Calculating Total Parenteral NutritionManual of Clinical Nutrition Management III- 101 Copyright © 2013 Compass Group, Inc.
b. gm dextrose x 100 = %dextrose
TPN volume
268 gm x 100 = 13.4% dextrose
2,000 mL- Final order:
2 liters 3.5% AA, 13.4% dextrose, and 2.8% lipid
D. Calculate a 3-in-1 solution with 1,250 mL fluid restriction. - Determine kcal to be provided as fat.
Estimated kcal x desired percent = kcal as fat
1,700 kcal x 30% = 510 kcal fat - Convert fat kcal to volume of lipid emulsion.
a. kcal fat ÷ kcal/gm = gm fat
510 kcal ÷ 9 kcal/gm = 56.7 gm fat
b. gm fat x 100% = % lipid
TPN volume
56.7 gm x 100% = 4.5% lipid
1,250 mL - Determine kcal to be provided from protein.
gm protein x kcal/gm = kcal as protein
70 gm x 4 kcal/gm = 280 kcal protein - Determine amino acid concentration (AA).
gm protein x 100 = %AA
TPN volume
70 gm x 100 = 5.6% AA
1,250 mL - Determine kcal to be provided from carbohydrate.
Estimated kcal needs - (kcal as fat + kcal as protein) = carbohydrate kcal
1,700 kcal – (510 kcal + 280 kcal) = 910 kcal carbohydrate - Determine carbohydrate concentration.
a. kcal dextrose ÷ kcal/gm dextrose = gm dextrose
910 kcal ÷ 3.4 kcal/gm = 268 gm dextrose
b. gm dextrose x 100 = % dextrose
TPN volume
268 gm x 100 = 21.4% dextrose
1250 mL - Final order:
1.25 liters 5.6% AA, 21.4% dextrose, and 4.5% lipid. This solution will not compound,
therefore the dextrose will have to be reduced to 12.3% dextrose until fluid
restrictions are lifted.
(See compounding guidelines for specific calculations. Section IV)
If your pharmacy uses a 15% amino acid stock solution, this will compound.
IV. Compounding Parenteral Nutrition
Assume stock solutions of 70% dextrose, 10% amino acids, and 20% lipids. - Determine TPN volume and grams of carbohydrate, protein, and fat.
- Determine volume of 70% dextrose stock solution.
- Determine volume of 10% amino acid stock solution.
- Determine volume of 20% lipid.
- Determine volume of sterile water and additives.
- Adjust dextrose or other substrates if solution cannot be compounded at the desired volume.
Sample calculations:
A. 2 - in-1 solution with fluid restriction 1,250 mL - Determine TPN volume and grams of carbohydrate, protein, and fat (see III.B.)
1,250 mL volume
250 mL 20% lipid
268 gm carbohydrate
70 gm protein - Determine volume of 70% dextrose solution.
gm dextrose ÷ gm/100 mL stock solution = volume of stock solution
268 gm ÷ 70 gm/100 mL = 383 mL 70% dextrose solution