Conversions and Calculations

(3/5) (All)
Multiple Prefix Mass Length Volume
1x103 Kilo kg km kL
1x100 basic g m L
1x10-1 Deci dg dm dL
1x10-2 Centi cg cm cL
1x10-3 Milli mg mm mL
1x10-6 Micro μg μm μL
1x10-9 Nano ng nm nL
1x10-12 Pico pg pm pL

Roman Numerals
ss = ½ L or l 50
I or I 1 C or c 100
V or v 5 D or d 500
X or x 10 M or m 1000

Apothecaries System
1 scruple 20 grains
1 dram 60 grains 3 scruples
1 ounce 480 grains 8 drams
1 pound 5760 grains 12 ounces
1 fluidram 60 minims
1 fluidounce 480 minims 8 fluidrams
1 pint 7680 minims 16 fluidounces
1 quart 32 fluidounces 2 pints
1 gallon 128 fluidounces 8 pints


Avoirdupois System
1 ounce [oz] 437.5 grains
1 pound [lb] 7000 grains, 16 oz



Other Conversions
1 inch 2.54 cm 1 L 33.8 fl. oz
1 foot 0.305 m 1 ml 16.2 minims
1 cc 1 mL 1 pint 473 ml
1 tsp 5 mL 1 gm 15.4 gr
1 fl. oz 29.57 mL 1 lb .454 kg
1 oz 28.35 g 1 gr 64.8 mg
1 kg 2.2 lbs 1 gallon 3790 ml



Calculating BSA [Body Surface Area]

BSA m2 = (W0.425 X H0.725 X 71.84)
10,000

BSA m2 = [{H (cm) X W (kg)}/3600]0.5

S = W0.425 X H0.725 X 71.84
Log S = Log W X 0.425 X Log (h) X 0.725 + 1.8564
(S = body surface in cm2, W = weight in kg, H = height in cm)



Rules for Child Dosing [CD]
Young^' s CD= (Age/(Age+12))X Adult Dose
Cowling^' s CD= ((Age at next Birthday)/24)X Adult Dose
Fried^' s CD= ((Age in months)/150)X Adult Dose
BSA CD= BSA of child [m^2 ] X dose per [m^2]
Alt.BSA CD= ((BSA of child [m^2 ])/(1.73 m))X Usual Adult Dose

Other Useful Equations
Molarity[g/l]= moles/Liter
Density [g/ml]= mass/volume
% error rate=(accepted-experimental value)/(accepted value) X 100
Percent of PI in a Product = (ml or gm of PI)/(Total ml or gm of product) X 100
Specific Gravity = (mass of substance)/(mass of equal amount of Water)
Related: grams= ml X SG
Alligation – Final Concentration =((C_1 Q_1 )+ (C_2 Q_2 )+ etc)/(Total Mass or Volume)
% error of Rx Balance= sensitivity/(quantity desired) X 100
Least Weighable Qty= (Sensitivity )/(%error tolerated) X 100
Aliquot Target Dose = ((Drug^' sLMQ)X (Dispensed wt of mix))/(Total Mix wt)
mOsmol/L = (Wt of substance in g/l)/(MW in g) X number of species X 1000
Henderson Hasselbach pH=pK_a+log⁡〖(A-)/HA〗



Dissociation Values (i) 80% (.2+.8+.8)
Substances that dissociate into 2 ions: 1.8
Substances that dissociate into 3 ions: 2.6
Substances that dissociate into 4 ions: 3.4
Substances that dissociate into 5 ions: 4.2
Freezing point of Electrolytes (i X 1.86 C)/(.52 C)= (MW of PI)/(x grams)
E of solution (MW of PI X 1.8)/(58.5 X i of PI) = (1 g)/(x g)

Calculating mEq
mEq= (mg X Valence)/(Atomic or formula wt)
mg= (mEq X Atomic or formula wt)/valence
Step 1: Find the equivalent weight
mol wt/valence = 74.5 g/1 = 74.5 g
Step 2: Determine the mEq weight, which is 1/1000 of the equivalent weight
mEq wt = 74.5 g/1000 = 0.0745 g = 74.5 mg
Step 3: Calculate concentration (1 mEq)/(mEq wt)= 2mEq/(x g)



Cost Effective Analysis (CEA)
CE ratio yields the "cost" to attain a unit of health improvement.

CE ratio:
[Expected cost of treatment ] - [expected cost of alternative ]
[Expected health outcome from treatment] –[ expected health outcome from alternative]


Is CEA necessary?
Treatment Health Outcome vs Alternative
Treatment Cost vs Alternative Better Worse
Higher Do CEA Use Alternative
Lower Use Treatment Do CEA
(4/5)
[Humanistics/Pharmacoeconomics Outcomes (9/23/2009 & 9/28/2009)
Fadi Alkhateeb, BSPharm, Ph.D.]



