ICU CLINICAL NUTRITION · ESPEN 2023 · ASPEN/SCCM 2016 · INDIA ICU GUIDELINE

ICU Energy
Requirement
Calculator.

Four-method hierarchy: Indirect Calorimetry → VCO₂-derived → Weight-based → Harris-Benedict legacy. Phase-adjusted delivery targets, protein prescription, and full clinical care plan for critically ill adults.

ESPEN 2023 Revised ASPEN/SCCM 2016 India ICU 2018 Harris-Benedict 1918 Weir 1949

4Calculation methods

ICGold standard

3ICU phases

2.5g/kg CRRT max

Indirect Calorimetry Preferred

Phase-Adjusted Delivery Targets

Protein + CRRT Override

Refeeding Risk Screening

Adults Only · ICU Use

Adult ICU Use Only. This tool is for registered dietitians, intensivists, and trained critical care clinicians. It does not apply to paediatric, obstetric, or general ward patients. Energy estimates must be integrated with ICU day, haemodynamic status, route tolerance, non-nutritional calories (propofol, citrate, dextrose), and refeeding risk before prescribing. Indirect calorimetry is the preferred method — predictive equation outputs are estimates only.

Patient Parameters

Step 1 of 4 — Demographics & Anthropometrics

01 Patient Demographics & Anthropometrics

Age (years)

Biological Sex

Current ICU Day Day 1 = admission day

Height (cm)

Actual / Current Weight (kg) Use for BMI calculation

Pre-admission / Dry Weight (kg) (preferred for dosing) ESPEN: use for BMI ≤30

Weight Basis to Use Auto selects per ESPEN 2019 rules

—BMI (kg/m²)

—IBW (kg)

—ABW (kg)

—Dosing Wt (kg)

02 Calculation Method Select highest available in hierarchy

1st PREFERRED

Indirect Calorimetry (IC)

Gold standard. Measures VO₂ and VCO₂ via Weir equation. Use when bedside calorimeter available.

2nd GOOD

VCO₂-derived Estimate

EE ≈ VCO₂ × 8.19. Read from ventilator display. Mechanically ventilated patients only (ESPEN).

3rd PRACTICAL

Weight-based ICU Estimate

20–25 kcal/kg (ESPEN) or 25–30 kcal/kg (ASPEN/India). Simple, widely recommended fallback.

4th LEGACY

Harris-Benedict × Stress Factor

BEE × activity × injury factor. Less preferred — may overestimate. Use only when other methods unavailable.

Measured EE from IC (kcal/day) Enter the resting energy expenditure (REE) value from calorimeter

Respiratory Quotient (RQ) (optional) Normal 0.7–1.0. Overfeeding >1.0, starvation <0.7

VCO₂ from Ventilator (mL/min) Read from ventilator display. EE = VCO₂ × 8.19 (Weir, RQ=0.85)

VO₂ (mL/min) (if available) If both VO₂ and VCO₂ available, full Weir formula used

💡 Ventilator EE note: VCO₂-derived EE assumes RQ 0.85 (mixed substrate utilisation). If both VO₂ and VCO₂ are entered, full Weir formula applies: EE = (3.941 × VO₂ + 1.106 × VCO₂) × 1.44. This method applies to mechanically ventilated patients only (ESPEN 2023).

Weight-based Protocol

⚠️ Predictive estimate: Weight-based equations are pragmatic but imprecise. Individual energy expenditure may vary ±30% from these estimates. Use phase-adjusted delivery targets and monitor tolerance closely.

🔴 Legacy mode selected. Harris-Benedict × stress factors may overestimate true energy expenditure in critically ill patients by 15–30%. ESPEN 2023 and the Indian ICU guideline both de-prioritise this method. Proceed only if IC, VCO₂, and weight-based methods are genuinely unavailable.

Clinical Condition / Injury–Stress Factor

Activity Factor

📐 Formula (Long 1979): TEE = BEE × Activity Factor × Injury Factor. BEE calculated from Harris-Benedict (1918) equations. Resulting TEE is an estimate — verify against clinical response and body weight trend.

