Enteral Nutrition Calculator – Tube Feeding Requirements
Calculate tube feeding nutritional requirements including calories, protein, and fluids
How to Use
- Enter patient's weight in kilograms
- Enter patient's height in centimeters
- Enter patient's age in years
- Select gender (male or female)
- Select activity level (sedentary to active)
- Select stress factor (none to severe based on illness severity)
- Click calculate to see complete nutritional requirements
What is Enteral Nutrition?
Enteral nutrition is the delivery of nutrients directly into the gastrointestinal tract via a feeding tube. It is used when patients cannot consume adequate nutrition orally but have a functioning digestive system. This method maintains gut integrity, supports immune function, and is more physiological than parenteral nutrition.
Common indications include neurological conditions affecting swallowing, critical illness, head and neck cancers, severe burns, and conditions requiring bowel rest with nutritional support.
How Requirements Are Calculated
This calculator uses the Mifflin-St Jeor equation to determine Basal Metabolic Rate (BMR), which represents the energy needed for vital functions at rest:
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
For women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Total energy needs are then calculated by multiplying BMR by activity and stress factors to account for increased metabolic demands during illness or injury.
Activity and Stress Factors
Activity and stress multipliers adjust baseline energy needs based on patient condition:
| Factor Type | Level | Multiplier |
|---|---|---|
| Activity | Sedentary (bedridden) | 1.2 |
| Activity | Light (limited mobility) | 1.375 |
| Activity | Moderate (ambulatory) | 1.55 |
| Activity | Active (fully mobile) | 1.725 |
| Stress | None (healthy) | 1.0 |
| Stress | Mild (minor surgery) | 1.2 |
| Stress | Moderate (major surgery) | 1.4 |
| Stress | Severe (trauma, burns) | 1.6 |
Protein Requirements
Protein needs are calculated based on body weight and adjusted for metabolic stress. Higher protein requirements support wound healing, immune function, and prevent muscle wasting during illness:
- No stress: 1.0-1.2 g/kg/day (maintenance)
- Mild stress: 1.2-1.5 g/kg/day (minor surgery, mild infection)
- Moderate stress: 1.5-1.8 g/kg/day (major surgery, severe infection)
- Severe stress: 1.8-2.0 g/kg/day (major trauma, burns, sepsis)
Fluid Requirements
Adequate fluid intake is essential for maintaining hydration, supporting kidney function, and facilitating nutrient delivery. Standard fluid requirements are 30-35 mL/kg/day, but may need adjustment based on:
- Fever (increase by 10-15% per degree C above 37°C)
- Excessive losses (diarrhea, vomiting, fistula output)
- Cardiac or renal dysfunction (may require fluid restriction)
- Environmental factors (heat, humidity)
- Age considerations (elderly may have altered fluid balance)
Clinical Application and Monitoring
These calculations provide initial estimates that should be refined based on clinical monitoring:
- Start enteral nutrition gradually and advance to goal rate over 24-48 hours
- Monitor tolerance (gastric residuals, abdominal distension, diarrhea)
- Assess nutritional status regularly (weight, laboratory values, wound healing)
- Adjust formula concentration and delivery rate based on tolerance
- Consider indirect calorimetry for critically ill patients when available
- Reassess requirements weekly or with changes in clinical condition
Frequently Asked Questions
- How accurate are these calculations for critically ill patients?
- While these calculations provide evidence-based estimates, critically ill patients have highly variable metabolic rates. Indirect calorimetry is the gold standard when available. Use these calculations as a starting point and adjust based on clinical response, laboratory values, and ongoing assessment.
- Should I use actual body weight or ideal body weight?
- For obese patients (BMI > 30), consider using adjusted body weight: IBW + 0.25(actual weight - IBW). For underweight patients, use actual weight. Consult with a dietitian for complex cases involving significant weight deviations.
- How do I select the appropriate stress factor?
- Choose based on clinical presentation: none for healthy individuals, mild for uncomplicated surgery or minor infections, moderate for major surgery or severe infections, and severe for major trauma, extensive burns, or sepsis. When in doubt, start conservatively and increase based on tolerance.
- Can I use this calculator for pediatric patients?
- This calculator is designed for adult patients using adult-specific equations. Pediatric patients require different calculation methods based on age, growth requirements, and developmental stage. Consult pediatric nutrition guidelines for patients under 18 years.
- How often should I reassess nutritional requirements?
- Reassess at least weekly in stable patients and more frequently (every 2-3 days) in critically ill or rapidly changing conditions. Adjust requirements based on weight trends, laboratory values (albumin, prealbumin), wound healing, and overall clinical status.