Ch. 3: Calculations Flashcards
Aminotheophylline to theophylline
Theophylline to aminotheophylline
A to T: multiply by 0.8
T to A: divide by 0.8
1 quart =
2 pints 960 mL (approx) 946 mL (actual)
1 gallon=
4 quarts 3840 mL (approx) 3785 mL (actual)
1 cup=
8 oz
240 mL (approx)
236.56 mL (actual)
1 pint=
16 oz 480 mL (approx) 473 mL (actual)
Isotonicity Formula
E-value = [(58.5) (i)] / [(MW of the drug) (1.8)]
If pt is underweight (TBW < IBW), use
TBW to dose all medications (to avoid overdosing)
If pt is normal weight (TBW=IBW)
Use TBW to dose most medications
Use IBW to dose aminophylline, theophylline, acyclovir
If pt is obese (TBW»_space; IBW), use
TBW for LMWH, UFH, vancomycin
IBW for aminophylline, theophylline, acyclovir
ABW for aminoglycosides
Ratio strength and percentage strength
100 divided by either strength
PPM to Percentage Strength
Move decimal LEFT 4 spaces
Percentage Strength to PPM
Move decimal RIGHT 4 spaces
Specific Gravity
SG= g/mL
Osmolarity
[weight (g/L) / MW (g/mole)] x (#of particles) x 1000
mols or mmols
mols= g/MW mmols= mg/MW
Milliequivalents
mEq= (mg x valence)/MW
OR
mEq= mmols x valence
Adjusted Body Weight (ABW)
IBW + 0.4 (TBW-IBW)
Phenytoin correction
total phenytoin / [(0.2 x albumin)+0.1]
1 grain =
65 mg
Dextrose (parenteral and enteral) equivalence in kcal
3.4 kcal/g
4 kcal/g
Lipid enteral equivalence in kcal
9 kcal/g
IV fat emulsion equivalence in kcal:
10% IVFE
20% IVFE
30% IVFE
10% = 1.1 kcal/mL 20% = 2 kcal/mL 30% = 3 kcal/mL
Amino acid (protein) equivalence in kcal
4 kcal/g
Fluid requirements
1500 mL + (20mL) (wt in kg - 20)
Nitrogen balance equation
g of protein / 6.25
NPC : N ratios
80: 1 most severely stressed
100: 1 severely stressed
150: 1 unstressed
Anion Gap Calculation
AG= Na - Cl - HCO3
CUTE DIMPLES Metabolic Acidosis Anion Gap Mnemonic
Cyanide Uremia Toluene Ethanol (alcoholic ketoacidosis) DKA Isoniazid Methanol Propylene glycol Lactic acidosis Ethylene glycol Salicylates
How are blood gas values presented?
pH/CO2/O2/HCO3/O2 sat