03 Clinical Context & Risk Modifiers

Ventilation Status

Haemodynamic Status

Feeding Route

Primary ICU Diagnosis

CRRT / Renal Replacement Therapy Protein target ↑ to 2.5 g/kg/day (ASPEN 2016)

Refeeding Risk Present Prolonged fasting >5 days, chronic malnutrition, alcoholism, chronic low intake

Propofol Infusion (significant dose) Contributes ~1.1 kcal/mL — deduct from energy prescription

Significant IV Dextrose / Glucose Citrate, glucose-containing fluids contribute non-nutritional calories

Propofol infusion rate (mL/hr) 1% propofol = 1.1 kcal/mL. 2% propofol = 0.55 kcal/mL (same calories at double concentration)

Propofol concentration

04 EN Safety Checklist ESPEN 2019 exclusion criteria

Check any that apply. Presence of these conditions may contraindicate early enteral nutrition:

Uncontrolled shock / haemodynamic instability Uncontrolled hypoxaemia / hypercapnia / acidosis Active upper GI bleeding Bowel ischaemia / infarction Bowel obstruction / ileus (suspected) Abdominal compartment syndrome High-output fistula (no distal access) Gastric aspirate >500 mL over 6 hours

Complete all required fields

ESPEN 2023 · ASPEN/SCCM 2016 · India ICU 2018 · Harris-Benedict 1918 · Long 1979 · Weir 1949

LIVE PREVIEW

—

kcal/day (full EE)

—

kcal/day delivery target

Protein —

Weight basis —

ICU phase —

Method —

Confidence —

EN caution flagged

Energy estimate requires integration with haemodynamic status, route tolerance, non-nutritional calories, and refeeding risk. This output supports — it does not replace — clinical judgment. Document method, weight basis, date, and assessor in the patient record.

🩺 ICU Dietitian Consultation →

MEASUREMENT HIERARCHY

1st

Indirect CalorimetryGold standard. Measures VO₂ + VCO₂

2nd

VCO₂-derived (ventilator)EE = VCO₂ × 8.19 (Weir)

3rd

Weight-based ICU estimate20–25 (ESPEN) or 25–30 (ASPEN)

4th

Harris-Benedict legacyBEE × activity × stress factor

ICU DIETITIAN

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Nutrition Consult

Our ICU-trained dietitians provide bedside indirect calorimetry, phase-adjusted feeding plans, refeeding management, and daily review for critically ill patients.

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PHASE-BASED TARGETS

D1–3

Early Acute<70% estimated EE — hypocaloric (ESPEN 2023)

D3–7

Late Acute80–100% measured EE when clinically appropriate

D7+

ConvalescentAdvance toward full requirements, optimise protein

EN EXCLUSION FLAGS

Uncontrolled shock

Active upper GI bleed

Bowel ischaemia

Bowel obstruction

Abdominal compartment syndrome

Gastric aspirate >500 mL/6h

High-output fistula

⚕️ Clinical Disclaimer: This ICU Energy Requirement Calculator is designed for use by registered dietitians, intensivists, and trained critical care clinicians in adult ICU settings only. It is not validated for paediatric, pregnant, or general ward patients. All energy estimates carry inherent inaccuracy — indirect calorimetry remains the gold standard (ESPEN 2023). Calculated estimates must be integrated with clinical status, ICU day, haemodynamic stability, feeding route tolerance, non-nutritional calorie sources (propofol, citrate, IV dextrose), refeeding risk, and individual patient response. Albumin and prealbumin are not reliable nutritional status markers in the ICU. The clinician holds final prescriptive responsibility. Reassess nutrition targets daily in the first week of ICU admission. Harris-Benedict × stress factor outputs are labelled legacy estimates and should not be treated as equivalent to measured energy expenditure. ESPEN 2023 · ASPEN/SCCM 2016 · India ICU Guideline 2018 · Harris-Benedict 1918 · Long 1979 · Weir 1949.

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