Ch. 3: Calculations

Question 1

Aminotheophylline to theophylline

Theophylline to aminotheophylline

Answer 1

A to T: multiply by 0.8

T to A: divide by 0.8

Question 2

1 quart =

Answer 2

2 pints 
960 mL (approx)
946 mL (actual)

Question 3

1 gallon=

Answer 3

4 quarts
3840 mL (approx)
3785 mL (actual)

Question 4

1 cup=

Answer 4

8 oz
240 mL (approx)
236.56 mL (actual)

Question 5

1 pint=

Answer 5

16 oz
480 mL (approx)
473 mL (actual)

Question 6

Isotonicity Formula

Answer 6

E-value = [(58.5) (i)] / [(MW of the drug) (1.8)]

Question 7

If pt is underweight (TBW < IBW), use

Answer 7

TBW to dose all medications (to avoid overdosing)

Question 8

If pt is normal weight (TBW=IBW)

Answer 8

Use TBW to dose most medications

Use IBW to dose aminophylline, theophylline, acyclovir

Question 9

If pt is obese (TBW&raquo_space; IBW), use

Answer 9

TBW for LMWH, UFH, vancomycin
IBW for aminophylline, theophylline, acyclovir
ABW for aminoglycosides

Question 10

Ratio strength and percentage strength

Answer 10

100 divided by either strength

Question 11

PPM to Percentage Strength

Answer 11

Move decimal LEFT 4 spaces

Question 12

Percentage Strength to PPM

Answer 12

Move decimal RIGHT 4 spaces

Question 13

Specific Gravity

Answer 13

SG= g/mL

Question 14

Osmolarity

Answer 14

[weight (g/L) / MW (g/mole)] x (#of particles) x 1000

Question 15

mols or mmols

Answer 15

mols= g/MW
mmols= mg/MW

Question 16

Milliequivalents

Answer 16

mEq= (mg x valence)/MW
OR
mEq= mmols x valence

Question 17

Adjusted Body Weight (ABW)

Answer 17

IBW + 0.4 (TBW-IBW)

Question 18

Phenytoin correction

Answer 18

total phenytoin / [(0.2 x albumin)+0.1]

Question 19

1 grain =

Answer 19

65 mg

Question 20

Dextrose (parenteral and enteral) equivalence in kcal

Answer 20

3.4 kcal/g

4 kcal/g

Question 21

Lipid enteral equivalence in kcal

Answer 21

9 kcal/g

Question 22

IV fat emulsion equivalence in kcal:
10% IVFE
20% IVFE
30% IVFE

Answer 22

10% = 1.1 kcal/mL
20% = 2 kcal/mL
30% = 3 kcal/mL

Question 23

Amino acid (protein) equivalence in kcal

Answer 23

4 kcal/g

Question 24

Fluid requirements

Answer 24

1500 mL + (20mL) (wt in kg - 20)

Question 25

Nitrogen balance equation

Answer 25

g of protein / 6.25

Question 26

NPC : N ratios

Answer 26

80: 1 most severely stressed
100: 1 severely stressed
150: 1 unstressed

Question 27

Anion Gap Calculation

Answer 27

AG= Na - Cl - HCO3

Question 28

CUTE DIMPLES Metabolic Acidosis Anion Gap Mnemonic

Answer 28

Cyanide
Uremia
Toluene
Ethanol (alcoholic ketoacidosis)
DKA
Isoniazid
Methanol
Propylene glycol
Lactic acidosis
Ethylene glycol
Salicylates

Question 29

How are blood gas values presented?

Answer 29

pH/CO2/O2/HCO3/O2 sat