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TPN calculations require careful monitoring and adjustment. Always consult with a clinical pharmacist or nutrition specialist. Monitor electrolytes, glucose, liver function, and triglycerides regularly. This calculator is for estimation only.
Calculate Total Parenteral Nutrition caloric components
Typical range: 20-30 kcal/kg/day
Provides 3.4 kcal/g
Provides 4 kcal/g (protein)
Provides 10 kcal/g (20% emulsion = 2 kcal/mL)
| Component | Energy Density | Typical Daily Range | Maximum |
|---|---|---|---|
| Dextrose | 3.4 kcal/g | 150-300 g/day (2-5 g/kg/day) | 5-7 g/kg/day |
| Amino Acids | 4 kcal/g | 70-100 g/day (1-1.5 g/kg/day) | 2.5 g/kg/day |
| Lipids (20%) | 2 kcal/mL = 10 kcal/g | 50-100 g/day (1 g/kg/day) | 2.5 g/kg/day |
| Cal:N Ratio | Clinical Situation | Interpretation |
|---|---|---|
| 80-100:1 | Critically ill, stressed patients | Higher protein needs |
| 100-150:1 | Standard maintenance TPN | Optimal for most patients |
| 150-200:1 | Renal insufficiency (no dialysis) | Protein restriction required |
| >200:1 | Severe renal failure | Minimal protein provision |
Total Parenteral Nutrition (TPN) is intravenous feeding that provides all daily nutritional requirements when the GI tract cannot be used. It contains dextrose (carbohydrates), amino acids (protein), lipids (fat), electrolytes, vitamins, and trace elements.
Dextrose provides 3.4 kcal/g. For example, 500 mL of D70 (70% dextrose) contains 350g dextrose = 1,190 kcal. Most TPN bags use D70 or D50 as the dextrose source.
The Cal:N ratio represents non-protein calories per gram of nitrogen. Since protein is 16% nitrogen, divide protein grams by 6.25 to get nitrogen. A ratio of 100-150:1 is typically optimal for protein utilization.
Lipid emulsions can cause hypertriglyceridemia, especially at doses >1 g/kg/day. Check triglycerides 4-6 hours after stopping lipids. Keep levels <400 mg/dL to reduce pancreatitis risk.
Refeeding syndrome occurs when nutrition is reintroduced too aggressively in malnourished patients, causing dangerous shifts in electrolytes (especially phosphate, potassium, magnesium). Start TPN at 50-70% of goal in at-risk patients.