Download Fluids & Electrolytes

Math Review
Ana Corona, DNP, FNP-C
Nursing Professor
July 2013
More presentations at: www.nurseana.com
Conversion Factors
1
1
1
1
1
1
1
1
1
Dram = 4 cc
Tbs = 15 cc
Tsp = 5 cc
Oz = 30 cc
gr = 60 mg
gm = 1,000 mg
mg = 1,000 ug (ug = micrograms)
hour = 60 minutes
kg = 2.2 pounds
Metric
mcg – microgram
mg – milligram
gm – gram
kg – kilogram
ml – milliliter
cc – cubic centimeter
Apothecary
gr – grain (for weight)
lb – pounds (for weight)
m – minim (for volume)
oz – ounce (for volume
Household
tsp – teaspoon
T or Tbs – tablespoon
c – cup
pt – pint
qt – quart
Metric to Metric
1
1
1
1
1
1
kg = 1000 gm
gm = 1000 mg
mg = 1000 mcg
L = 1000 ml = 1000 cc
ml = 1000 mcl
ml = 1 cc
Household to Household
1 Tbs = 3 tsp
1 oz = 2 Tbs
Between Systems:
gr 1 = 60 mg
gr 5 = 300 mg
gr 15 = 1000 mg = 1 g
gr 1/150 = 0.4 mg
1 oz = 30 ml
1 dr = 4 ml
1 Tbs = 15 ml
1 tsp = 5 ml
1 min = 15 ml
1 min = 0.06 ml = 1 drop
Basic Formula
Desired Dose x
Dose on Hand
or
D xV=A
H
VOL.
Dose on Hand
= VOL.
Desired Dose
Infusion Time
Infusion Time = Total Volume to be Infused
mL/hr being infused
or
Total Volume to Infuse ÷
gtt / min
x 60 mi
Flow Rate
Total Volume (mL) x Set Calibration (gtt/mL)
Time (min)
Flow Rate = mL/hr diveded by Division Factor
Division Factor = 60 divided by calibration
1. Ordered ceclor 500 mg. Have ceclor 400 mg in
5 ml. How many ml will you give?
Desired Dose order
Have on hand
Formula:
X Volume ml
1
=
D X V ml =
H
1
ORDERED QUANTITY 500 mg
 WANTED QUANTITY ____ ml
 CONVERSION FACTOR 400 mg / 5 ml (Given in the
problem)
 SETUP
500 mg x 5 ml
_______________ = ______ml
400 mg
 CROSS OUT the units which cancel
out, leaving no units except the
WANTED QUANTITY unit (In this
case, you want the answer in ml).
 500 mg x 5 ml
_______________ = ______ml
400 mg
Do the Basic Math
 Multiply the numbers across, then
divide the number on top by the
number on bottom.
(500 x 5)
400
2500
(2500 divided by 400)
400
 = 6.25 ml.
2. Ordered tylenol 10 grains. Have tylenol 160 mg
in 1.6 ml. How many ml will you give?
 ORDERED QUANTITY 10 gr
 WANTED QUANTITY ____ ml
 CONVERSION FACTORS 60 mg in 1 gr
(we expect you to know this) and 160
mg in 1.6 ml (Given in the problem)
 SETUP
10gr x 60 mg x 1.6 ml
__________________ = ______ml
1 gr x 160 mg
 CROSS OUT the units which cancel
out, leaving nothing but the WANTED
QUANTITY
10 gr x 60 mg x 1.6 ml
__________________ = ______ml
1 gr x 160 mg
Do The Basic Math
 Multiply the numbers across, then
divide the number on top by the
number on bottom.
 10 x 60 x 1.6 = ml
 1 X 160
 = 6 ml.
3. IV problem using the same method
 You have an IV running at 21
gtts/min using macrodrip (15 gtt/ml)
tubing.
 You are going to switch the infusion
over to an Abbott pump.
 How many cc/hr will you set the
pump at to keep the infusion running
at the same rate?
