Manual of Clinical Nutrition

Calculating Total Parenteral Nutrition

Manual of Clinical Nutrition Management III- 100 Copyright © 2013 Compass Group, Inc.

B. Calculate a 2-in-1 solution with a fluid restriction of 1,250 mL.

1. Determine kcal to be provided as fat.
   Estimated kcal x desired percent = kcal as fat
   1,700 kcal x 30% = 510 kcal fat


2. Convert fat kcal to volume of lipid emulsion.
   A 20% lipid solution is preferred for fluid-restricted patients.
   kcal as fat ÷ kcal/mL lipid emulsion = volume lipid
   510 kcal ÷ 2 kcal/mL (20% emulsion) = 255 mL
   This can be rounded to 250 mL, leaving 1,000 mL for the remaining TPN solution.


3. Determine kcal to be provided from protein.
   Estimated protein needs x kcal/gm protein = kcal protein
   70 gm x 4 kcal/gm = 280 kcal protein


4. Determine amino acid concentration (AA).
   gm protein x 100 = % AA
   TPN volume
   70 gm x 100 = 7.0% AA
   1,000 mL


5. 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


6. Determine carbohydrate concentration.
   a. Carbohydrate kcal ÷ kcal/gm dextrose = gm dextrose
   910 kcal ÷ 3.4 kcal/gm = 268 gm dextrose
   b. gm dextrose x 100 = % dextrose
   volume TPN
   268 gm x 100 = 26.8% dextrose
   1,000 mL


7. Final order:
   1 liter 7% AA, 26.8% dextrose, and 250 mL 20% lipid. This solution will not
   compound, so the dextrose will have to be reduced to 17.5% 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.
   C. Calculate a 3-in-1 solution with 2,000 mL fluid.


8. Determine kcal to be provided as fat.
   Estimated kcal x desired percent = kcal as fat
   1,700 kcal x 30% = 510 kcal fat


9. 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 dextrose x 100 = % dextrose
   volume TPN
   268 gm x 100 = 26.8% dextrose
   1,000 mL
   9 kcal/gm is used as an estimate; however, lipid emulsions are actually 10 kcal/gm because of
   components other than fat within the emulsion.


10. Determine kcal to be provided from protein.
    gm protein x kcal/gm = kcal as protein
    70 gm x 4 kcal/gm = 280 kcal protein


11. Determine amino acid concentration (AA).
    gm protein x 100 = %AA
    TPN volume
    70 gm x 100 = 3.5%AA
    2,000 mL


12. 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


13. Determine carbohydrate concentration.
    a. kcal dextrose ÷ kcal/gm dextrose = gm dextrose
    910 kcal ÷ 3.4 kcal/gm = 268 gm dextrose