Calculations

Question 1

How many grams is 1 oz?

Answer 1

28.4 g

Question 2

How many grams is 1 lb?

Answer 2

454 g

Question 3

How much does 1 grain (gr) weigh?

Answer 3

65 mg (approx)
64.8 mg (actual)

Question 4

how many mmol does 1 mEq of K+, Na+, and other monovalent ions??

Answer 4

1 mmol

Question 5

How many mmol does 1 mEq of Ca++ and other divalent ions?

Answer 5

0.5 mmol

Question 6

Aminophylline and theophylline conversion

Answer 6

amino –> theo; multiply by 0.8

theo –> amino; divide by 0.8

Question 7

ratio strength

Answer 7

one unit of solute contained in the total amount of a solution (1:500)

Question 8

PPM to percentage

Answer 8

Move decimal left 4 places

Question 9

Percentage to PPM

Answer 9

Move decimal right 4 places

Question 10

Specific gravity (SG)

Answer 10

the ratio of the density of a substance to the density of water
weight of substance/weight of water
SG > 1 = substance heavier than water
SG < 1 = substance lighter than water

SG = g/mL16

Question 11

Ratio strength to percentage

Answer 11

100/ ratio strength

Question 12

Percentage to ratio strength

Answer 12

100/% strength

Question 13

Osmolarity

Answer 13

the number of particles per liter of solution

Question 14

Dissocation of particles

Answer 14

The number of particles of a particular compound when in solution
Ex:
# of dissociation particles of dextrose = 1
# of dissociation particles of NS = 2 (breaks down into Na+ and Cl-)

Question 15

Dissociation of KCl

Answer 15

2

Question 16

Dissociation of Sodium acetate

Answer 16

2

Question 17

Dissociation of Calcium chloride (CaCl2)

Answer 17

3

Question 18

Dissociation of sodium citrate (Na3C6H5O7)

Answer 18

4

Question 19

Osmolarity equation

Answer 19

mOsm/L = wt of substance (g/L)/molecular weight (g/mole) X # of particles X 1000

Question 20

Tonicity

Answer 20

describes osmolarity in context of body fluids

Question 21

Dissociation factor (i)

Answer 21

percentage that dissociates into ions
Ex:
i = 1.8 means 80% of compound will dissociate
i = 1 means 0% will dissociate

Question 22

Dissociation factor

Answer 22

1 ion = 1
2 ions = 1.8
3 ions = 2.6
continue to add 0.8 for each ion

Question 23

E value

Answer 23

The amount of drug that produces a certain osmolarity and the amount of NaCl that produces the same osmolarity

Question 24

E value equation

Answer 24

E = 58.5 x diss. factor / MW of drug x 1.8

Question 25

1 gallon = ____ mL

Answer 25

3785 mL

Question 26

Molecular weight of NaCl

Answer 26

58.5

Question 27

What is a mole?

Answer 27

grams/MW

mmol = mg/MW

Question 28

For all species, the numeric value of mEq is equal to mmol (t/f)

Answer 28

False

only monovalent species

Question 29

Milliequivalents formula

Answer 29

mEq = (mg x valence) / MW

Question 30

BMI formula

Answer 30

kg/m^2

Question 31

BMI classifcations

Answer 31

< 18.5: underweight
18.5-24.9: Normal weight
25-29.9: Overweight
>30: Obese

Question 32

Normal wasit circumference

Answer 32

women: 35 inch or less
Men: 40 inch or less

Question 33

What value usually indicates dehydration?

Answer 33

BUN;SCr ration > 20:1

both lab values will increase during dehydration

Question 34

What weight should be used when calculating CrCL?

Answer 34

Underweight (TBW < IBW): use TBW
Noraml weight (BMI <25): use IBW
Overweight: Use ABW

Question 35

What drug class do you use ABW in obese patients?

Answer 35

Aminoglycosides

Question 36

What body weight would you use for dosing LMWH, UFH, vanco in obese pts

Answer 36

usually TBW