Perenteral and Enteral Calculations and Nutritional Information
Prepared By: Aladin A. Siddig, Ph. D.
Dept of Pharmaceutical and Administrative Sciences
(4/5)

Macronutrients:
Carbohydrate (e.g., dextrose)
Protein (e.g., amino acids)
Fat (e.g., lipid emulsions)

Micronutrients:
Electrolytes
Vitamins
Trace elements
Parameter Water Requirement
Based on age:
Neonates 120-180 ml/kg/day
1-12 months 150 ml/kg/day
(maximum, 200 ml)
Based on Weight
< 10 kg 1000 ml/kg/day
10-20 kg 1000 ml + 50 ml/kg/day over 10 kg
< 20 kg 1500 ml + 20 ml/kg/day over 20 kg



Base on Body Surface Area
m2 X 1500 ml/day/m2 __ml/day
Based on Caloric Requirement
1.2 ml/kcal X kcal/day __ml/day
Caloric Requirements
For males:
BEE = 66.67 + {13.75 X weight (kg)} + {5 X Height (cm)} – {6.76 X Age (yr)}
For females:
BEE = 655.1 + {9.56 X weight (kg)} + {1.86 X Height (cm)} – {4.68 X Age (yr)}
The total daily expenditure (TDE) of energy, as calculated, may be adjusted for activity and stress factor

BEE X activity factor X stress factors = TDE
Activity factors:
Confined to bed: 1.2
Ambulatory: 1.3
Stress Factors:
Surgery: 1.2
Infection: 1.4 –1.6
Trauma: 1.3 –1.5
Burns: 1.5 –2. 1

Dextrose provides 3.4 kcal of energy per gram, each 100 ml of 25% dextrose injection provides 85 kcal of energy. For enteral nutrition, the factor used is 4 kcal/g.
Protein Requirements
In TPN, protein is provided as protein hydrolysate or amino acids.
The purpose of the protein support is not to produce energy; although energy is produced by proteins by a factor of 4 kcal/g but rather to build tissue and body strength. A patient’s caloric needs should be provided by nonprotein calories.
The daily quantity of protein required in adults is generally estimated to be about:
0.8 g/kg/day in unstressed patient;
0.8 to 1 g/kg of body weight for a mildly stressed patient
1.2 g/kg for a renal dialysis patient
1.1 to 1.5 g/kg for moderately stressed patient
1.5 to 2 g/kg for severely stressed patient and those with critical illness or trauma, and
3 g/kg for severely burned patient.
Infants may require 2 to 3 g/day/day, children 1.5 to 2 g/kg/day, and teenagers 1 to 1.5 g/kg/day of protein

Lipid (Fat) Requirements
The proportion of calories provided by lipids is usually too restricted to 30% to 40% of the total daily calories.
Lipids provide 9 kcal of energy per gram.

Micronutrients
Standard quantities of electrolytes may be used as parenteral nutrition or modified as required.
Parenteral Nutrition
Step-1 Calculate the total calories using BEE-equation and stress the stress factors.
Step-2 Calculate the daily quantity (g) of amino acids (protein) required based on 0.8 g/kg of body weight and adjusted as needed for stress factors and certain disease states.
Step-3 Calculate the number of calories by amino acids (from step 2) at 4 kcal/g.
Step-4 Calculate the kcal of lipid required for 30% to 40% of the total daily calories.
Step-5 Calculate the grams of lipids required (from step-4) based on 9 kcal/g or based on the lipid emulsion used.
Step-6 Calculate the quantity of carbohydrate required based on 3.4 kcal/g after accounting for the contribution of the lipids
Step-7 Calculate the daily fluid requirements using 30 ml/kg/day.
Body Mass Index (BMI)
According to the National Institutes of Health (NIH), individuals with a BMI:
Less than 18.5 may be considered underweight;
Between 18.5 and 24.9 may be considered normal
Between 25 and 29.9 are considered overweight;
30 and above are considered obese;
Over 40 are considered extremely obese.

For an elderly person, a BMI of less than 21 can be a sign of malnutrition.
BMI in most people is an indicator of high body fat (this may not be the case for persons who are especially muscular).


BMI= (wt [lb])/(height〖[in]〗^2 ) X 704.5
DRVs [Daily reference values] also have been established for cholesterol, sodium, and potassium, which do not contribute calories.

DRVs for the energy-producing nutrients are calculated as follows:
Total fat based on 20-35 percent of calories
Saturated fat based on less than 10 percent of calories
Carbohydrate based on 45-65 percent of calories
Protein based on 10-35 percent of calories (applicable only to adults and children over 4 years of age)
Fiber based on 11.5 g of fiber per 1000 calories
The following quantities of nutrients are considered the upper limit for the maintenance of good health:
Total fat: less than 65 g
Saturated fat: less than 20 g
Cholesterol: less than 300 mg
Sodium: less than 2300 mg (persons with hypertension, less than 1500 mg).
The daily values of sodium and cholesterol are the same regardless of the calorie diet