 GIVEN QUANTITY 21 gtts/min
 WANTED QUANTITY ____ ml/hr (cc and ml
are equivalent)
 CONVERSION FACTORS 60 min/ hr (you
know this) and 15 gtt/ml (Given in the
problem)
 SETUP
21 gtts x 60 min x 1 ml
__________________ = ______ml/hr
1 min x 1 hr x 15 gtts
 CROSS OUT the units which cancel
out, leaving nothing but the WANTED
QUANTITY
21 gtts x 60 min x 1 ml
__________________ = ml/hr
1 min x 1 hr x 15 gtts
Do The Basic Math
 Multiply the numbers across, then
divide the number on top by the
number on bottom.
 (21 x 60 x 1) divided by ( 1 x 1 x 15)
= 84 ml/hr.
Question 1-4
1. 1/4 ounce = _________ cc.
2. How many cc in 3.75 Tbls
3. Ordered tylenol 600 mg. Have tylenol
250 mg in ½ tsp. How many cc will
you give?
4. Ordered ceclor 550 mg. Have ceclor
400 mg in 5 ml. How many mL will
you give?
Answer to Question 1
Dimensional Analysis
Method
Answer Units = cc
Conversion Factor =
30cc/oz
1/4 oz
30 cc
_____ X ____ =7.5cc
1 oz
Old Fashion Method
There are 30 cc in
one ounce. Multiply
The number of
oz x 30cc to obtain
the correct answer.
1/4oz x 30 cc = 7.5
cc
Answer to Question 2
Dimensional Analysis Method
Answer Units = cc
Conversion Factor = 15 cc/1 TBLS
3.75 TBLS.
15 cc
_______ X
______ = 56 cc
1 TBLS.
Answer to Question 2
Old Fashion Method
First convert the half teaspoon to cc
Then use the standard formula
(dose ordered/dose available x the
number of cc). There are 5 cc in one
teaspoon
5cc x 1/2 tsp = 2 . 5 cc.
Now use the standard formula:
600 mg/250 mg x 2 . 5 cc = 6 cc.
Answer to question 3
Dimensional Analysis Method
Answer Units = cc
Conversion Factors = 250 mg/ 1/2 tsp
AND 5 cc/1 tsp
600 mg
1/2 tsp
5 cc
______ X _______ X ______ = 6 cc
250 mg
1 tsp
Answer to question 3
Old Fashion Method
First convert the half teaspoon to cc
Then use the standard formula
(dose ordered/dose available x the
number of cc). There are 5 cc in one
teaspoon
5cc x 1/2 tsp = 2 . 5 cc.
Now use the standard formula:
600 mg/250 mg x 2 . 5 cc = 6 cc.
Answer to question 4
Dimensional Analysis Method
Answer Units = mL
Conversion Factor = 400 mg/ 5mL
550 mg
5 mL
______ X ________ = 6.875 mL
400 mg
Answer to Question 4
Old Fashion Method
Just use the standard
ordered/available x ml formula
550/400 x 5 ml = 6 . 875 ml.
Rounding
 How do you give
6.875cc? Mathematically, this
number rounds to 6.9 ml. However,
in the clinical setting, you would need
to give this in a 10 ml syringe which
has marks every 0.2 ml.
 You would therefore have to draw up
either 6 . 8 ml or 7 ml. I would give
6 . 8 ml, rather than "round" 6.87 ml
clear up to 7 ml, to avoid any
possible overdose.
Question 5
5. Ordered tylenol 15 grains. Have
tylenol 160 mg in 1.6 mL. How many
mL of tylenol will you give?
Answer for question 5
Dimensional Analysis Method
Answer Units = mL
Conversion Factors = 160 mg/ 1.6 mL
tsp AND 60 mg/1 gr
15 gr
60 mg
1.6 mL
_____X _____ X _______ = 9 mL
1 gr
160 mg
Answer for question 5
 Old Fashion Method
First convert the 15 grains into mg.
There are 60 mg in one grain, so 15 x
60 = 900 mg.
 Now use the standard formula.
900mg/160 mg x 1.6 mL = 9 mL.
Question 6
 Ordered Demerol 80 mg and Vistaril
50 mg IM. You have Demerol in 1 mL
ampules with 100 mg/ml.
 Vistaril is in a 10 mL multi- dose vial
labeled 50 mg/ml. What is the total
volume to be given?
First, why do I care about total volume?
 These medications are ordered together to
treat pain and nausea.
 They can be given mixed in the same
syringe, to avoid giving the patient
separate IM injections.
