of Administration
im
ip
iv
po
sq
intramuscular
Intraparitoneal
intravenous
orally
subcutaneous
in a muscle
in the perineum
in a vein
by mouth
under the skin
Scales
Postal Scales - Small
Up to 5 kg – in 1 g increments
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www.salestores.com
Postal Scales - Large
Up to 55 lb – will measure in 5 or 10 g increments
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www.salestores.com
Jewelry Scales
Up to 100 g– in 0.01 g increments
Ebay Seller – ravenscalesonline
Formulary
Exotic Companion Medicine
Handbook for Veterinarians
(Acrobat PDF Instant Download) by
Linda Harrison
exoticdvm.com
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Exotic Animal Formulary (3rd edition)
Edited by James W. Carpenter, MS,
DVM
Exotic Animal Formulary [Hardcover]
by James W. Carpenter, MS, DVM
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 14 of 18
Practice Problem
You have a juvenile fox with skin infection from mange.
The animal weighs 1800 gm.
You are to give 15 mg of sulfa/trimethoprin per kg PO BID for 10 days and
ivermectin 0.2mg/kg, IM, Repeat in 2 weeks. Your ivermectin solution is 1%.
27. How many mL of sulfa/trimethoprim will it receive each
dose?
28. How will the sulfa/trimethoprim be administered?
29. How many doses of the sulfa/trimethoprim will it receive
total before treatment is stopped?
30. How many mL of ivermectin will it receive?
31. How will the ivermectin be administered?
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 15 of 18
The Power of Percentages
Percentages are used heavily in 2 critical areas of wildlife rehabilitation:
A percentage means PARTS PER HUNDRED
A percentage can be written several ways:
Stomach Capacities & Fluid Therapy
with the percent symbol
10%
as a decimal
0.10
_10_
100
or as a ratio
Calculating Straight Percentages
To find the percentage of any number, set up a ratio calculation:
Label the calculation as “whole” and “percent” (or part)
The left is your control side and the bottom whole is always one hundred
The top is the percent you want to find
On the right, the whole is the number you know
Cross multiply to find the percentage of that number
For example, The ratio to discover 5% of the number 250 would be:
As in any other ratio problem, you then multiply the 2 diagonals that
you have and divide by the remaining number
Straight Percentages are used to determine stomach capacity as well as daily fluid needs.
Stomach Capacity
Baby animals have a defined stomach capacity according to species and age. Underfeeding may result in malnutrition,
while overfeeding can cause severe distress and diarrhea. Calculating stomach capacity is a necessary component of wildlife
rehabilitation.
Daily Fluid Requirements
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The daily requirement for MOST animals is between 5 and 10 percent of their NORMAL body weight.
MOST stable adults need about 5 percent, and some animals such as raptors will get this amount in their food.
Growing babies need more, about 10 percent.
Animals actively losing fluids, such as happens with diarrhea, will require more.
Fluid Replacement Calculations
Fluid requirements are based on the NORMAL weight of the animal and calculation MUST be based on this number.
When an animal is dehydrated, its NORMAL weight has been reduced by a percentage directly related to the fluid loss.
Finding the normal (pre-dehydration) weight is necessary for accurate fluid replacement and maintenance.
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 16 of 18
Step by Step Rehydration
Finding the Whole of a Percentage (Normal Body Weight)
1. Weigh the animal (IN GRAMS) and save the number:
We use grams to calculate fluid replacement because it is easily converted to mL (most common measure of fluids).
2. Determine the percentage of dehydration:
Skin Turgor
Mouth
Eyes
1-2 seconds
Dry Mucous
Membranes
Normal to Dull
2-5 seconds
Mucous Membranes
are red, dry, tacky
Dull and Sunken
Cataract-like
appearance in pupils
5+ seconds
Tongue dried and
cracked
Tongue white, dried
and cracked
No Return
Other
Sunken eyes
Sunken eyes might not
be visible
Seriousness
5%
Moderate
8%
Severe
12 %
Life Threatening
15%
Death Imminent
Depression
Lethargic
Skin Wrinkled
Shock
Skin Dry and Wrinkled
3. Subtract the percentage from 100. This is your (percentage of normal weight):
4. Set up your calculation:
Degree
100 – (degree of dehydration) =
You now have the animal’s pre-dehydration
NORMAL weight. It is this weight that you must
use to calculate BOTH Daily Fluid Requirements
and Rehydration Fluids in the next steps.
Three Day Rehydration Protocoliv
As we stated on the previous page, the daily requirement for MOST animals is between 5 and 10 percent of their
NORMAL body weight. This amount must be supplied daily IN ADDITION TO the extra fluids given to rehydrate an animal.
Because a compromised animal may not be able to absorb a huge amount of fluids all at once, and trying this may even
overburden the systems, the additional rehydration fluids are replaced slowly over a period of three days. After the needed
amount is calculated, half is given the first day, and the remaining amount is again divided and given on days two and three.
1.
Calculate the daily fluid requirement for the animal. Save this number as “daily need.”
Animal’s NORMAL weight in grams X Needed daily percentage (5-10%)
2.
Calculate the total replacement fluid needed to counteract the dehydration.
Save this number as “replacement total.”
Animal’s NORMAL weight in grams X Percentage of fluid loss (from chart)
3.
Divide the “replacement total” number in half. Add the daily need to the resulting answer.
This is the total amount of fluids you will give the first day in MILLILITERS. Divide this by how many times you will
administer the fluids throughout the first day.
( Replacement total ÷ 2 )
4.
+
Daily need ( from step 5 ) = Total
Divide the “replacement total” number by 4. Add the daily need to the resulting answer.
This is the total amount of fluids you will give on both days two and three in MILLILITERS. Divide this by how many
times you will administer the fluids throughout each of the days.
( Replacement total ÷ 4 )
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
+
Daily need ( from step 5 ) = Total
Page 17 of 18
Practice Problem
You have an adult squirrel that weighs 500 grams.
According to the chart it is suffering from 5% dehydration.
You will rehydrate him over 3 days also supplying his 5% daily needed fluids.
32. What is his normal (non-dehydrated) weight?
33. What is the total fluid amount he will receive the first day?
34. What is the total fluid amount he will receive the second day?
35. What is the total fluid amount he will receive the third day?
This course is also available online at www.WildlifeRehabilitationSchool.com
Part 2 of this series will debut on the website in April including:
Caloric intake calculations
Zoo diet evaluation
Understanding milk formulas
i
T. Trimpe 2008 http://sciencespot.net/
Foundations of nursing, Lois White, Cengage Learning, 2005
iii
Janusz Szajewski, MD , Warsaw Poison Control Centre (August, 1991). "Propylene glycol (PIM 443)." IPCS
INChem. Retrieved July 2, 2009.
iv
The three day rehydration protocol is the standard we at Red Creek Wildlife Center have been using for
over twenty years. This is the protocol I learned when I first began rehabbing. I did not develop this
protocol but do not have the original information for whom to credit.
ii
Math Made Easy for the Wildlife Rehabilitator
©2012 Red Creek Wildlife Center, Inc
Page 18 of 18