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aminophylline to theophylline
1 aminophylline / 0.8 theophylline
measurements
1 grain / 65 milligrams
1 cup / 8 oz
1 pint / 473 ml
1 quart / 2 pints (946 ml)
1 gallon / 4 quarts (3785 ml)
BMI
weight (lbs) / height (cm)
2
X 704.5
BMI classifications
< 18.5
: under weight
18.5 - 24.9
: normal
25 - 29.9
: over weight
> 30
: obese
Ideal Body Weight (IBW)
men
: 50 + 2.3(ht (in inches) - 60)
female
: 45.5 + 2.3(ht (in inches) - 60)
BUN:Scr ratio
ratio > 20 indicates dehydration
CrCl
(140 - age) x (wt in kg) / 72 x Scr
underweight
: (<18.5) use actual weight
normal
: (18.5 - 24.9) use IBW
overweight
: (>25) use adjusted body weight
adj body weight
: IBW + 0.4 (TBW - IBW)
*TBW - actual weight
GFR levels
>90
: stage 1
60 - 89
: stage 2
30 - 59
: stage 3
15 - 29
: stage 4
<15
: stage 5
Specific Gravity
SG = weight (g) / volume (ml)
water
: specific gravity of 1
TPNs
Carbs
: 4 kcal / g
Fat
: 9 kcal / g
protein
: 4 kcal / g
dextrose
: 3.4 kcal / g
amino acids
: 4 kcal / g
glycerin
: 4.3 kcal / g
IVFE 10%
: 1.1 kcal / ml
IVFE 20%
: 2 kcal / ml
IVFE 30%
: 3 kcal / ml
Determining Fluid Needs
When weight over 20 kg: 1500 ml + (20 ml)(wt in kg - 20)
Protein requirements
non-hospitalized
: 0.8 - 1 g/kg/day
hospitalized
: 1.2 - 2 g/kg/day
Activity factor
Confined to bed
: 1.2
Out of bed
: 1.3
BEE (Basal Energy Expenditure)
BEE = non-proteins or lipids and dextrose
Determining grams of nitrogen from protein
Nitrogen intake = grams of protein intake / 6.25
NPC:N ratio - first calculate nitrogen intake
- then divide non-protein (lipids and dextrose) by grams of nitrogen
Corrected Calcium
Ca
corrected
= calcium
serum
+ (4.0 - albumin)(0.8)
calcium + phosphate
: should not exceed 45mEq/L
mOsml/L
mOsml/L = wt of substance (g/L) / MW (g/mole) X (# of particles) X 1,000
Dissociation of particles for mOsml/L
dextrose
: 1
mannitol
: 1
potassium chloride
: 2
sodium choloride
: 2
sodium acetate
: 2
calcium chloride:3
sodium citrate
: 4
Isotonicity: E-value
E = (58.5)(i) / (MW of drug)(1.8)
i = dissociation of ions
1 ion
: 1
2 ions
: 1.8
3 ions
: 2.6
4 ions
: 3.4
5 ions
: 4.2
*add 0.8 when adding an ion
moles and millimoles
moles = g / MW
mmols = mg / MW
mEq formula
(mg x valence) / MW
OR
mEq = mmlols X valence
compound and its valence electron for mEq formula
ammonium chloride (NH4Cl)
: 1
potassium chloride (KCl)
: 1
potassium gluconate
: 1
sodium acetate
: 1
sodium bicarbonate
: 1
calcium carbonate
: 2
calcium chloride
: 2
disodium phosphate
: 2
ferrous sulfate
: 2
magnesium sulfate
: 2
Temperature Conversions
Celius = (F - 32) / 1.8
Farenheit = (C x 1.8) + 32
Calcium Tablet Conversion
Calcium Carbonate
: 40% elemental
Calcium acetate
: 21% elemental
Calculating ANC
ANC = WBC X (segs + bands) / 100
Anion Gap equation
Na - Cl - HCO
3
*anion gap >12mEq/L considered high
Henderson hasslebalch
pH = pka + log (base / acid)
*ammonium is acidic
weak acid
: pH > pka
weak base
: pH < pka
*pkw = pka + pkb
: pkw = 14
Dilution and Concentration
Q1 X C1 = Q2 X C2
Drug-Nutrient interactions with enteral feedings
warfarin
tetracycline
ciprofloxacin
phenytoin
Percent Ionization
% ionization = 100 / 1+ 10
pka-pH
MWQ (minimum weighable quantity)
Mwq = SR (sensitivity requirement) / % of error
* change % to decimal first
Author
capnhue
ID
278751
Card Set
Calculations
Description
Calculations
Updated
2014-07-28T20:20:50Z
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