 In order to correctly draw up the two
medications in one syringe, you need to
know how many cc of each medication you
will give, and the total volume you will end
up with in the syringe.
Answer to question 6
Dimensional Analysis Method
Answer Units = mL
Conversion Factors = 100 mg/ 1 mL
(Demerol) AND 50 mg/mL (Vistaril)
Demerol 80 mg
1 mL
_____________ X _____
= 0.8 mL
100 mg
Vistaril 50 mg
1 mL
___________ X _______
= 1 mL
50 mg
0.8 mL + 1 mL = 1.8 mL
Answer to question 6
Old Fashion Method (Ordered over
Available)
Demerol 80mg/100mg x 1mL = 0.8 mL
Vistaril 50 mg/50mg x 1 mL = 1mL
0.8mL + 1mL = 1.8 mL
Question 7
 Ordered Penicillin 75,000 units. Have
10 mL vial labeled Penicillin 100,000
units/ 5 mL
 How many mL will you give?
Answer to question 7
Dimensional Analysis Method
Answer Units = mL
Conversion Factor = 100,000u/5 mL
75,000 u
5 mL
________ X ________ = 3.75 mL
(Round to 3.8 mL)
100,000 u
Answer to question 7
Old Fashion Method
 75,000 u/100,000 u x 5 ml = 3.75 cc.
 However, the closest you can measure
in a 5 cc syringe will be 3.7 and 3.8, so
you may round up to 3.8 ml.
Note: be careful with multidose
vials.
 The label will state both how much is
in the vial AND the dose
concentration. YOU NEED TO KNOW
THE DOSE CONCENTRATION.
 This problem states that the vial
holds 10 ml of fluid, but the dose
concentration is 100,000 units/ 5ml.
 This is the information you need to
solve the problem.
Question 8
 At the end of your 8 hour shift, you are
calculating I&O for your patient.
 When you received report from the
previous shift it was stated that this
patient had 375 cc remaining in her IV
for you to count.
 During your shift the patient ate one
egg and a slice of toast for breakfast
and had a hamburger, french fries
and 4 oz. of tea for lunch.
 She also drank two cartons of milk at
8 oz. each and had 150cc of pop. The
client then became nauseated and
vomited 150 cc.
 She also starting having stomach
cramps and passed two liquid stools.
 After vomiting, she has only eaten
and retained one 90 cc orange
popsickle.
 She voided clear yellow urine three
times during your shift: 250 cc, 365
cc, and 200 cc.
 You hung a new 1000 cc bag of IV
fluid which now has 650 cc in it.
 The patient also received Keflex 250
mg IVPB in 50 cc of N/S one time
during your shift.
Question
 What is this patient's I&O for your
shift?
How to Calculate the Intake
 Oral Intake - the patient drank 4 oz
of tea (120 cc), two 8 oz cartons of
milk (2 x 240 cc = 480 cc), 150 cc of
pop, and ate one 90 cc popsickle.
 This is all of her total oral intake,
which comes to 840 cc.
 IV fluid - the patient had 375 cc up in
her IV when you started this shift.
 Sometime during your shift all of that
375 cc went into the patient.
 You then hung a new bag with 1000
cc in it.
 As you are getting ready to do I&O
for your shift you note that only 650
cc are remaining in that bag you
hung.
 This means that 1000 - 650 = 350 cc
of IV fluid from that bag went into
your patient during your shift, so you
count 375 cc + 350 cc = 725 cc IV
fluid in your intake. The remaining
650 cc in the bag is left for the next
shift to count.
 IVPB - (IV piggybacks or IV meds)
Your patient had one 50 cc IVPB so
add this 50 cc to the patient's intake.
 Total Intake is the sum of her oral
intake (840cc) added to her IV fluid
(725 cc) plus her IV med (50 cc)
1615 cc total intake
How to Calculate the Output
 For output, you add up the amount of
emesis (150 cc) plus the amount of
urine (250cc + 365 cc+ 200 cc).
 If the patient had an N/G connected
to suction, you would count the N/G
drainage as output also.
 Total Output is the sum of her emesis
(150 cc) added to her urine
(815cc) + an unknown amount in
liquid stool
 Total Output is recorded as
965+ cc
You should get lots of practice with
this type of problem during your
clinicals.