Gastroenterology & Nutrition | Parenteral Nutrition

Initiating Parenteral Nutrition

1. Use computerized order sheets for initiating TPN. First-time users please read through these instructions in full before using the calculator.

2. Enter age in months or years

3. Enter weight in kg.

4. Enter length or height.

5. BMI is automatically calculated. If BMI > 95%, then consider potential confounding factors: edema, ascites, altered body composition. If present, make calculations using ideal body weight (IBW).

6. Enter stress factor consideration. Most patients receiving PN require no adjustment.

7. The first 'Calculate' sequence will automatically provide the predicted REE, adjusted REE, and TDEE. In addition, the expected fluid requirement will be determined. These values can be altered to meet special requirements.

8. Pick the route of infusion as 'Central' or 'Peripheral'.

9. Determine the desired amount of 20% IL to infuse daily. The calculator automatically subtracts this energy infusion and fluid amount from the totals required.

10. The second 'Calculate' will now use the remaining fluid, the remaining calories, and the known amino acid requirment for age to calculate the needed dextrose concentration, amino acid concentration, and infusion rates.

11. These values will appear in appropriate boxes along with a determination of total calories compared to the estimated needs. Dextrose concentrations are rounded to the closest 2.5%. Amino acid concentrations are rounded to the nearest 0.5%.

12. Default values for electrolyte and mineral requirements lead to automatic assignment of concentrations within the desired amount of fluid. Alterations in electrolyte per kg can be made. Re-calculation of concentration will follow.

13. Changes in cc/day, cc/kg/day, kcal/kg/day, and IL gm/kg/day will produce re-calculation of PN constituent concentrations and rates.

14. Note if standard vitamin and trace element additives are required.

15. Review if special circumstances exist for fluid replacement. Enter supplemental fluid type and rate.

16. Decide if any medications are necessary. Click and quantitate heparin or famotidine. Add other medications.

17. Monitoring:

    • follow clinical appearance of the child, particularly state of hydration and level of consciousness
    • review daily the typed label on the PN solution to assure that actual consituents match those desired
    • daily weight
    • in infants, measure length weekly. Measure OFC monthly
    
    

18. Laboratory testing: Many TPN protocols call for periodic measurement of multiple laboratory values. Experience indicates, however, that significant clinical problems are most effectively identified by careful review of patient status rather than by structured routine laboratory testing. Such testing often reveals inconsequential deviations from laboratory normals that do not affect the patient course. Particular attention to individual conditions that predispose to laboratory abnormalities is more efficient and useful. In addition, patients receiving TPN are ill with additional problems. Those problems usually mandate measurement of lab values that would be considered routine. Please refer to specific clinical situations outlined in the following sections.